Synergistic effects of musking and autohaemorrhaging on the duration of death feigning in dice snakes (Natrix tessellata).

Predation exerts a significant selection pressure on prey, shaping a multitude of traits that serve as antipredator defences. In turn, natural selection could favour combinations of antipredator defences with synergistic effects that enhance prey survival. An especially interesting antipredator defence is death feigning (DF), present in a wide variety of taxa and usually characterized by the prey lying motionless often along with defaecation, musking and autohaemorrhaging (AH). All these aspects of the DF display should work in conjunction with one another, intensifying the overall effect of the display and in turn facilitating quicker escape. To confirm this hypothesis, we tested 263 dice snakes (Natrix tessellata) directly in the field. We noted the occurrence of smearing faeces, musk and AH, and we measured the duration of DF, expecting to see a negative association between the occurrence of these behaviours and the duration of DF. Our results affirm our hypothesis: dice snakes that smeared themselves in musk and faeces prior to DF and had AH during DF spent significantly less time in DF. Our results highlight the functional integration of antipredator behaviours across different phases of predator-prey interactions, emphasizing the need for future research to prioritize studying the sequential display of behaviours.

Diverse aging rates in ectothermic tetrapods provide insights for the evolution of aging and longevity.

Comparative studies of mortality in the wild are necessary to understand the evolution of aging; yet, ectothermic tetrapods are underrepresented in this comparative landscape, despite their suitability for testing evolutionary hypotheses. We present a study of aging rates and longevity across wild tetrapod ectotherms, using data from 107 populations (77 species) of nonavian reptiles and amphibians. We test hypotheses of how thermoregulatory mode, environmental temperature, protective phenotypes, and pace of life history contribute to demographic aging. Controlling for phylogeny and body size, ectotherms display a higher diversity of aging rates compared with endotherms and include phylogenetically widespread evidence of negligible aging. Protective phenotypes and life-history strategies further explain macroevolutionary patterns of aging. Analyzing ectothermic tetrapods in a comparative context enhances our understanding of the evolution of aging.

Intersexual Differences in Behaviour and Resource Use of Specialist Phengaris teleius Butterflies.

Although the behaviour of the Large Blue butterflies of the genus Phengaris (= Maculinea) is relatively well studied, most empirical data come from investigations of their dispersal and oviposition. Here, we assessed overall intersexual differences in resource use by tracking Phengaris teleius (Bergsträsser, 1779) individuals and recording the duration of their behaviours. Females were characterised by frequent, short flights, and devoted more time to resting and oviposition. Males engaged in numerous, but usually short interactions, and spent most of the time in flight exploring their surroundings for receptive females. Their average flight time was significantly longer compared to females. Average feeding time did not differ between the sexes but was shorter when butterflies were feeding on Sanguisorba officinalis L. Intraspecific interactions within P. teleius were three times longer than those with other insect species, and interactions between sexes were particularly long lasting. Significantly shorter interspecific interactions imply that butterflies can easily recognise conspecifics and differentiate between sexes, which offers obvious fitness benefits. Both sexes, but especially females, showed strong association with their larval host plant, and less so with other flowers of similar colour and shape. Females predominantly used their host plant for feeding, which possibly indicates neuro-sensory constraints towards this resource.

Priming third-party ostracism does not lead to increased affiliation in three Serbian communities.

Young children rely on establishing and maintaining social relationships. As a consequence, social exclusion poses a significant threat that should be avoided actively. Previous research reports that children react to ostracism with an increased tendency to affiliate. For example, they draw more affiliative pictures and engage in more faithful (over)imitation following primes depicting social exclusion. However, all prior studies to date tested this effect in children from strongly socially independent societies, emphasizing individual freedom and psychological autonomy. The current study tested whether these effects also occur among children growing up in a society where social interdependence is emphasized more strongly. We assessed affiliative reactions to video primes depicting either third-party ostracism or control stimuli among 128 preschoolers (Mage = 4.73 years) from an urban community (Belgrade), a semi-urban community (Pozarevac), and a rural community (Kostolac) in Serbia. Across communities, children detected ostracism when it was depicted in the priming stimuli. However, children neither drew more affiliative pictures nor engaged in more faithful overimitation following primes depicting ostracism as compared with control stimuli. The two measures for affiliation (i.e., affiliative drawings and increased overimitation) were not linked on an individual level. Although these results suggest that young children from diverse societies are capable of recognizing third-party social exclusion, their response to such information is strongly shaped by cultural values on social interdependence.

Effect of Capture, Phenotype, and Physiological Status on Blood Glucose and Plasma Corticosterone Levels in Free-Ranging Dice Snakes.

AbstractTheoretically, animals integrate intrinsic and extrinsic factors to respond appropriately to the wide range of stressors they encounter during their life span. We examined how stress response varies between sexes and among morphotypes in wild dice snakes (Natrix tessellata). We also considered reproductive and feeding status and antipredator behavior. We used two indicators of stress (glucose [GLUC] and corticosterone [CORT] levels) at eight sampling time intervals (immediately after capture, up to 17 h after) and a large sample size (N=113 snakes). Concentrations of both markers increased sharply after capture (an equivalent of predation). This acute phase occurred earlier for GLUC (30 min) compared to CORT (60 min). Then the values plateaued to very high levels without decline over time, indicating prolonged saturation of the hypothalamus-pituitary-adrenal axis. In contrast to our expectations, we found no effect of sex, morphotype, or reproductive status. Yet the CORT stress response of those individuals displaying death-feigning (DF) antipredator behavior was attenuated compared to those that did not. Low stress hormones levels may facilitate the expression of DF (high levels supporting fleeing behavior). The presence of partially digested material in the stomach was associated with higher blood GLUC during the plateau. Assaying blood GLUC requires very little blood but was as good as CORT at gauging acute stress response. The prolonged plateau suggests that captivity should be minimized during field studies.

Inside the shell: body composition of free-ranging tortoises (Testudo hermanni).

Body condition indices (BCI - mass scaled by size) are widely used in ecological studies. They presumably reflect variations of endogenous fat reserves in free-ranging animals. In the field, however, accurately quantifying internal body reserves is a difficult task. This is especially true in armoured animals where convenient clues that may guide BCI assessment (e.g. visible subcutaneous fat deposits) remain inaccessible. Alternatively, inclusive dissections may provide anatomical abacuses to estimate body reserves in living individuals. Sacrificing animals for this purpose is not acceptable. We opportunistically tested the ability of BCI to estimate body reserves in 13 free-ranging Hermann's tortoises (Gmelin, 1789) dissected soon after they died from natural causes. On average, BCI values were lower in dissected tortoises relative to living individuals (N > 10,000 measurements), but they remained within the range of variation of the studied populations. Shell mass relative to body mass was high and showed considerable inter-individual variation (33.5% to 52.3%). Stomach and digestive tract content represented another important and variable part of total body mass (4.4% to 14.5%). The contribution of fat bodies was negligible (0.0% to 0.5%). Overall, in the studied tortoises, variations of body condition are weakly determined by variations of fat stores. Other endogenous (e.g. muscles, visceral tissues, liver) and "exogenous" (e.g. digestive tract content, clutch) elements should be considered to better understand age and sex specific life-history trade-offs faced by chelonians.

Biologer: an open platform for collecting biodiversity data.

BACKGROUND: We have developed a new platform named "Biologer" intended for recording species observations in the field (but also from literature resources and collections). The platform is created as user-friendly, open source, multilingual software that is compatible with Darwin Core standard and accompanied by a simple Android application. It is made from the user's perspective, allowing everyone to choose how they share the data. Project team members are delegated by involved organisations. The team is responsible for development of the platform, while local Biologer communities are engaged in data collection and verification. NEW INFORMATION: Biologer has been online and available for use in Serbia since 2018 and was soon adopted in Croatia and Bosnia and Herzegovina. In total, we have assembled 536 users, who have collected 163,843 species observation records data from the field and digitalised 33,458 literature records. The number of active users and their records is growing daily. Out of the total number of gathered data, 89% has been made open access by the users, 10% is accessible on the scale of 10×10 km and only 1% is closed. In the future, we plan to provide a taxonomic data portal that could be used by local and national initiatives in Eastern Europe, aggregate all data into a single web location, create detailed data overview and enable fluent communication between users.

When carapace governs size: variation among age classes and individuals in a free-ranging ectotherm with delayed maturity.

Juvenile growth strongly impacts life-history traits during adulthood. Yet, in juveniles with delayed maturity, elusiveness has hindered age-specific studies of growth, precluding any detailed research on its consequences later in life. Different complex growth patterns have been extracted from captive animals, suggesting species-specific trajectories occur in free-ranging animals. How pronounced are growth and body size variation (VBS) throughout a long-lived ectotherm's life? Is VBS constant among age classes prior to maturity, or do compensatory and/or cumulative effects driven by long-lived-animal-specific strategies create distinct VBS cohorts, to ensure survival? To tackle the issue, we modelled growth data from continuous and dense annual capture-mark-recapture sampling (5096 body measurements of 1134 free-ranging individuals) of both immature and mature, long-lived Hermann's tortoises. We analysed population, cohort, and individual-based growth and VBS. Growth ring inferred ages were cross validated with annual recaptures in 289 juveniles. Analyses unravelled an S-shaped growth curve and identified three age cohorts across which VBS increases in a step-wise manner. Neonate-specific constraints and compensatory effects seem to control VBS until 4 years of age, possibly promoting survival with size. Subsequently, a hardened carapace takes over and cumulative effects fuelled by faster growth progressively increase VBS. Whereas ungulates are in a hurry to attain adult size before growth ceases (minimizing VBS), indeterminately growing tortoises can shape individual asymptotic sizes even after growth decelerates. Tortoise size is clearly shaped by age-specific ecological constraints; interestingly, it is likely the carapace that conducts the strategy, rather than maturity per se.