General and Comparative Endocrinology

Ethyl-iophenoxic acid (Et-IPA) is widely recognized as a useful biomarker to confirm oral bait consumption in eutherian species. In historical studies on marsupials, Et-IPA was rapidly eliminated from brushtail possums (Trichosurus vulpecula) and swamp wallabies (Wallabia bicolor) suggesting limited use for marsupial species. However, a 1 mg oral dose of Et-IPA was detectable in the marsupial Tasmanian devils (Sarcophilus harrisii) for [≥] 56 days suggesting the biomarker can be used in a devil bait vaccine program. To assess Et-IPA marking in off-target marsupials that may consume baits, we administered 1 mg oral doses of Et-IPA to brushtail possums, forester kangaroos (Macropus giganteus tasmaniensis), spotted-tailed quolls (Dasyurus maculatus) and eastern quolls (Dasyurus viverrinus). Liquid chromatography with tandem mass spectrometry was used to detect and quantify serum Et-IPA. Et-IPA was detected in the serum on day 2 but was not detected by day 14 in any of the species tested, including the two quoll species which are in the same carnivorous Dasyuridae family as the devils. The rapid elimination of Et-IPA in the marsupials included in this study suggests it is not useful as a biomarker for these species. Furthermore, rapid elimination in the kangaroos and possums suggests that Et-IPA is unlikely to accumulate in the food chain following distribution of Et-IPA-marked oral bait vaccines for Tasmanian devils. Short summary for non-expertsA recent study in Tasmanian devils (Sarcophilus harrisii) challenged the concept that ethyl iophenoxic acid (Et-IPA) is not a useful serum biomarker for marsupials. Using the same sensitive liquid chromatography-tandem mass spectrometry method we detected serum Et-IPA in four marsupial species on day two post-ingestion but by day 14, serum Et-IPA was undetectable. These findings indicate that Et-IPA is an unsuitable biomarker for these species and suggest that Et-IPA from devil bait vaccines is unlikely to bioaccumulate in the Tasmanian environment.

Markhor (Capra falconeri) is a charismatic, threatened, large, high-altitude bovid found in parts of central and south Asia. The species faces threats such as habitat loss, hunting, poaching, livestock competition, hybridisation, and disease, yet research on wild populations is challenging. Various biological aspects, including surveys, diet, population dynamics, interactions with livestock, hybridisation, and disease, have been studied locally, along with behavior and reproductive biology, but details such as pregnancy, oestrus, and parturition timing remain unestablished. We conducted the first systematic, detailed, and fine-scale characterization of the reproductive steroid profiles of two males and five female markhors (Capra falconeri heptneri) in a captive population at the Padmaja Naidu Himalayan Zoological Park (PNHZP), West Bengal, India. We collected weekly fecal samples, standardized and validated measurements of progesterone (fP4M) and testosterone (fTM) metabolites, and conducted reproductive profiling to assess reproductive stages in both sexes. Analyses of annual fP4M and fTM data from male and female markhor individuals showed similar profiles and synchronicity, with individual variation, and peaks and baselines were evident for both hormones. In both sexes, significantly higher hormone titres were observed during the sexually active and inactive phases. Non-invasive measurement of reproductive hormones accurately reflected ovarian function in females, helping establish mating, gestation, and parturition timelines in female markhors and determine the breeding season in males. These approaches support husbandry and breeding management by identifying optimal pairing, diagnosing pregnancy, and predicting parturition in both captive and wild populations. When applied correctly, these tools could greatly aid population monitoring of other endangered species across high-altitude regions worldwide.

Transcriptomic analyses are widely used to elucidate the molecular mechanisms driving gametogenesis and reproduction in fish, yet their accuracy depends heavily on appropriate normalization of gene expression data. Conventional approaches that rely on single or multiple reference genes are problematic during teleost oogenesis, as profound structural and physiological remodeling of the ovary challenges the assumption that commonly used reference transcripts remain stable. In this study, we assessed by qPCR the transcriptional variability of four widely used reference genes (actb, ef-1, gapdh, and 18S rRNA) throughout the oogenic cycle of the thicklip grey mullet (Chelon labrosus), using geNorm and NormFinder analyses, and we additionally evaluated total cDNA concentration as an alternative normalization factor. To examine the performance and interpretive consequences of each normalization strategy, we compared expression patterns of key steroidogenic genes (star, cyp19a1a, and cyp11b) normalized by individual reference genes, combinations of reference genes, or total cDNA concentration. All evaluated reference genes displayed notable transcriptional variability across oogenesis, confirming their limited suitability as sole internal controls. In contrast, normalization approaches integrating multiple reference genes and/or total cDNA concentration consistently provided greater stability and more reliable biological interpretation. These results support a refined and more robust normalization framework for transcriptional analyses in fish ovaries, particularly during stages of extensive tissue remodeling. Our findings demonstrate cDNA-based normalization is straightforward, rapid, and easy to implement across laboratories, providing a practical alternative for achieving accurate, reproducible transcript quantification in fish ovary studies.

Capturing and handling wild animals is essential for ecological and evolutionary research, yet their effects on physiology, behaviour, and reproductive success remain poorly understood. We investigated short- and longer-term consequences of a capture-handling-restraint protocol in wild great tits (Parus major) over three breeding seasons. To assess short-term responses, we measured circulating corticosterone, a metabolic hormone that responds to unpredictable challenges, and automatically recorded provisioning behaviour. We also explored whether environmental and individual traits were related to provisioning latency (i.e., time to resume provisioning after capture). To evaluate longer-term effects, we monitored provisioning in the days following capture and related it to reproductive success (fledgling number and body condition). We predicted that longer handling would increase stress-induced corticosterone and provisioning latency, that these variables would be positively correlated, and that higher corticosterone and longer latencies would be associated with lower reproductive success. After capture, great tits showed elevated corticosterone and delayed provisioning. Contrary to our predictions, handling duration was negatively associated with stress-induced corticosterone in males (but not females) and did not affect provisioning latency. Provisioning latency was unrelated to corticosterone, environmental, or individual variables. Following capture, parents resumed provisioning, and short-term responses had little influence on reproductive success. We show that parental behaviour and physiology are affected by capture restraint protocols on the short term, but offspring condition and survival are not. However, these results should be interpreted cautiously, as our study lacks an uncaptured control group. Our findings highlight that evaluating welfare impacts requires rigorous study design incorporating both immediate and longer-term behavioural and fitness effects.

Cortisol is a major endogenous glucocorticoid that regulates numerous physiological processes. In plasma, cortisol and its inactive metabolite cortisone bind to corticosteroid-binding globulin (CBG) and albumin, leaving only the unbound fraction available for receptor activation and metabolism. Changes in ligand or protein concentrations alter unbound fractions. Existing binding equations are difficult to extend to multi-ligand, multi-protein systems and do not readily capture competitive endogenous binding interactions. The goal of this study was to develop a plasma protein binding model that quantitatively describes binding species and predicts unbound concentrations across physiological states. Total and unbound cortisol and cortisone, CBG and albumin were measured in plasma from healthy premenopausal women (n=13) at baseline and after 7 days of 30 mg hydrocortisone treatment. Reversible 1:1 binding models were implemented in COPASI and MATLAB/Simulink, and dissociation constants (Kd) were estimated by fitting binding models to observed unbound concentrations. A model describing simultaneous binding of cortisol and cortisone to CBG and albumin yielded in vivo Kd values for cortisol:CBG, cortisone:CBG, cortisol:albumin, and cortisone:albumin of 0.0130 {micro}M, 0.169 {micro}M, 172 {micro}M, and 519 {micro}M, respectively. Model predictions agreed with observed unbound cortisol and cortisone, and bootstrap resampling confirmed stable Kd estimates. This work provides a quantitative framework for predicting unbound cortisol and cortisone across physiological and disease states by accounting for both changes in ligand and protein concentrations. This enables extrapolation without reparameterization and supports exploration of conditions such as pregnancy, adrenal insufficiency, and liver disease, informing interpretation of altered cortisol concentrations in these populations. Significance statementThis work establishes a framework to predict in vivo cortisol and cortisone binding. The developed model was applied to predict unbound cortisol and cortisone concentrations in physiological and pathophysiological states and can be integrated into pharmacokinetic models. Our analysis demonstrates that cortisol and cortisone binding affinities estimated in the native plasma environment differ from those measured using purified proteins. These differences have important implications for predicting and analyzing unbound cortisol concentrations. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=114 SRC="FIGDIR/small/718600v1_ufig1.gif" ALT="Figure 1"> View larger version (27K): org.highwire.dtl.DTLVardef@1d9254corg.highwire.dtl.DTLVardef@11fadd5org.highwire.dtl.DTLVardef@cdbc26org.highwire.dtl.DTLVardef@fba0c0_HPS_FORMAT_FIGEXP M_FIG C_FIG Created in BioRender. Authement, A. (2026) https://BioRender.com/zl1bg0k

Within species, male testosterone is often linked to mating competition and paternal care, suggesting that sex differences in endogenous testosterone values across mammals may covary with broader reproductive strategies. Using a structured literature search, we compiled 63 studies, spanning 31 non-human species and 9 human populations, reporting endogenous, non-experimentally manipulated testosterone values for both adult males and females within the same population and context. From these studies, we calculated male-to-female testosterone ratios, and analysed these data using Bayesian phylogenetic multilevel models. We tested whether testosterone dimorphism was associated with paternal care and sexual size dimorphism while accounting for sampling matrix, assay method, breeding context, and wild versus captive setting. Across non-human mammals, neither paternal care nor sexual size dimorphism (indexing competition) showed a clear association with testosterone ratios, and the same pattern emerged in the primate-only subset. By contrast, sampling matrix was consistently associated with testosterone dimorphism across all analyses, with lower male-to-female ratios in non-blood than in blood-based measures. In primates, testosterone ratios were also lower in captive than in wild populations, although this pattern was not clearly supported in the broader non-human dataset. In the human-only analysis, testosterone ratios did not clearly differ between industrialized and small-scale societies, whereas the matrix effect remained evident. Overall, our results suggest that sampling matrix is a major source of variation even for ratio-based measures, highlighting the need for caution when inferring between-species endocrine differences from studies using different substrates. More broadly, directly comparable, non-experimentally manipulated testosterone data for both sexes remain rare across mammals, limiting comparative inference.

Telomere length (TL) is increasingly used in ecology as a biomarker of individual quality and environmental stress, yet research on non-model species with complex life histories remains limited. Because TL varies among tissues and across ages in a species-specific manner, identifying non-lethal tissues that reliably reflect whole-organism telomere dynamics is essential for longitudinal telomere studies in the field. This study aimed to evaluate tissue-specific TL in Japanese eel (Anguilla japonica), an endangered catadromous fish. We first mapped the chromosomal distribution of telomeric sequences using fluorescent in situ hybridization (FISH), the first application of this method in this species. We then tested whether muscle and caudal fin, which can be sampled easily and non-lethally, can serve as suitable proxy tissues for TL measurements in wild individuals. Relative telomere length (RTL) was quantified by qPCR in blood, brain, caudal fin, gonads, heart, liver, and muscle. FISH analysis confirmed telomeric repeats at all chromosomal ends, with only weak interstitial signals on three chromosomal pairs unlikely to affect qPCR-based estimates. A generalized additive mixed model and Wilcoxons signed-rank tests revealed significant inter-tissue differences: RTL was shortest in the brain and muscle and longest in liver, blood and caudal fin. Muscle and caudal fin RTL were significantly correlated with RTL in many other tissues, supporting their use as proxy tissues for longitudinal TL monitoring, including responses to environmental variation. Both total length and age were tested as explanatory variables for RTL, and the model including total length showed a better fit than the age-based model. Non-linear relationships between RTL and total length observed in several tissues suggest physiological shifts associated with growth and sexual differentiation. Overall, these findings advance understanding of telomere dynamics in eels and establish muscle and caudal fin as suitable tissues for repeated, non-lethal TL assessment in ecological and conservation contexts.

Birdsong mediates territory acquisition and mate choice. In agonistic interactions, local songs generally elicit stronger responses than songs from more distant populations. However, the molecular mechanisms associated with differential responses to local vs. foreign songs are poorly understood. We addressed this knowledge gap by combining behavioral assays in the field with blood transcriptomic analysis, using a within-subjects design to ask whether male song sparrows (Melospiza melodia) show differential gene expression when exposed to playback of local and foreign songs. Transcriptomic profiles reflected the difference in behavioral response to local vs. foreign songs, with individuals exposed to local songs showing greater expression of genes associated with song perception and production, anti-inflammatory responses and energy metabolism. Our study suggests that changes in expression of key molecular pathways correlate with behavioral responses to geographic song variation, providing insight into the potential mechanisms regulating signal recognition and response to social challenges. HighlightsO_LIGene expression in sparrow blood was measured after simulated territorial intrusion. C_LIO_LIStronger response to local songs was associated with differential gene expression. C_LIO_LISong-associated genes (FOXP2, NRXN1) had higher expression when birds heard local songs. C_LIO_LIGene expression in the blood contains potential biomarkers of song recognition. C_LI

To attract mating partners, female mammals communicate their reproductive status through one or multiple sensory modalities, providing redundant or complementary information. Chimpanzees (Pan troglodytes) are an excellent model for studying multimodal communication. Exaggerated sexual swellings of females serve as a visual proxy for ovulation but increased male mating interest during maximum swelling suggests that olfactory cues may pinpoint fertility more accurately than the swelling alone. Here, we combined gas chromatography-mass spectrometry, hormonal analyses, and bioassays to examine (1) whether chemical composition of female anogenital odours changes during the fertile period, and (2) whether males are able to detect these changes. Our results suggest that, in addition to prominent olfactory changes associated with swelling stages, chemical cues provide complementary information regarding the timing of the fertile window. These changes, however, are minor compared to those related to swelling stages. Male behavioural responsiveness in bioassays was too low to draw conclusions regarding their ability to detect these subtle shifts when presented with a chemical cue only. Overall, our findings support the existence of a multimodal fertility cue in chimpanzees, wherein visual signals are complemented by subtle olfactory changes indicating the timing of the fertile period.

Scyphozoan jellyfish have a complex life cycle that includes a characteristic transition known as strobilation. Retinoid signaling has been suggested to be involved in jellyfish metamorphosis and development. However, the genomic basis of signaling pathways associated with metamorphosis has not been sufficiently compared at the class level. Experimental studies have reported that indole compounds can induce metamorphosis in some jellyfish species. Indole- and tryptophan-derived metabolites are known to function as ligands for the aryl hydrocarbon receptor (AhR) in other organisms. However, the potential role of AhR signaling in jellyfish metamorphosis has not been previously explored. We compared the distribution of retinoid- and AhR-associated gene families across multiple scyphozoan genomes. This analysis aimed to characterize their distribution patterns in relation to signaling pathways associated with development and environmental responses. A standard gene prediction and annotation pipeline was applied to 20 species from 21 publicly available scyphozoan reference genome assemblies retrieved from the NCBI database. The distribution and copy number of these gene families were compared across species. Retinoid-associated gene families were detected across almost all Scyphozoa genomes, and core components of AhR signaling (AhR, ARNT) were identified in most species. These results suggest that scyphozoan genomes contain genetic components of retinoid- and AhR-related signals. This study presents the distribution of gene families related to developmental signaling across Scyphozoa using a comparative genomic approach. It does not imply direct functional involvement of retinoid or AhR signaling, but instead focuses on potential signaling pathways at the genome level. It also provides an overview of currently available scyphozoan genomic data. These findings provide a basis for future hypothesis generation and functional validation in jellyfish metamorphosis research.

BACKGROUNDAdrenal insufficiency is primarily treated with replacement of cortisol, which is the predominant circulating glucocorticoid. Human adrenals also secrete corticosterone and emerging evidence suggests this may be a safer glucocorticoid replacement therapy. However, little is known about corticosterone in humans, particularly related to its metabolism. METHODSTo investigate the secretion and metabolism of corticosterone in comparison with cortisol, we: 1) investigated the diurnal rhythm of circulating cortisol/ corticosterone in 7 healthy volunteers; 2) quantified A-ring reduction of both hormones in human hepatic cytosol and 3) measured glucocorticoid metabolites in vivo in 24 healthy men; 4) determined the pharmacokinetics of corticosterone via intravenous infusion of 2,2,4,6,6,17,21,21-[2H]8-corticosterone; 5) assessed the response of corticosterone and cortisol to 1mcg ACTH in 279 healthy volunteers. RESULTSThe natural diurnal rhythm of corticosterone closely mirrored that of cortisol, and accounted for [~]3% of total circulating glucocorticoid concentrations. Daily corticosterone production, as measured through urinary steroid profiling, was approximately 10-fold lower than cortisol, and corticosterone demonstrated substantially greater metabolism by both 5- and 5{beta}-reductase than cortisol. In keeping with greater metabolism, the half-life of corticosterone was 28.5 {+/-} 3.3 minutes. Finally, corticosterone demonstrated a greater relative rise in response to ACTH than cortisol, particularly in men, revealing sex-specific differences. CONCLUSIONSCorticosterone is a dynamic glucocorticoid with faster metabolism and greater response to stimulation than cortisol in humans. These data raise the possibility of distinct roles for these two glucocorticoids and highlight important pharmacokinetic differences with implications for the therapeutic potential of corticosterone replacement in humans.

Introducing cognitive enrichment from an early age has the potential to enhance an animals capacity to learn both simple and complex tasks, promote neural plasticity, and support cognitive development. This is applicable for young cattle who are at a critical stage in their development and could benefit from the influence cognitive enrichment has on their behavioral expression. This study aims to explore the effects cognitive enrichment has on weaned dairy calves through analyzing behavioral measures of voluntary participation and short-term behavioral reactions to enrichment exposure. Our study involved a total of five pairs of weaned calves (n=8 treatment; n=2 control). The treatment groups were presented with three variations of a puzzle box, each equipped with unique challenges that offer different solutions (push, slide, pull). These boxes were provided to the calves twice daily over the span of nine days in an isolated corridor located behind their pen. We hypothesized that motivated calves would consistently engage with cognitive enrichment voluntarily over time and express directed natural behaviors, reflecting sustained participation across repeated trials. Results demonstrated that calves consistently visited the cognitive enrichment area across trials, with an average latency of 75.7 {+/-} 47.0s from the pen to the enrichment. Secondly, the calves spent a significant proportion of trial time within the enrichment area at 65% (870.1 {+/-} 21s). Lastly, all calves expressed a broad range of behaviors in line with their natural exploration within the enrichment area, while the puzzle box treatment groups expressed higher durations of behavioral expressions when compared to the control (F=11.7, p<0.0001). Combined, these results indicate the calves motivations to voluntarily participate in a cognitive challenge. While these are promising findings for cognitive enrichment and its applicability to dairy calves, further work is needed to understand broader parameters. Specifically, how can social dynamics influence enrichment interaction in groups, how can this type of enrichment be implemented on farms, and what are the long-term effects to providing cognitive enrichment in the early stages of development.

Stable isotope analysis provides an important tool for reconstructing past livestock management practices and landscape use. However, isotopic data for sheep from Late Iron Age (AD 375/400-1050) Denmark remain limited. Here, we present bulk bone collagen {delta}{superscript 1}3C, {delta}{superscript 1}N, and {delta}3S isotope analyses of 27 sheep (Ovis aries) from six archaeological sites in Denmark, dated to the Germanic Iron Age (AD 375/400-750) and Viking Age (AD 750-1050). The analysed sheep exhibit a consistent pattern of enriched {delta}13C values relative to previously published isotopic datasets for Scandinavian livestock, while {delta}15N values display substantial inter-individual variability. Sulfur isotope values fall within moderate ranges consistent with mixed terrestrial and coastal environmental influences. The decoupling of {delta}13C enrichment from elevated {delta}15N values suggests that the observed carbon isotope signal does not reflect marine protein consumption but rather the incorporation of a 13C-enriched plant resource into sheep diets. We propose that eelgrass (Zostera sp.), either through direct grazing in coastal environments or supplementary foddering with harvested eelgrass, represents a plausible dietary source to explain this isotopic pattern. The results indicate that Late Iron Age sheep management strategies in Denmark incorporated coastal plant resources within flexible pastoral systems, potentially supporting intensified wool production associated with expanding textile economies. HighlightsO_LIStable isotope values of Late Iron Age sheep show some dietary marine input. C_LIO_LIEnriched {delta}13C values suggest eelgrass as supplementary fodder. C_LIO_LI{delta}34S values indicate adaptive grazing across coastal and inland landscapes. C_LI

In sex-role reversed species, females are socially polyandrous and compete for multiple mates, whereas males conduct the majority of parental care. To understand the extent to which physiological differences between females and males are shaped by sex roles, we examined sex differences in gene expression in sex-role reversed northern jacanas (Jacana spinosa). Given that females compete for mating opportunities, and males cycle between courtship and parental care, we predicted that transcriptomic profiles would be more similar between females and courting males, in contrast to female and parenting males. Leveraging a high quality de novo genome assembly, we conducted RNA-seq on two brain regions associated with the regulation of social behavior: the preoptic area of the hypothalamus and the nucleus taeniae. The majority of genes differentially expressed between the sexes were male-biased. Of these male-biased genes, the majority were located on the Z-chromosome. Contrary to our prediction, the greatest difference in autosomal gene expression was between females and courting males, in the preoptic area of the hypothalamus. Several differentially expressed genes related to elements of hormone signaling that are likely to be behaviorally salient, including higher expression of androgen receptor in females relative to parenting males, and higher expression of prolactin receptor in males, regardless of breeding stage. Some sex-associated gene networks were also associated with competitive traits, whereas others were associated with aggressive behaviors, regardless of sex. Few genes were differentially expressed between courting and parenting males, yet some nonetheless had connections to behavioral endocrinology, including prolactin, thyroid and insulin-like growth factor pathways. Our investigation of sex differences in gene expression can help to reveal the molecular mechanisms underlying female competition and male parental care in socially polyandrous species. We conclude that social polyandry is not a simple reversal in the direction of sex-biased gene expression in the brain, but rather a result of complex genetic and hormonal interactions that warrants further study.

Early detection of ovulation and pregnancy in the common marmoset is crucial for reproductive studies, yet hCG kits lack cross-reactivity with marmoset CG, and current methods remain labor-intensive. Here, we developed monoclonal antibodies against marmoset CG and CG{beta}, and established a non-invasive immunochromatographic CG assay. By eliminating invasive blood sampling, this assay supports 3Rs principles and enables practical endocrine monitoring. The assay detected urinary CG surges preceding ovulation, enabling efficient embryo recovery through artificial insemination (75%). Early pregnancy was detected at approximately 17 days post-ovulation. In addition, pregnancy detection in squirrel monkeys suggests conservation of CG features among certain New World primates. Overall, this simple, non-invasive assay provides a practical tool for marmoset research and establishes a foundation for future conservation-oriented reproductive monitoring following appropriate species-specific validation.

Giant pangolin (Smutsia gigantea) is one of the least studied pangolin species worldwide, with no published hematological and biochemical data available. We report the first blood parameters from a rehabilitated adult male from Campo Maan National Park (southern Cameroon). Hematological and biochemical findings are described and discussed in relation to available data from other pangolin species. These preliminary results provide the first reference framework for this species and highlight their relevance for clinical assessment, health monitoring, and conservation management.

The protein composition of sperm and seminal fluid are key to male fitness. However, we currently lack an understanding of the factors that shape seminal proteome composition. The common bedbug (Cimex lectularius) mates by traumatic insemination, subjecting the ejaculate to a unique selective environment as sperm traverse the female genital and paragenital system. We provide the first high-throughput proteomic characterisation of the sperm and seminal fluid proteome in a hemimetabolous insect and the first in-depth proteomic characterisation of the male bedbug reproductive system. Our analysis revealed conserved and unique features of the sperm and seminal fluid proteome with possible links to features of sperm behaviour linked to traumatic insemination. The sperm proteome showed elevated rates of molecular evolution, unlike most other studied species. Conversely, the sperm proteome also contained many conserved proteins. Notably, we found an expansion of Sperm-leucylaminopeptidases (S-Laps) in bedbugs and other hemimetabolous insects, suggesting the origin of S-Laps is perhaps even more ancient than previously thought. Using in silico protein-ligand binding predictions, we show that S-Laps have likely retained catalytic activity. Our results provide a list of candidate proteins involved in reproduction and a foundation for future studies of this expanding global pest.

Black soldier fly larvae (BSFL) have quickly become one of the most farmed animals in the world. However, little is known about how to monitor stress and welfare in these animals. The difficulty of welfare assessment is compounded by the fact that BSFL live in their feed and prefer darkness. This behaviour makes it challenging to observe potential welfare indicators without inducing stress via disturbing the larvae or moving them into the light. However, acoustic devices may be able to pick up signatures of stress in the population even while they are out of sight, allowing for remote monitoring of animals in natural conditions (in the feed and/or in the dark). Acoustic monitoring of this type has been deployed for the detection of insects in stored grains, suggesting this method holds some promise for assessing insect behavioural signatures. In this study, we aimed to identify general, acoustic signatures of stress in BSFL by recording them during exposure to two stressors (light or shaking) or in a low-stress control condition. Our data suggest there are consistent differences in the acoustic recordings of the non-stressed and stressed conditions that may indicate the animals behaviours shift consistently in response to stress. Ultimately, the data suggest acoustic monitoring may hold promise for larval behaviour and/or welfare assessment and should be further explored in response to a variety of stressors across the larval life stage.

Venom is an important functional trait that helps predatory animals capture prey. Centipede predatory venoms are complex cocktails of multiple proteins, such as neurotoxins (scoloptoxins), cytotoxins, {beta}-pore-forming toxins, and enzymes. We examined venom phenotypes in two closely related and co-occurring centipede species, Scolopendra morsitans (n=28) and S. hardwickei (n=11), in peninsular India to determine whether their venoms are similar or dissimilar. An integrated proteo-transcriptomic approach was used to characterise the venom phenotypes of the two species across multiple individuals in peninsular India. We used species occurrence records and species distribution models to assess the distributional overlap among these species within the peninsular Indian region. The species showed significant overlap in their current and projected geographical ranges, corresponding with their co-occurrence. We characterised the venom profiles of both species and found that the venoms were cocktails of enzymes, {beta}-pore-forming toxins, and neurotoxins comprising 110 and 84 proteins in S. morsitans and S. hardwickei, respectively. However, the venom composition of both species differed significantly in toxin abundance and species-specific protein repertoires. This indicates trait divergence in venom phenotypes, suggesting that distinct venom compositions may facilitate coexistence among ecologically similar predatory centipedes. The observed variation in venom phenotypes among co-distributed species opens up important avenues for future research into their ecological roles and functional significance. In this study, we provided a detailed account of venom composition across multiple individuals from the species geographic range and highlighted the importance of investigating the role of venom as a trait that could influence species interactions and shape communities in these diverse tropical forests.

Prolonged association between mothers and their offspring is common in ungulates, with the level of maternal investment likely to play a central role in shaping this trait. Here we examined patterns of association between mothers and offspring over time, the apparent benefits of association to offspring, and costs to mothers. We analyzed 40 years worth of census data from an individually-monitored, food-limited population of red deer (Cervus elaphus) on the Isle of Rum, Scotland. Starting from birth, female calves associated more frequently with their mothers than male calves in their first year. Calves also associated less with their mothers if the mother did not conceive a new calf. Association frequency decreased with mothers age and population density, and survival over the first year was not related to mother-calf association. Yearlings, now in their second year, were more often associated with their mothers if they were female, if there was no subsequent calf (or the subsequent calf died as a neonate), and if they were still being suckled. Increased association between mothers and yearlings was associated with increased survival to adulthood at 28 months, but suckling a yearling did not improve its probability of survival. For individuals that reached maturity, increased association in the yearling year was associated with slightly shorter adult life spans. The level of association between a calf and mother was not associated with the mothers immediate survival or fecundity. Our findings suggest that juveniles born to poor-condition mothers benefit from prolonged association through improved yearling survival.