Body Size Research Articles

The Slithering Dead: Does locomotor performance affect post-capture death feigning in dice snakes (Natrix tessellata, Laurenti 1768)?

Abstract Functional constraints between different types of antipredator behavior should be common, especially if they are on the opposite sides of the behavioral spectrum such as flight and post-capture immobility. We examined a potential compromise between post-capture immobility displays and sprint speed in dice snakes (Natrix tessellata), using a field-based approach. We sampled snakes (N=238) from two populations: from a dense island population free of mammal predators, and from a less dense mainland population, preyed upon by both bird and mammal predators. We explored the effects of sexual maturity, temperature, body size, presence of palpable food in the gut and injuries on the occurrence and duration of post-capture immobility as well as sprint speed. Our results confirm the existence of functional constraints between locomotor performance and post-capture immobility in dice snakes. Faster dice snakes start escaping promptly after release, while slower individuals utilize more passive antipredator behaviors such as death feigning. Local adaptations seem to have great influence on behavioral compromise, since the mammal-free island population exhibited a higher incidence of post-capture immobility and a significantly lower sprint speed, compared to the less dense mainland population. Additionally, immature individuals tended to avoid death feigning and their post-capture immobility lasted shorter compared to adult individuals. It remains to be seen how individuals adjust their behavior to accomodate locomotor constraints, and in which specific phases of the predator-prey interaction these adjustments occur.

Relative muscle indices and healthy reference values for sarcopenia assessment using T10 through L5 computed tomography skeletal muscle area

Sarcopenia is the age-related loss of skeletal muscle mass and function. Computed tomography (CT) assessments of sarcopenia utilize measurements of skeletal muscle cross-sectional area (SMA), radiation attenuation (SMRA), and intramuscular adipose tissue (IMAT). Unadjusted SMA is strongly correlated with both height and body mass index (BMI); therefore, SMA must be adjusted for body size to assess sarcopenic low muscle mass fairly in individuals of different heights and BMI. SMA/height (rather than SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMA/height^2$$\\end{document}) provides optimal height adjustment, and vertebra-specific relative muscle index (RMI) equations optimally adjust for both height and BMI. Since L3 measurement is not available in all CT scans, sarcopenic low muscle mass may be assessed using other levels. Both a mid-vertebral slice and an inferior slice have been used to define ‘L3 SMA’, but the effect of vertebral slice location on SMA measurements is unexplored. Healthy reference values for skeletal muscle measures at mid- and inferior vertebra slices between T10 and L5, have not yet been reported. We extracted T10 through L5 SMA, SMRA, and IMAT at a mid-vertebral and inferior slice using non-contrast-enhanced CT scans from healthy, adult kidney donor candidates between age 18 and 73. We compared paired differences in SMA between the mid-vertebral slice versus the inferior slice. We calculated the skeletal muscle gauge as SMGHT=SMRA∗SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMG_{HT}=SMRA*SMI_{HT}$$\\end{document}. We used allometric analysis to find the optimal height scaling power for SMA. To enable comparisons with other published reference cohorts, we computed two height-adjusted measures; SMIHT=SMA/height\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}=SMA/height$$\\end{document} (optimal) and SMIHT2=SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}=SMA/height^2$$\\end{document} (traditional). Using the young, healthy reference cohort, we utilized multiple linear regression to calculate relative muscle index z-scores (RMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT}$$\\end{document}, RMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT2}$$\\end{document}), which adjust for both height and BMI, at each vertebra level. We assessed Pearson correlations of each muscle area measure versus age, height, weight, and BMI separately by sex and vertebra number. We assessed the differences in means between age 18–40 versus 20–40 as the healthy, young adult reference group. We reported means, standard deviations, and sarcopenia cutpoints (mean-2SD and 5th percentile) by sex and age group for all measures. Sex-specific allometric analysis showed that height to the power of one was the optimal adjustment for SMA in both men and women at all vertebra levels. Differences between mid-vertebra and inferior slice SMA were statistically significant at each vertebra level, except for T10 in men. SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}$$\\end{document} was uncorrelated with height, whereas SMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}$$\\end{document} was negatively correlated with height at all vertebra levels. Both SMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT}$$\\end{document} and SMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMI_{HT2}$$\\end{document} were positively correlated with BMI at all vertebra levels. RMIHT\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT}$$\\end{document} was uncorrelated with BMI, weight, and height (minimal positive correlation in women at L3inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L3}_{inf}$$\\end{document}, L4mid\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L4}_{mid}$$\\end{document}, and L5inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L5}_{inf}$$\\end{document}) whereas RMIHT2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$RMI_{HT2}$$\\end{document} was uncorrelated with BMI, but negatively correlated with height and weight at all levels. There were no significant differences in SMA between 18–40 versus 20–40 age groups. Healthy reference values and sarcopenic cutpoints are reported stratified by sex, vertebra level, and age group for each measure. Height to the power of one (SMA/height) is the optimal height adjustment factor for SMA at all levels between T10mid\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {T10}_{mid}$$\\end{document} through L5inf\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$\\hbox {L5}_{inf}$$\\end{document}. The use of SMA/height2\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$SMA/height^2$$\\end{document} should be discontinued as it retains a significant negative correlation with height and is therefore biased towards identifying sarcopenia in taller individuals. Measurement of SMA at a mid-vertebral slice is significantly different from measurement of SMA at an inferior aspect slice. Reference values should be used for the appropriate slice. We report sarcopenic healthy reference values for skeletal muscle measures at the mid-vertebral and inferior aspect slice for T10 through L5 vertebra levels. Relative muscle index (RMI) equations developed here minimize correlation with both height and BMI, producing unbiased assessments of relative muscle mass across the full range of body sizes. We recommend the use of these RMI equations in other cohorts.

Age and Body Size of the Endemic and Critically Endangered Frog Species Rana tavasensis (Baran and Atatür, 1986) in Türkiye

This study used skeletochronology to assess the relationships between age and body length among individuals in a population of the Tavas Frog (Rana tavasensis), located in the Çakıroluk plateau, Tavas district, Denizli province. The age varied from 3 to 12 years in both adult males and females. The age was 2 years in two subadult males, while it was 1 year in one juvenile specimen. The mean SVL and age of the adult individuals of the Çakıroluk population were 62.75 mm and 6.70 years in male specimens and 58.04 mm and 6.12 years in female specimens. A positive correlation was found between body size (SVL) and age in adult female and male individuals of the species. Because the number of individuals of the species is rapidly decreasing, species protection measures, based on knowledge related to the age structure and breeding features of these frogs, must be put into action urgently.

Can waterfowl buffer the mortality risk induced by GPS tags? A cautionary tale for applied inference across species

GPS tags have become a common tool in ecological studies of animal behaviour and demography despite previous research indicating negative impacts on vital rates across a variety of taxa. Many researchers face tradeoffs when deciding whether they are an appropriate tool because GPS tags may impact vital rates, but they provide detailed data on movements and behaviour that often cannot be obtained in other ways. Using band recovery data, we evaluated the strength of effects induced by GPS tags on annual mortality of adult females across 13 waterfowl taxa, and examined whether taxa with a slower life-history strategy and larger body size were more resilient to GPS tag effects than their fast-lived counterparts with small body size. All species were exposed to hunting, which may interact with underlying processes affecting the impact of GPS tags on mortality, but also allowed for robust analysis of overall annual mortality. Hazard ratios, indicating the risk of death for individuals wearing GPS tags compared to those wearing only metal bands, ranged from 1.13 to 3.25 and the mean proportional difference in survival between marker types across species was 0.33. The magnitude of tag effects was surprisingly consistent across life-history tempo and body size, indicating that slower-lived species did not buffer the effect of wearing GPS tags. Our results highlight that even large, long-lived species, which are generally better at buffering their mortality against environmental adversity, are not immune to the effects GPS tags can have on survival and mortality. The results of our study emphasize the importance of testing for such effects across taxa in future research as technology advances.

Empowered by representation: How plus‐size models create brand evangelists

AbstractTraditional beauty standards are evolving as brands embrace diversity and equity through inclusive communication strategies. This paradigm shift is evident in the transition from stereotypical slender models to the inclusion of more diverse plus‐size models in brand communication. However, an important question arises: Does the presence of a plus‐size model in an advertisement enhance consumer support for a brand? The present research encompasses six studies, including one field study and five experimental studies, that delve into the relationship between models' body size and brand evangelism. The findings demonstrate that featuring a plus‐size model in an advertisement enhances brand evangelism among consumers. Further, consumer empowerment is the underlying mechanism driving this effect. Finally, this research identifies the moderating role of empathy such that consumers with higher levels of empathy experience a heightened sense of empowerment through inclusive brand communication. By illuminating these dynamics, this research contributes to the growing literature of diversity, equity, and inclusion in brand communication.

Nutrition effects larval survival and the development of morphological traits in male and female flour beetles, but genital size and shape remains canalized.

The caloric content and macronutrient ratio of diet consumed is a major source of phenotypic variation in most animal populations. While these nutritional effects have been well-documented for a variety of life-history and morphological traits, the effects of nutrition on male genitals are poorly understood but genitals are thought to be more canalised than general morphology and hence less susceptible to variation in nutrition. Even less is known about the effects of nutrition on female genital form, which to our knowledge, have never been investigated. Here we tested for effects of juvenile dietary macronutrients (protein and carbohydrate) on larval survival, adult morphology, including genital size and shape in male and female flour beetles (Tribolium castaneum). We found there was nutritionally induced plasticity in larval survival and morphology, although the latter effect was variable, with body size being most responsive to dietary macronutrients and genital size and shape being least responsive. Functionally equivalent morphological traits in the sexes responded similarly to nutrition. Previously, we showed that the genitalia of male and female T. castaneum are subject to strong stabilizing sexual selection, and our current findings suggest that developmental mechanisms reduce the nutritional sensitivity of male and female genitals, possibly to ensure matching during mating.

What determines the antipredator strategy in antlion larvae? Burrowing ability decreases the duration of post‐contact immobility

Abstract For prey exhibiting alternative antipredator strategies, selecting the most effective one is critical for survival. However, what determines such selection remains an open question. We hypothesised that this selection depends on prey skill. We test this idea in Myrmeleon immaculatus De Geer, 1773 (Neuroptera: Myrmeleontidae) antlion larvae that exhibit two alternative antipredator behaviours: post‐contact immobility (PCI) and burying. As the larvae live under sandy soils, PCI is only a temporary strategy, and eventually, all larvae will burrow. However, deciding how long to remain immobile before burying may depend on how fast larvae bury themselves (i.e., how quickly the individual can camouflage itself in the substrate). In a tropical forest from the Yucatan peninsula, Mexico, we measured the PCI duration, bury time and body size of 45 larvae in a fine‐grained experimental substrate. We also measured the mandible length to assess their effects on burying skills. The PCI duration was consistently shorter in larvae that took less time to bury but was longer and more variable in larvae that took more time to bury. This effect was independent of larvae body size. Mandible length did not affect burial time. Our findings suggest that when a given prey should select between two mutually excluding antipredator strategies, the intrinsic skill to perform the most relevant one (how fast burying themselves, in this case) may modulate the duration of the other (PCI, in this case). This reinforces the role of predation as a selective force that modulates prey behaviours.

Metabolic rate does not scale with body size or activity in some tick species.

Respiration in ticks is highly efficient and exceptionally low. Ticks can survive years between bloodmeals by having low activity and respiration to conserve energetic resources. Our objective was to compare metabolic (VCO2) and activity rates across 6 tick species. We predicted that VCO2 would be different among species and scale linearly with activity and body mass. Activity and CO2 production were measured for 32h in 6 tick species: Dermacentor andersoni, D. variabilis, Haemaphysalis longicornis, Rhipicephalus appendiculatus, R. microplus, and R. sanguineus. Individual ticks were measured for 30min three times to ensure breathing occurred. Absolute and mass-specific VCO2, total activity, body mass, and ventilation patterns were compared among species. As expected, ticks did not always breathe during the 30-minute measurements, especially R. sanguineus. Ventilation patterns differed among species with R. microplus having primarily cyclic patterns and R. appendiculatus having discontinuous gas exchange. VCO2 did not scale with body mass in most species. Haemaphysalis longicornis and R. sanguineus had the lowest VCO2; however, H. longicornis was the second most active species. Life history, including questing behavior and range expansion, could be contributing to differences between species. For instance, H. longicornis had exceptionally low metabolic rates despite above average activity levels, suggesting an energetic advantage which may underlie recently documented range expansions in North America. Our results demonstrate how ticks utilize energetic resources to maximize longevity. Future research describing questing behavior and distribution modeling may help explain differences in metabolic rates and activity and impacts on life history traits.

Thermal and morphometric correlates of the extremely low rate of energy use in a wild frugivorous primate, the Mayotte lemur

Primates spend on average half as much energy as other placental mammals while expressing a wide range of lifestyles. However, little is known about how primates adapt their rate of energy use in the context of natural environmental variations. Using doubly labelled water, behavioral and accelerometric methods, we measured the total energy expenditure (TEE) and body composition of a population of Eulemur fulvus (N = 12) living in an agroforest in Mayotte. We show that the TEE of this medium-sized cathemeral primate is one of the lowest recorded to date in eutherians. Regression models show that individual variation in the rate of energy use is predicted by fat-free mass, body size, thigh thickness and maximum temperature. TEE is positively correlated with increasing temperature, suggesting that thermoregulation is an important component of the energy budget of this frugivorous species. Mass-specific TEE is only 10% lower than that of a closely related species previously studied in a gallery forest, consistent with the assertion that TEE varies within narrow physiological limits. As lemur communities include many species with unique thermoregulatory adaptations, circadian and/or seasonal temperature variations may have constituted a major selective pressure on the evolution of lemur metabolic strategies.

Contrasting macroevolutionary patterns in pelagic tetrapods across the Triassic-Jurassic transition.

The iconic marine raptorial predators Ichthyosauria and Eosauropterygia co-existed in the same ecosystems throughout most of the Mesozoic Era, facing similar evolutionary pressures and environmental perturbations. Both groups seemingly went through a massive macroevolutionary bottleneck across the Triassic-Jurassic (T/J) transition that greatly reduced their morphological diversity, leaving pelagic lineages as the only survivors. However, analyses of marine reptile disparity across the T/J transition have usually employed coarse morphological and temporal data. We comprehensively compare the evolution of ichthyosaurian and eosauropterygian morphology and body size across the Middle Triassic to Early Jurassic interval and find contrasting macroevolutionary patterns. The ecomorphospace of eosauropterygians predominantly reflects a strong phylogenetic signal, resulting in the clustering of three clades with clearly distinct craniodental phenotypes, suggesting 'leaps' towards novel feeding ecologies. Ichthyosaurian diversification lacks a discernible evolutionary trend, as we find evidence for a wide overlap of craniodental morphologies between Triassic and Early Jurassic forms. The temporal evolution of ecomorphological disparity, fin shape and body size of eosauropterygians and ichthyosaurians during the Late Triassic does not support the hypothesis of an abrupt macroevolutionary bottleneck near the T/J transition. Rather, an important turnover event should be sought earlier, during times of rapid sea level falls.

Farmed crickets (Orthoptera: Gryllidae) raised with dermestids (Coleoptera: Dermestidae) suffer from reduced and delayed growth, but not enough to explain reports of dramatic yield loss.

The mass production of insects for food and feed is an expanding North American industry. Facilities that mass rear insects are at risk of pest infestations because the optimal environmental conditions for rearing beneficial species may also support the development of pest species. Here, we present the first recorded results detailing the interactions between dermestids and farmed crickets. Cricket farms have reported extremely low harvest yield during heavy dermestid infestations, but the exact reasons for this low yield are unknown. Many dermestid larvae are covered in dense, detachable, barbed setae called hastisetae, which are used by the larvae as an active trapping system against arthropod predators. We designed a series of experiments to test the hypotheses that a dermestid pest of cricket farms, black larder beetle (Dermestes ater DeGeer (Coleoptera: Dermestidae)), may be directly impacting Gryllodes sigillatus Walker (Orthoptera: Gryllidae) yield through the physical effects of hastisetae ingestion and/or indirectly impacting cricket yield through competition for fishmeal, a primary source of protein in conventional cricket feed. Our predictions that G. sigillatus life history and survival would be negatively affected by dermestids were largely refuted. Females fed infested diets grew less mass, but not smaller body size, compared to females fed uninfested diets. We also found that while G. sigillatus experienced delayed growth early in life after living with dermestids, they were able to tolerate living with, and consuming, dermestid larvae. We discuss how these findings have led to new hypotheses concerning how dermestid infestations drive reductions in cricket farm yield.

Secular Trends in Gross Motor Coordination: A Study of Peruvian Children Living at High Altitude.

To (1) describe secular trends in gross motor coordination (GMC) scores by sex and age; (2) investigate GMC trends adjusted for concomitant secular trends in height, weight, and overall physical fitness; and (3) examine trends in children's frequencies within different GMC categories. The sample comprises 1562 Peruvian children (690 in 2009 and 872 in 2019), aged 6-11years, from Junín (a high-altitude region). GMC was assessed with the KörperkoordinationsTest für Kinder. Physical fitness was assessed with handgrip strength, standing long jump, and shuttle-run test. Height and weight were measured with standardized protocols. Analysis of variance, covariance, and logistic regression were used. A negative secular trend in GMC (based on raw scores) for boys and girls aged 6-8years was observed. However, a positive trend was observed at 11years of age but only in boys. Finally, there were no significant changes in the likelihood of children having below-normal GMC from 2009 to 2019. Secular trends in GMC were negative in Peruvian children, especially at 6-8years of age. Further, body size and physical fitness trends did not affect the negative secular trend. A high prevalence of children had below-normal GMC in both 2009 and 2019.

Juveniles of a biparental cichlid fish compensate lack of parental protection by improved shoaling performance

Parental brood care greatly affects offspring’s fitness, but the specific effects of care on the collective behaviour of independent offspring are less well understood. It has been suggested that the loss of care induces increased sibling cooperation to compensate parental contributions. However, the empirical evidence is ambiguous. Here, we examined how the loss of early parental care affects the collective behaviour, i.e. shoaling performance of independent juveniles in a genetically heterogeneous lab-population of the biparental cichlid fish Pelvicachromis pulcher. Applying a split-clutch design, we reared in- and outbred offspring with or without parents. In the experiment, we examined shoal density (inter-individual distance) in relation to body size of the shoaling fish. Dense shoaling reduces predation risk and small fish may benefit strongest because they are particularly vulnerable to predation by gape-limited predators. Juveniles reared without parents formed denser shoals and they adjusted shoaling behaviour depending on own body size compared to juveniles reared with parents; especially smaller fish formed dense shoals. Inbreeding did not significantly affect shoaling performance. This indicates that juveniles compensate missing parental care by adjusting their shoaling behaviour depending on own vulnerability. Our study contributes to the understanding of the co-evolution of brood care and sibling cooperation.

PSLBII-5 Impacts of residual feed intake measured as a heifer in drylot on mature cows and calves grazing native pasture

Abstract Selection for feed efficiency is crucial for improving economic and environmental sustainability in beef cattle production. Residual feed intake (RFIfat) is a commonly used measure of feed efficiency and is determined in a drylot setting by calculating the difference between observed and expected dry matter intake (DMI), where expected feed intake is adjusted for metabolic body weight (BW), average daily gain (ADG) and body fatness. Lower RFIfat cattle are more efficient animals as they eat less than predicted for the same growth, body size and body fatness. Limited studies have been conducted evaluating the role of RFIfat on the subsequent performance of cow-calf pairs on native range. Kinsella Composite cows and calves (n = 120) grazed native pasture from July 11 to Sept 12 (summer) and from Sept 13 to Nov 2 (fall) of 2023 were included in this study. All dams had previously been evaluated for RFIfat as a heifer (8 to 12 mo of age) using the GrowSafe Feed Intake System (Vytelle, Canada). Cow and calf ADG were subjected to an analysis of covariance using lm function from stats R core package (R Core Team, 2024), with cow age (2 to 8 yr of age) as the fixed effect and RFIfat as the covariate, analyzing separately by season. An unbalanced Tukey HDS post-hoc were applied for age and p-values < 0.05 were considered significant. Weight gain was assessed on cows with an initial BW on pasture of 598.4 ± 68.4 kg, and 2 to 8 yr of age, and on calves having an initial on pasture BW of 106 ± 21.5 kg, and 65 ± 14 d of age. Cow age affected (P < 0.01) cow ADG during summer, with the youngest dams (2 yr old) gaining more weight than older animals (7 yr old; Figure 1A). No effect of RFIfat was found on cow weight gain during summer grazing. However, during fall grazing, RFIfat affected (P < 0.01) cow ADG (Figure 1B). Low-RFIfat cows (efficient) had increased weight gain during fall grazing as compared with high-RFIfat cows (inefficient: Figure 1B). Calf ADG was not affected (P > 0.1) by cow age, cow RFIfat and cow ADG during summer and fall. We conclude that cows with low RFIfat exhibited superior body weight gain, during fall grazing on native range when forage nutrient quality and quantity become limiting.

Taylor's law on abundance unravels the role of traits and environmental conditions on population dynamics.

The variance-mean scaling in population abundance or Taylor's power law (TPL) has been reported hundreds of times and is related to ecological processes such as competition, dispersal or territoriality. In this sense, the TPL was extensively validated to resume population variability and to show the action of ecological mechanisms. Baumgartner and Peláez (2024) combine databases of fish dynamics along the United States, species traits, species phylogeny and climatic conditions, estimating the TPL for 180 species along 972 populations. The observed scaling suggests that the variability of the population decreases with abundance. Notably, 68% of the variation in the variance-mean scaling was explained by species traits and environmental conditions. Specifically, the life history of the species, associated with its body size, was the main explanation for the TPL, also reporting that the variability of the population increased faster with mean abundance in the headwaters than in other river sections. Equally important, the diversity of the community in which the species were inserted did not affect the scaling. These results provide overwhelming evidence on the nature of TPL on large geographic scales and how they are affected by species biology and environmental conditions. A contribution that should motivate further empirical and theoretical analysis of the TPL and its determinants.

Rare vesicourethral foreign body caused by sexual eccentricity - case report

BackgroundThere are many types of foreign bodies in the bladder and urethra. The most common way is to insert foreign bodies through the external urethra by oneself or by others. It is often seen in situations such as masturbation, mental disorder, curiosity, etc. This article discusses the clinical diagnosis and treatment methods and preventive measures for foreign bodies in the bladder and urethra caused by sexual fetishes.Case presentationThis article introduces a rare case. The patient was a 54-year-old male who inserted a thermometer into his urethra during masturbation and could not remove it. During the operation, we tried various methods to remove the thermometer many times, but due to the angle of the thermometer embedded in the bladder and urethra and the smooth tip of the thermometer, it could not be removed with foreign body forceps. Finally, a homemade negative pressure aspirator (consisting of a section of infusion tube and a 50 ml syringe) was used to completely remove the thermometer from the bladder and urethra. The Written informed consent was obtained from patient did not experience complications such as mercury leakage and bladder and urethral perforation. A telephone follow-up 4 months later showed that the patient urinated smoothly without discomfort such as frequent urination and urgency.DiscussionThere are many types of vesicourethral foreign bodies. When treating vesicourethral foreign bodies clinically, these can be removed through endoscopy, laparoscopy or open surgery according to the size, type and nature of the foreign bodies. At the same time, in order to effectively prevent the occurrence of bladder and urethra foreign bodies, sex education should be vigorously promoted.

VARIAÇÃO BIOMÉTRICA E REPRODUÇÃO DO BIVALVE Anomalocardia flexuosa (BIVALVIA; VENERIDAE) EM DIFERENTES ÁREAS DE PESCA

The bivalve Anomalocardia flexuosa is one of the main fishing resources utilized in artisanal fishing in northeastern Brazil. The objective of the study was to identify the reproductive and biometric variations in the A. flexuosa shell across different fishing areas in the estuary of the Goiana and Megaó rivers in Northeast Brazil, generating information to support strategies for its conservation. Three bimonthly sampling points were used, with P1 being characterized by manual fishing; P2 by more intensive fishing than P1, with the use of less potent fishing gear; and P3 by high-intensity fishing with tools that enhance the collection capacity, such as long-handled nets. For each specimen collected, shell length, shell height, shell width, total weight wet weight, and meat yield were measured to assess size patterns of the organisms and meat yield. Histological analyses were also conducted to identify the reproductive stages. From the analysis of 5,188 captured specimens, it was observed that with P3 presented the lowest body sizes, possibly reflecting overfishing at the site. Growth models were isometric for shell measurements and negative allometric for the length-weight relationship in P1 and P2, and positive allometric in P3. Photomicrographs were taken of 32 specimens for P1, withe 45% males, 48% females and 7% unidentified; and 25 specimens in P3, 12% males, 52% females and 36% unidentified. Regarding reproductive stages, the most representative were the “maturation” and “mature” stages. Due to the evidence of overfishing in P3 and high potential yield in other points, we highlight the need for efficient management actions that mitigate the impacts of overfishing, such as rotation of fishing areas.

BIOLOGICAL ASPECTS OF Ameivula nigrigula (SQUAMATA: TEIIDAE): FEEDING HABIT, SEXUAL DIMORPHISM, REPRODUCTION AND MATURATION OF FEMALES

Life history information plays a crucial role in comprehending the evolutionary processes that shape ecological patterns within species, but there is limited information available on the reproductive and other aspects of tropical Squamata. In this study, we present a comprehensive analysis of dietetic and morphometric data, specifically related to the size and sex determination of Ameivula nigrigula, aiming to investigate if there is sexual dimorphism and identify the onset of sexual maturity in female individuals. By thoroughly examining the stomach contents, we observed that the majority of specimens retain food remnants, with a prevalence of small prey items such as Hymenoptera and Isoptera. Our findings reveal a lack of sexual dimorphism in terms of body size, indicating that males and females possess similar dimensions and proportions. Moreover, our investigations suggest that different color patterns do not correspond to distinct stages of female development, as chromatic variations are observed in both juvenile and ovigerous females. Consequently, dorsal coloration may not serve as a reliable indicator of sexual maturity. The observed chromatic variation is likely a form of polymorphism within the population, lacking the potential to determine life stages. Furthermore, our examination of female fertility reveals the presence of one to two eggs per female, consistent with findings in other Teiidae species.

Mechanical drivers of intrinsic foot muscle for maximum toe flexor strength in upright standing across different body size

This study aimed to evaluate maximum toe flexor strength, foot arch height, intrinsic toe flexor muscle size and foot arch stiffness among individuals with different body sizes, and to compare these variables between sitting and standing positions. Maximum toe flexor strength in sitting and standing, and intrinsic foot muscle thicknesses (flexor hallucis brevis: FHB, flexor digitorum brevis: FDB, abductor hallucis: AH and quadratus plantae: QP), were measured using a toe grip dynamometer and a B-mode ultrasound in healthy young men. FHB was thicker than AH, FDB and QP, AH was thicker than FDB and QP, and no significant difference was found between FDB and QP. Toe flexor strength was correlated with FHB and AH, and foot arch height was correlated with FHB. Toe flexor strength was greater in standing than in sitting. Stepwise multiple regression analysis identified FHB and AH as determinants of toe flexor strength in standing, and the relative muscle strength values per body weight in standing were determined by QP, foot arch index and foot arch stiffness. Overweight individuals had a decreased rate of increase in relative toe flexor strength compared to normal individuals. These results suggest that a large muscle thickness of intrinsic foot muscle a key contributor to toe flexor strength. Moreover, toe flexor muscle in upright standing could have the potential to generate force independently of intrinsic foot muscle size, but obese individuals who chronically put weight on their feet might impair the force amplification mechanism in upright standing.

The effect of developmental temperature on olfaction in a moth revealed by its interaction with body mass

There is a growing interest in the effects of climate warming on olfaction, as temperature may affect this essential sense. In insects, the response of the olfactory system to developmental temperature might be mediated by body size or mass because body size and mass are negatively affected by developmental temperature in most ectotherms. We tested this hypothesis of a mass-mediated effect of developmental temperature on olfaction in the moth Spodoptera littoralis. We measured the olfactory sensitivity of male to female sex pheromone and five plant odors using electroantennography. We compared males reared at an optimal temperature (25 °C with a daily fluctuation of ±5 °C) and at a high temperature (33 ± 5 °C) close to the upper limit of S. littoralis. On average, the olfactory sensitivity of males did not differ between the two developmental temperatures. However, our analyses revealed an interaction between the effects of developmental temperature and body mass on the detection of the six chemicals tested. This interaction is explained by a positive relationship between antennal sensitivity and body mass observed only with the high developmental temperature. Our results show that the effect of developmental temperature may not be detected when organism size is ignored.