The effect of temperature on the rate of conversion of p,p-DDT to p,p-DDE in brook trout (Salvelinus fontinalis).

Brook trout (Salvelinus fontinalis) were maintained in flowing fresh water at 2, 10, and 18 degrees C and injected intramuscularly with p,p-[-14C]DDT. Fish were killed at intervals up to 16 weeks after injection, and analyzed by a combination of thin-layer chromatography, gas-liquid chromatography, and liquid-scintillation counting. Only one labelled metabolite, p,p-DDE, was detected during the experimental period. Its rate of production varied with temperature; after 16 weeks, about 9, 13, and 19 percent of the original p,p-DDT in fish maintained at 2, 10, and 18 degrees C, respectively, had been converted.     

Absence of Nepotism in Worker–Queen Care in Polygynous Colonies of the Ant Ectatomma tuberculatum

The question of the occurrence of nepotism in insect societies is central to inclusive fitness theory. Here we investigated the existence of nepotism in the facultative polygynous ant Ectatomma tuberculatum because various characteristics of this species may have favored the evolution of nepotistic behavior toward queens. We thus studied worker–queen care toward their mother queen vs. an unrelated unfamiliar queen, to determine if workers cared preferentially for their mother. Although we tried to facilitate the expression of nepotistic behaviors, we did not detect significant nepotism confirming the general trend of an absence of nepotism in social insects. We discuss about the specific causes that can explain the absence of nepotism in E. tuberculatum regarding the particular social organization of this species and its ecological dominance in the mosaic of arboreal ants.     

Behavioral and Chemical Correlates of Long-Term Queen Adoption in the Facultative Polygynous Ant Ectatomma tuberculatum

In ants, queen adoption is a common way of achieving secondary polygyny but the mechanisms involved are little known. Here we studied the process of long-term adoptions of alien queens in the facultative polygynous ant Ectatomma tuberculatum. In eight out of 10 successful adoption experiments, all the introduced queens showed similar behavior and fecundity as the resident queens even after 2 months, indicating complete integration into the colony. Chemical analysis revealed that the cuticular hydrocarbon profiles of resident and introduced queens were clearly distinct from those of workers and that they did not change after adoption. We propose that queen-specific cuticular hydrocarbon profile may represent a reliable signal of queen’s fertility and discuss about the evolution of high level of queen acceptance in E. tuberculatum.     

Construction of an Yucatec Maya soil classification and comparison with the WRB framework

Background

Nepal is small in size but rich in bio-cultural diversity. The rugged terrain of the country is home to a number of unique assemblages of fauna, some of which are endemic. Not only faunal resources the country also harbors some very ancient populations whose interrelationship with these diverse faunal resources is very intimate and thus demands scientific study. Animals play important role in both material and spiritual spheres of their life. There are more than hundred groups of such populations in the country and the group Tamang is one of these. The present paper studies Tamang-animal relationships in central Nepal. There is a growing trend of scientific ethnozoological studies all across the globe, but this field is yet in its infancy in Nepal. The country is losing important fauna as well as ancient human cultures at the advent of development processes. As a result, ethnozoological knowledge is also teetering on the brink of extinction.

Methods

Ethnozoological data were collected by applying different participatory approaches techniques such as semi-structured interviews, participatory rural appraisal, key informant interviews and focus group discussions. Quantitative data were obtained by employing a household level questionnaire survey. Data were collected from the period of September 2004 to August 2005. Most of the animals were identified up to the species level with the help of standard taxonomic keys.

Results

The Tamang community treasures knowledge on various uses of 41 genera belonging to 28 families. Out of total number of animals, 14.6% belong to the Invertebrate group and the rest to the Vertebrate group. Of the total uses 58% fall in the food and medicinal use category, 16% in the magico-religious use category, 18% in the category of omen indication, and 2% each in the categories such as weather forecasting, trophy, ethnomusical and taboos.

Conclusions

The Tamang maintain strong ties with animals both at a material as well as spiritual level. While some animals are the sources of important traditional medicines, others are omen indicators and weather forecasters. High priority should be given in conservation of those animals which are of high consensus value to the community.     

One-step synthesis of polyesters specialties for biomedical applications

Polyesters are widely used for biomedical applications such as drug delivery systems and resorbable implants. The degradation kinetic of these biopolymers can be tailored by the introduction of functional groups in their backbone, leading to a modification of their morphology and hydrophilicity. This is usually realized via long multistep reaction pathways. This contribution describes the emergence of one-step procedures for this purpose including enzymatic and Lewis acid catalyzed polycondensation as well as coordinative ring opening polymerization.     

Low intraspecific aggression level in the polydomous and facultative polygynous ant Ectatomma tuberculatum

Nestmate recognition is a key feature of social insects, as it preserves colony integrity. However, discrimination of non‐nestmates and nestmate recognition mechanisms are highly variable according to species and social systems. Here, we investigated the intraspecific level of aggression in the facultative polygynous and polydomous ant, Ectatomma tuberculatum Olivier (Hymenoptera: Formicidae: Ectatomminae), in a population with a strong genetic structure. We found that the intraspecific level of aggression was generally low in this population of E. tuberculatum. However, the level of aggression was significantly correlated with the geographical distance, suggesting that both genetic and environmental cues could be involved in nestmate recognition and discrimination mechanisms. Moreover, polydomy was confirmed by the absence of aggression between workers from nests at a distance of 3 m, while the level of aggression was significantly higher between workers from nests separated by a distance of 10 or 1300 m. Field experiments showed that the low level of aggression between neighbouring colonies was associated with shared foraging areas, which could suggest that familiarization processes may occur in this species. We propose that the particular social organization of this species, with secondary polygyny, polydomy, and budding, may have favoured a high acceptance threshold, because of the low probability of interactions with unrelated conspecifics, the high cost of erroneously rejecting nestmates, and the low cost of accepting non‐nestmate workers. The resulting open recognition system can thus allow privileged relationships between neighbouring colonies and promote the ecological dominance of E. tuberculatum in the mosaic of arboreal ants.     

Mate Choice in Mus musculus Is Relative and Dependent on the Estrous State

Mate choice is a critical behavioral decision process with profound impact on evolution. However, the mechanistic basis of mate choice is poorly understood. In this study we focused on assortative mate choice, which is known to contribute to the reproductive isolation of the two European subspecies of house mouse, Mus musculus musculus and Mus musculus domesticus. To understand the decision process, we developed both full mating and limited-contact paradigms and tested musculus females'' preference for musculus versus domesticus males, mimicking the natural musculus/domesticus contact zone. As hypothesized, when allowed to mate we found that sexually receptive musculus females exhibited a robust preference to mate with musculus males. In contrast, when non-receptive, females did not exhibit a preference and rather alternated between males in response to male mount attempts. Moreover in a no-choice condition, females mated readily with males from both subspecies. Finally, when no physical contact was allowed, and therefore male''s behavior could not influence female''s behavior, female''s preference for its own subspecies was maintained independently of the estrous state. Together, our results suggest that the assortative preference is relative and based on a comparison of the options available rather than on an absolute preference. The results of the limited-contact experiments highlight the interplay between female''s internal state and the nature of the interaction with prospective mates in the full mating conditions. With these experiments we believe we established an assortative mate preference assay that is appropriate for the investigation of its underlying substrates.     

Understanding shifts in wildfire regimes as emergent threshold phenomena

Ecosystems driven by wildfire regimes are characterized by fire size distributions resembling power laws. Existing models produce power laws, but their predicted exponents are too high and fail to capture the exponent's variation with geographic region. Here we present a minimal model of fire dynamics that describes fire spread as a stochastic birth-death process, analogous to stochastic population growth or disease spread and incorporating memory effects from previous fires. The model reproduces multiple regional patterns in fire regimes and allows us to classify different regions in terms of their proximity to a critical threshold. Transitions across this critical threshold imply abrupt and pronounced increases in average fire size. The model predicts that large regions in Canada are currently close to this transition and might be driven beyond the threshold in the future. We illustrate this point by analyzing the time series for large fires (>199 ha) from the Canadian Boreal Plains, found to have shifted from a subcritical regime to a critical regime in the recent past. By contrast to its predecessor, the model also suggests that a critical transition, and not self-organized criticality, underlies forest fire dynamics, with implications for other ecological systems exhibiting power-law-like patterns, in particular for their sensitivity to environmental change and control efforts.