Body Size Research Articles

Reduced palatability, fast flight, and tails: Decoding the defence arsenal of Eudaminae skipper butterflies in a Neotropical locality.

Prey often rely on multiple defences against predators, such as flight speed, attack deflection from vital body parts, or unpleasant taste, but our understanding on how often and why they are co-exhibited remains limited. Eudaminae skipper butterflies use fast flight and mechanical defences (hindwing tails), but whether they use other defences like unpalatability (consumption deterrence), and how these defences interact, has not been assessed. We tested the palatability of 12 abundant Eudaminae species in Peru, using training and feeding experiments with domestic chicks. Further, we approximated the difficulty of capture explained by flight speed and quantified by wing loading. We performed phylogenetic regressions to find any association between multiple defences, body size, and habitat preference. We found a broad range of palatability in Eudaminae, within and among species. Contrary to current understanding, palatability was negatively correlated with wing loading, suggesting that faster butterflies tend to have lower palatability. The relative length of hind wing tails did not explain the level of butterfly palatability, showing that attack deflection and consumption deterrence are not mutually exclusive. Habitat preference (open or forested environments) did not explain the level of palatability either, although butterflies with high wing loading tended to occupy semi-closed or closed habitats. Finally, the level of unpalatability in Eudaminae is size dependent. Larger butterflies are less palatable, perhaps because of higher detectability/preference by predators. Altogether, our findings shed light on the contexts favouring the prevalence of single vs. multiple defensive strategies in prey.

Climbing ability of European pond turtles sharply declines on slopes steeper than 36°: Implications for shoreline management

Inadequate shoreline management might be detrimental to semiaquatic ground-dwelling taxa that utilize shorelines for migrations, basking and nesting sites. Although turtles are often associated with shorelines, limited knowledge of their climbing abilities hinders adequate management of these habitats. In this study we tested the climbing abilities of adult Emys orbicularis (N = 60) to explore the effect which artificial shorelines could have on their dispersal and habitat use. Over 90% of turtles were able to successfully climb a 36° slope. At steeper inclinations, female climbing success drastically dropped. Furthermore, climbing steeper inclinations is more time and energy consuming and might limit habitat use. Our results suggest that body size is the limiting factor of turtle climbing ability, regardless of sex. However, larger and less agile female turtles are especially susceptible to steep shorelines, since their fitness directly depends on their ability to reach favourable nesting sites. Based on our results, we suggest that slopes of artificial shorelines in European pond turtle habitats should not exceed 36° angles. Additionally, the shoreline surface should be textured (e.g. with grooves). Further studies should focus on locomotor abilities of other semiaquatic, ground-dwelling taxa (e.g. newts, toads, turtles), particularly as they pertain to obstacles around their reproductive centres.

Blouch: Bayesian Linear Ornstein-Uhlenbeck Models for Comparative Hypotheses.

Relationships among species in the tree of life can complicate comparative methods and testing adaptive hypotheses. Models based on the Ornstein-Uhlenbeck process permit hypotheses about adaptation to be tested by allowing traits to either evolve towards fixed adaptive optima (e.g., regimes or niches) or track continuously changing optima that can be influenced by other traits. These models allow estimation of the effects of both adaptation and phylogenetic inertia - resistance to adaptation due to any source - on trait evolution, an approach known as the "adaptation-inertia" framework. However, previous applications of this framework, and most approaches suggested to deal with the issue of species non-independence, are based on a maximum likelihood approach and thus it is difficult to include information based on prior biological knowledge in the analysis, which can affect resulting inferences. Here I present Blouch, (Bayesian Linear Ornstein-Uhlenbeck Models for Comparative Hypotheses), which fits allometric and adaptive models of continuous trait evolution in a Bayesian framework based on fixed or continuous predictors and incorporates measurement error. I first briefly discuss the models implemented in Blouch, and then the new applications for these models provided by a Bayesian framework. This includes the advantages of assigning biologically meaningful priors when compared to non-Bayesian approaches, allowing for varying effects (intercepts and slopes), and multilevel modeling. Validations on simulated data show good performance in recovering the true evolutionary parameters for all models. To demonstrate the workflow of Blouch on an empirical dataset, I test the hypothesis that the relatively larger antlers of larger bodied deer are the result of more intense sexual selection that comes along with their tendency to live in larger breeding groups. While results show that larger bodied deer that live in larger breeding groups have relatively larger antlers, deer living in the smallest groups appear to have a different and steeper scaling pattern of antler size to body size than other groups. These results are contrary to previous findings and may argue that a different type of sexual selection or other selective pressures govern optimum antler size in the smallest breeding groups.

Sex and mental health are related to subcortical brain microstructure

Some mental health problems such as depression and anxiety are more common in females, while others such as autism and attention deficit/hyperactivity (AD/H) are more common in males. However, the neurobiological origins of these sex differences are poorly understood. Animal studies have shown substantial sex differences in neuronal and glial cell structure, while human brain imaging studies have shown only small differences, which largely reflect overall body and brain size. Advanced diffusion MRI techniques can be used to examine intracellular, extracellular, and free water signal contributions and provide unique insights into microscopic cellular structure. However, the extent to which sex differences exist in these metrics of subcortical gray matter structures implicated in psychiatric disorders is not known. Here, we show large sex-related differences in microstructure in subcortical regions, including the hippocampus, thalamus, and nucleus accumbens in a large sample of young adults. Unlike conventional T1-weighted structural imaging, large sex differences remained after adjustment for age and brain volume. Further, diffusion metrics in the thalamus and amygdala were associated with depression, anxiety, AD/H, and antisocial personality problems. Diffusion MRI may provide mechanistic insights into the origin of sex differences in behavior and mental health over the life course and help to bridge the gap between findings from experimental, epidemiological, and clinical mental health research.

Eye size does not change with artificial selection on relative telencephalon size in guppies (Poecilia reticulata).

Variation in eye size is sometimes closely associated with brain morphology. Visual information, detected by the retina, is transferred to the optic tectum to coordinate eye and body movements towards stimuli, and thereafter distributed into other brain regions for further processing. The telencephalon is an important visual processing region in many vertebrate species and a highly developed region in visually dependent species. Yet, the existence of a coevolutionary relationship between telencephalon size and eye size remains relatively unknown. Here, we use male and female guppies artificially selected for small- and large-relative-telencephalon-size to test if artificial selection on telencephalon size results in changes in eye size. In addition, we performed an optomotor test as a proxy for visual acuity. We found no evidence that eye size changes with artificial selection on telencephalon size. Eye size was similar in both absolute and relative terms between the two selection regimes, but was larger in females. This is most likely because of the larger body size in females, but it could also reflect their greater need for visual capacity due to sex-specific differences in foraging and mating behaviour. Although the optomotor response was stronger in guppies with a larger telencephalon, we found no evidence for differences in visual acuity between the selection regimes. Our study suggests that eye size and visual perception in guppies does not change rapidly with strong artificial selection on telencephalon size.

Modeling body size information within weight labels using probability distributions.

What images of bodies do we associate with thinness and fatness? Can our representations of weight-related words be described by simple probability distributions? To answer these questions, the present study examined participants' perceptions of a set of weight-related words using a pictural scale. 259 French women indicated the thinnest, fattest, and best-fitting figures for 13 words. We then used their responses to construct PERT probability distributions, simple skewed distributions allowing to visualize what body sizes were associated with each word. In particular, the variability of the distributions showed how different weight labels can have more or less precise meanings. We found some evidence that the lowest body mass index associated with a label shifted towards thinner figures as body dissatisfaction increased. Using the same method, we investigated the boundaries of what participants consider the ideal body, and showed that the inclusion of their own body in these boundaries predicted their levels of body dissatisfaction. We argue that PERT distributions can be a useful, easy-to-use tool in body image research for modeling the representations of weight labels in different populations.

One size does not fit all: Optimizing size-inclusive model photography mitigates fit risk in online fashion retailing

AbstractDespite retailers’ interest in moving away from thin-model photography to embrace body-size diversity, online fashion shopping predominantly features thin models. While concerns about negative consequences for sales impede industry-wide changes, we demonstrate that consumers and retailers benefit from optimally portraying diverse bodies. Three studies unveil the “Dissimilarity-Risk Deterrence Effect,” wherein thin models dissuade consumers with larger clothing sizes from online purchasing due to perceived body-size dissimilarity and heightened fit-risk perception. Eight experiments demonstrate that models of consumers’ own size mitigate the effect, enhancing online purchase decisions, while controlling for mechanisms like positive affect, authenticity and social identification. The effect extends across various clothing items but attenuates when body size matters less to fit evaluation. Moreover, the effect is concealed by retailers’ risk-reducing strategies, such as measurement information and free product return policies. This research underscores the strategic significance of diverse product imaging to improve supply chain efficiency and consumer well-being.

Indexing left ventricular end-systolic dimension to body size: Association with mortality in patients with degenerative mitral regurgitation.

In patients with degenerative mitral regurgitation (DMR), left ventricular (LV) dysfunction is associated with increased risk of heart failure and excess mortality. LV end-systolic diameter (LVESD) is an established trigger for intervention, yet recommended LVESD thresholds apply poorly to patients with small body size. Whether LV normalization to body surface area (BSA) may be used as a trigger for DMR correction is unknown. We examined the link between LVESD index (LVESDi) and outcome in DMR to identify appropriate thresholds for excess mortality. This study focuses on 2753 consecutive patients with DMR due to flail leaflets diagnosed in tertiary centres from Europe and the United States, with prospective echocardiographic measurement of LVESD and BSA and long-term follow-up. The primary endpoint was mortality after diagnosis under conservative management. Secondary endpoints were mortality under conservative and surgical management and postoperative mortality of patients who underwent surgery. The optimal LVESDi cut-off for mortality prediction was 20 mm/m2. Irrespective of management type, 10-year survival was lower with LVESDi ≥20 mm/m2 than with LVESDi <20 mm/m2 (both p < 0.001). After covariate adjustment, LVESDi ≥20 mm/m2 was independently predictive of mortality under conservative management (adjusted hazard ratio [HR] 1.41, 95% confidence interval [CI] 1.15-1.75), and with conservative and surgical management (adjusted HR 1.34, 95% CI 1.17-1.54). LVESDi remained associated with poorer postoperative outcome in patients who underwent intervention. LVESDi showed higher incremental predictive value over the baseline model compared to LVESD. The association between LVESDi ≥20 mm/m2 and outcome was consistent in subgroups of patients with DMR. In severe DMR due to flail leaflets, LVESDi is a marker of risk additive and incremental to LVESD. Its use in clinical practice should lead to earlier referral to mitral valve surgery and improved long-term outcome.

Year-round sampling of the fish community in a boreal lake: differences between summer and winter influence estimates of species composition, catch, and fish size.

Boreal lakes experience pronounced seasonal variation in abiotic factors, especially light, temperature, and oxygen. A deep boreal humic lake was sampled year-round to test putative changes in total fish catch, species composition, catch-per-unit-effort (CPUE), habitat use, fish size, and condition. Monthly sampling was conducted in Lake Pääjärvi, southern Finland, during one full year in 2020-2021 as well as in March and August 2021 and 2022. The fish community was dominated by cyprinid species in all months, but the percentage of percid fish caught increased during the warm summer period. Most fish were caught in littoral habitats and the highest catches occurred in summer, but some species (e.g., ruffe, Gymnocephalus cernua, and pikeperch, Sander lucioperca) remained abundant in the winter catch. The body size of fish was larger in the winter catch, while condition factor was higher in summer for most species. Fish species proportions in total catch, CPUE, and average size of fish were closest to the annual mean values in September, which may be used as the optimal period to monitor fish communities of similar deep boreal lakes. Our findings highlight the need for year-round research to reveal the impacts of rising temperatures and diminishing ice-covered periods in fish communities and lake food webs.

Plasticity in mosquito size and thermal tolerance across a latitudinal climate gradient.

Variation in heat tolerance among populations can determine whether a species is able to cope with ongoing climate change. Such variation may be especially important for ectotherms whose body temperatures, and consequently, physiological processes, are regulated by external conditions. Additionally, differences in body size are often associated with latitudinal clines, thought to be driven by climate gradients. While studies have begun to explore variation in body size and heat tolerance within species, our understanding of these patterns across large spatial scales, particularly regarding the roles of plasticity and genetic differences, remains incomplete. Here, we examine body size, as measured by wing length, and thermal tolerance, as measured by the time to immobilisation at high temperatures ("thermal knockdown"), in populations of the mosquito Aedes sierrensis collected from across a large latitudinal climate gradient spanning 1300 km (34-44° N). We find that mosquitoes collected from lower latitudes and warmer climates were more tolerant of high temperatures than those collected from higher latitudes and colder climates. Moreover, body size increased with latitude and decreased with temperature, a pattern consistent with James' rule, which appears to be a result of plasticity rather than genetic variation. Our results suggest that warmer environments produce smaller and more thermally tolerant populations.

Body Size Remains the Major Source of Sex Disparity Despite Updated Liver Transplant Allocation Policies.

Efforts to address US liver transplant (LT) access inequities continue, yet disparities linked to candidate traits persist. Analyzing national registry data pre- and post-Acuity Circle (AC) policy, our study assessed the impact of low body surface area (BSA) on LT waitlist mortality. The outcomes of LT candidates listed in the pre-AC era (n = 39 227) and post-AC (n = 38 443) were compared for patients with low BSA (22.9% pre-AC and 23.3% post-AC). Fine-Gray competing risk models highlighted that candidates with low BSA had a lower likelihood of LT both pre-AC (hazard ratio [HR] 0.93; 95% confidence interval [CI], 0.92-0.95) and post-AC (HR 0.96; 95% CI, 0.94-0.98), with minimal improvement in waitlist mortality/dropout risk from pre-AC (HR 1.15; 95% CI, 1.09-1.21) to post-AC (HR 1.13; 95% CI, 1.06-1.19). Findings were mostly reaffirmed by Cox regression models incorporating the trajectory of Model for End-stage Liver Disease (MELD) scores as time-dependent covariates. Regions 3, 5, and 7 showed notable LT waitlist disparities among low BSA patients post-AC policy. Causal mediation analysis revealed that low BSA and the difference between MELD-sodium and MELD 3.0 (MELD_D, as a proxy for the potential impact of the introduction of MELD 3.0) largely explained the sex disparity in AC allocation (percent mediated 90.4). LT waitlist disparities for female candidates persist, largely mediated by small body size. Although MELD 3.0 may reduce some disparities, further body size adjustments for in allocation models are justified.

Coevolution of larval signalling and worker response can trigger developmental caste determination in social insects.

Eusocial insects belong to distinct queen and worker castes, which, in turn, can be divided into several morphologically specialized castes of workers. Caste determination typically occurs by differential nutrition of developing larvae. We present a model for the coevolution of larval signalling and worker task allocation-both modelled by flexible smooth reaction norms-to investigate the evolution of caste determination mechanisms and worker polymorphism. In our model, larvae evolve to signal their nutritional state to workers. The workers evolve to allocate time to foraging for resources versus feeding the brood, conditional on the larval signals and their body size. Worker polymorphism evolves under accelerating foraging returns of increasing body size, which causes selection to favour large foraging and small nursing workers. Worker castes emerge because larvae evolve to amplify their signals after obtaining some food, which causes them to receive more food, while the other larvae remain unfed. This leads to symmetry-breaking among the larvae, which are either well-nourished or malnourished, thus emerging as small or large workers. Our model demonstrates the evolution of nutrition-dependent caste determination and worker polymorphism by a self-reinforcement mechanism that evolves from the interplay of larval signalling and worker response to the signals.

Molecular identification and morphological variations of Amblyomma lepidum imported to Egypt, with notes about its potential distribution under climate change.

The tick Amblyomma lepidum is an ectoparasite of veterinary importance due to its role in transmitting livestock diseases in Africa, including heartwater. This study was conducted in 2023 to monitor Amblyomma spp. infestation in dromedary camels imported from Somalia, Ethiopia, and Sudan to Egypt. This study inspected 200 camels at the Giza governorate's camel market that had been imported from Somalia, 200 from Ethiopia, and 200 from Sudan for tick infestation. Specimens were identified using morphological characteristics and phylogenetic analyses of the 12S and 16S rRNA genes. Clusters were calculated using an unweighted pair-group method with arithmetic averages (UPGMA) dendrogram to group the specimens according to their morphometric characteristics. The morphometric analysis compared the body shape of ticks collected from different countries by analyzing dorsal features. Principal component analysis (PCA) and canonical variate analysis (CVA) were performed to obtain body shape variation among specimens from different countries. Results indicated that camels were infested by 57 males Amblyomma lepidum, and no female specimens were observed; among these specimens, one may have a morphological abnormality. The results suggest that A. lepidum specimens collected from camels imported to Egypt from African countries exhibit locally adapted morphology with variations among specimens, particularly variations in body size. This adaptation suggests minimal potential for genetic divergence. Ecological niche modeling was used to predict the areas in Africa with suitable climates for A. lepidum. The study confirmed that East African countries might have the most favorable climatic conditions for A. lepidum to thrive. Interestingly, the amount of rain during the wettest quarter (Bio16) had the strongest influence on the tick's potential distribution, with suitability decreasing sharply as rainfall increased. Future predictions indicate that the climatic habitat suitability for A. lepidum will decrease under changing climate conditions. However, historical, current, and future predictions indicate no suitable climatic habitats for A. lepidum in Egypt. These findings demand continuous surveillance of A. lepidum in camel populations and the development of targeted strategies to manage tick infestations and prevent the spread of heartwater disease.

Remarks on the functional morphology of the earliest mammals

AbstractThe earliest mammals are characterized by a series of derived characters when compared to their synapsid predecessors. In comparison to non-mammalian synapsids, these features include highly efficient teeth, a small body size, a parasagittal limb posture, as well as a reduced number of ribs and girdle elements and light-weighted tails. We argue that the mammalian body construction and its functionality are constituted by a set of partially interrelated morphological traits, including akinetic skulls, tooth anatomy, and food processing; body size, locomotor speed, and tail reduction; the posture of the body and the construction of the girdle elements; as well as body torsion and rib reduction. By discussing these features from a biomechanical view, we demonstrate that high speed was the most important evolutionary advantage of the small earliest mammals over their larger synapsid ancestors, as well as over dinosaurs at the end of the Mesozoic.

Far from the walking pace. Ecological and evolutionary consequences of the suboptimal locomotion speeds in non-adult humans.

Locomotion activities are part of most human daily tasks and are the basis for subsistence activities, particularly for hunter-gatherers. Therefore, differences in speed walking-related variables may have an effect, not only on the mobility of the group, but also on its composition. Some anthropometric parameters related to body length could affect walking speed-related variables and contribute to different human behaviors. However, there is currently little information on the influence of these parameters in nonadult individuals. Overall, 11 females and 17 male child/adolescents, 8-17 years of age, volunteered to participate in this cross-sectional study. Five different pace walking tests were performed on a treadmill to calculate the optimal locomotion speed (OLS) and U-shaped relationship between the walking energy expenditure and speed (χ2 cost of transport [CoT]) (i.e., energetic walking flexibility). The mean OLS was 3.05 ± 0.13 miles per hour (mph), with no differences between sexes. Similarly, there were no sex differences in walking flexibility according to the χ2 CoT. Body height (p < .0001) and femur length (p < .001) were positively correlated with χ2 CoT; however, female child/adolescents mitigated the effect of height and femur length when walking at suboptimal speeds. Consistent with prior observations in adults, our findings suggest that anthropometric parameters related to body stature are associated with reduced suboptimal walking flexibility in children and adolescents. Taken together, these results suggest that children and adolescents can adapt their pace to the one of taller individuals without a highly energetic penalty, but this flexibility decreases with increasing body size.

Machine Vision Analysis of Ujumqin Sheep’s Walking Posture and Body Size

The ability to recognize the body sizes of sheep is significantly influenced by posture, especially without artificial fixation, leading to more noticeable changes. This study presents a recognition model using the Mask R-CNN convolutional neural network to identify the sides and backs of sheep. The proposed approach includes an algorithm for extracting key frames through mask calculation and specific algorithms for head-down, head-up, and jumping postures of Ujumqin sheep. The study reported an accuracy of 94.70% in posture classification. We measured the body size parameters of Ujumqin sheep of different sexes and in different walking states, including observations of head-down and head-up. The errors for the head-down position of rams, in terms of body slanting length, withers height, hip height, and chest depth, were recorded as 0.08 ± 0.06, 0.09 ± 0.07, 0.07 ± 0.05, and 0.12 ± 0.09, respectively. For rams in the head-up position, the corresponding errors were 0.06 ± 0.05, 0.06 ± 0.05, 0.07 ± 0.05, and 0.13 ± 0.07, respectively. The errors for the head-down position of ewes, in terms of body slanting length, withers height, hip height, and chest depth, were recorded as 0.06 ± 0.05, 0.09 ± 0.08, 0.07 ± 0.06, and 0.13 ± 0.10, respectively. For ewes in the head-up position, the corresponding errors were 0.06 ± 0.05, 0.08 ± 0.06, 0.06 ± 0.04, and 0.16 ± 0.12, respectively. The study observed that sheep walking through a passage exhibited a more curved knee posture compared to normal measurements, often with a lowered head. This research presents a cost-effective data collection scheme for studying multiple postures in animal husbandry.

Tracing microplastic pollution in Mahi River estuary, Gulf of Khambhat, Gujarat, and their influence on functional traits of macrobenthos.

Most maritime habitats contain microplastic (MPs) contamination. The quality of the benthic ecosystem's habitat is declining as MPs accumulate in marine system. The contamination of MPs must therefore be investigated. We studied MPs pollution in the Mahi River, estuary, and macrobenthos. In the present study, the abundance of MPs fragments gradually decreased from the high tide zone to the low tide zone and muddy sediment has high MPsconcentrations due to sediment characteristics and particle size. The majority of sediment and biota MPs were fibrous and black. MPs in both silt and biota have identical chemical compositions (modified cellulose), shapes, and colors. A significant source of pollutants and MPs fluxing into the ocean is well within the river system. Perinereis aibuhitensis ingested the most MPs out of 11 species, whereas Amphipods did not show any presence of MPs. Our findings showed that functional characteristics are essential for macrobenthos MPs intake. MPs in macrobenthos are high due to biological functions such as feeding, ecological groups, feeding mechanisms, body size, and bioturbation. MPs in marine sediment and organisms aretracked down to the Mahi River exceeding 50km. The present work has investigated the idea that the macrobenthos that live in the sediment are ingesting the MPs that are building up there and this ingestion relies on the macrobenthos' functional characteristics.

Elevated human impact on islands increases the introduction and extinction status of native insular reptiles

In the Anthropocene, the ranges of introduced species are expanding, while extinction‐prone species are contracting. Introductions and extinctions are caused by how species respond to human impacts, but it is unknown why the ranges of some species expand and some contract. Here, we test whether this opposite response of human impact is due to introduced and extinction‐prone species falling at opposite ends of geographic, evolutionary, or ecological trait continua. We constructed a database of native range maps, traits, phylogenetic relationships, and the introduction and extinction‐prone status of squamate reptiles with ranges native to the Western Hemisphere. Across &gt; 3000 snake and lizard species (88% of known native squamates), 142 had been introduced elsewhere and 483 were extinction‐prone (i.e. vulnerable, endangered, critically endangered, extinct in the wild, extinct). To explain variation in status, we first tested if the same human‐impacted regions in the Americas contained the native ranges of species of either status. Second, we tested for phylogenetic signal in species status. Finally, we tested the explanatory power of multiple trait continua. The native ranges of introduced and extinction‐prone reptiles were clustered in island regions with high human impact versus mainland regions with lower human impact. Phylogenetic signal was weak for status, but introduced and extinction‐prone species were clustered in different clades. All geographic and ecological traits that explained each status supported the opposite ends hypothesis. Introduced species had larger, edgier ranges, while extinction‐prone species had smaller, simpler ranges. Introduced species were mostly herbivorous/omnivorous, while extinction‐prone species were mostly carnivorous. Introduced species produced larger clutches, while extinction‐prone species had smaller body sizes. In the Anthropocene, the native ranges of introduced and extinction‐prone species are in the same human‐impacted regions where trait continua, having opposite effects, determine whether species ranges expand or contract in the continuing face of global change.

Morphometric comparison of linear body size of IPB D1 chickens and native chickens through discriminant analysis

Animal protein production from chickens predominantly comes from purebred chicken farms rather than local ones. Improving the genetic quality of local chickens in Indonesia can be achieved through developing IPB D1 chickens. This study aims to identify distinguishing variables between IPB D1 chickens and native chickens using linear body measurements through discriminant analysis. The research involved IPB D1 chickens and native chickens in the layer phase, employing descriptive statistical analysis, T2-Hotelling, Fisher linear discriminant analysis, and Wald-Anderson classification. Results showed that IPB D1 roosters and native roosters differ in femur length (X1), tarsometatarsus circumference (X4), maxilla length (X7), and comb height (X8) with a morphometric dissimilarity of 2.06. IPB D1 hens and native hens differ in tarsometatarsus circumference (X4) and wing length (X6), with a morphometric dissimilarity of 1.41. The Wald-Anderson classification, based on natural selection, suggests removing particular chickens that are not classified as IPB D1 and native chickens from their respective groups to produce chickens that match their characteristics.

Identifying candidate genes and biological pathways in muscle development through multi-tissue transcriptome comparisons between male and female geese

Males and females have long shown disparities in body weight and height; yet, the underlying mechanisms influencing growth and development remain unclear. Male and female Zhedong White Geese (ZDW) geese have long been selected for large body size and egg production, respectively. This led to a large difference in body weight between males and females, making them a unique model for studying the effects of sex on growth and development. This study aimed to elucidate these mechanisms by comparing the transcriptomes of muscle and pituitary tissues in male and female ZDW geese to identify the critical genes responsible for the effects of sex on growth performance. Our analysis revealed 1101 differentially expressed genes (DEGs) in leg musculature (507 upregulated, 594 downregulated), 773 DEGs in breast musculature (311 upregulated, 462 downregulated), and 517 DEGs in the pituitary gland (281 upregulated, 236 downregulated) between male and female geese. These DEGs were significantly enriched in gene ontology and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways associated with endocrine metabolism (e.g., hormonal activities), muscle formation (e.g., sarcomere and myofibril), and bone formation (e.g., bone morphogenesis and cartilage formation). The upregulated genes in males were enriched in KEGG pathways involving nutrient digestion and absorption (vitamin and protein), as well as the secretion of digestive juices (gastric acid and bile). Through protein–protein interaction analyses, we also observed high-density gene networks related to muscle fiber development, calcium ion metabolism, mitochondrial respiratory chain, and bone development. Therefore, our multi-tissue transcriptome analysis provides a deeper understanding of the complex and systematic gender-driven effects on growth and development in geese. IGF1, GHRHR, and NCAPG-LCORL and pathways related to myogenesis might play vital roles in gender differences before hormones exert their effect.