Tropical Climate

Stable isotope analyses are widely used to determine trophic levels in ecological studies. We have investigated the effects of carbonate removal via acidification on the stable carbon and nitrogen isotopic composition of 33 species of tropical benthic macrofauna, and we report guidelines for standardizing this procedure for higher taxa in tropical coral reef ecosystems. Many tropical benthic invertebrates are small in size, and therefore body tissue isolation (separating organic carbon from inorganic structures) is difficult and time-consuming. Literature reviews of invertebrate studies show a lack of consistent procedures and guidelines for preparation techniques, especially for carbonate removal via acidification of whole individuals. We find that acidification decreases the δ13C values of samples containing carbonate, with shifts ranging from 0.21 to 3.20‰, which can be related to CaCO3 content (assessed by a carbonate proxy), justifying acid pre-treatment. Carbonate-containing taxa benefiting from acidification included Amphinomida, Terebellida (Annelida), Anomura, Brachyura, Caridea, Amphipoda, Tanaidacea (Arthropoda) and Edwardsiida (Cnidaria). The δ13C shifts of samples containing no carbonate varied up to 0.02 ± 0.20‰. As this induced δ13C shift was lower than the range of an average trophic level shift (0.5 to 1‰), we conclude that acid pre-treatment is unnecessary. Carbonate-free taxa consisted of Eunicida, Phyllodocida (Annelida) and Mollusca. We note minimal impact of acidification on δ15N values except for Brachyura, which showed a shift of 0.83 ± 0.46‰, which is still lower than a single trophic level shift (2.9–3.8‰). We conclude that for trophic level studies, both the δ13C and the δ15N of carbonate-rich macrofauna can be determined from the same acidified sample. Copyright © 2008 John Wiley & Sons, Ltd.

Social wasps from temperate zones have clear annual colony cycles, and the young queens hibernate during winter. In the subtropics, the only previously reported evidence for the existence of “hibernation” is the facultative winter aggregations of females during harsh climate conditions. As in temperate-zone species analyzed so far, we show in this study that in the paper wasp, Polistes versicolor, a subtropical species, body size increases as an unfavorable season approaches. Our morphological studies indicate that larger females come from winter aggregations—that is, they are new queens. Multivariate analyses indicate that size is the only variable analyzed that shows a relationship to the differences. Given the absence of a harsh climate, we suggest that the occurrence of winter aggregations in tropical P. versicolor functions to allow some females to wait for better environmental conditions to start a new nest, rather than all being obliged to start a new nest as soon as they emerge.

Since the 1990s, rising commodity prices and declining per capita cultivated area have led to decreases in food production, eroding food security in many communities (2). Many regions that lack food security rely on local agricultural production to meet their food needs. Primarily ...

Leaf-cutting ants (Atta spp.) are known for their extensive defoliation in neo-tropical forests and savannahs. Debate about the costs and benefits of their activities has been largely dominated by their detrimental effects on agriculture and agroforestry. However, the large accumulation of nutrients and changes in soil properties near their nests might benefit plants growing near them. Here, we test whether trees use nutrients that accumulate in debris piles near, or refuse chambers within, leaf-cutting ant nests. At two tropical sites (a moist tropical forest site in Panama and a savannah site in Brazil), we fed leaves labelled with the stable isotope 15N to two species of leaf-cutting ants (Atta colombica and Atta laevigata) and traced the stable isotope label in plants surrounding the two nests. Thus, we show that plants in both sites access resources associated with Atta nests. In addition, leaf tissue of trees near the nests labelled with 15N had significantly higher calcium co...

The evolution of industrial-era warming across the continents and oceans provides a context for future climate change and is important for determining climate sensitivity and the processes that control regional warming. Here we use post-ad 1500 palaeoclimate records to show that sustained industrial-era warming of the tropical oceans first developed during the mid-nineteenth century and was nearly synchronous with Northern Hemisphere continental warming. The early onset of sustained, significant warming in palaeoclimate records and model simulations suggests that greenhouse forcing of industrial-era warming commenced as early as the mid-nineteenth century and included an enhanced equatorial ocean response mechanism. The development of Southern Hemisphere warming is delayed in reconstructions, but this apparent delay is not reproduced in climate simulations. Our findings imply that instrumental records are too short to comprehensively assess anthropogenic climate change and that, in ...

Summary: Purpose: Cerebral malaria (CM) is suspected to be a potential cause of epilepsy in tropical areas, but little information is available. The purpose of this study was to evaluate the role of CM in epilepsy among children in Mali.  Methods: An exposed–nonexposed study was performed to identify children who had epilepsy after malaria in the 0- to 15-year age group. The exposure factor was CM defined according to World Health Organization (WHO) criteria, and the nonexposure factor was symptomatic malaria without the characteristics of CM (NCM). All the children underwent a screening questionnaire and were examined by a medical physician. After the screening phase, a specialist in neuropediatrics examined the children suspected to have epilepsy. EEG and computed tomography (CT) scans were performed in some of these patients.  Results: In total, 101 subjects who had had CM and 222 who had had NCM were included. Fifty-four children (CM, 34; NCM, 20) were suspected to have epilepsy, and six were confirmed (CM, five; NCM, one). The incidence rate was 17.0 per 1000 person-years in the CM group and 1.8 per 1000 person-year in the NCM group; thus the relative risk (RR) was 9.4 [95% confidence interval (CI), 1.3–80.3; p = 0.02]. After adjustment on age and duration of follow-up, the RR was 14.3 (95% CI, 1.6–132.0; p = 0.01).  Conclusions: The risk of sequelar epilepsy is significantly higher in the CM group compared with the NCM group. A reevaluation of this cohort should be carried out later to search for temporal epilepsy that appeared after age 10 years.

The genomic era facilitates the understanding of how transcriptional networks are interconnected to program seed development and filling. However, to date, little information is available regarding dicot seeds with a transient perisperm and a persistent, copious endosperm. Coffea arabica is the subject of increasing genomic research and is a model for nonorthodox albuminous dicot seeds of tropical origin.The aim of this study was to reconstruct the metabolic pathways involved in the biosynthesis of the main coffee seed storage compounds, namely cell wall polysaccharides, triacylglycerols, sucrose, and chlorogenic acids. For this purpose, we integrated transcriptomic and metabolite analyses, combining real-time RT-PCR performed on 137 selected genes (of which 79 were uncharacterized in Coffea) and metabolite profiling.Our map-drawing approach derived from model plants enabled us to propose a rationale for the peculiar traits of the coffee endosperm, such as its unusual fatty acid composition, remarkable accumulation of chlorogenic acid and cell wall polysaccharides.Comparison with the developmental features of exalbuminous seeds described in the literature revealed that the two seed types share important regulatory mechanisms for reserve biosynthesis, independent of the origin and ploidy level of the storage tissue.

Seed desiccation sensitivity limits the ex situ conservation of up to 47 % of plant species, dependent on habitat. Whilst desirable, empirically determining desiccation tolerance levels in seeds of all species is unrealistic. A probabilistic model for the rapid identification of woody species at high risk of displaying seed desiccation sensitivity is presented. The model was developed using binary logistic regression on seed trait data [seed mass, moisture content, seed coat ratio (SCR) and rainfall in the month of seed dispersal] for 104 species from 37 families from a semi-deciduous tropical forest in Panamá. For the Panamanian species, only seed mass and SCR were significantly related to the response to desiccation, with the desiccation-sensitive seeds being large and having a relatively low SCR (i.e. thin 'seed' coats). Application of this model to a further 38 species, of known seed storage behaviour, from two additional continents and differing vegetation types (drylan...

In addition to repeated reexperiencing of the event, the delayed effects of severe psychological trauma, i.e., post traumatic stress disorder (PTSD), present a paradoxical mix of symptoms. There is enhancement of the self-preservative catecholamine states; anger and fear with a contrasting sense of meaninglessness and a blunting of the emotional responses of the attachment behavior so critical for species preservation. Hormonally, there is a striking separation of the catecholamine response, which stays elevated and that of the hypothalamo-pituitary-adrenal (HPA) axis, which may remain at normal levels. Pathophysiologically, the reexperiencing of the trauma and the arousal may be associated with dysfunction of the locus coeruleus, amygdala and hippocampal systems. This article explores the consequences of an additional dysfunction: a dissociation of the hemispheres that appears to be responsible for the alexithymic avoidance and failure of the cortisol response that so often follow severe psychological trauma. There is neurophysiological evidence that the left and right hemispheres subserve different emotional sets that correspond to “control” and “appraisal,” i.e., very approximately to the self and species preservative behavioral complexes, respectively. Several studies point to physiological dissociation of hemispheric functions during alexithymia. This raises the question: What has been lost if in this condition the right side no longer fully contributes to integrated cerebral function? Right hemispheric damaged children lose critical social skills and in adults the related sense of familiarity critical for bonding is lost. Such losses of social sensibilities may account for the lack of empathy and difficulties with bonding found in sociopathy and borderline personality: conditions now believed to result from repeated psychological trauma during development. On the other hand, systems that promote right hemispheric contributions provide solacing access to a “Higher Power.” They also appear to protect against socially disordered behavior, substance abuse, the failure of the HPA axis and some aspects of the pathophysiology of chronic disease.

The current scale of deforestation in tropical regions and the large areas of degraded lands now present underscore the urgent need for interventions to restore biodiversity, ecological functioning, and the supply of goods and ecological services previously used by poor rural communities. Traditional timber plantations have supplied some goods but have made only minor contributions to fulfilling most of these other objectives. New approaches to reforestation are now emerging, with potential for both overcoming forest degradation and addressing rural poverty.

The English publication was issued by the International Council on Archives, The National Archives of the Republic of Indonesia and the National Archives of the Netherlands on the occasion of the international conference The Preservation of Archives in Tropical Climates, which was held in Jakarta 5-8 November 2001. It contains an extensive overview of currently available resources on issues in relation to preservation and conservation in tropical climates, focusing on books and writing materials, building and storage facilities, disaster preparedness and integrated pest management. The second part of the book consists over 1400 literature references.

Assessing Creepy Crawlies Arthropods are the most diverse group of terrestrial animal species, yet estimates of the total number of arthropod species have varied widely, especially for tropical forests. Basset et al. (p. 1481 , see the cover) now provide more reliable estimates of total arthropod species richness in a tropical rainforest in Panama. Intensive sampling of a half hectare of forest yielded just over 6000 arthropod species. Scaling up this result to the whole forest suggests that the total species diversity lies between 17,000 and 40,000 species.

A review of the literature since 2009 reveals a staggering health and economic burden resulting from neglected tropical diseases in Panama and the six countries of Central America (referred to collectively here as 'Central America'). Particularly at risk are the 10.2million people in the region who live on less than $2 per day, mostly in Guatemala, Honduras, Nicaragua and El Salvador. Indigenous populations are especially vulnerable to neglected tropical diseases. Currently, more than 8million Central American children require mass drug treatments annually (or more frequently) for their intestinal helminth infections, while vector-borne diseases are widespread. Among the vector-borne parasitic infections, almost 40% of the population is at risk for malaria (mostly Plasmodium vivax infection), more than 800,000 people live with Chagas disease, and up to 39,000 people have cutaneous leishmaniasis. In contrast, an important recent success story is the elimination of onchocercia...