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- Researcher- Vidyasagar University; Assistant Professor- Rampurhat College, West Bengal, India. Email: layekujjwal@yah... moreResearcher- Vidyasagar University; Assistant Professor- Rampurhat College, West Bengal, India. Email: layekujjwal@yahoo.co.in
Working on- Palynology, Plant reproductive biology, Plant-pollinator interactions, Honeybee biology, Stingless bee biology, Honey, Propolis(Researcher- Vidyasagar University; Assistant Professor- Rampurhat College, West Bengal, India. Email: layekujjwal@yahoo.co.in<br />Working on- Palynology, Plant reproductive biology, Plant-pollinator interactions, Honeybee biology, Stingless bee biology, Honey, Propolis)edit
Andrographis paniculata (Brum. f.) Wall. ex Nees is an important medicinal plant of tropical Asia and has been used widely for a long time for different clinical ailments. Despite profuse flowering and a high percentage of fruit set, the... more
Andrographis paniculata (Brum. f.) Wall. ex Nees is an important medicinal plant of tropical Asia and has been used widely for a long time for different clinical ailments. Despite profuse flowering and a high percentage of fruit set, the number of seedlings in the natural population is the bare minimum. The knowledge regarding the seed ecology and seedling phenology of A. paniculata, is needed to formulate conservation strategies for the species. Therefore, a detailed study on seed ecology and seedling phenology has been conducted. During seed ecological studies, seed production, seed-set percentage, seed-ovule ratio, mechanism of seed dispersal, seed structure along with germination status, viability, dormancy and its breaking, and percentage of moisture content loss have been studied. Seeds exhibit some kind of dormancy [germination percentage (GP) = 28.51 ± 0.98, mean germination time (MGT) = 33.07±0.89 days, and germination index (GI) = 0.73 ± 0.08] which can be effectively overcome through acid scarification using H2SO4 and hot water treatment. The species shows epigealphanerocotylar germination. The hypocotyls exhibit rapid growth, and cotyledons emerged at 7.52 ± 0.27 TARA (Time After Radicle Appearance in days). Seedling is characterised by a thickened, hairy hypocotyl, a distinct collet, a pair of paracotyledons, and three pairs of eophylls in opposite decussate phyllotaxy. The studies on seed ecology and seedling phenology play a significant role in understanding how the shortening of the inception period enhances the germination status, and distinct seedling morphology provides the opportunity to formulate conservation strategies in their wild habitat.
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Nectar robbing is common in angiosperms, especially in long tubular flowers or flowers with spurs that keep nectar out of reach of visitors. However, the robbing behaviour of bees is less understood. Here, we studied the sesame visitors,... more
Nectar robbing is common in angiosperms, especially in long tubular flowers or flowers with spurs that keep nectar out of reach of visitors. However, the robbing behaviour of bees is less understood. Here, we studied the sesame visitors, their robbing behaviour, and the impacts of robbing on plant reproductive fitness. Diverse insect species (primarily members of Hymenoptera) visited sesame flowers. The most effective pollinators were Amegilla zonata, Apis cerana, Apis dorsata, Apis florea, Ceratina binghami, Halictus acrocephalus and Xylocopa amethystina. Almost all visitors with variable percentages revealed the nectar-robbing phenomenon. Robbing activity depended on a complex of multiple attributes, including the visitor's body size, the corolla tube length, the availability and accessibility of nectar, and the resource-collecting task allocation of bees. Robbing activity varied according to flower-visiting species, flowering period and daytime. Robbing was comparatively higher in the late flowering period at 10.00-14.00 h. In the case of robbing visits, flower handling time was lower, and the visitation rate remained higher than non-robbing visits. Robbing visits did not significantly affect fruit and seed sets of sesame. Therefore, we can interpret the nectar-robbing interactions on sesame as commensal, with pollinators benefitting without altering the plant's reproductive fitness.
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The reproductive success of flowering plants relates to flower-visitor communities and plant-pollinator interactions. These traits are species- and region-specific and vary across regions, pollinator groups, and plant species. However,... more
The reproductive success of flowering plants relates to flower-visitor communities and plant-pollinator interactions. These traits are species- and region-specific and vary across regions, pollinator groups, and plant species. However, little literature exists on the spatiotemporal variation
in visitor activity, especially in India. Here, we aimed to depict the spatial and temporal variation in visitor activity on the curry plants (Bergera koenigii). Data were collected at different daytime slots from three vegetation zones (confirmed by field surveys and normalized difference vegetation index values in remote sensing)—dense, medium-density, and low-density vegetation in West Bengal, India. The visitors’ richness, diversity, and abundance were higher in the area with dense vegetation.
Considering daytime patterns, higher values for these parameters were obtained during 10.00–14.00 h. For most visitors, the flower handling time was shorter, and the visitation rate was higher in dense vegetation areas (at 10.00–14.00 h) than in medium- and low-density vegetation areas. The proportions of different foraging categories varied over time. Vital pollinators were Apis cerana, Apis dorsata, Appias libythea, Halictus acrocephalus, Nomia iridescens, and Tetragonula iridipennis. However, the effectiveness of pollinators remained region-specific. Therefore, it can be concluded that floral visitors’ richness, diversity, abundance, and plant-visitor interactions varied spatially with their surrounding vegetation
types and also changed daytime-wise.
in visitor activity, especially in India. Here, we aimed to depict the spatial and temporal variation in visitor activity on the curry plants (Bergera koenigii). Data were collected at different daytime slots from three vegetation zones (confirmed by field surveys and normalized difference vegetation index values in remote sensing)—dense, medium-density, and low-density vegetation in West Bengal, India. The visitors’ richness, diversity, and abundance were higher in the area with dense vegetation.
Considering daytime patterns, higher values for these parameters were obtained during 10.00–14.00 h. For most visitors, the flower handling time was shorter, and the visitation rate was higher in dense vegetation areas (at 10.00–14.00 h) than in medium- and low-density vegetation areas. The proportions of different foraging categories varied over time. Vital pollinators were Apis cerana, Apis dorsata, Appias libythea, Halictus acrocephalus, Nomia iridescens, and Tetragonula iridipennis. However, the effectiveness of pollinators remained region-specific. Therefore, it can be concluded that floral visitors’ richness, diversity, abundance, and plant-visitor interactions varied spatially with their surrounding vegetation
types and also changed daytime-wise.
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Pollinators provide crucial ecosystem services, i.e., pollination, which determines crops’ reproductive fitness and yield. As pollinators decline, flowering crops might face pollination-deficit stress depending on their dependence on... more
Pollinators provide crucial ecosystem services, i.e., pollination, which determines crops’ reproductive fitness and yield. As pollinators decline, flowering crops might face pollination-deficit stress depending on their dependence on pollinators and pollinator availability. Here, we assessed
the dependency of some crops (belonging to diverse plant families) on biotic pollinators based on their maximum reproductive potential in a supplementary pollination treatment and minimum reproductive success in a pollinator exclusion treatment. Additionally, we determined the pollen
transfer limitation of the crops in open field conditions. We also determined the influence of the different reproductive traits with the index of dependency of crops on pollinators (IDP) and the coefficient of pollination deficit (D). Based on the values of IDP, members of Cucurbitaceae are obligatorily dependent on pollinators for their fruit set. Members of Brassicaceae and Rutaceae are highly reliant on pollinators. A few crops, like Lablab purpureus and Nigella sativa, are less dependent
on pollinators. In open field conditions, most crops have a low pollination deficit, some without pollen transfer limitations, and only a few crops (Citrus × limon and Citrus maxima) show a higher pollination deficit. The IDP is negatively influenced by the pollen–ovule ratio, which also negatively affects the pollination deficit of the crops. This study will be useful in understanding and mitigating the effects of pollinator losses, as well as in choosing crops (those under pollination deficit stress and largely dependent on pollinators for fruit set) for supplemental pollination services to increase agricultural production.
the dependency of some crops (belonging to diverse plant families) on biotic pollinators based on their maximum reproductive potential in a supplementary pollination treatment and minimum reproductive success in a pollinator exclusion treatment. Additionally, we determined the pollen
transfer limitation of the crops in open field conditions. We also determined the influence of the different reproductive traits with the index of dependency of crops on pollinators (IDP) and the coefficient of pollination deficit (D). Based on the values of IDP, members of Cucurbitaceae are obligatorily dependent on pollinators for their fruit set. Members of Brassicaceae and Rutaceae are highly reliant on pollinators. A few crops, like Lablab purpureus and Nigella sativa, are less dependent
on pollinators. In open field conditions, most crops have a low pollination deficit, some without pollen transfer limitations, and only a few crops (Citrus × limon and Citrus maxima) show a higher pollination deficit. The IDP is negatively influenced by the pollen–ovule ratio, which also negatively affects the pollination deficit of the crops. This study will be useful in understanding and mitigating the effects of pollinator losses, as well as in choosing crops (those under pollination deficit stress and largely dependent on pollinators for fruit set) for supplemental pollination services to increase agricultural production.
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Intercropping is practiced in modern intensive agriculture considering many benefits, including additive crop yield. However, it may have competitive or facilitative interactions between pollinator-dependant crops. Here, we investigated... more
Intercropping is practiced in modern intensive agriculture considering many benefits, including additive crop yield. However, it may have competitive or facilitative interactions between pollinator-dependant crops. Here, we investigated the reproductive aspects of pigeonpea (Cajanus cajan). We assessed the influence of blooming pigeonpea on pollinator’s assemblage and the yield of neighbouring non-leguminous crops (e.g., coriander, mustard). For these, we recorded floral visitors and the yield of the targeted crops from two types of fields―closely situated and distantly situated concerning pigeonpea plantation. Pigeonpea is autogamous, but pollinator’s visits enhance fruit and seed sets. Bright, nectariferous flowers emitted several volatile organic compounds and were visited by numerous insect species. The prime pollinators of pigeonpea are carpenter bees and leafcutter bees. In contrast, halictidae, honeybees and stingless bees mainly pollinate the co-blooming non-leguminous crops...
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The evaluation of quality and purity of crude drugs by means of various parameters is the most important aspect of pharmacognosy. The present study deals with pharmacognostic and phytochemical evaluation of Cleome viscosa L. of the family... more
The evaluation of quality and purity of crude drugs by means of various parameters is the most important aspect of pharmacognosy. The present study deals with pharmacognostic and phytochemical evaluation of Cleome viscosa L. of the family Cleomaceae. The leaves of it are used by the tribal people in diarrhoea, blood dysentery, boils and also to cure swelling the body due to kidney trouble. The parameters like micromorphological, anatomical, physical constant and fluorescence analysis have been employed for the pharmacognostical evaluation of different parts of this plant. Microchemical and histochemical parameters are used for phytochemical screening. Leaves are amphistomatic and anomocytic types. Stomatal index is 21.35 on the upper surface and 24.30 on the lower surface. Palisade ratio is 5.06. Glandular multicellular, uniseriate or multiseriate trichomes with swollen tip are present on both surfaces. In T.S. of petiole, number of vascular bundles are five and arranged in semiluna...
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Abstract The objective of this study was to test the hypothesis that pollinator sharing among cashew (Anacardium occidentale L.) and co-blooming magnetic bee-friendly plants facilitate higher productivity of cashew nuts. We examined the... more
Abstract The objective of this study was to test the hypothesis that pollinator sharing among cashew (Anacardium occidentale L.) and co-blooming magnetic bee-friendly plants facilitate higher productivity of cashew nuts. We examined the reproductive efficacy of cashew in three sites with distinct vegetation pattern (site I: sparsely distributed individuals, without association of co-blooming magnetic bee-friendly plant; site II: densely distributed individuals, without association of co-blooming magnetic bee-friendly plant; site III: densely distributed individuals, associated with co-blooming magnetic bee-friendly plants). Floral traits (including flowering time, flower architecture, number of flowers per panicle, hermaphrodite- male flower ratio, floral rewards, anthesis time and longevity of flower) does not differ among the study sites. According to the value of relative pollinator service (RPS), Apis dorsata was the primary pollinator of cashew and also shared by the co-blooming bee-friendly plants. The abundance of pollinators was the highest in site III and the lowest in site I. The nut yield was also significantly higher in site III cashew orchard which was in association with magnetic bee-friendly plants. Therefore, we can conclude that the association of co-blooming magnetic plants increased nut yield of cashew through the enhancement of pollinator's services.
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The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may... more
The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may vary according to crop species and geographical location. Fennel (Foeniculum vulgare) is an important spice crop cultivated in Indian states. However, comprehensive knowledge about pollination demand and yield enhancement potential of managed bees is still unknown. Here, we conducted a replicated study in two successive years (2020 and 2021) in West Bengal by combining pollinator surveys, pollinator-exclusion experiments, and field manipulation on fennel, which quantifies the impacts of supplemental stingless bees (Tetragonula iridipennis) pollination on native pollinators and crop yield. The crop species attracted many insect species belonging to diverse groups. Among those, important native pollinators (based on “approximate pollination value”) were ...
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Stingless bees are generalist visitors, forage with a high degree of floral fidelity, and thereby play an important role as pollinators. Management of stingless bees is considered to be an enhancer of crop yield and as well as an... more
Stingless bees are generalist visitors, forage with a high degree of floral fidelity, and thereby play an important role as pollinators. Management of stingless bees is considered to be an enhancer of crop yield and as well as an eco-friendly strategy to conserve biodiversity. While Tetragonula iridipennis Smith is one of the most common species of stingless bees, its foraging behavior is not very well understood. Therefore, we conducted this study to estimate the maximum foraging distance, foraging trips (number and duration), resource carrying capacity and resource loading-unloading time of the dammar bee (T. iridipennis) in West Bengal, India. Flight range was estimated by feeder training and capture-recapture techniques. The maximum foraging distance of 319.86 ± 53.01 m was recorded with an artificial feeding technique, whereas 840.21 ± 105.94 m was recorded as the maximum homing distance in capture-recapture technique. Flight distance significantly differed according to seasons as well as from colony to colony. Number of foraging trips performed daily by a forager significantly depended on the distance of resources, attributes of resources (type, quality, availability and accessibility), seasons and weather conditions. Resource loading time as well as duration of foraging trips varied according to day time and depended on resource availability and accessibility. Resource unloading times for nectar and pollen loads were much lower than the resin or latex loads. Plant resources collecting bees allocated their tasks into several groups, and this task allocation showed flexibility to some extent depending on the demand of the colony and surrounding resource availability.
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The chapter provides information about distribution, nesting biology and floral resources of red dwarf honeybee (Apis florea Fabricius) in West Bengal, India. The bee species showed a selection preference to human habitation for its... more
The chapter provides information about distribution, nesting biology and floral resources of red dwarf honeybee (Apis florea Fabricius) in West Bengal, India. The bee species showed a selection preference to human habitation for its colony settlement. Its abundance also significantly varied according to seasons. During winter to summer, the bees densely colonized due to favourable weather conditions, availability of nesting sites and floral resources. To collect rewards, foragers visited on a large number of plant species including wild and cultivated plants. The foragers maintain a high degree of floral fidelity in each bout. The bee-visited plants were diversified with respect to habit and flower characters. Therefore, the bee species is regarded as a generalist visitor and important pollinator of tropical flora.
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The paper reports flowering phenology, floral visitors of Trianthema portulacastrum and melissopalynological analyses of 8 honey samples and 374 pollen loads of Apis florea, collected during May to August from Bankura district, West... more
The paper reports flowering phenology, floral visitors of Trianthema portulacastrum and melissopalynological analyses of 8 honey samples and 374 pollen loads of Apis florea, collected during May to August from Bankura district, West Bengal. T. portulacastrum flowers during April to October. Flowers open at 6.30-7.00 am in the morning. Anther dehiscence takes place after 30 minutes from flower opening. Closing of the flower takes place at about 11.30 am – 12.15 pm. During the opening phase of the flower, a number of visitors viz. Apis cerana, A. florea, Augochloropsis metallica, Halictus sp., Pseudoborbo bevani and Trigona iridipennis visit the flower for nectar or pollen. Melissopalynological analyses revealed that all the honey samples were multifloral in origin and T. portulacastrum present in all the honey samples. Regarding the pollen foraging scenario of the bee species, T. portulacastrum also played an important role during those months. The overall result reflects the importa...
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Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is... more
Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is difficult in cavity-nesting natural stingless bee colonies. Furthermore, it is detrimental to the wild bee’s colony and may threaten their survivability. We analyzed adhered body surface pollen of incoming nectar foragers (which were smeared incidentally during nectar foraging) as an alternative method to determine nectariferous flora of Tetragonula iridipennis in West Bengal, India. By this method, we have identified 75 pollen types. The number of obtained pollen types was lower in the human-altered habitats of Midnapore city (44 pollen types) than the semi-natural habitats of Garhbeta (71 pollen types). Excluding a few pollen types of non-nectariferous plants, most of the pollen types came from nectariferous plants of both crop and non-crop specie...
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Abstract Watermelon (Citrullus lanatus) is an important crop cultivated in India and other warmer regions of the world. The crop is dependent on insect pollinators for its fruit set. However, information about pollination ecology in... more
Abstract Watermelon (Citrullus lanatus) is an important crop cultivated in India and other warmer regions of the world. The crop is dependent on insect pollinators for its fruit set. However, information about pollination ecology in Indian states remains undetermined. We used a replicated field-scale experiment to identify the native pollinators and their foraging behaviour, including abundance, visitation rate, duration of visit, and pollination efficiency. We compared treatments with open-pollinated, hand-pollinated and the addition of two managed pollinator species to estimate the yield enhancement potential of managed stingless bees and western honey bees and their impact on native pollinator species. We found that ants, bees, butterflies, beetles, and wasps visited the flowers either for nectar, pollen, and/or floral tissue. Regarding the ‘pollinator importance’ value of the visitors, Halictus acrocephalus and Lasioglossum funebre were the most effective native pollinators. Despite their contribution, the plants showed a significant pollination deficit in the open-pollinated system which can be overcome by supplementary pollination services through the management of western honey bees (Apis mellifera) and/or stingless bees (Tetragonula iridipennis). However, the application of A. mellifera colonies greatly reduces the abundance, visitation rate and foraging time (amount of time spent per visit on a flower) of native pollinators. Hence, the utilization of managed stingless bee colonies for pollination services is more suitable and has a lesser impact on native pollinator species, which may lead to sustainable agricultural practices.
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An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming... more
An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming period. Among those honeybees, stingless bee, solitary bees, and butterflies are legitimate visitors; all of them showed a selective preference for male flowers (flower sex type selection index ranged from 0.41 to 0.62). The plant species showed a pollination deficit in nature (coefficient of pollination deficit, D = 0.20), resulting in low fruit set in an open-pollination system. However, the value was significantly increased by the supplementary pollination services of a managed dammar bee colony. Furthermore, the quality of the fruits also improved in hand-pollinated and managed bee-pollinated systems in comparison to an open pollination system. Therefore, it is generally recommended that farmers use Indian dammar bee colonies in their agricultu...
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Abstract One-hundred-and-five species corresponding to 38 families were identified through pollen analyses of 53 Apis dorsata honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently... more
Abstract One-hundred-and-five species corresponding to 38 families were identified through pollen analyses of 53 Apis dorsata honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently encountered were Fabaceae, Arecaceae, Asteraceae and Myrtaceae. Fabaceae had the greatest representation in number of pollen types (18 types), followed by Asteraceae (nine types), Cucurbitaceae (seven types), Lamiaceae and Myrtaceae (each with six types) and Malvaceae and Rutaceae (each with five types). Most of the honey samples correspond to class I. The presence of dominant pollen was detected in 18 samples. The predominant pollen types were Borassus flabellifer, Sesamum indicum (during summer), Eucalyptus globulus (during late autumn), Brassica nigra, Eucalyptus globulus (during winter) and Borassus flabellifer and Lannea coromandelica (during spring). The unifloral honeys obtained mostly during late autumn and winter were dominated by Eucalyptus globulus type. In monsoon and autumn unifloral honeys containing predominant pollen types (> 45%) were not found. However, according to frequency distribution the pollen types represented as very frequent were Peltophorum pterocarpum, Tridax procumbens (in monsoon) and Acacia auriculiformis, Cocos nucifera, Eucalyptus globulus, Tridax procumbens and Ziziphus mauritiana (in autumn). The seasonal diversity of pollen types obtained was at a maximum during spring (36 types) and minimum during late autumn (14 types). Seasonal variation in the number of pollen types per sample range from 5.86 ± 1.87 (during late autumn) to 6.86 ± 1.95 (during autumn) and exhibit low correlation (r = 0.31) with floral diversity. The diversity of pollen types per unifloral honey sample remains lower than multifloral honeys.
Research Interests: Botany, Plant Biology, Biology, Palynology, Pollen, and 5 moreMyrtaceae, Honey Bees, Fabaceae, Eucalyptus Globulus, and Grana
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Pollen cell frequencies within hive of Apis dorsata in Bankura and Paschim Medinipur districts of West Bengal remain maximum mean value of 8.74 during the month of April and minimum mean value of 3.47 in August. The pollen cell frequency... more
Pollen cell frequencies within hive of Apis dorsata in Bankura and Paschim Medinipur districts of West Bengal remain maximum mean value of 8.74 during the month of April and minimum mean value of 3.47 in August. The pollen cell frequency of hive was very positively correlated to the pollen stack number with a correlation coefficient (r) value of 0.96. The stack number per pollen cell varied from mean value of 9.40 (during April) to 4.27 (in August). Each pollen stack was made up of an average of 9.88 pairs of pollen pellets. The number of pollen grains per pollen stack ranged from 572450 to 1052480 with an average value of 817370. Among the melissopalynologically analyzed 1336 pollen stacks, 865 (64.75%) were unifloral, 407 (30.46%) were bifloral and 64 (4.79%) were multifloral in pollen compositions. Though from each pollen cell 1 to 7 pollen types were obtained, but majority of the pollen cells contain 3 pollen types. A total of 84 pollen types belonging to 39 plant families were identified. Among them most frequently occurred pollen type was Eucalyptus globulus, followed by Borassus flabellifer, Brassica nigra, Acacia auriculiformis, Sesamum indicum, Terminalia arjuna, Lannea coromandelica, Alangium salvifolium, Shorea robusta and Phoenix sylvestris.
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Flowering plants and pollinators are in a mutualistic association, where pollinators collect floral resources and plants receive pollination services. Bees and other pollinators are declining in many parts of the world, and their loss... more
Flowering plants and pollinators are in a mutualistic association, where pollinators collect floral resources and plants receive pollination services. Bees and other pollinators are declining in many parts of the world, and their loss affects the functional composition of fauna, flora, and habitats. Different strategies are being deployed to improve pollinator services, including the management of bees. Sustainable management of a bee species strongly depends on floral resource availability. Therefore, beekeepers need to have adequate knowledge about the surrounding vegetation (especially nectar and pollen sources for the bee species). Diverse methodologies are used around the world to determine floral resources for bees. Field surveys and pollen analysis of honey, corbicular/scopal pollen loads, residual pollens in brood cells, forager’s body surface pollen content, and internal organs (gut, intestine, crop, etc.) were used by the researchers. For pollen identification, most resear...
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Pollen loads of <i>Apis mellifera</i> were analysed to assess their daily pollen collection, polleniferous flora and their pollen biomass contribution in southern West Bengal, India. After that, the pollen host selection and... more
Pollen loads of <i>Apis mellifera</i> were analysed to assess their daily pollen collection, polleniferous flora and their pollen biomass contribution in southern West Bengal, India. After that, the pollen host selection and pollen foraging activity of the bee species were also determined. The average daily harvest of pollen loads per honey bee colony was 8.5 g to 127.2 g. The pollen flow through the colonies was the highest during spring, followed by winter and summer, whereas during the monsoon it was the lowest. The weight of a single pollen load ranged from 3.22 mg to 11.73 mg and greatly varied within each season, but seasonal average values do not statistically differ. Families that contributed major amount of biomass were Arecaceae, Myrtaceae, Brassicaceae, Fabaceae, Pedaliaceae and Apiaceae. Taxa providing large amounts of biomass were <i>Brassica nigra</i>, <i>Eucalyptus globulus</i>, <i>Borassus flabellifer</i>, <i>Sesa...
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Chromolaena odorata (L.) R.M. King & H. Rob. is a fast growing weed native to the Neotropics and introduced in several regions of Africa, the Pacific Islands, and Southeast Asia, including West Bengal in India. It is one of the world’s... more
Chromolaena odorata (L.) R.M. King & H. Rob. is a fast growing weed native to the Neotropics and introduced in several regions of Africa, the Pacific Islands, and Southeast Asia, including West Bengal in India. It is one of the world’s most widespread and troublesome invasive alien plant species (IAPS) that severely infest natural habitats and crop fields. However, extensive data documents about the reproductive ecology are unknown, especially within West Bengal. This study assesses the floral biology, floral volatile organic compounds (VOCs), and floral visitors of the weed. The weed species flowers from October to January. Florets are white to purple, with short, narrow corolla tubes and deep-seated nectar.
Abundant VOCs are benzyl stearate, 2,4-decadienal, n-hexadecanoic acid, 1-hexyl-2-nitrocyclohexane, and o-decyl hydroxylamine. Flower heads were visited by numerous insect groups, though the diversity of Lepidoptera (mainly butterflies) was higher than the other insect orders. The weed is pollinated by diverse insect groups (e.g., butterflies, flies, honeybees, leafcutter bees, solitary bees, and wasps). However, vital pollination services to the weed were provided by butterflies (based on the ‘approximate pollination value’). Our findings may conclude that the clustered capitula, longer stigmatic receptivity, and broad array of pollinators resulted in too much fruit set. It is one of the critical factors that support the high growth rate and invasive nature of the weed in dry habitats.
Abundant VOCs are benzyl stearate, 2,4-decadienal, n-hexadecanoic acid, 1-hexyl-2-nitrocyclohexane, and o-decyl hydroxylamine. Flower heads were visited by numerous insect groups, though the diversity of Lepidoptera (mainly butterflies) was higher than the other insect orders. The weed is pollinated by diverse insect groups (e.g., butterflies, flies, honeybees, leafcutter bees, solitary bees, and wasps). However, vital pollination services to the weed were provided by butterflies (based on the ‘approximate pollination value’). Our findings may conclude that the clustered capitula, longer stigmatic receptivity, and broad array of pollinators resulted in too much fruit set. It is one of the critical factors that support the high growth rate and invasive nature of the weed in dry habitats.
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In the present work, bee foraging plants were determined by palynological analysis of colony stored samples (honey and pollen) of Apis dorsata collected from southern West Bengal, India. Then flowering phenology and pollen morphologies... more
In the present work, bee foraging plants were determined by palynological analysis of colony stored samples (honey and pollen) of Apis dorsata collected from southern West Bengal, India. Then flowering phenology and pollen morphologies were described to evaluate the forage preference of the bee species. In addition, chemical cues were analysed using gas chromatography-mass spectrometry (GC-MS). Foraging strategy of the bee species was profitable in that almost all the bee-visited plants were utilised for both nectar and pollen sources. The bee species became generalist visitor of several plants having diverse life form, flower characters and pollen morphologies. However, most of the bee-visited plants were of trees with synchronous type of flowering. Most plants had small-sized, yellow, cream and white coloured flowers and pollen was openly presented. We did not find any patterns in the morphological traits of bee collected pollen, though the pollen types were predominantly of medium sized with trizonocolporate apertural pattern and reticulate surface ornamentation. Floral volatile organic compounds (VOCs) of bee visited plants were also diversified. Compounds frequently found in the floral VOC bouquets were amphetamine-3-methyl; butane, 2-cyclopropyl; 2,3-butanediol; cyclohexan, 1-methyl-5-(1-methylethyl); D-limonene; methyl (2E)-2-methoxy-2-butenoate; phenol, 4-[2-(methylamino)ethyl]; phthalic acid, di(2-propylpentyl)ester; propanamide, N-(aminocarbonyl) and pyrrolo[1,2-a]pyrazine-1,4-dione, hexahydro-3-(2-methylpropyl). In conclusion, floral traits and chemical cues of plants influence the host selection specificity (to collect floral rewards) of the rock bees.
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Stingless bees are generalist visitors, forage with a high degree of floral fidelity, and thereby play an important role as pollinators. Management of stingless bees is considered to be an enhancer of crop yield and as well as an... more
Stingless bees are generalist visitors, forage with a high degree of floral fidelity, and thereby play an important role as pollinators. Management of stingless bees is considered to be an enhancer of crop yield and as well as an eco-friendly strategy to conserve biodiversity. While Tetragonula iridipennis Smith is one of the most common species of stingless bees, its foraging behavior is not very well understood. Therefore, we conducted this study to estimate the maximum foraging distance, foraging trips (number and duration), resource carrying capacity and resource loading-unloading time of the dammar bee (T. iridipennis) in West Bengal, India. Flight range was estimated by feeder training and capture-recapture techniques. The maximum foraging distance of 319.86 ± 53.01 m was recorded with an artificial feeding technique, whereas 840.21 ± 105.94 m was recorded as the maximum homing distance in capture-recapture technique. Flight distance significantly differed according to seasons as well as from colony to colony. Number of foraging trips performed daily by a forager significantly depended on the distance of resources, attributes of resources (type, quality, availability and accessibility), seasons and weather conditions. Resource loading time as well as duration of foraging trips varied according to day time and depended on resource availability and accessibility. Resource unloading times for nectar and pollen loads were much lower than the resin or latex loads. Plant resources collecting bees allocated their tasks into several groups, and this task allocation showed flexibility to some extent depending on the demand of the colony and surrounding resource availability.
Research Interests:
The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may... more
The yield of many crops benefits from pollinating insects; thus, recently reported declines in pollinator abundance and diversity are concerning for global food production. The pollinator dependency and amount of yield enhancement may vary according to crop species and geographical location. Fennel (Foeniculum vulgare) is an important spice crop cultivated in Indian states. However, comprehensive knowledge about pollination demand and yield enhancement potential of managed bees is still unknown. Here, we conducted a replicated study in two successive years (2020 and 2021) in West Bengal by combining pollinator surveys, pollinator-exclusion experiments, and field manipulation on fennel, which quantifies the impacts of supplemental stingless bees (Tetragonula iridipennis) pollination on native pollinators and crop yield. The crop species attracted many insect species belonging to diverse groups. Among those, important native pollinators (based on "approximate pollination value") were Apis cerana, Apis dorsata, Apis florea, and Oxybelus furculatus in open condition (i.e., without field manipulation and in the absence of managed bees). We derived the coefficient of pollination deficit (D) from the fruit set percentages in open and manual cross-pollination treatments. The obtained value (D = 0.18) implies that the crop species have pollen transfer limitations, resulting in retardation of crop yield. From field manipulation with managed stingless bee colonies, the abundance of visitors (especially stingless bee foragers) on fennel increased (without altering the foraging activity of other native pollinators), thereby fruit set and crop yield increased by about 14.89 and 19.31%, respectively. Native managed stingless bees had no negative impacts on other native unmanaged species and can be promoted as complementary and short-term means of boosting yields and improving agricultural sustainability.
Research Interests:
Research Interests: Zoology()
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In the present work, bee foraging plants were determined by palynological analysis of colony stored samples (honey and pollen) of Apis dorsata collected from southern West Bengal, India. Then flowering phenology and pollen morphologies... more
In the present work, bee foraging plants were determined by palynological analysis of colony stored samples (honey and pollen) of Apis dorsata collected from southern West Bengal, India. Then flowering phenology and pollen morphologies were described to evaluate the forage preference of the bee species. In addition, chemical cues were analysed using gas chromatography-mass spectrometry (GC-MS). Foraging strategy of the bee species was profitable in that almost all the bee-visited plants were utilised for both nectar and pollen sources. The bee species became generalist visitor of several plants having diverse life form, flower characters and pollen morphologies. However, most of the bee-visited plants were of trees with synchronous type of flowering. Most plants had small-sized, yellow, cream and white coloured flowers and pollen was openly presented. We did not find any patterns in the morphological traits of bee collected pollen, though the pollen types were predominantly of mediu...
Research Interests:
Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is... more
Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is difficult in cavity-nesting natural stingless bee colonies. Furthermore, it is detrimental to the wild bee's colony and may threaten their survivability. We analyzed adhered body surface pollen of incoming nectar foragers (which were smeared incidentally during nectar foraging) as an alternative method to determine nectariferous flora of Tetragonula iridipennis in West Bengal, India. By this method, we have identified 75 pollen types. The number of obtained pollen types was lower in the human-altered habitats of Midnapore city (44 pollen types) than the semi-natural habitats of Garhbeta (71 pollen types). Excluding a few pollen types of non-nectariferous plants, most of the pollen types came from nectariferous plants of both crop and noncrop species. Non-crop flowering plants (viz. Ailanthus excelsa, Borassus flabellifer, Eucalyptus tereticornis, Lannea coromandelica, Peltophorum pterocarpum, and Tectona grandis) provided a significant amount of nectar to the bee species and, therefore, play an important role in the conservation of the bee species.
Research Interests:
Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is... more
Knowledge about floral resources is essential for bee management and conservation. Pollen analysis of honey is the most traditional method for determining the nectar resources of a bee species. However, the collection of honey samples is difficult in cavity-nesting natural stingless bee colonies. Furthermore, it is detrimental to the wild bee's colony and may threaten their survivability. We analyzed adhered body surface pollen of incoming nectar foragers (which were smeared incidentally during nectar foraging) as an alternative method to determine nectariferous flora of Tetragonula iridipennis in West Bengal, India. By this method, we have identified 75 pollen types. The number of obtained pollen types was lower in the human-altered habitats of Midnapore city (44 pollen types) than the semi-natural habitats of Garhbeta (71 pollen types). Excluding a few pollen types of non-nectariferous plants, most of the pollen types came from nectariferous plants of both crop and noncrop species. Non-crop flowering plants (viz. Ailanthus excelsa, Borassus flabellifer, Eucalyptus tereticornis, Lannea coromandelica, Peltophorum pterocarpum, and Tectona grandis) provided a significant amount of nectar to the bee species and, therefore, play an important role in the conservation of the bee species.
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The objective of this study was to test the hypothesis that pollinator sharing among cashew (Anacardium occidentale L.) and co-blooming magnetic bee-friendly plants facilitate higher productivity of cashew nuts. We examined the... more
The objective of this study was to test the hypothesis that pollinator sharing among cashew (Anacardium occidentale L.) and co-blooming magnetic bee-friendly plants facilitate higher productivity of cashew nuts. We examined the reproductive efficacy of cashew in three sites with distinct vegetation pattern (site I: sparsely distributed individuals, without association of co-blooming magnetic bee-friendly plant; site II: densely distributed individuals, without association of co-blooming magnetic bee-friendly plant; site III: densely distributed individuals, associated with co-blooming magnetic bee-friendly plants). Floral traits (including flowering time, flower architecture, number of flowers per panicle, hermaphrodite-male flower ratio, floral rewards, anthesis time and longevity of flower) does not differ among the study sites. According to the value of relative pollinator service (RPS), Apis dorsata was the primary pollinator of cashew and also shared by the co-blooming bee-friendly plants. The abundance of pollinators was the highest in site III and the lowest in site I. The nut yield was also significantly higher in site III cashew orchard which was in association with magnetic bee-friendly plants. Therefore, we can conclude that the association of co-blooming magnetic plants increased nut yield of cashew through the enhancement of pollinator's services.
Research Interests:
Watermelon (Citrullus lanatus) is an important crop cultivated in India and other warmer regions of the world. The crop is dependent on insect pollinators for its fruit set. However, information about pollination ecology in Indian states... more
Watermelon (Citrullus lanatus) is an important crop cultivated in India and other warmer regions of the world. The crop is dependent on insect pollinators for its fruit set. However, information about pollination ecology in Indian states remains undetermined. We used a replicated field-scale experiment to identify the native pollinators and their foraging behaviour, including abundance, visitation rate, duration of visit, and pollination efficiency. We compared treatments with open-pollinated, hand-pollinated and the addition of two managed pollinator species to estimate the yield enhancement potential of managed stingless bees and western honey bees and their impact on native pollinator species. We found that ants, bees, butterflies, beetles, and wasps visited the flowers either for nectar, pollen, and/or floral tissue. Regarding the 'pollinator importance' value of the visitors, Halictus acrocephalus and Lasioglossum funebre were the most effective native pollinators. Despite their contribution, the plants showed a significant pollination deficit in the open-pollinated system which can be overcome by supplementary pollination services through the management of western honey bees (Apis mellifera) and/or stingless bees (Tetragonula iridipennis). However, the application of A. mellifera colonies greatly reduces the abundance, visitation rate and foraging time (amount of time spent per visit on a flower) of native pollinators. Hence, the utilization of managed stingless bee colonies for pollination services is more suitable and has a lesser impact on native pollinator species, which may lead to sustainable agricultural practices.
Research Interests:
This study investigated the suitability of honey sample collection methods for determining the botanical origin of honey through palynological analysis. We used three methods to collect honey samples in three different modes viz.... more
This study investigated the suitability of honey sample collection methods for determining the botanical origin of honey through palynological analysis. We used three methods to collect honey samples in three different modes viz. extracted honey using a honey extractor, squeezed honey and pipetted honey (collected by micropipette/dropper from honey cells only) during 2017 to 2019 in West Bengal, India. We considered two native honey bee species (Apis dorsata and Apis florea) and one introduced bee species (Apis mellifera). Pollen composition differed significantly, both quantitatively and qualitatively, among the honey samples of the different methods. The number of pollen grains in extracted honey and squeezed honey was significantly higher than that of pipetted honey. Furthermore, some pollen types of nectar deficient, but polleniferous plants (viz. Capparis zeylanica, Echinochloa frumentacea, Papaver somniferum, Poaceae type, Nelumbo nucifera, Solanum melongena, and Solanum sisymbriifolium), were also present in extracted and squeezed honeys. We concluded that some pollen grains present in extracted and squeezed honey samples came from stored pollen loads or bee bread in the hive. Hence, the pollen spectrum for pipetted honey samples was more accurate in depicting the bees foraging on nectariferous plants.
Research Interests: Honey()
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We studied the floral ecology, floral visitors and breeding system of Citrus × limon in West Bengal, India. We calculated a coefficient of pollination deficit (D) and also estimated the values of 'relative pollinator service (RPS)' to... more
We studied the floral ecology, floral visitors and breeding system of Citrus × limon in West Bengal, India. We calculated a coefficient of pollination deficit (D) and also estimated the values of 'relative pollinator service (RPS)' to determine primary polli nators of the plant species. The cultivar is fully self-compatible and produces protandric hermaphrodite flowers and male flowers with considerable amount of floral rewards. Several insects like honey bees, solitary bees, carpenter bees, flies and butterflies visited the flowers. Among those, primary pollinators were Halictus sp. and Nomia sp., and important secondary pollinators were Apis dorsata and Xylocopa fenestrata. Considering the visitors' group, the cultivar is principally pollinated by solitary bees. Besides diverse floral visitors, the cultivar showed medium pollination deficit (D = 0.49) and resulting in low fruit-set. Furthermore, premature fruit abortion is also high in all pollination treatments which lead to a low fruit-set of this lemon variety in West Bengal. K e y w o r d s : pollination deficit, relative pollinator service, self-compatible, solitary bee Р Е З Ю М Е Лаек, У., Кунду, А., Кармакар, П. Экология цветения, посетители цвет-ка и система размножения Гандхараджского лимона (Citrus × limon L. Osbeck). Исследована экология цветения, режим посещений цветка и систе-ма раз мно жения Citrus × limon в Западной Бенгалии, Индия. Для определения первичных опылителей вида мы рассчитали ко эф фициент дефицита опы-ления (D), а также оценили значения «относительного вклада опылителей» (RPS). Сорту свойственно самоопыление, в результате которого появляются протандрические гермафродитные цветки и мужские цветки со значитель-ным количеством тычинок. Ряд насекомых, таких как медоносные пчелы, одиночные пчелы, плотничьи пчелы, мухи и бабочки, посетил цветки. Сре-ди них первичными опылителями были Halictus sp. и Nomia sp., и важными вто ричными опылителями были Apis dorsata и Xylocopa fenestrata. Установлено, что сорт в основном опыляется группой одиночных пчел. При всем разноо-бразии посетителей, сорт показал средний дефицит опыления (D = 0,49) и, как следствие, низкое плодоношение. Кроме того, преждевременное преры-вание развития плодов сохранялось при всех вариантах опыления, которые приводили к низкой урожайности этого сорта лимона в Западной Бенгалии. Ключевые слова: дефицит опыления, относительный вклад опылителя, само-опыление, одиночная пчела Переведено редколлегией
Research Interests:
An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming... more
An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming period. Among those honeybees, stingless bee, solitary bees, and butterflies are legitimate visitors; all of them showed a selective preference for male flowers (flower sex type selection index ranged from 0.41 to 0.62). The plant species showed a pollination deficit in nature (coefficient of pollination deficit, D = 0.20), resulting in low fruit set in an open-pollination system. However, the value was significantly increased by the supplementary pollination services of a managed dammar bee colony. Furthermore, the quality of the fruits also improved in hand-pollinated and managed bee-pollinated systems in comparison to an open pollination system. Therefore, it is generally recommended that farmers use Indian dammar bee colonies in their agricultural land to increase the quantity and quality of the yield of bitter gourd.
Research Interests:
An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming... more
An experiment was conducted to determine the pollination deficit in bitter gourd (Momordica charantia L.) and the effect of the use of Indian dammar bee as pollinator on the yield. Diverse native visitors were recorded during the blooming period. Among those honeybees, stingless bee, solitary bees, and butterflies are legitimate visitors; all of them showed a selective preference for male flowers (flower sex type selection index ranged from 0.41 to 0.62). The plant species showed a pollination deficit in nature (coefficient of pollination deficit, D = 0.20), resulting in low fruit set in an open-pollination system. However, the value was significantly increased by the supplementary pollination services of a managed dammar bee colony. Furthermore, the quality of the fruits also improved in hand-pollinated and managed bee-pollinated systems in comparison to an open pollination system. Therefore, it is generally recommended that farmers use Indian dammar bee colonies in their agricultural land to increase the quantity and quality of the yield of bitter gourd.
Research Interests:
Pollen loads of Trigona iridipennis Smith were analyzed on a comparative basis between rural and semi-urban areas of Paschim Medinipur district, West Bengal in order to explore the botanical origin of pollen loads and pollen foraging... more
Pollen loads of Trigona iridipennis Smith were analyzed on a comparative basis between rural and semi-urban areas of Paschim Medinipur district, West Bengal in order to explore the botanical origin of pollen loads and pollen foraging activity of the bee species. Altogether 72 plants belonging to 37 families were recognized as pollen resources for the bee species. Major pollen contributing families were Myrtaceae, Fabaceae, Arecaceae and Cannabaceae. Very frequent pollen types were Borassus flabellifer, Brassica juncea, Delonix regia, Eucalyptus tereticornis, Syzygium cumini and Trema orientalis. The diversity of pollen type remains higher in rural areas of Garhbeta in comparison to the semi-urban areas of Midnapore town. Majority of natural forest trees, weeds and cultivated crops those were detected from rural areas were not recognized within the pollen spectrum in semi-urban areas of Midnapore town. In general, we found that T. iridipennis preferred tree habit with small sized flowers as a source of pollen. The most common shapes of the bee visited flowers were dish-like and brush-like, and the preferred flower colours were yellow, white or cream.
Research Interests:
Pollen loads of Apis mellifera were analysed to assess their daily pollen collection, polleniferous flora and their pollen biomass contribution in southern West Bengal, India. After that, the pollen host selection and pollen foraging... more
Pollen loads of Apis mellifera were analysed to assess their daily pollen collection, polleniferous flora and their pollen biomass contribution in southern West Bengal, India. After that, the pollen host selection and pollen foraging activity of the bee species were also determined. The average daily harvest of pollen loads per honey bee colony was 8.5 g to 127.2 g. The pollen flow through the colonies was the highest during spring, followed by winter and summer, whereas during the monsoon it was the lowest. The weight of a single pollen load ranged from 3.22 mg to 11.73 mg and greatly varied within each season, but seasonal average values do not statistically differ. Families that contributed major amount of biomass were Arecaceae, Myrtaceae, Brassicaceae, Fabaceae, Pedaliaceae and Apiaceae. Taxa providing large amounts of biomass were Brassica nigra, Eucalyptus globulus, Borassus flabellifer, Sesamum indicum, Acacia auriculiformis, Coriandrum sativum, Cocos nucifera, Phoenix sylvestris and Mikania scandens (Asteraceae). As the bee species foraged on 26.32% (80 plant taxa) of the local angiosperm flora, the broad polylecty category was inferred. The pollen host selection by the bee species significantly depends on the flower availability index (FAi) and pollen availability index (PAi) rather than on an individual flower's pollen quality (in term of pollen morphological characteristics and crude protein content) and pollen quantity (number of pollen grains/flower and amount of pollen biomass/flower). The pollen foraging activity of the bee species varied according to time as well as season. The activity was higher between 9.00 and 10.00 am. Seasonally, the highest activity was observed in spring and the lowest during the monsoon. Furthermore, the ratio of pollen foragers to total incoming foragers also varied according to the time of day as well as the season, and was largely dependent of resource availability.
Research Interests:
The present study aimed to determine floristic composition and pollen morphology of Nayachar Island, a recently developed estuarine island of West Bengal, India. The study revealed 85 plant species belonging to 35 families. Fabaceae is... more
The present study aimed to determine floristic composition and pollen morphology of Nayachar Island, a recently developed estuarine island of West Bengal, India. The study revealed 85 plant species belonging to 35 families. Fabaceae is the most preponderant family, whereas the members of Poaceae and Cyperaceae were with higher densities. Trees were predominant life forms, which demonstrate a typical mangrove ecosystem. Among the identified taxa, 15 were true mangroves, 29 were mangrove associates and remaining 41 taxa were of other types. Regarding the pollen morphology, mangroves exhibits diversified pollen morphological characters. All the pollen types were radially symmetrical except the members of Arecaceae. Among the studied species, pollen shape classes also greatly varied with prolate, sub prolate, prolate spheroidal, spheroidal, oblate spheroidal, sub oblate and oblate types. The amb (equatorial outline viewed from pole) was also varied between circular, triangular, sub triangular and rarely tetra angular. Apertural patterns were predominantly of trizonocolporate type. The commonest forms of surface ornamentations are reticulate, punctate or psilate type.
Research Interests:
One-hundred-and-five species corresponding to 38 families were identified through pollen analyses of 53 Apis dorsata honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently encountered were... more
One-hundred-and-five species corresponding to 38 families were identified through pollen analyses of 53 Apis dorsata
honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently encountered
were Fabaceae, Arecaceae, Asteraceae and Myrtaceae. Fabaceae had the greatest representation in number of pollen types
(18 types), followed by Asteraceae (nine types), Cucurbitaceae (seven types), Lamiaceae and Myrtaceae (each with six
types) and Malvaceae and Rutaceae (each with five types). Most of the honey samples correspond to class I. The presence
of dominant pollen was detected in 18 samples. The predominant pollen types were Borassus flabellifer, Sesamum indicum
(during summer), Eucalyptus globulus (during late autumn), Brassica nigra, Eucalyptus globulus (during winter) and Borassus
flabellifer and Lannea coromandelica (during spring). The unifloral honeys obtained mostly during late autumn and winter
were dominated by Eucalyptus globulus type. In monsoon and autumn unifloral honeys containing predominant pollen
types (> 45%) were not found. However, according to frequency distribution the pollen types represented as very frequent
were Peltophorum pterocarpum, Tridax procumbens (in monsoon) and Acacia auriculiformis, Cocos nucifera, Eucalyptus
globulus, Tridax procumbens and Ziziphus mauritiana (in autumn). The seasonal diversity of pollen types obtained was at
a maximum during spring (36 types) and minimum during late autumn (14 types). Seasonal variation in the number of
pollen types per sample range from 5.86 ± 1.87 (during late autumn) to 6.86 ± 1.95 (during autumn) and exhibit low
correlation (r = 0.31) with floral diversity. The diversity of pollen types per unifloral honey sample remains lower than
multifloral honeys.
honeys collected from Bankura and Paschim Medinipur districts, West Bengal. The families most frequently encountered
were Fabaceae, Arecaceae, Asteraceae and Myrtaceae. Fabaceae had the greatest representation in number of pollen types
(18 types), followed by Asteraceae (nine types), Cucurbitaceae (seven types), Lamiaceae and Myrtaceae (each with six
types) and Malvaceae and Rutaceae (each with five types). Most of the honey samples correspond to class I. The presence
of dominant pollen was detected in 18 samples. The predominant pollen types were Borassus flabellifer, Sesamum indicum
(during summer), Eucalyptus globulus (during late autumn), Brassica nigra, Eucalyptus globulus (during winter) and Borassus
flabellifer and Lannea coromandelica (during spring). The unifloral honeys obtained mostly during late autumn and winter
were dominated by Eucalyptus globulus type. In monsoon and autumn unifloral honeys containing predominant pollen
types (> 45%) were not found. However, according to frequency distribution the pollen types represented as very frequent
were Peltophorum pterocarpum, Tridax procumbens (in monsoon) and Acacia auriculiformis, Cocos nucifera, Eucalyptus
globulus, Tridax procumbens and Ziziphus mauritiana (in autumn). The seasonal diversity of pollen types obtained was at
a maximum during spring (36 types) and minimum during late autumn (14 types). Seasonal variation in the number of
pollen types per sample range from 5.86 ± 1.87 (during late autumn) to 6.86 ± 1.95 (during autumn) and exhibit low
correlation (r = 0.31) with floral diversity. The diversity of pollen types per unifloral honey sample remains lower than
multifloral honeys.
Research Interests:
For successful establishment of meliponiculture with Trigona iridipennis Smith, several attributes such as nesting substrates, orientations, elevation, internal characteristics of nests, floral resources, and foraging activity were... more
For successful establishment of meliponiculture with Trigona iridipennis Smith, several attributes such as nesting substrates,
orientations, elevation, internal characteristics of nests, floral resources, and foraging activity were studied in Bankura district
of West Bengal, India. The most commonly found nesting substrate was tree trunks, especially within the cavities in tree
trunks of Butea monosperma. Majority of the wild nests were oriented westward direction with an elevation of > 2–≤ 3 m
from the ground level. The mean cavity size was 204.3 ± 92.45 × 159 ± 17.59 × 174.5 ± 26.13 mm
. The diversified local
angiosperm flora supports the broad polylectic foraging habit of the bee species. Most of the visited plants were of tree
habits and had small-sized flowers with yellow, white, and cream colours. The best represented families were Fabaceae and
Asteraceae. The plants intensely utilized by the bee species were Acacia auriculiformis, Borassus flabellifer, Brassica nigra,
Eucalyptus globulus, and Lannea coromandelica. In contrast to majority of multifloral honey samples, all the pollen loads
were unifloral which reflects the high degree of floral fidelity behaviour of the bee species. The foraging activity of the bee
species varied according to time hours, plant species, weather conditions, and seasons. It was confined to daytime from 5.00
to 18.00 h, reaching its zenith during 9.00–11.00 h and 15.00–1600 h. Maximum activity was observed in spring, followed
by winter, late autumn, summer, autumn, and monsoon. Mean number of foragers without pollen load and resin load was
much higher than pollen foragers and resin foragers.
orientations, elevation, internal characteristics of nests, floral resources, and foraging activity were studied in Bankura district
of West Bengal, India. The most commonly found nesting substrate was tree trunks, especially within the cavities in tree
trunks of Butea monosperma. Majority of the wild nests were oriented westward direction with an elevation of > 2–≤ 3 m
from the ground level. The mean cavity size was 204.3 ± 92.45 × 159 ± 17.59 × 174.5 ± 26.13 mm
. The diversified local
angiosperm flora supports the broad polylectic foraging habit of the bee species. Most of the visited plants were of tree
habits and had small-sized flowers with yellow, white, and cream colours. The best represented families were Fabaceae and
Asteraceae. The plants intensely utilized by the bee species were Acacia auriculiformis, Borassus flabellifer, Brassica nigra,
Eucalyptus globulus, and Lannea coromandelica. In contrast to majority of multifloral honey samples, all the pollen loads
were unifloral which reflects the high degree of floral fidelity behaviour of the bee species. The foraging activity of the bee
species varied according to time hours, plant species, weather conditions, and seasons. It was confined to daytime from 5.00
to 18.00 h, reaching its zenith during 9.00–11.00 h and 15.00–1600 h. Maximum activity was observed in spring, followed
by winter, late autumn, summer, autumn, and monsoon. Mean number of foragers without pollen load and resin load was
much higher than pollen foragers and resin foragers.
Research Interests:
Pollen cell frequencies within hive of Apis dorsata in Bankura and Paschim Medinipur districts of West Bengal remain maximum mean value of 8.74 during the month of April and minimum mean value of 3.47 in August. The pollen cell frequency... more
Pollen cell frequencies within hive of Apis dorsata in Bankura and Paschim Medinipur districts
of West Bengal remain maximum mean value of 8.74 during the month of April and minimum
mean value of 3.47 in August. The pollen cell frequency of hive was very positively correlated to
the pollen stack number with a correlation coefficient (r) value of 0.96. The stack number per
pollen cell varied from mean value of 9.40 (during April) to 4.27 (in August). Each pollen stack
was made up of an average of 9.88 pairs of pollen pellets. The number of pollen grains per
pollen stack ranged from 572450 to 1052480 with an average value of 817370. Among the
melissopalynologically analyzed 1336 pollen stacks, 865 (64.75%) were unifloral, 407 (30.46%)
were bifloral and 64 (4.79%) were multifloral in pollen compositions. Though from each pollen
cell 1 to 7 pollen types were obtained, but majority of the pollen cells contain 3 pollen types. A
total of 84 pollen types belonging to 39 plant families were identified. Among them most
frequently occurred pollen type was Eucalyptus globulus, followed by Borassus flabellifer,
Brassica nigra, Acacia auriculiformis, Sesamum indicum, Terminalia arjuna, Lannea
coromandelica, Alangium salvifolium, Shorea robusta and Phoenix sylvestris.
of West Bengal remain maximum mean value of 8.74 during the month of April and minimum
mean value of 3.47 in August. The pollen cell frequency of hive was very positively correlated to
the pollen stack number with a correlation coefficient (r) value of 0.96. The stack number per
pollen cell varied from mean value of 9.40 (during April) to 4.27 (in August). Each pollen stack
was made up of an average of 9.88 pairs of pollen pellets. The number of pollen grains per
pollen stack ranged from 572450 to 1052480 with an average value of 817370. Among the
melissopalynologically analyzed 1336 pollen stacks, 865 (64.75%) were unifloral, 407 (30.46%)
were bifloral and 64 (4.79%) were multifloral in pollen compositions. Though from each pollen
cell 1 to 7 pollen types were obtained, but majority of the pollen cells contain 3 pollen types. A
total of 84 pollen types belonging to 39 plant families were identified. Among them most
frequently occurred pollen type was Eucalyptus globulus, followed by Borassus flabellifer,
Brassica nigra, Acacia auriculiformis, Sesamum indicum, Terminalia arjuna, Lannea
coromandelica, Alangium salvifolium, Shorea robusta and Phoenix sylvestris.
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The chapter provides information about distribution, nesting biology and floral resources of red dwarf honeybee (Apis florea Fabricius) in West Bengal, India. The bee species showed a selection preference to human habitation for its... more
The chapter provides information about distribution, nesting biology and floral resources of red dwarf honeybee (Apis florea Fabricius) in West Bengal, India. The bee species showed a selection preference to human habitation for its colony settlement. Its abundance also significantly varied according to seasons. During winter to summer, the bees densely colonized due to favourable weather conditions, availability of nesting sites and floral resources. To collect rewards, foragers visited on a large number of plant species including wild and cultivated plants. The foragers maintain a high degree of floral fidelity in each bout. The bee-visited plants were diversified with respect to habit and flower characters. Therefore, the bee species is regarded as a generalist visitor and important pollinator of tropical flora.