Habitat degradation and seasonality affect physiological stress levels of Eulemur collaris in littoral forest fragments

Forest fragmentation and edge effects impact body condition, fur condition and ectoparasite prevalence in a nocturnal lemur community

Forest fragmentation and edge effects are two major threats to primate populations. Primates inhabiting fragmented landscapes must survive in a more degraded environment, often with lower food availability compared to continuous forests. Such conditions can have deleterious effects on animal physiological health, yet some primates thrive in these habitats. Here, we assessed how forest fragmentation and associated edge effects impact three different components of physiological health in a nocturnal primate community in the Sahamalaza-Iles Radama National Park, northwest Madagascar. Over two periods, 6 March 2019-30 October 2019 and 10 January 2022-17 May 2022, we collected data on body condition, fur condition scores and ectoparasite prevalence for 125 Mirza zaza, 51 Lepilemur sahamalaza, 27 Cheirogaleus medius and 22 Microcebus sambiranensis individuals, and we compared these metrics between core and edge areas of continuous forest and fragmented forest. Body condition scores for all species varied between areas, with a positive response to fragmentation and edge effects observed for M. zaza and L. sahamalaza and a negative response for C. medius and M. sambiranensis. Fur condition scores and ectoparasite prevalence were less variable, although M. zaza and L. sahamalaza had a significantly negative response to fragmentation and edge effects for these two variables. Interestingly, the impacts of fragmentation and edge effects on physiological health were variable-specific. Our results suggest that lemur physiological responses to fragmentation and edge effects are species-specific, and body condition, fur condition and ectoparasite prevalence are impacted in different ways between species. As other ecological factors, including food availability and inter/intraspecific competition, likely also influence physiological health, additional work is required to determine why certain aspects of lemur physiology are affected by environmental stressors while others remain unaffected. Although many nocturnal lemurs demonstrate resilience to fragmented and degraded habitats, urgent conservation action is needed to safeguard the survival of their forest habitats.

Monitoring the stress physiology of free-ranging mugger crocodiles (Crocodylus palustris) across diverse habitats within Central Gujarat, India

Animals face several challenges in their natural environment, and to cope with such conditions, they may exhibit contrasting physiological responses that directly affect their overall well-being and survival. In this study, we assessed physiological responses via faecal glucocorticoid metabolite (fGCM) measurements in free-ranging mugger crocodiles inhabiting diverse habitats in Gujarat, India. We sampled muggers within Charotar, a rural area (Zone A) with local people having high tolerance towards the presence of muggers, and Vadodara, a region having both urban (Zone B) and rural (Zone C) areas with high levels of human-mugger conflict (HMC). Further, muggers in Vadodara live in water bodies that are mostly polluted due to sewage disposal from adjoining chemical industries. To measure fGCM (mean ± SEM, ng/g dry faeces) levels in muggers, scats were collected during both breeding (N = 107 scats) and non-breeding (N = 22 scats) seasons from all three zones. We used captive muggers (a focal enclosure) to biologically validate (via capture and restraint) the selected fGCM assay (11-oxoetiocholanolone assay). We showed a significant (P < 0.05) 11-fold increase in fGCM levels between pre-capture (540.9 ± 149.2, N = 11) and post-capture (6259.7 ± 1150.5, N = 11) samples. The validated assay was applied to free-ranging muggers during the breeding season, and Zone A showed significantly (P < 0.05) lower fGCM levels (542.03 ± 71.3) compared to muggers of Zone B (1699.9 ± 180.8) and Zone C (1806.4 ± 243.2), both zones having high levels of HMC with polluted water bodies. A similar contrast in fGCM levels was also observed during the non-breeding season. Overall, the study demonstrated that fGCM levels in muggers varied across habitats, and such variation could be due to a multitude of ecological factors that the species experience in their immediate local environment. Moreover, high fGCM levels in muggers of Vadodara during both breeding and non-breeding seasons may indicate a condition of chronic stress, which could be maladaptive for the species.

Feather corticosterone is lower in translocated and historical populations of the endangered Laysan duck (Anas laysanensis)

Identifying reliable bioindicators of population status is a central goal of conservation physiology. Physiological stress measures are often used as metrics of individual health and can assist in managing endangered species if linked to fitness traits. We analysed feather corticosterone, a cumulative physiological stress metric, of individuals from historical, translocated, and source populations of an endangered endemic Hawaiian bird, the Laysan duck (Anas laysanensis). We hypothesized that feather corticosterone would reflect the improved reproduction and survival rates observed in populations translocated to Midway and Kure Atolls from Laysan Island. We also predicted less physiological stress in historical Laysan birds collected before ecological conditions deteriorated and the population bottleneck. All hypotheses were supported: we found lower feather corticosterone in the translocated populations and historical samples than in those from recent Laysan samples. This suggests that current Laysan birds are experiencing greater physiological stress than historical Laysan and recently translocated birds. Our initial analysis suggests that feather corticosterone may be an indicator of population status and could be used as a non-invasive physiological monitoring tool for this species with further validation. Furthermore, these preliminary results, combined with published demographic data, suggest that current Laysan conditions may not be optimal for this species.

Glucocorticoids and land cover: a largescale comparative approach to assess a physiological biomarker for avian conservation

As humans alter landscapes worldwide, land and wildlife managers need reliable tools to assess and monitor responses of wildlife populations. Glucocorticoid (GC) hormone levels are one common physiological metric used to quantify how populations are coping in the context of their environments. Understanding whether GC levels can reflect broad landscape characteristics, using data that are free and commonplace to diverse stakeholders, is an important step towards physiological biomarkers having practical application in management and conservation. We conducted a phylogenetic comparative analysis using publicly available datasets to test the efficacy of GCs as a biomarker for large spatial-scale avian population monitoring. We used hormone data from HormoneBase (51 species), natural history information and US national land cover data to determine if baseline or stress-induced corticosterone varies with the amount of usable land cover types within each species' home range. We found that stress-induced levels, but not baseline, positively correlated with per cent usable land cover both within and across species. Our results indicate that GC concentrations may be a useful biomarker for characterizing populations across a range of habitat availability, and we advocate for more physiological studies on non-traditional species in less studied populations to build on this framework. This article is part of the theme issue 'Endocrine responses to environmental variation: conceptual approaches and recent developments'.

Halotolerant and plant growth-promoting endophytic fungus Aspergillus terreus CR7 alleviates salt stress and exhibits genoprotective effect in Vigna radiata

Soil salinity is one of the major environmental stresses that results in reduction of cultivable land and decreased productivity. In the present study, halotolerant and plant growth-promoting endophytic fungi were isolated from Catharanthus roseus, and their effect in mitigating salt stress in Vigna radiata was evaluated. An isolate CR7, identified to be Aspergillus terreus, showing plant growth promotion activities, viz. IAA production (23.43 ± 0.79 μg/ml), phosphate solubilization (133.63 ± 6.40 μg/ml), ACC deaminase activity (86.36 ± 2.70 μmol α-ketobutyrate/h/mg protein) etc. and ability to grow at 15% NaCl was selected for further in vivo studies. Colonization of CR7 was carried out in V. radiata which was subjected to different concentrations of salt (150, 200, and 250 mM NaCl). Under salt stress, A. terreus CR7 inoculated plants showed substantially improved root and shoot length, biomass, chlorophyll content, relative water content, phenolics, protein content, and DPPH scavenging activity. Endogenous IAA level was enhanced by 5.28-fold in treated plants at maximum salt stress. Inoculation of A. terreus CR7 affected oxidative stress parameters, exhibiting an increase in catalase and superoxide dismutase and reduction in proline, electrolyte leakage, and malondialdehyde content. Fluorescent microscopic analysis of roots revealed improved cell viability and decreased levels of glutathione and hydrogen peroxide under salt stress in treated plants. The isolate A. terreus CR7 also protected against DNA damage induced by salt stress which was evaluated using comet assay. A decrease in DNA tail length, tail moment, and olive tail moment to the extent of 19.87%, 19.76%, and 24.81%, respectively, was observed in A. terreus CR7-colonized plants under salt stress. It can be concluded that A. terreus CR7 can be exploited for alleviating the impact of salt stress in crop plants.

Deciphering the mandibular shape variation in a group of Malagasy primates using Fourier outline analysis

OBJECTIVES

Among living Malagasy primates, the family Lemuridae has previously been recognized as presenting a higher mandibular morphological variation than other families. We conducted a quantitative analysis of mandibular size and shape within the five genera (Lemur, Eulemur, Hapalemur, Prolemur, and Varecia) associated with a set of covariables that could explain this variation.

MATERIALS AND METHODS

We used Fourier outline analysis on the left hemimandible of 182 specimens covering the Lemuridae family. The influence of the phylogeny but also seven covariables (genus, diet, sex, sexual behavior, mating system, ecoregion, and forest type) on mandibular variation was examined using multivariate statistics and model selection.

RESULTS

Our results indicate that the high level of morphological variation within the family, associated with a phylogenetic effect and differences in diet, is due to a strong distinction between the genera Prolemur and Hapalemur and the other genera of the family. A second analysis, correcting this strong effect, indicates that mandibular shape variation is influenced not only by the phylogeny and the diet but by a combination of all the covariables.

DISCUSSION

The analysis of morphological variation is a powerful tool with major applications, both for the estimation of biological diversity and for the understanding of the fundamental parameters of species' ecology. Our work indicates that, if mandibular shape variation is mainly driven by dietary adaptation, other variables describing ecology and habitat should be considered and taken into account for an integrative understanding of species resources and the establishment of conservation measures.

A meta-analysis of human disturbance effects on glucocorticoid hormones in free-ranging wild vertebrates

Free-ranging wild vertebrates need to cope with natural and anthropogenic stressors that cause short and/or long-term behavioural and physiological responses. In areas of high human disturbance, the use of glucocorticoid (GC) hormones as biomarkers to measure stress responses is an increasingly common tool for understanding how animals cope with human disturbance. We conducted a meta-analysis to investigate how human disturbances such as habitat conversion, habitat degradation, and ecotourism influence baseline GC hormones of free-ranging wild vertebrates, and we further test the role of protected areas in reducing the impact of such disturbances on these hormones. A total of 58 studies met the inclusion criteria, providing 152 data points for comparing levels of GC hormones under disturbed and undisturbed conditions. The overall effect size suggests that human disturbance does not cause a consistent increase in levels of GC hormones (Hedges' g = 0.307, 95% CI = -0.062 to 0.677). However, when the data were analysed by disturbance type, living in unprotected areas or in areas with habitat conversion were found to increase GC hormone levels compared to living in protected or undisturbed areas. By contrast, we found no evidence that ecotourism or habitat degradation generates a consistent increase in baseline GC hormone levels. Among taxonomic groups, mammals appeared more sensitive to human disturbance than birds. We advocate the use of GC hormones for inferring major human-caused contributors to the stress levels of free-ranging wild vertebrates - although such information needs to be combined with other measures of stress and interpreted in the context of an organism's life history, behaviour, and history of interactions with human disturbance.

Animal-friendly behavioral testing in field studies: examples from ground squirrels

Field studies of behavior provide insight into the expression of behavior in its natural ecological context and can serve as an important complement to behavioral studies conducted in the lab under controlled conditions. In addition to naturalistic observations, behavioral testing can be an important component of field studies of behavior. This mini review evaluates a sample of behavioral testing methods in field studies to identify ways in which behavioral testing can be animal-friendly and generate ethologically relevant data. Specific examples, primarily from studies of ground squirrels, are presented to illustrate ways in which principles of animal-friendly behavioral testing can be applied to and guide testing methods. Tests conducted with animals in their natural habitat and that elicit naturally occurring behavioral responses can minimize stress and disturbance for animals, as well as disruption of the larger ecosystem, and can have high ethological validity. When animals are trapped or handled as part of a study, behavioral testing can be incorporated into handling procedures to reduce overall disturbance. When behavior is evaluated in a testing arena, the arena can be designed to resemble natural conditions to increase the ethological relevance of the test. Efforts to minimize time spent in testing arenas can also reduce disturbance to animals. Adapting a behavioral test to a species or habitat conditions can facilitate reduced disruption to subjects and increased ethological relevance of the test.

Environmental Stress and the Primate Microbiome: Glucocorticoids Contribute to Structure Gut Bacterial Communities of Black Howler Monkeys in Anthropogenically Disturbed Forest Fragments

Animals living in anthropogenically disturbed habitats are exposed to environmental stressors which can trigger physiological reactions, such as chronic elevations of glucocorticoid hormones. Physiological responses to stressors may induce changes in the gut microbiome, most likely, facilitated by the gut–brain communication. Although these effects have been observed in humans and animal models, elucidating gut bacterial changes in wild animals under natural stressful conditions is still an ongoing task. Here we analyzed the association between physiological stress related to anthropogenic forest disturbance and changes in gut bacterial communities of black howler monkeys (Alouatta pigra) living in forest fragments in Mexico. We measured individuals’ fecal glucocorticoid metabolites (fGCMs) as an index of physiological stress and created inventories of fecal bacterial communities sequencing the 16S rRNA gene to assess gut microbiome change. We evaluated environmental stress by estimating differences in food availability – feeding tree diversity and biomass – in each group’s habitat. We found that both fGCMs and food availability indices were related to gut bacterial community shifts in black howler monkeys. Furthermore, using structural equation modeling, we found that a decrease in food availability, estimated through reductions in feeding tree basal area, increased fGCMs, which in turn induced increases in bacterial richness. Our findings show that the activation of the hypothalamic–pituitary–adrenal (HPA)-axis, which is a physiological response sensitive to environmental stressors such as the ecological disturbance of a habitat, contributes to structure the gut microbiome of arboreal primates in disturbed forests.

Seasonal drivers of faecal glucocorticoid metabolite concentrations in an African strepsirrhine primate, the thick-tailed greater galago (Otolemur crassicaudatus)

As global non-human primate populations show dramatic declines due to climate change, land transformation and other anthropogenic stressors, it has become imperative to study physiological responses to environmental change in order to understand primate adaptability and enhance species conservation strategies. We examined the effects of seasonality on faecal glucocorticoid metabolite (fGCM) concentrations of free-ranging male and female thick-tailed greater galagos (Otolemur crassicaudatus) in an Afromontane habitat. To do so, we established an enzyme immunoassay (EIA) for monitoring fGCM concentrations in the species using a biological validation. Following this, faecal samples were collected each month over the course of a year from free-ranging males and females situated in the Soutpansberg Mountains, Limpopo, South Africa. Multivariate analyses revealed lactation period was a driver of fGCM levels, whereas sex and food availability mostly influenced seasonal fGCM concentrations in the total population. Thus far, the results of this study show that drivers of fGCM levels, an indication of increased adrenocortical activity, in O. crassicaudatus are numerous and complex within the natural environment. The species may be adapted to such conditions and an extreme change to any one component may result in elevated fGCM levels. This increases our understanding of strepsirrhine primate physiology and offers initial insights into species adaptability to a challenging environment.

Maternal stress effects on infant development in wild Verreaux's sifaka (Propithecus verreauxi)

Abstract

Maternal effects mediated by nutrients or specific endocrine states of the mother can affect infant development. Specifically, pre- and postnatal maternal stress associated with elevated glucocorticoid (GC) output is known to influence the phenotype of the offspring, including their physical and behavioral development. These developmental processes, however, remain relatively poorly studied in wild vertebrates, including primates with their relatively slow life histories. Here, we investigated the effects of maternal stress, assessed by fecal glucocorticoid output, on infant development in wild Verreaux’s sifakas (Propithecus verreauxi), a group-living Malagasy primate. In a first step, we investigated factors predicting maternal fecal glucocorticoid metabolite (fGCM) concentrations, how they impact infants’ physical and behavioral development during the first 6 months of postnatal life as well as early survival during the first 1.5 years of postnatal life. We collected fecal samples of mothers for hormone assays and behavioral data of 12 infants from two birth cohorts, for which we also assessed growth rates. Maternal fGCM concentrations were higher during the late prenatal but lower during the postnatal period compared to the early/mid prenatal period and were higher during periods of low rainfall. Infants of mothers with higher prenatal fGCM concentrations exhibited faster growth rates and were more explorative in terms of independent foraging and play. Infants of mothers with high pre- and postnatal fGCM concentrations were carried less and spent more time in nipple contact. Time mothers spent carrying infants predicted infant survival: infants that were more carried had lower survival, suggesting that they were likely in poorer condition and had to be cared for longer. Thus, the physical and behavioral development of these young primates were impacted by variation in maternal fGCM concentrations during the first 6 months of their lives, presumably as an adaptive response to living in a highly seasonal, but unpredictable environment.

Significance statement

The early development of infants can be impacted by variation in maternal condition. These maternal effects can be mediated by maternal stress (glucocorticoid hormones) and are known to have downstream consequences for behavior, physiology, survival, and reproductive success well into adulthood. However, the direction of the effects of maternal physiological GC output on offspring development is highly variable, even within the same species. We contribute comparative data on maternal stress effects on infant development in a Critically Endangered primate from Madagascar. We describe variation in maternal glucocorticoid output as a function of ecological and reproductive factors and show that patterns of infant growth, behavioral development, and early survival are predicted by maternal glucocorticoids. Our study demonstrates how mothers can influence offspring fitness in response to challenging environmental conditions.

Efficacy of rhizobacteria for degradation of profenofos and improvement in tomato growth

Pesticides are widely used for managing pathogens and pests for sustainable agricultural output to feed around seven billion people worldwide. After their targeted role, residues of these compounds may build up and persist in soils and in the food chain. This study evaluated the efficiency of bacterial strains capable of plant growth promotion and biodegradation of profenofos. To execute this, bacteria were isolated from an agricultural area with a history of repeated application of profenofos. The profenofos degrading bacterial strains with growth-promoting characteristics were identified based on biochemical and molecular approaches through partial 16S ribosomal rRNA gene sequencing. The results revealed that one strain, Enterobacter cloacae MUG75, degraded over 90% profenofos after 9 days of incubation. Similarly, plant growth was significantly increased in plants grown in profenofos (100 mg L^-1) contaminated soil inoculated with the same strain. The study demonstrated that inoculation of profenofos degrading bacterial strains increased plant growth and profenofos degradation. Novelty statementPesticides are extensively applied in the agriculture sector to overcome pest attacks and to increase food production to fulfill the needs of the growing world population. Residues of these pesticides can persist in the environment for long periods, may enter the groundwater reservoirs and cause harmful effects on living systems highlighting the need for bioremediation of pesticide-contaminated environments. Microbes can use pesticides as a source of carbon and energy and convert them into less toxic and non-toxic products. Application of profenofos degrading rhizobacteria in interaction with the plants in the rhizosphere can remediate the pesticide-contaminated soils and minimize their uptake into the food chain. Hence, this approach can improve soil health and food quality without compromising the environment.

Risk awareness of black-and-gold howler monkeys living in an urban environment in south-west Paraguay

As urbanisation increases, wild primates are exposed to urban environments which come with a distinct and often novel set of risks. Urban habitats can form a matrix of forest fragments and anthropogenic structures, including buildings, electric cables and roads, which can limit movement and force species to live in hazardous areas. We studied five groups of urban black and gold howler monkey (Alouatta caraya) in Pilar, Paraguay, to investigate whether the monkeys are aware of anthropogenic risks based on their patterns of self-scratching behaviour, an indicator of stress, and how they used the space available to them. Using a Risk Index created for the study, we ranked the level of risk attributed to different zones of their home range, awarding each zone with a hazard score. Using Quantum GIS and kernel density estimation, we determined the relationship between habitat use and hazard score. Using a Spearman’s rank correlation, we found nonsignificant relationships between the hazard score and self-scratching behaviour for four groups, suggesting a lack of awareness. However, there was a significant negative relationship between the hazard score and home range use for four groups, indicating that they spent more time in areas with lower levels of anthropogenic risk.

Life on the edge: behavioural and physiological responses of Verreaux's sifakas (Propithecus verreauxi) to forest edges

Forest edges change micro-environmental conditions, thereby affecting the ecology of many forest-dwelling species. Understanding such edge effects is particularly important for Malagasy primates because many of them live in highly fragmented forests today. The aim of our study was to assess the influence of forest edge effects on activity budgets, feeding ecology, and stress hormone output (measured as faecal glucocorticoid metabolite - fGCM - levels) in wild Verreaux's sifakas (Propithecus verreauxi), a group living, arboreal lemur. We observed five habituated groups: three living in the forest interior and two at an established forest edge. There was no difference in average daily temperatures between edge and interior habitats; however, within the edge site, the average daily temperature incrementally increased over 450 m from the forest edge towards the interior forest of the edge habitat, and the population density was lower at the edge site. Activity budgets differed between groups living in the two microhabitats, with individuals living near the edge spending more time travelling and less time feeding. Groups living near the edge also tended to have smaller home ranges and core areas than groups in the forest interior. In addition, edge groups had elevated average fGCM concentrations, and birth rates were lower for females living in the edge habitat. Combined with lower levels of fruit consumption at the edge, these results suggest that nutritional stress might be a limiting factor for Verreaux's sifakas when living near a forest edge. Hence, Verreaux's sifakas appear to be sensitive to microhabitat characteristics linked to forest edges; a result with implications for the conservation of this critically endangered lemurid species.

A meta-analysis of anthropogenic impacts on physiological stress in wild primates

As humanity continues to alter the environment extensively, comprehending the effect of anthropogenic disturbances on the health, survival, and fitness of wildlife is a crucial question for conservation science. Many primate populations occupy suboptimal habitats prone to diverse anthropogenic disturbances that may be sources of acute and chronic stress. Quantification of glucocorticoid (GC) concentrations has repeatedly been used to explore the impact of disturbances on physiological stress. Although it is still debated, prolonged elevation of GC levels may impair reproduction, growth, and immune system activity of individuals. We quantified the effect of anthropogenic disturbances on physiological stress in primates with a global meta-analysis based on data from 26 articles, covering 24 distinct species in 13 different countries. Anthropogenic disturbances were classified into 6 distinct categories: habitat loss, habitat degradation, ongoing logging, hunting, tourism, and other human activities. We calculated effect sizes (Hedges' g) with the standardized mean difference in GC concentrations between primates affected by human activity and their undisturbed conspecifics. We ran random-effects models and subgroup analyses to estimate the overall effect as well as a cumulative effect size for each disturbance category. Overall, primates inhabiting sites subject to anthropogenic disturbances exhibited significantly higher GC levels (g = 0.60; 95% CI: 0.28-0.93). Habitat loss and hunting were overall associated with increased GC concentrations, whereas the cumulative effects of the other disturbances were not statistically significant. Biologically, high GC levels may increase fitness by enabling individuals to overcome the challenges linked to anthropogenic disturbances. However, primates in disturbed environments may have sustained elevated GC levels. To strengthen future research, it is necessary to control confounding factors systematically (e.g., diet, reproductive status, predatory pressure, and resource availability) and improve understanding of the link between GC levels and the health, fitness, and survival of animals.

Influence of cereal harvest on adrenocortical activity in European hares (Lepus europaeus)

Anthropogenic disturbances, such as habitat modifications and machines, are associated with increased levels of faecal glucocorticoid metabolites (fGCMs) in mammals, an indicator of a stress response. One human-caused process provoking incisive habitat alterations is harvesting arable crops. We investigated the effect of cereal harvest on fGCM concentrations in European hares (Lepus europaeus) in arable landscapes in lower Austria during the year 2018 by collecting 591 faecal samples before, during and after cereal harvest. fGCMs were analysed using an enzyme immunoassay, and data were analysed using linear mixed-effects models. We found that neither cereal harvest nor farming practice (organic vs. conventional) caused an overall increase in the hares’ stress level. Lower vegetation density and higher proportions of bare ground were negatively correlated with fGCM concentrations, whereas the proportion of stubble fields was significantly positively correlated with fGCM concentrations in European hares. A change to more open landscapes might decrease time spent avoiding predation, and fallen grains may provide a beneficial additional food source for the hares. This indicates that European hares are well adapted to an opening up of the landscape and short-term disturbances such as cereal harvesting. In conclusion, cereal harvest had no large impact on European hares’ adrenocortical activity in an arable landscape with small average field size and enough available non-farmed areas.

Comparison of the Glucocorticoid Concentrations between Three Species of Lemuridae Kept in a Temporary Housing Facility

We compared the glucocorticoid concentrations in response to various types of potential stressors present during standard operation of a temporary housing facility between three species, namely, ring-tailed lemurs, collared brown lemurs and white-headed lemurs. The levels of faecal glucocorticoid metabolites (FGMs) were measured non-invasively on a daily basis during a 30-day period. A total of 510 faecal samples were collected. Concentrations of immunoreactive glucocorticoid hormone metabolites were measured in the obtained extracts by using an enzyme immunoassay. The polyclonal antibodies used in this assay were directed against the metabolite 11-oxo-etiocholanolone I. We found all three monitored lemur species to respond to specific potentially stressful situations by increasing (p < 0.05) the FGM levels within one to two days after the event. Although housed in the same room, differences in response to potentially stressful situations were found in white-headed lemurs compared to ring-tailed lemurs. Increased mean levels of the FGMs were found more frequently in white-headed lemurs than in ring-tailed lemurs. The results suggest that this species may be more sensitive to changes in its surroundings. In general, the levels of the FGMs showed a similar pattern during 30 days of monitoring suggesting that all groups of lemurs responded in a similar manner to the same events. However, we recorded the differences in the absolute values of glucocorticoid concentrations between the monitored species likely due to the differences in sex ratios in the groups and presence of lactating females in the ring-tailed lemurs.

Realized distribution patterns of crowned lemurs (Eulemur coronatus) within a human-dominated forest fragment in northern Madagascar

Due to the impact of anthropogenic activities on forest extent and integrity across Madagascar, it is increasingly necessary to assess how endangered lemur populations inhabiting human-dominated forest fragments can effectively sustain themselves ecologically. Our research addresses this concern by exploring how the distribution patterns of a small population of crowned lemurs (Eulemur coronatus), occupying a degraded forest fragment at Oronjia Forest New Protected Area in northern Madagascar, are impacted by the availability of key ecological and anthropogenic factors. We hypothesize that the distribution of E. coronatus within the fragment is limited by the availability of critical ecological resources and conditions and the intensity of anthropogenic features and activities. To examine this, we used MaxEnt to develop a species distribution model using presence-only occurrence records and 10 independent background covariates detailing the site's ecological and anthropogenic aspects. The results indicate that the realized distribution patterns of E. coronatus within human-dominated forest fragments are strongly associated with sections of forest that contain sparsely and sporadically distributed resources, such as freshwater and continuous hardwood vegetation. We conclude that the distribution of E. coronatus at Oronjia is shaped by their need to maximize foraging opportunities in a degraded forest landscape where they are subject to both environmental and anthropogenic stressors.

Individual behavioral differences and health of golden-headed lion tamarins (Leontopithecus chrysomelas)

Individual behavioral differences may influence how animals cope with altered environments. Depending on their behavioral traits, individuals may thus vary in how their health is affected by environmental conditions. We investigated the relationship between individual behavior of free-living golden-headed lion tamarins (Leontopithecus chrysomelas) responding to a novel object (to assess exploration-avoidance), and their habitat use and health status (endoparasitism; clinical measures: biometric data, heart rate, respiratory frequency, and temperature; fecal glucocorticoid metabolites). As parasite transmission can be affected by individual variation in social contact and social grooming, we also evaluated whether more sociable individuals show higher endoparasite loads compared with less sociable animals. Four groups living in landscapes with different levels of human disturbance were investigated: two in degraded forest fragments in an agricultural matrix (DFAM-higher disturbance), and two in a cocoa agroforestry system (cabruca-lower disturbance) in the Atlantic forest of South Bahia, Brazil. Using a subjective ratings approach, highly correlated adjective descriptors were combined to produce z-score ratings of one derived variable ("confidence"), which was selected to characterize the tamarins' exploration/avoidance responses during a novel object test. The higher the confidence score, the longer female tamarins spent foraging for prey independent of landscape, and the greater their body mass independent of sex and landscape. Only DFAM individuals showed intestinal parasite infection. Endoparasite loads were positively correlated with the number of grooming partners, suggesting an association between social grooming and transmission (more groomers = more endoparasites). Individual behavior, including in a test situation, may thus have some predictive value for behavior in a free-living context, and for its health consequences.

Life in a fragment: Evolution of foraging strategies of translocated collared brown lemurs, Eulemur collaris, over an 18-year period

While the drivers of primate persistence in forest fragments have been often considered at the population level, the strategies to persist in these habitats have been little investigated at the individual or group level. Considering the rapid variation of fragment characteristics over time, longitudinal data on primates living in fragmented habitats are necessary to understand the key elements for their persistence. Since translocated animals have to cope with unfamiliar areas and face unknown fluctuations in food abundance, they offer the opportunity to study the factors contributing to successful migration between fragments. Here, we illustrated the evolution of the foraging strategies of translocated collared brown lemurs (Eulemur collaris) over an 18-year period in the Mandena Conservation Zone, south-east Madagascar. Our aim was to explore the ability of these frugivorous lemurs to adjust to recently colonized fragmented forests. Although the lemurs remained mainly frugivorous throughout the study period, over the years we identified a reduction in the consumption of leaves and exotic/pioneer plant species. These adjustments were expected in frugivorous primates living in a degraded area, but we hypothesize that they may also reflect the initial need to cope with an unfamiliar environment after the translocation. Since fragmentation is often associated with the loss of large trees and native vegetation, we suggest that the availability of exotic and/or pioneer plant species can provide an easy-to-access, nonseasonal food resource and be a key factor for persistence during the initial stage of the recolonization.

Do functional traits offset the effects of fragmentation? The case of large-bodied diurnal lemur species

Primates worldwide are faced with increasing threats making them more vulnerable to extinction. Anthropogenic disturbances, such as habitat degradation and fragmentation, are among the main concerns, and in Madagascar, these issues have become widespread. As this situation continues to worsen, we sought to understand how fragmentation affects primate distribution throughout the island. Further, because species may exhibit different sensitivity to fragmentation, we also aimed to estimate the role of functional traits in mitigating their response. We collated data from 32 large-bodied lemur species ranges, consisting of species from the families Lemuridae (five genera) and Indriidae (two genera). We fitted Generalized Linear Models to determine the role of habitat fragmentation characteristics, for example, forest cover, patch size, edge density, and landscape configuration, as well as the protected area (PA) network, on the species relative probability of presence. We then assessed how the influence of functional traits (dietary guild, home range size) mitigate the response of species to these habitat metrics. Habitat area had a strong positive effect for many species, and there were significantly negative effects of fragmentation on the distribution of many lemur species. In addition, there was a positive influence of PAs on many lemur species' distribution. Functional trait classifications showed that lemurs of all dietary guilds are negatively affected by fragmentation; however, folivore-frugivores show greater flexibility/variability in terms of habitat area and landscape complexity compared to nearly exclusive folivores and frugivores. Furthermore, species of all home range sizes showed a negative response to fragmentation, while habitat area had an increasingly positive effect as home range increased in size. Overall, the general trends for the majority of lemur species are dire and point to the need for immediate actions on a multitude of fronts, most importantly landscape-level reforestation efforts.

Lactating Coquerel's sifaka (Propithecus coquereli) exhibit reduced stress responses in comparison to males and nonlactating females

Cortisol is a glucocorticoid hormone that plays a principal role in metabolic function and stress responses in wild primates. Stressors are ubiquitous in environments and elicit a variety of physiological and behavioral responses. While stress responses are adaptive in the short-term, they can have negative effects when experienced over longer durations. As a physiological stressor, the process of lactation is an energetically expensive activity for mammals. Milk production increases water loss and increased hydration demands are amplified in mammalian species inhabiting xeric habitats, including lemur species living in northwestern Madagascar-the region for this research work. Here, sifakas give birth during the dry season (May-October) and wean infants during the subsequent wet season (November-April). The author collected fecal samples during the 24 weeks following infant births in 10 groups of Coquerel's sifaka in Ankarafantsika Park, Madagascar. The author analyzed the samples by comparing the first 12-week time block to the second 12-week time block, which corresponded to the dry and the beginning of the wet seasons, respectively. Analyses were based on 375 samples collected over two birth seasons (2010 and 2011). A linear mixed model determined the relationships between reproductive class and temporal cortisol variation. The three reproductive classes had significantly different cortisol concentrations. Lactating females had lower cortisol than adult males and nonlactating females in all weeks postnatal. Males had significantly higher cortisol in weeks 13-24 relative to weeks 1-12. Examining seasonal changes in cortisol concentrations demonstrates how lemurs respond physiologically to the energetic constraints of lactation during the critical life history stage of infant development.

Lemur catta in small forest fragments: Which variables best predict population viability?

Habitat fragmentation is an increasingly serious issue affecting primates in most regions where they are found today. Populations of Lemur catta (ring-tailed lemur) in Madagascar's south-central region are increasingly restricted to small, isolated forest fragments, surrounded by grasslands or small-scale agriculture. Our aim was to evaluate the potential for population viability of L. catta in nine forest fragments of varying sizes (2-46 ha, population range: 6-210 animals) in south-central Madagascar, using a set of comparative, quantitative ecological measures. We used Poisson regression models with a log link function to examine the effects of fragment size, within-fragment food availability, and abundance of matrix resources (food and water sources) on L. catta population sizes and juvenile recruitment. We found a strong association between overall population size and (a) fragment size and (b) abundance of key food resources Melia azedarach and Ficus spp. (per 100 m along transect lines). Juvenile recruitment was also associated with fragment size and abundance of the two above-mentioned food resources. When the largest population, an outlier, was removed from the analysis, again, the model containing fragment size and abundance of M. azedarach and Ficus spp. was the best fitting, but the model that best predicted juvenile recruitment contained only fragment size. While our results are useful for predicting population presence and possible persistence in these fragments, both the potential for male dispersal and the extent of human disturbance within most fragments play crucial roles regarding the likelihood of long-term L. catta survival. While seven of the nine fragments were reasonably protected from human disturbance, only three offered the strong potential for male dispersal, thus the long-term viability of many of these populations is highly uncertain.

Trends in forest fragment research in Madagascar: Documented responses by lemurs and other taxa

The rise in research investigating fragmentation and its impact on primates and other taxa reflects the growing presence of fragmented landscapes themselves. Although numerous studies report the negative effects of fragmentation on biodiversity, it is difficult to generalize responses to fragmentation for specific taxonomic groups, such as non-human primates, when studies have not employed a definitive concept of fragmentation or fragments themselves. Madagascar's high degree of fragmentation, wealth of endemic taxa, and extensive history of ecological research provide the opportunity to compare fragmentation studies across similar contexts. We conducted a literature search of peer-reviewed articles on fragmentation in Madagascar to characterize its trends. A total of 70 articles, 46 of which concentrated on lemurs, tested the impacts of fragmentation on Malagasy taxa, while additional sources conducted research in one or more fragments without testing its effects (n = 112 total, 79 on lemurs). Studies on lemurs most frequently tested fragmentation's impacts on genetics and biodiversity metrics (n = 16 and 15 studies, respectively), although health, modeling, behavioral, and cross-disciplinary techniques were also reported. Responses to fragmentation were reported for 49 lemur species, with most studies concentrated in eastern Madagascar (87%). Although there was variation in the metrics reported in studies testing the effects of fragmentation on Malagasy species, the most common measures were fragment area, isolation, or comparison to a control site. Landscape-scale approaches and examination of fragmentation per se were rarely employed. Characterizing trends of fragmentation research in Madagascar emphasizes the challenges of documenting fragmentation's effects while highlighting the benefits of research within fragmented landscapes, particularly when combined with consideration for how the matrix within human-modified landscapes may impact primate populations.

Faecal glucocorticoid metabolite profiles in diademed sifakas increase during seasonal fruit scarcity with interactive effects of age/sex class and habitat degradation

Glucocorticoids are metabolic byproducts of animals' physiological responses to ecological or social challenges and are thought to represent an adaptive response allowing beneficial responses to short-term challenges. Glucocorticoid metabolites (GCs) can be assayed non-invasively through faeces and therefore can be a useful tool to gauge the health of populations experiencing natural and/or anthropogenic stressors. However, the response of GCs to anthropogenic stressors varies, with both higher and lower GC levels reported. Here, we describe variation in GC secretion within eight diademed sifaka (Propithecus diadema) groups across 1 year. These groups span a gradient of anthropogenic habitat disturbance, including groups in continuous forest ('CONT') and disturbed fragments ('FRAG'), and indicators of health suggest that FRAG groups are negatively impacted by habitat disturbance. We monitored phenology, used focal animal follows to quantify diet and collected faeces (n = 547) from which we quantified GC content using enzyme immunoassay. All groups showed elevated lean-season GCs, but with a single, brief peak. GCs were inversely correlated with feeding time. No overall effect of habitat (CONT vs. FRAG) was found, but the lean-season peak was significantly higher in CONT groups. There was a significant season*age-sex interaction; adult females had an attenuated lean-season response compared with groupmates. The observed lean-season 'challenge' is consistent with previous lemur studies, as well as mammals in general. Low and largely invariable GC levels in FRAG, within the context of observed health and nutritional declines, suggest that FRAG groups employ a strategy whereby the adrenal response to stressors is downregulated. More research is needed to contextualize our observations of GC variation and health on an individual level, both in terms of corroborating evidence for ecological and social stressors, and longer-term quantification of reproductive success and fitness.

Pesticide-induced oxidative stress and antioxidant responses in tomato (Solanum lycopersicum) seedlings

Excessive use of pesticides can adversely affect the growth of non-target host plants in different ways. Pesticide-induced stress can affect non-target plants through elevated levels of reactive oxygen species (ROS) responsible for detrimental effects on cell metabolism, biochemical and other physiological activities. In response to oxidative stress, plant activates antioxidant defense system consisting of both enzymatic and non-enzymatic components. In the present investigation, three commonly used pesticides, emamectin benzoate, alpha-cypermethrin and imidacloprid, were assessed for causing oxidative stress in tomato. The oxidative damage induced by these pesticides at five different concentrations i.e. 1/4X, 1/2X, recommended application dose (X), 2X and 4X in the root and shoot tissues of tomato plant/seedlings were evaluated. Following pesticide exposure for 35 days, cell viability, cell injury, total soluble sugar (TSS) and total soluble proteins (TSP) were measured. Antioxidant activities were estimated by measuring activity levels of superoxide dismutase (SOD), catalase (CAT), glutathione reductase (GR) peroxidase (POD), ascorbate peroxidase (APX) and proline. Hydrogen peroxide (H₂O₂) levels were analysed as ROS, lipid peroxidation was measured in term of thiobarbituric acid reactive substances (TBARS) as membrane damage caused by ROS was also assessed. Analysis of the data revealed that pesticides application at higher concentrations significantly elevated ROS levels and caused membrane damage by the formation of TBARS, increased cell injury and reduced cell viability both in root and shoot tissues compared with non-treated plants. Moreover, a gradual decrease in the levels of TSS and TSP was observed in plants subjected to increasing doses of pesticides. To cope with pesticide-induced oxidative stress, a significant increase in levels of antioxidants was observed in the plants exposed to higher doses of pesticides. Shoot tissues responded more drastically by producing higher levels of antioxidants as compared to root tissues indicating the direct exposure of shoots to foliar application of pesticides. Taken together, these results strongly suggested that the application of pesticides above the recommended dose can provoke the state of oxidative stress and can cause oxidative damages in non-target host plants.

Characterization of seasonal reproductive and stress steroid hormones in wild Radiated Tortoises, Astrochelys radiata

The critically endangered Radiated Tortoise (Astrochelys radiata) is endemic to the southern coastlines of Madagascar. Once common, wild populations of this tortoise have undergone dramatic declines in recent years. Although there have been studies documenting reproductive activities, reproductive physiological parameters are unknown yet may be crucial in the recovery of the species. Over four research seasons in remote field locations native to A. radiata, we surveyed for, radio-tracked, and sampled wild, free ranging tortoises. We sampled and measured stress and reproductive parameters (corticosterone [CORT], testosterone [T], estradiol-17β [E2], and progesterone [P]) in 311 plasma samples from 203 wild A. radiata, capturing their active period. Generally, hormone concentrations were associated with body condition, temperature, and humidity. There was wide variation in CORT that varied monthly and by group. Juvenile tortoises maintained more than twice the mean basal CORT concentrations than either adult sex, with the most dramatic distinctions in the middle of the wet season. For adult sex hormones, the last months of the dry season and into the wet season when ground humidities are low and just begin to rise prior to temperature declines, male T concentrations gradually increased to a peak before returning to near undetectable values into the dry season. We had limited data for T concentrations in females, but found average T concentrations were much lower than in males and positively correlated with larger female home range sizes. For female hormone cycles, E2 also peaked in the early 1/3 of the wet season along with male T, and was followed by an uptick in P which correlates to the putative ovulatory cycle. Females tracked over four years showed variation in patterns of P, indicating that number and frequency of clutches vary. Our results suggest that 1) there is high species plasticity in response to stress; 2) A. radiata reproductive cycling is somewhat dissociated with courtship timing and is instead triggered by environmental cues; and 3) individual female reproductive output is irregular. This study is oone of the first to document and describe multi-year seasonal stress and reproductive hormones in a free-ranging Malagasy chelonian. These data may be used to identify key high-production habitats for conservation, and aide in captive management and reproduction in assurance colonies for species health and survival.

Black-and-white snub-nosed monkey (Rhinopithecus bieti) feeding behavior in a degraded forest fragment: clues to a stressed population

Rapid global deforestation has forced many of the world's primates to live in fragmented habitats, making the understanding of their behavioral responses to degraded and fragmented habitats a key challenge for their future protection and management. The black-and-white snub-nosed monkey (Rhinopithecus bieti) is an endangered species endemic to southwest China. The forest habitat ranges from near-continuous to fragmented. In this study, we investigated the activity budget and diet of a R. bieti population that live in an isolated and degraded habitat patch at Mt. Lasha in Yunnan Province, near the current southern limit of the species. We used our data along with data from six other sites in more-continuous habitats across its range to model factors that predict stress, including feeding effort and time feeding on lichens against potential predictive parameters. Models showed feeding effort across all sites increased with increasing altitude and latitude, and with decreasing food species diversity. There was also a strong positive relationship between feeding effort and time feeding lichens. The Mt. Lasha R. bieti population exploited a total of 36 food species, spending 80.2% of feeding time feeding on lichens, Bryoria spp. and Usnea longissima. These figures are more comparable to those living in the north than those living in the mid- and southern part of the species' range. Given the models for feeding effort and time feeding on lichens, the unexpectedly high time spend feeding on lichens and feeding effort relative to latitude and elevation are suggestive of a stressed population at Mt. Lasha.

Expanding the actions of cortisol and corticosterone in wild vertebrates: A necessary step to overcome the emerging challenges

We conducted a review of scientific articles published between 2000 and 2014 and evaluated how frequently various aspects of cortisol and corticosterone (CORT) actions have been considered in studies on wild vertebrates. Results show that (1) the notion that CORT are stress-responsive hormones is central in our theoretical frameworks and it is reflected by the fact that several articles refer to CORT as "stress hormones". (2) The large majority of studies do not contemplate the possibility of decrease and no change in CORT levels in response to chronic stressors. (3) Our ideas about CORT actions on energy balance are slanted towards the mobilization of energy, though there are several studies considering -and empirically addressing- CORT's orexigenic actions, particularly in birds. (4) The roles of CORT in mineral-water balance, though widely documented in the biomedical area, are virtually ignored in the literature about wild vertebrates, with the exception of studies in fish. (5) Adrenocorticotropic hormone (ACTH) independent regulation of CORT secretion is also very scarcely considered. (6) The preparative, permissive, suppressive and stimulatory actions of CORT, as described by Sapolsky et al. (2000), are not currently considered by the large majority of authors. We include an extension of the Preparative Hypothesis, proposing that the priming effects of baseline and stress-induced CORT levels increase the threshold of severity necessary for subsequent stimuli to become stressors. Studies on animal ecology and conservation require integration with novel aspects of CORT actions and perspectives developed in other research areas.

The next step for stress research in primates: To identify relationships between glucocorticoid secretion and fitness

Glucocorticoids are hormones that mediate the energetic demands that accompany environmental challenges. It is therefore not surprising that these metabolic hormones have come to dominate endocrine research on the health and fitness of wild populations. Yet, several problems have been identified in the vertebrate research that also apply to the non-human primate research. First, glucocorticoids should not be used as a proxy for fitness (unless a link has previously been established between glucocorticoids and fitness for a particular population). Second, stress research in behavioral ecology has been overly focused on "chronic stress" despite little evidence that chronic stress hampers fitness in wild animals. Third, research effort has been disproportionately focused on the causes of glucocorticoid variation rather than the fitness consequences. With these problems in mind, we have three objectives for this review. We describe the conceptual framework behind the "stress concept", emphasizing that high glucocorticoids do not necessarily indicate a stress response, and that a stress response does not necessarily indicate an animal is in poor health. Then, we conduct a comprehensive review of all studies on "stress" in wild primates, including any study that examined environmental factors, the stress response, and/or fitness (or proxies for fitness). Remarkably, not a single primate study establishes a connection between all three. Finally, we provide several recommendations for future research in the field of primate behavioral endocrinology, primarily the need to move beyond identifying the factors that cause glucocorticoid secretion to additionally focus on the relationship between glucocorticoids and fitness. We believe that this is an important next step for research on stress physiology in primates.

The effect of habitat disturbance on the abundance of nocturnal lemur species on the Masoala Peninsula, northeastern Madagascar

Madagascar is one of the world's biodiversity hotspots. The island's past and current rates of deforestation and habitat disturbance threaten its plethora of endemic biodiversity. On Madagascar, tavy (slash and burn agriculture), land conversion for rice cultivation, illegal hardwood logging and bushmeat hunting are the major contributors to habitat disturbance. Understanding species-specific responses to habitat disturbance across different habitat types is crucial when designing conservation strategies. We surveyed three nocturnal lemur species in four forest types of varying habitat disturbance on the Masoala Peninsula, northeastern Madagascar. We present here updated abundance and density estimates for the Endangered Avahi mooreorum and Lepilemur scottorum, and Microcebus sp. Distance sampling surveys were conducted on 11 transects, covering a total of 33 km after repeated transect walks. We collected data on tree height, bole height, diameter at breast height, canopy cover and tree density using point-quarter sampling to characterise the four forest types (primary lowland, primary littoral, selectively logged and agricultural mosaic). Median encounter rates by forest type ranged from 1 to 1.5 individuals (ind.)/km (Microcebus sp.), 0-1 ind./km (A. mooreorum) and 0-1 ind./km (L. scottorum). Species density estimates were calculated at 232.31 ind./km² (Microcebus sp.) and 121.21 ind./km² (A. mooreorum), while no density estimate is provided for L. scottorum due to a small sample size. Microcebus sp. was most tolerant to habitat disturbance, exhibiting no significant effect of forest type on abundance. Its small body size, omnivorous diet and generalised locomotion appear to allow it to tolerate a variety of habitat disturbance. Both A. mooreorum and L. scottorum showed significant effects of forest type on their respective abundance. This study suggests that the specialist locomotion and diet of A. mooreorum and L. scottorum make them susceptible to the effects of increasing habitat disturbance.

Proximal and Distal Predictors of the Spider Monkey's Stress Levels in Fragmented Landscapes

The rapid loss, fragmentation and degradation of tropical forests threaten the survival of many animal species. However, the way in which these phenomena affect animal health has been poorly explored, thus limiting the design of appropriate conservation strategies. To address this, here we identified using linear mixed models the effect of proximal (diet, activity pattern, hunting and logging) and distal (sum of the basal areas of fruiting-tree species [SBAFS], landscape forest cover and degree of forest fragmentation) variables over fecal glucocorticoid metabolite (fGCM) levels-hormones associated with animal health and fitness-of six groups of spider monkeys (Ateles geoffroyi) inhabiting six landscapes with different spatial structures in Mexico. Proximal variables showed a stronger predictive power over fGCMs than distal. In this sense, increases in travel time, the occurrence of hunting, and reductions in rest time and fruit consumption resulted in higher fGCM levels. Regarding distal variables, increases in SBAFS were negatively related to fGCM levels, thus suggesting that food scarcity increases stress hormone levels. Nevertheless, contrary to theoretical expectations, spider monkeys living in smaller tracts of forest spent less time travelling, but the same time feeding on fruit as those in more forested areas. The lower net energy return associated with this combination of factors would explain why, contrary to theoretical expectations, increased forest cover was associated with increased levels of fGCMs in these groups. Our study shows that, at least in the short term, spider monkeys in fragmented landscapes do not always present higher levels of stress hormones compared to those inhabiting continuous forest, and the importance of preserving fruit sources and controlling hunting for reducing the levels of stress hormones in free ranging spider monkeys.

When can we measure stress noninvasively? Postdeposition effects on a fecal stress metric confound a multiregional assessment

Measurement of stress hormone metabolites in fecal samples has become a common method to assess physiological stress in wildlife populations. Glucocorticoid metabolite (GCM) measurements can be collected noninvasively, and studies relating this stress metric to anthropogenic disturbance are increasing. However, environmental characteristics (e.g., temperature) can alter measured GCM concentration when fecal samples cannot be collected immediately after defecation. This effect can confound efforts to separate environmental factors causing predeposition physiological stress in an individual from those acting on a fecal sample postdeposition. We used fecal samples from American pikas (Ochotona princeps) to examine the influence of environmental conditions on GCM concentration by (1) comparing GCM concentration measured in freshly collected control samples to those placed in natural habitats for timed exposure, and (2) relating GCM concentration in samples collected noninvasively throughout the western United States to local environmental characteristics measured before and after deposition. Our timed‐exposure trials clarified the spatial scale at which exposure to environmental factors postdeposition influences GCM concentration in pika feces. Also, fecal samples collected from occupied pika habitats throughout the species' range revealed significant relationships between GCM and metrics of climate during the postdeposition period (maximum temperature, minimum temperature, and precipitation during the month of sample collection). Conversely, we found no such relationships between GCM and metrics of climate during the predeposition period (prior to the month of sample collection). Together, these results indicate that noninvasive measurement of physiological stress in pikas across the western US may be confounded by climatic conditions in the postdeposition environment when samples cannot be collected immediately after defecation. Our results reiterate the importance of considering postdeposition environmental influences on this stress metric, especially in multiregional comparisons. However, measurements of fecal GCM concentration should prove useful for population monitoring within an eco‐region or when postdeposition exposure can be minimized.

Eco-evo-devo of the lemur syndrome: did adaptive behavioral plasticity get canalized in a large primate radiation?

BACKGROUND

Comprehensive explanations of behavioral adaptations rarely invoke all levels famously admonished by Niko Tinbergen. The role of developmental processes and plasticity, in particular, has often been neglected. In this paper, we combine ecological, physiological and developmental perspectives in developing a hypothesis to account for the evolution of 'the lemur syndrome', a combination of reduced sexual dimorphism, even adult sex ratios, female dominance and mild genital masculinization characterizing group-living species in two families of Malagasy primates.

RESULTS

We review the different components of the lemur syndrome and compare it with similar adaptations reported for other mammals. We find support for the assertion that the lemur syndrome represents a unique set of integrated behavioral, demographic and morphological traits. We combine existing hypotheses about underlying adaptive function and proximate causation by adding a potential developmental mechanism linking maternal stress and filial masculinization, and outline an evolutionary scenario for its canalization.

CONCLUSIONS

We propose a new hypothesis linking ecological, physiological, developmental and evolutionary processes to adumbrate a comprehensive explanation for the evolution of the lemur syndrome, whose assumptions and predictions can guide diverse future research on lemurs. This hypothesis should also encourage students of other behavioral phenomena to consider the potential role of developmental plasticity in evolutionary innovation.

Redtail and red colobus monkeys show intersite urinary cortisol concentration variation in Kibale National Park, Uganda

Non-invasive measurement of urinary cortisol is a proven method of evaluating the impact of environmental stressors on wild primates. Variation in cortisol concentrations can reflect physiological stress, and prolonged elevation of circulating cortisol can significantly affect individual and population-level health. In a previous study, we found that urinary cortisol concentrations in grey-cheeked mangabeys (Lophocebus albigena) were higher at a highly disturbed site (Mainaro) in Kibale National Park, Uganda compared with a minimally disturbed site (Ngogo) in the same habitat. Here, we expand on this research, reporting on cortisol concentrations in two other cercopithecid monkeys (Cercopithecus ascanius and Piliocolobus rufomitratus) at the same two sites. We hypothesized that C. ascanius would show no difference between sites, given its preference for secondary forests, while P. rufomitratus would have higher cortisol concentrations at the disturbed site. Contrary to expectations, both species exhibited significantly higher cortisol concentrations at Ngogo (minimally disturbed) compared with Mainaro (disturbed). We suggest that these results may be caused by inter- or intragroup social dynamics, intersite differences in predation rate, fruit/food availability and chemistry, or a combination of these factors. These initial evaluations of urinary cortisol concentrations provide testable hypotheses on habitat disturbance and Kibale primate ecophysiology.