Body Shape Variation Research Articles

Multi-modal locomotor costs favor smaller males in a sexually dimorphic leaf-mimicking insect

BackgroundIn most arthropods, adult females are larger than males, and male competition is a race to quickly locate and mate with scattered females (scramble competition polygyny). Variation in body size among males may confer advantages that depend on context. Smaller males may be favored due to more efficient locomotion leading to higher mobility during mate searching. Alternatively, larger males may benefit from increased speed and higher survivorship. While the relationship between male body size and mobility has been investigated in several systems, how different aspects of male body morphology specifically affect their locomotor performance in different contexts is often unclear.ResultsUsing a combination of empirical measures of flight performance and modelling of body aerodynamics, we show that large body size impairs flight performance in male leaf insects (Phyllium philippinicum), a species where relatively small and skinny males fly through the canopy in search of large sedentary females. Smaller males were more agile in the air and ascended more rapidly during flight. Our models further predicted that variation in body shape would affect body lift and drag but suggested that flight costs may not explain the evolution of strong sexual dimorphism in body shape in this species. Finally, empirical measurements of substrate adhesion and subsequent modelling of landing impact forces suggested that smaller males had a lower risk of detaching from the substrates on which they walk and land.ConclusionsBy showing that male body size impairs their flight and substrate adhesion performance, we provide support to the hypothesis that smaller scrambling males benefit from an increased locomotor performance and shed light on the evolution of sexual dimorphism in scramble competition mating systems.

Influence of oceanographic conditions on the body shape variability of Scomber japonicus larvae from the western coast of the Baja California Peninsula

AbstractPacific chub mackerel (Scomber japonicus) is a relevant fishery resource shared among three countries in the northeastern Pacific. The spatiotemporal distribution of larvae has been related to the convergence of oceanographic mesoscale structures, which can generate considerable variability in the morphology of fish larvae. The main goal of this work was to describe the shape changes of larval S. japonicus and their relationship with oceanographic variability, through geometric morphometric analysis to assess the seasonal variability of 10 homologous landmarks distributed on the pre‐anal section of 331 larvae from off the western coast of the Baja California Peninsula (WCBCP), Mexico (2006–2008). The results showed two principal morphotypes in Pacific chub mackerel larvae: The first morphotype had a more hydrodynamic body (longer and shallower head), influenced by increased sea surface flow and colder sea surface temperatures mainly during spring, and the second morphotype had robust larvae (shorter and deeper head) under slower current flow and warmer sea surface temperatures during winter and summer. We concluded that changes in larval body shape are influenced mainly by sea surface flow and sea temperatures, probably associated with the ability to reach higher swimming speeds during feeding success.

Mismatch between shape changes, early growth, and condition for a temperate reef fish from an oceanic island

Settlement is a key process in the life history of marine fish, when shape and ecological changes occur during the transition from a pelagic larva to a benthic juvenile. We studied the covariation of shape changes, condition, and pre- and post-settlement growth of settlers (17–30 mm) of the wrasse, Pseudolabrus gayi, from the Robinson Crusoe island, south-eastern Pacific. Specimens were collected during late March 2018 from four locations at 20 m depth and from a large, natural intertidal pool. The morphospace and the allometry were characterised by landmark-based geometric morphometrics, size and growth were estimated using sagittae otolith microstructure analysis, and condition was determined using the Fulton index. The settler’s phenotype varied from a robust shape with ventrally oriented mouth opening, to slender specimens with frontally oriented mouth, with similar body morphospace among sites. The mean pelagic larval duration was 44.8 ± 4.6 days, settling at 19 ± 2 mm SL. The mean post-settlement growth rate was low (0.09 mm day−1), showing low static allometry (3%). Differences among locations occurred in terms of settler’s condition and growth prior and after settlement, suggesting effects of the microhabitat and potential predators. Therefore, the variability in the settler’s morphospace was decoupled of pre- and post-settlement growth and condition during the transition from pelagic to benthic habitat. Finally, this study highlights the dynamic nature of the settlement–transition period for a temperate reef fish in a period when phenotype variations in body shape and early life-history traits vary asynchronously.

Stock identification of Kawakawa Euthynnus affinis (Cantor, 1849) from Peninsular Malaysia using discriminant analysis

Small epipelagic and migratory, Eutynnus affinis (kawakawa) is one of the commercially significant tunas of Indo-Pacific’s tropical and subtropical waters. Consequently, successful management must ensure its sustainability. Unfortunately, the management and stock structure of certain migratory species in the area are not clear. The current study aimed to discriminate the E. affinis through body shape variations and to evaluate the variations among seven populations of E. affinis. A total of 114 individuals of E. affinis collected from two main geographic area, Straits of Malacca and South China Sea. Multivariate analyses, such as discriminant function analyses (DFA) of 12 morphometric characters was carried out to discriminate seven populations of E. affinis. The results revealed there is a significant variation among the body shape and seven populations of E. affinis. The average shapes of populations from Terengganu, Kelantan, and Johor were approximately similar to each other. In contrast, the average shapes of populations from Selangor were separated. This present study is the first report using morphometric method conducted on E. affinis from Peninsular Malaysian waters.

Testing spatial and environmental factors to explain body shape variation in the widespread Central American Blackbelt cichlid Vieja maculicauda (Teleostei: Cichlidae)

Abstract Body-shape variability may respond to the interaction between history and environment, particularly in species whose range includes known biogeographical barriers. Central America has traditionally been regarded to have functioned as a complete land-bridge connecting two continents since the Plio-Pleistocene and as an incomplete one since much earlier. This history has helped shape species diversification and distributions. Vieja maculicauda is a widely distributed cichlid, found throughout most of the Atlantic slope of Central America, across three of the four geological blocks that make up this region and whose borders are known dispersal barriers. We asked whether there is an effect of geologic blocks on body shape of V. maculicauda as determined by geometric morphometric assessment of 151 individuals from across its range. We asked how much variance in body shape is explained by environmental variables. We used a CVA and a MANCOVA to determine whether a relationship between body shape and geologic blocks exists. For testing body shape correlation against geographic and environmental variables, we used a Mantel test. Our results suggest that body shape in V. maculicauda can be segregated by geologic blocks, while the correlation results showed no strong correlation between our sets of variables.

Morphometric variation of Middle-American cichlids: Theraps– Paraneetroplus clade (Actinopterygii: Cichliformes: Cichlidae)

This study assesses the patterns of variation in body shape, and relations of morphological similarity among species of theTheraps–Paraneetroplusclade in order to determine whether body shape may be a trait in phylogenetic relations. A total of 208 specimens belonging to 10 species of theTheraps–Paraneetroplusclade were examined. The left side of each specimen was photographed; in each photograph, 27 fixed landmarks were placed to identify patterns in body shape variation. Images were processed by using geometric morphometrics, followed by a phylogenetic principal component analysis. The phylogenetic signal for body shape was then calculated. To determine the relations in morphological similarity, a dendrogram was created using the unweighted pair group method and arithmetic mean values, while a Procrustes ANOVA and post-hoc test were used to evaluate significant differences between species and habitats. We found three morphological groups that differed in body length and depth, head size, and the position of the mouth and eyes. The body shape analysis recovered the morphotypes of seven species, and statistical differences were demonstrated in eight species. Based on traits associated with cranial morphology,Wajpamheros nourissati(Allgayer, 1989) differed the most among the species examined. No phylogenetic signal was found for body shape; this trait shows independence from ancestral relatedness, indicating that there is little congruence between morphological and genetic interspecific patterns. As evidenced by the consistently convergent morphology of the species in theTheraps–Paraneetroplusclade, the diversification of the group is related to an ecological opportunity for habitat use and the exploitation of food resources. Although no phylogenetic signal was detected for body shape, there appears to be an order associated with cranial morphology-based phylogeny. However, it is important to evaluate the intraspecific morphologic plasticity produced by ecological segregation or partitioning of resources. Therefore, future morphological evolutionary studies should consider cranial structures related to the capture and processing of food.

Ecology of fear in highly invasive fish revealed by robots

SummaryInvasive species threaten biodiversity and ecosystem functioning. We develop an innovative experimental approach, integrating biologically inspired robotics, time-series analysis, and computer vision, to build a detailed profile of the effects of non-lethal stress on the ecology and evolution of mosquitofish (Gambusia holbrooki)—a global pest. We reveal that brief exposures to a robotic predator alter mosquitofish behavior, increasing fear and stress responses, and mitigate the impact of mosquitofish on native tadpoles (Litoria moorei) in a cause-and-effect fashion. Effects of predation risk from the robot carry over to routine activity and feeding rate of mosquitofish weeks after exposure, resulting in weight loss, variation in body shape, and reduction in the fertility of both sexes—impairing survival, reproduction, and ecological success. We capitalize on evolved responses of mosquitofish to reduce predation risk—neglected in biological control practices—and provide scientific foundations for widespread use of state-of-the-art robotics in ecology and evolution research.

In the Spotlight-Graduate student.

What got you interested in biology? I remember always having an interest in biology, but growing up this was challenging for my parents to nurture. They did not have the scientific background to answer the constant curiosities and inquiries. Nonetheless, they were determined to support me in other ways and alternatively bought me many books about human anatomy and animals. My interest in science intensified in high school through my science classes and during my first research experience as a high school student research assistant at the National Institutes of Health (NIH). This is where I learned the beauty of critical thinking along with the scientific method. Taking a diversity of undergraduate biology courses and having had the opportunity to do undergraduate research, I came to appreciate finding the simplicity in the complex. Learning, searching, and seeing all the different methods to look at complicated processes in the natural world helped me realize that biology adds excitement to life. It allows us to probe the underlying basis of the diversity in life and explore what makes each individual unique. When did you know evodevo was for you? The diversity of our surroundings is what drew me to EvoDevo. The same ingredients that made me who I am are the ingredients that made the insect that landed on my food and the rest of the living species here on earth. The same ingredients were used and evolved to make so many diverse organisms. Even though I do not look like the insects I study, studying them may lead us to understand general principles driving the evolution of all organisms, including humans. EvoDevo combines so many different methodologies to ask questions about how the same genetic toolkit evolved over time to produce enormous variations in body size, shape, and function. How did you find your M.Sc. advisor? What drew me to Dr. Leslie Pick's research was my desire to learn more about genetics. I sent her an interest email during my time as an undergraduate student at the University of Maryland and once in her lab, I fell in love with insects. Their diversity and how they can be fantastic study subjects to deepen our understanding of molecular genetics and development ultimately drew me to her lab. What leads your research: experimental tool, organism, or question? It is a combination of organisms and experimental tools. My current research involves using conserved developmental regulatory genes to assess the effectiveness and risk of RNAi implementation. We are asking how susceptible each species is to RNAi, allowing us to study the function of genes in non-model insects. How does your identity intersect with being a scientist? Being a Latina, first-generation student, and daughter of immigrant parents, my path has been full of obstacles. I often questioned if I had a place in the scientific community. I am grateful that I have found mentorship that has helped me navigate what it means to be a scientist and realize my goals. Being in a department and attending conferences that build an inclusive culture has helped me realize that I can be a scientist and belong. As a Latina scientist, I would like to tackle science with humility to ultimately give back to this scientific community that has provided me so much, give back to my community through the language of science.

Condition- and context-dependent alternative reproductive tactic in Drosophila prolongata

Abstract Species with intense male–male competition for access to females often show alternative reproductive tactics (ARTs) where males of lower competitive ability adopt a sneaky behavior to gain access to mates. These ARTs are usually associated with intrasexual dimorphisms, in that males with distinct morphologies show different tactics. In some cases, however, males adopt different tactics without being dimorphic. Male Drosophila prolongata exhibit continuous variation in body size and shape, with enlarged forelegs that they use in male-male contests and in courtship, including stimulation of the female’s abdomen. During this “leg vibration,” however, nearby males can intercept the courted female and mate without their own courtship. Here, we studied the causes and consequences of these different mating tactics in competitive mating trials between males varying in their size and shape. We found that male mating tactics were condition-dependent. Whereas large, high-condition males were more likely to show leg vibration in their courtship, smaller, lower-condition males were more likely to intercept. However, the number of offspring produced was independent of male condition and reproductive tactic. We discuss possible scenarios for the evolution and maintenance of the ARTs and some future directions for the study of ARTs in this species and in general.

Different Evolutionary Pathways Lead to Incomplete Convergence of Elongate Body Shapes in Carnivoran Mammals.

Although convergence is often recognized as a ubiquitous feature across the Tree of Life, whether the underlying traits also exhibit similar evolutionary pathways towards convergent forms puzzles biologists. In carnivoran mammals, "elongate," "slender," and "long" are often used to describe and even to categorize mustelids (martens, polecats, and weasels), herpestids (mongooses), viverrids (civets and genets), and other carnivorans together. But just how similar these carnivorans are and whether there is convergence in the morphological component that contribute to elongation has never been assessed. Here, I found that these qualitatively described elongate carnivorans exhibited incomplete convergence towards elongate bodies compared to other terrestrial carnivorans. In contrast, the morphological components underlying body shape variation do not exhibit convergence despite evidence that these components are more elongate in elongate carnivorans compared to nonelongate carnivorans. Furthermore, these components also exhibited shorter but different phylogenetic half-lives towards more elongate adaptive peaks, indicating that different selective pressures can create multiple pathways to elongation. Incorporating the fossil record will facilitate further investigation of whether body elongation evolved adaptively or if it is simply a retained ancestral trait.[Axial skeleton; body elongation; convergent evolution; macroevolution; phylogenetic comparative methods; thoracolumbar vertebrae.].

AgentDress: Realtime Clothing Synthesis for Virtual Agents using Plausible Deformations.

We present a CPU-based real-time cloth animation method for dressing virtual humans of various shapes and poses. Our approach formulates the clothing deformation as a high-dimensional function of body shape parameters and pose parameters. In order to accelerate the computation, our formulation factorizes the clothing deformation into two independent components: the deformation introduced by body pose variation (Clothing Pose Model) and the deformation from body shape variation (Clothing Shape Model). Furthermore, we sample and cluster the poses spanning the entire pose space and use those clusters to efficiently calculate the anchoring points. We also introduce a sensitivity-based distance measurement to both find nearby anchoring points and evaluate their contributions to the final animation. Given a query shape and pose of the virtual agent, we synthesize the resulting clothing deformation by blending the Taylor expansion results of nearby anchoring points. Compared to previous methods, our approach is general and able to add the shape dimension to any clothing pose model. Furthermore, we can animate clothing represented with tens of thousands of vertices at 50+ FPS on a CPU. We also conduct a user evaluation and show that our method can improve a user's perception of dressed virtual agents in an immersive virtual environment (IVE) compared to a realtime linear blend skinning method.

Quantifying nonlinear temporal effects of ethanol preservation on round goby (Neogobius melanostomus) anatomical traits.

Geometric morphometrics provides a powerful means of evaluating differences in phenotypic traits among specimens. However, inferences of trait variability can be confounded when measurements are based on preserved samples. We evaluated effects of ethanol preservation on morphology over a 22-week time period for a Laurentian Great Lakes invasive fish, round goby (Neogobius melanostomus, Pallas 1814), using sets of 17 lateral and six dorsal landmarks. We tested whether ethanol preservation affected the magnitude of inter-population variation between individuals collected from lake and river habitats. Generalized least square regression determined that length did not significantly vary through the preservation time series for fish from either population, while mass decreased significantly. Body shape variation was summarized using principal component analysis, which revealed that most preservation-associated changes occurred in the first 14 days. The lateral shape experienced a large magnitude change during the first 24 h in ethanol then only minor changes for the remainder of the study. The dorsal shape began to revert to pre-preservation measurements about 14 days following preservation. Additionally, differences in shape were apparent between the two populations throughout the experiment; however, the magnitude of differences between populations varied depending on whether dorsal or lateral landmarks were considered. Our study demonstrates that tissue responses to ethanol preservation can be more complex than a simple loss of mass, resulting in difficult to predict consequences for geometric morphometric analyses, including variable responses depending on the anatomical region being analyzed.

Body shape variations help to diminish taxonomy uncertainty in juvenile swimming crab Callinectes Stimpson, 1860

The American continent harbors thirteen species of the genus Callinectes, eight of which are distributed in Atlantic South America. This genus has three identification keys for adult individuals only, proposed by Williams and Melo. The first one uses sexual characters to distinguish the species, which prevents the identification of juveniles due to the presence of a sealed abdomen. The other two are similar, both use the form and arrangement of the carapace teeth and have never been systematically tested on juveniles. Therefore, no formal identification keys have been proved to be useful for identify juvenile Callinectes based on any characters. Consequently, there is a lack of baseline studies in taxonomic variation regarding the differences between individuals of this genus. In this study, we investigated the suitability of identification keys, developed for adult individuals of the genus Callinectes, for juvenile individuals. Therefore, we evaluated the degree of dissimilarity of the body shape using the 2D landmark geometric morphometric technique. We compared the results of intra- and interspecific body shape with the key descriptions proposed by Williams and Melo for adults. This study included 537 individuals (juveniles and adults) and is the first effort to propose diagnosis for juvenile Callinectes, demonstrating that the carapace shape is a variable structure with potential to identify juveniles of these species. The results of mean body shape showed the possibility of extending the identification keys developed for adults to earlier ontogenetic classes (juveniles) when analyzed in conjunction with more distinguishable morphological characters tested in this study.

Landmark-based geometric analysis of body shape variation and meristic plasticity among populations of Alburnoides idignensis from Tigris River Drainage, Persian Gulf Basin, Iran

Landmark-based geometric analysis of body shape variation and meristic plasticity among populations of Alburnoides idignensis from Tigris River Drainage, Persian Gulf Basin, Iran

The relationship between sternum variation and mode of locomotion in birds

BackgroundThe origin of powered avian flight was a locomotor innovation that expanded the ecological potential of maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). The avian sternum is the anchor for the major flight muscles and, despite varying widely in morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal variation across a broad phylogenetic scope of birds using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches to test hypotheses of sternum size allometry and the correlation of sternal shape with both size and locomotory capabilities, including flightlessness and the highly varying flight and swimming styles of Neornithes.ResultsWe find evidence for isometry of sternal size relative to body mass and document significant allometry of sternal shape alongside important correlations with locomotory capability, reflecting the effects of both body shape and musculoskeletal variation. Among these, we show that a large sternum with a deep or cranially projected sternal keel is necessary for powered flight in modern birds, that deeper sternal keels are correlated with slower but stronger flight, robust caudal sternal borders are associated with faster flapping styles, and that narrower sterna are associated with running abilities. Correlations between shape and locomotion are significant but show weak explanatory power, indicating that although sternal shape is broadly associated with locomotory ecology, other unexplored factors are also important.ConclusionsThese results display the ecological importance of the avian sternum for flight and locomotion by providing a novel understanding of sternum form and function in Neornithes. Our study lays the groundwork for estimating the locomotory abilities of paravian dinosaurs, the ancestors to Neornithes, by highlighting the importance of this critical element for avian flight, and will be useful for future work on the origin of flight along the dinosaur-bird lineage.

Body shape variation of Garra rufa (Teleostei, Cyprinidae) populations in the Tigris basin in Iran using geometric morphometric analysis

Geometric morphometric method was used to examine the body shape variations among the six populations of Garra rufa , in Iranian part of Tigris basin. A total of 15 landmark-points was used for 170 specimens to hypothesize population differentiation of G. rufa in the six rivers and reservoir. In discriminant function analysis, 85.9% of original grouped cases correctly classified. Principal component analysis (PCA) and canonical variates analysis (CVA) confirmed the significant difference between the populations. The results revealed that the studied populations are divided into three clades based on differences in body depth, caudal peduncle length, backward moving of anal fin. Caudal peduncle showed shortening trend in five populations. Narrower body shape was dominated among specimens of four regions. Studies on body shape provide supporting data on fisheries, stock management, and conservative programs.

Stock Identification of Engraulis encrasicolus (Linnaeus, 1758) by Discriminant Function Analysis (DFA) of Morphometric Characters in The North of Atlantic and Mediterranean Moroccan Coasts

The European anchovy, Engraulis encrasicolus (Linnaeus, 1758) is a small pelagic fish found in the eastern Atlantic, the Mediterranean Sea and the Black Sea. Anchovy (E. encrasicolus) are among the important finfishes harvested in Moroccan coasts. The stock structure of European anchovy in NW Africa is not truly known (FAO, 2013). To effectively manage the anchovy fisheries, it is important to understand the anchovy stock structure. Therefore, discriminant function analysis (DFA) based on morphometric characters was conducted on a total of 204 adult anchovy specimens, seasonally collected by commercial fishing vessels from the region of Mehdia in the North Atlantic area and from the region of M’diq in the Mediterranean coast during the year 2019. Body shape variation, which is often environmentally induced, may provide a good record population structuring. Our data were subjected to univariate statistics of variance (ANOVA) by using SPSS 20 software version. The morphometric characteristics show a separation of two stocks of Engraulis encrasicolus between the two localities. These findings will have major implications for anchovy fisheries management in Morocco.

Ecological Drivers of Carnivoran Body Shape Evolution.

AbstractMorphological diversity is often attributed as adaptations to distinct ecologies. Although biologists have long hypothesized that distinct ecologies drive the evolution of body shape, these relationships are rarely tested across macroevolutionary scales in mammals. Here, I tested hypotheses that locomotor, hunting, and dietary ecologies influenced body shape evolution in carnivorans, a morphologically and ecologically diverse clade of mammals. I found that adaptive models with ecological trait regimes were poor predictors of carnivoran body shape and the underlying morphological components that contribute to body shape variation. Instead, the best-supported model exhibited clade-based evolutionary shifts, indicating that the complexity and variation of body shape landscape cannot be effectively captured by a priori ecological regimes. However, ecological adaptations of body shapes cannot be ruled out, as aquatic and terrestrial carnivorans exhibited opposite allometric patterns of body shape that may be driven by different gravitational constraints associated with these different environments. Similar to body size, body shape is a prominent feature of vertebrate morphology that may transcend one-to-one mapping relationships between morphology and ecological traits, enabling species with distinct body shapes to exploit similar resources and exhibit similar ecologies. Together, these results demonstrate that the multidimensionality of both body shape morphology and ecology makes it difficult to disentangle the complex relationship among morphological evolution, ecological diversity, and phylogeny across macroevolutionary scales.

Molecular identification and morphological variations of Dermacentor albipictus collected from two deer species in northern Mexico.

In total, 57 ticks were collected from six white-tailed deer (Odocoileus virginianus) and three mule deer (O. hemionus) in northern Mexico during the 2017, 2018 and 2019 hunting seasons. Morphological features of adult male and female ticks were observed and photographed using a stereo-microscope and scanning electron micrography. The ticks were identified as Dermacentor albipictus based on taxonomic keys. Molecular analysis using DNA amplification of the 16S rDNA and cytochrome oxidase 1 (COI) genes was employed to resolve the phylogenetic relationships from 18 strains of Dermacentor species. Bayesian phylogenetic analysis was performed in order to obtain a phylogenetic tree based on the concatenated sequence in the D. albipictus clade. The geometric morphometric analysis compared the body shape of ticks collected from specimens of two deer species by analyzing nine dorsal and ventral landmarks from both males and females. The results suggest that body shape variation in dorsal structures might be related to the host.

Shape Analysis as an Additional Tool in Roe Deer (Capreolus capreolus) Management: A New Approach Based on the Relationship between Mandible Shape and Trophic Resources.

Simple SummaryIn recent years, the numerical increase of the roe deer population in Italy has shifted attention to new tools for the management of these populations. The use of biometric data for a correct assessment of the status of ungulate populations is now a standardized and commonly used procedure. In this study, we tried to verify whether, in addition to biometric analyses, morphometrics could be used as a supplementary tool for roe deer management. The study of geometric morphometry has made a major impact by aiding technological and methodological advances. By using Cartesian coordinates of reference points, this method is capable of capturing morphologically distinct shape variables, which can be used as rapid indicators of the status of populations, and thus have the potential to be very useful for wildlife management.The analysis of body shape variability has always been a central element in biology. More recently, geometric morphometry has developed as a new field in shape analysis, with the aim to study body morphological variations and the identification of their causes. In wildlife management, geometric morphometry could be a useful tool to compare the anatomical structures of an organism and quantify its geometric information in order to relate them to environmental factors, thus identifying the causes and effects of the variation and acting management and/or conservation plans. The aim of our study is to evaluate the relationship between roe deer mandible shape and trophic resources available during autumn and winter. We applied a geometric morphometry approach consisting of a Relative Warp analysis of landmark data in 26 roe deer fawn mandibles. Each sample was assigned to an age category and to an environmental category based on the territory carrying capacity. The mandible shape of samples under 8 months of age is likely influenced by the availability of trophic resources. Our findings suggest that the mandible shape is a reliable instrument to assess resource availability. Geometric morphometry could thus represent an additional tool for roe deer management.