Article

Long-Term Trends and Correlates of Antler Anomalies in Roe Deer

Authors:
To read the full-text of this research, you can request a copy directly from the authors.

Abstract

Length and structural complexity of antlers provide an indication of individual quality in many ungulates in the context of female mate choice and trophy hunting. Selectivity of hunters for individuals with various antler sizes may have bearing on the population structure. It is less well understood, however, whether and how antler anomalies may signal individual characteristics. We used data on 2,461 roe deer (Capreolus capreolus) males harvested by stalking during 1966–2011 in western Poland to test hypotheses explaining probability of occurrence of accessory, broken, and malformed antlers. By employing a multinomial logistic regression, we showed that the probability of occurrence of broken and malformed antlers increased in males older than 2 years. Probability of occurrence of accessory and, in young males, broken antlers was higher in individuals with increased body weight. Occurrence of malformed antlers decreased over the study period. Contrary to our prediction, we did not detect an effect of distance to forest on the probability of malformed antlers occurring. We conclude that the main premise of compensatory culling is not supported in roe deer. © 2014 The Wildlife Society.

No full-text available

Request Full-text Paper PDF

To read the full-text of this research,
you can request a copy directly from the authors.

ResearchGate has not been able to resolve any citations for this publication.
Article
Full-text available
Habitat constrains and shapes successful ecological and physiological strategies and thus provides the context for the evolution of life-history traits. The stress axis plays a vital role in the endocrine system and is a critical component adapting mammals to particular habitat pressures. It is subject to both individual activational and organizational plasticity as well as to evolutionary modification. To illustrate, I examine the suite of traits of the stress axis associated with breeding frequency in male mammals, which varies in a continuum from semelparity to iteroparity. During the breeding season, males in species at the semelparous end of the continuum exhibit high concentrations of free corticosteroids, low concentrations of glucocorticoid-binding protein, a failure of the negative feedback system, a gonadal axis that is not inhibited by high corticosteroid concentrations, and immunosuppression. Iteroparous species exhibit the opposite traits. The evolutionary constraints selecting for the former may partially be related to phylogeny (in marsupials) as well as to an interaction of the restrictions imposed by the environment on female reproduction, the mating system, the high costs of reproduction, and the low adult survival during the nonbreeding season.
Article
Full-text available
We studied characteristics of paired antlers, including types of asymmetry, from 1,501 Alaskan moose (Alces alces gigas). We observed no evidence of antisymmetry in moose antlers, but number of tines was greater on left than right antlers, indicating directional asymmetry. Absolute and relative fluctuating asymmetry (FA) occurred for palm characteristics but not for beam circumference. Relative FA varied inversely with the overall size of antlers for attributes of the palm, which was expected for a secondary sexual characteristic. Smaller-antlered males exhibited greater FA than did larger-antlered moose in palm characteristics. Because large-antlered males, which mate most often among moose and other polygynous cervids, expressed the least relative FA, we hypothesize that this metric indicates quality of individual moose. Whether symmetry of antlers is related to antler breakage or honest advertisement or whether females select mates based on FA is unknown and deserves additional study.
Article
Full-text available
This paper investigates variation in female fecundity in relation to effects of age and body weight within and between 15 populations of roe deer Capreolus capreolus (Linnaeus, 1758) in Britain. Analyses were based on carcass material and fecundity was assessed from the presence/absence and number of fertilised ovulations (corpora lutea) and implanted foetuses. A significant proportion (> 10%) of does ovulated in their first year in some populations, but such precocious reproductive activity rarely resulted in successful implantation of a foetus. Generally, the majority of yearling does (in their second year) conceived successfully, but average potential litter size was lower than among older animals. There was no consistent age- related variation in fecundity among does older than 2 years. Differences in fecundity between age and body weight classes suggest weight thresholds may exist for the onset of puberty and for successful conception as an adult. Fecundity of adults and yearlings was highly variable between populations and in some populations was considerably lower than previously reported for this species. Although differences between populations were correlated with differences in body weight, this relationship was insufficient to explain the wide variation in fecundity across Britain, suggesting fecundity body weight thresholds will be defined independently in separate populations.
Article
Full-text available
Development of ornamental characters exposed to directional selection may be particularly sensitive to the effect of parasitic infections. Antlers are ornamental characters of importance in intraspecific interactions, and are in reindeer (Rangifer) developed by both males and females. By antihelmintic treatment of naturally infected female reindeer we show that parasite intensities affect development of antler asymmetry, but not antler length. These results suggest that asymmetry in antlers may reflect parasite intensities and thus be of importance in intraspecific assessment of genetic resistance towards infectious organisms.
Article
Full-text available
A novel, simple, and objective method is presented for ageing roe deerCapreolus capreolus (Linnaeus, 1758) evaluated on 471 lower jaws from roe deer of known age (351 with permanent premolars). It is based on tooth eruption patterns and presence/absence of wear characters in jaws from roe deer integrated in a scoring system. Permanent cheek teeth emerge in May–July in the year af ter birth, which enables precise age determination of individuals with deciduous premolars. For individuals with permanent cheek teeth, the method provides the correct age for all individ uals younger than 13 months and > 80% of all individuals between 13 and 24 months old. For older in dividuals the accuracy decreases, but decent accuracy is achieved to the age of 48 months. Males have higher wear rates than females corroborating recent documentation of sex-specific life history tactics in ungulates. The data originate from two separated Danish roe deer populations exposed to contrasting habitats, but no difference in wear rate is found between populations. Thus, previous concern about the validity of age determination methods based on tooth wear may have been overstated. The findings demonstrate that objective measures of tooth wear can provide the basis for age determination in ungulate species that are otherwise difficult to age. Key words Capreolus capreolus -age determination-known age-mo lar wear-objective age criteria
Article
Full-text available
Formation of primary cranial appendages (pedicles and first antlers) in deer is initiated by a specialized periosteum, for whichGoss (1983) introduced the term antlerogenic periosteum. The antlerogenic periosteum (AP) is located on the external frontal crests, this area of the deer skull most likely being of neural crest origin. As was discovered byHartwig (1968b) andHartwig andSchrudde (1974), AP is capable of autonomous differentiation even when grafted to other regions of the body, thereby causing the growth of ectopic pedicles and antlers. This means that the cells of the AP are determined for pedicle and antler formation. There is further evidence that the cells forming the bony component of regenerating antlers are derivatives of the AP and that the AP contains crucial morphogenetic information for antler shape. The cells of the AP and its derivative, the antler perichondrium, exhibit features (high glycogen content, long life spanin vitro) that are normally only found in embryonic cells. These findings support our hypothesis, originally based on studies of double-head antlers, that the growth of both primary cranial appendages (pedicles and first antlers) and of regenerated antlers depends on a population of antlerogenic periosteal stem cells. In fallow and red deer, formation of both pedicles and antlers occurs by a process of modified endochondral ossification, whereas in the roe deer there is evidence that the pedicles are formed solely by intramembranous ossification, while antler growth proceeds by endochondral ossification. The transformation of pedicle skin to antler velvet is a specific reaction of the integument to an inductive signal originating from subdermal (presumably periosteal/perichondrial) antlerogenic cells. Occurrence of ectopic antlers reveals that also skull bone periosteum from outside the pedicle anlage area is capable of producing antler structures when exposed to strong unphysiologic stimuli. Contrary to AP, this periosteum is however not determined for cranial appendage formation, since its transplantation to other body regions does not cause ectopic pedicle and antler growth.
Article
Full-text available
In all areas where they have been studied, male roe deer are believed to have a territorial mating system, although few quantitative studies have been conducted and there remains considerable debate about the function of male roe deer territories. We observed 139 aggressive interactions between male roe deer in Storfosna Island (Norway) during one territorial season (March–August). We recognised seven rank levels of escalation according to the potential danger of the behaviour. On the basis of the number of escalation levels included in the interactions, the complexity of the fights was also scored. We recorded the presence of other individuals during the interaction, the age, the antler size, the territorial status and the residency status of the two contestants and tested how these variables affected escalation, complexity and outcome of the fights. Most of the interactions ended with low levels of escalation, and physical contact occurred only in fights between two territorial bucks. The escalation was also affected by the difference in antler size index (the bucks escalated more when the difference in antler size was smaller) and increased with an increasing number of female deer present during the interaction. The resident buck won in 81% of the fights. When it drew or lost, it was generally both inferior in age and antler size, and the duration and escalation of the interactions were higher. However, even when a fight was lost, no territory loss occurred. These results are consistent with the evolutionary game theory and the proposed low risk–low gain strategy of roe deer bucks.
Article
Full-text available
Accessory (supernumerary) antlers are an infrequent phenomenon in male cervids. These bony protuberances grow mostly from permanent pedicles, which developed in response to a repeated or a severe trauma to frontal, nasal or parietal bones. They regularly undergo seasonal mineralization, casting and regrowth and may persist for many years. Three examples of accessory antlers in telemetacarpal cervids, roe deer (Capreolus capreolus), white-tailed deer (Odocoileus virginianus) and moose (Alces alces), are presented. The initiation of accessory antlerogenesis, the progress of growth and development, and the mineralization and casting of accessory antlers were mostly identical or similar to processes observed in the antlerogenesis of lateral antlers. The antlerogenic property of the competent periosteum, located within the "antler territory", appears to play a crucial role in the development of accessory antlers. The variability in location and the progress of development of accessory antlers, which were observed in several antlerogenic cycles, is discussed in relationship to the origin of deciduous antlers in extinct ancestors of cervids.
Article
Full-text available
The dynamics of ungulate populations depend not only on the size, but also on the sex- and age-structure of the population. Successful management therefore depends on obtaining estimates of the age composition. Variation in performance due to age can be fairly well described by stages, and simple, rough methods for ageing cervids can therefore be useful to management. We assessed the performance of three relatively simple and objective methods based on tooth wear (height of molar), weight of eye lenses and diameter of pedicles (males only) on a sample of 77 female and 81 male European roe deer Capreolus capreolus from Lier, Norway. The relationship between tooth wear and age was linear, whereas the relationship between weight of eye lenses and diameter of pedicles was curvilinear with age, likely making them unreliable for old age classes. However, as only three males and six females ≥ 6 years old were included, we were unable to assess the uncertainty in age estimation for older age classes precisely. No simple method could precisely age roe deer, even up to five years of age. Our results do suggest that tooth wear, i.e. height of molar, can serve as a very simple and objective measure of age in roe deer, given that moderate precision (an error rate of ± 1 year and a success rate of 70% up to four years of age) is sufficient to reach management aims. As residuals between age estimates based on tooth wear and diameter of pedicle were not correlated, combining these methods improved the fit slightly. Since tooth wear may differ between areas, the scales presented here may perform less well in other areas, and a calibration for each area is clearly recommended.
Article
Full-text available
Forest fragmentation may benefit generalist herbivores by increasing access to various substitutable food resources, with potential consequences for their population dynamics. We studied a European roe deer (Capreolus capreolus) population living in an agricultural mosaic of forest, woodlots, meadows and cultivated crops. We tested whether diet composition and quality varied spatially across the landscape using botanical analyses of rumen contents and chemical analyses of the plants consumed in relation to landscape metrics. In summer and non-mast winters, roe deer ate more cultivated seeds and less native forest browse with increasing availability of crops in the local landscape. This spatial variation resulted in contrasting diet quality, with more cell content and lower lignin and hemicellulose content (high quality) for individuals living in more open habitats. The pattern was less marked in the other seasons when diet composition, but not diet quality, was only weakly related to landscape structure. In mast autumns and winters, the consumption of acorns across the entire landscape resulted in a low level of differentiation in diet composition and quality. Our results reflect the ability of generalist species, such as roe deer, to adapt to the fragmentation of their forest habitat by exhibiting a plastic feeding behavior, enabling them to use supplementary resources available in the agricultural matrix. This flexibility confers nutritional advantages to individuals with access to cultivated fields when their native food resources are depleted or decline in quality (e.g. during non-mast years) and may explain local heterogeneities in individual phenotypic quality.
Article
Full-text available
Based on recent work by Fox and Andersen (2006), this paper describes substantial extensions to the effects package for R to construct effect displays for multinomial and proportional-odds logit models. The package previously was limited to linear and generalized linear models. Effect displays are tabular and graphical representations of terms - typically high-order terms - in a statistical model. For polytomous logit models, effect displays depict fitted category probabilities under the model, and can include point-wise confidence envelopes for the effects. The construction of effect displays by functions in the effects package is essentially automatic. The package provides several kinds of displays for polytomous logit models.
Article
Full-text available
The iodine-containing hormones produced by the thyroid gland play a role in the complex neuro-hormonal regulation of antler development. The proper function of the thyroid depends on the adequate iodine supply of the organism, which is directly related to the iodine content of food and drinking water. The purpose of this study was to explore the connection between the iodine content of the water base, which has a strong correlation with the iodine concentration of environmental components available to animals, and the antler weight of roe deer (Capreolus capreolus) shot in Hungarian hunting areas. Using a general linear model, controlling for the collective effects of other environmental factors (deer population density, harvest rate, land use, and soil fertility information), the iodine content of the water base explained 51.4% of the total variance of antler weights. The results suggest that antler weights increase with increasing iodine concentration regardless of other factors; thus, the environmental iodine distribution can be a limiting factor suppressing roe deer performance assessed here as antler weight. Further experimental studies of controlled iodine uptake are needed to define the exact physiological iodine requirements of roe deer bucks.
Article
Full-text available
There is growing concern about the evolutionary consequences of human harvesting on phenotypic trait quality in wild populations. Undesirable consequences are especially likely with trophy hunting because of its strong bias for specific phenotypic trait values, such as large antlers in cervids and horns in bovids. Selective hunting can cause a decline in a trophy trait over time if it is heritable, thereby reducing the long-term sustainability of the activity itself. How can we build a sustainable trophy hunting tradition without the negative trait-altering effects? We used an individual-based model to explore whether selective compensatory culling of ‘low quality’ individuals at an early life stage can facilitate sustainability, as suggested by information from managed game populations in eastern and central Europe. Our model was rooted in empirical data on red deer, where heritability of sexual ornaments has been confirmed and phenotypic quality can be assessed by antler size in individuals as young as 1 year. Simulations showed that targeted culling of low-quality yearlings could counter the selective effects of trophy hunting on the distribution of the affected trait (e.g. antler or horn size) in prime-aged individuals. Assumptions of trait heritability and young-to-adult correlation were essential for compensation, but the model proved robust to various other assumptions and changes to input parameters. The simulation approach allowed us to verify responses as evolutionary changes in trait values rather than short-term consequences of altered age structure, density and viability selection. We conclude that evolutionarily enlightened management may accommodate trophy hunting. This has far reaching implications as income from trophy hunting is often channelled into local conservation efforts and rural economies. As an essential follow-up, we recommend an analysis of the effects of trophy hunting in conjunction with compensatory culling on the phenotypic and underlying genetic variance of the trophy trait.
Article
Full-text available
1. Although life-history theory predicts substantial costs of reproduction, individuals often show positive correlations among life-history traits, rather than trade-offs. The apparent absence of reproductive costs may result from heterogeneity in individual quality. 2. Using detailed longitudinal data from three contrasted ungulate populations (mountain goats, Oreamnos americanus; bighorn sheep, Ovis canadensis; and roe deer, Capreolus capreolus), we assessed how individual quality affects the probability of detecting a cost of current reproduction on future reproduction for females. We used a composite measure of individual quality based on variations in longevity (all species), success in the last breeding opportunity before death (goats and sheep), adult mass (all species), and social rank (goats only). 3. In all species, high-quality females consistently had a higher probability of reproduction, irrespective of previous reproductive status. In mountain goats, we detected a cost of reproduction only after accounting for differences in individual quality. Only low-quality female goats were less likely to reproduce following years of breeding than of nonbreeding. Offspring survival was lower in bighorn ewes following years of successful breeding than after years when no lamb was produced, but only for low-quality females, suggesting that a cost of reproduction only occurred for low-quality females. 4. Because costs of reproduction differ among females, studies of life-history evolution must account for heterogeneity in individual quality.
Article
Full-text available
A wild 5-yr-old red deer (Cervus elaphus) was eulled from a privately owned herd because of deformed antlers, retained velvet and bilateral symmetrical testicular hypogonadism. The clinical and pathological changes seen in this deer were most consistent with congenital hypoplasia, but testicular atrophy was an alternative possibility for the etiology of their condition.
Article
Full-text available
In female vertebrates, differences in fitness often correspond to differences in phenotypic quality, suggesting that larger females have greater fitness. Variation in individual fitness can result from variation in life span and/or variation in yearly reproductive success, but no study has yet assessed the relationships between the components of fitness and phenotypic quality while controlling for life span. We tried to fill this gap using data from long-term monitoring (23 years) of marked roe deer and bighorn sheep, two ungulates with very different life histories. In both species, we found a strong positive relationship between an adult female's mass and her probability of reaching old age: over the long term, bigger is indeed better for ungulate females. On the other hand, we found no evidence in either species that heavier females had higher fitness when differences in life span were accounted for: over the short term, bigger is not necessarily better. Our results indicate that, while broad differences in phenotypic quality affect individual fitness, when differences in life span are accounted for phenotypic quality has no residual effect on fitness. Therefore, within a given range of phenotypic quality, bigger is not always better, for reasons which may differ between species.
Book
Since the first drawings left on walls of ancient caves, human beings have been fascinated with that unique phenomenon of the animal kingdom, the presence of horns and antlers. From the mythical ''unicorn'' exercising the power over life and death to the perceived aphrodisiacal and other medical properties of rhinoceros horns and growing antlers, these conspicuous protuberances have had a significant place in the history of mankind. Part of that ancient interest in antlers and horns was due to their value as sym­ bols of masculinity; this interest persists today in trophy hunting, an honorable tradition carried on for centuries in many countries of the world. This book, which deals with evolution, morphology, physiology, and behavior, has not been devised as a comprehensive review of the subject of horns, prong­ horns, and antlers; rather, it is a series of chapters stimulating thoughts, discus­ sions, and initiation of new studies. As editors, we did not interfere with the content of articles nor with the opin­ ions and interpretations of our contributors, and we left them to decide whether to accept the suggestions of our reviewers. Despite the fact that various aspects of cranial appendages have been studied since the end of the eighteenth century, many controversial views still exist, as witnessed in various chapters of this book.
Chapter
Body and antler size in Cervidae are important qualities contributing to dominance among males and to their value as trophies. Variation in these characteristics has occupied the interest of many people over the centuries and much speculation about the underlying causes of this variation has resulted. The basic importance of genetics to antler development is inferred primarily from the differences in antler expression among species but not from any specific information about genetic differences between cervids. The genetic basis of variation in antlers among individuals within a species is just beginning to be understood. Information on genetic variability has only recently been mentioned relative to antler development (Smith et al. 1983). The major difficulty in establishing an understanding of the genetic basis of antler development is the lack of quantitative data on the inheritance of antler characteristics. Supplying this information is a monumental task because of the need to maintain a large number of breeding animals in captivity.
Chapter
The importance of the endocrine system in the regulation of antler growth, mineralization, velvet shedding, and casting was established a long time ago (for details see Chapter 8). However, there has not yet been an extensive investigation of the role of the phylogenetically younger nervous system, which is more precise in action, more responsive to rapidly changing external and internal conditions, and more coordinated with other body functions.
Article
Purulent inflammation caused by Staphylococcus xylosus was first described at the basis of antler in an 8 years old male fallow deer (Dama dama). The condition of the animal was normal but building of the antler was irregular. On the right side trophy with abnormal antler developed.
Chapter
The fact that the “true” horns are a product of the skin, and “‘horns’ of deer” develop as bone protuberances, and thus both are not homologous by nature was already known to Aristotle (Peck 1965). Despite this, both antlers and horns are frequently considered homologous terms (Frick 1937; Geist 1966a, 1974a; Janis 1982; Kiltie 1985). Moreover, the common view that antlers and horns have been developed by natural selection primarily as weapons—a view we find in Democritos (Mulachius 1843) and supported by E. Darwin’s (1794) notion (adopted by C. Darwin 1859,1871)-persists in the present zoological systematic and behavioral interpretations (e. g Geist 1966a, 1974a; Clutton-Brock 1982; Janis 1982; Kiltie 1985).
Chapter
Of all of the wild mammalian ungulates, the cervids may well be the most intensively investigated. Scientific articles and books abound on the ecology, behavior, and physiology of deer. No doubt the white-tailed deer Odocoileus virginianus of North America and the red deer Cervus elaphus of Europe and New Zealand have been the most studied. Interest by hunters, biomedical researchers, and those who sell antlers for medicine has led to numerous articles and two earlier books on the phenomenon of antler growth (Brown 1982; Goss 1983). One would suspect that the nutritional requirements of antler growth have been well established.
Article
W latach 1966-1980 w środowisku krajobrazu rolniczego o pow. 15 tys. ha przeprowadzono badania nad funkcjonowaniem populacji sarn. Celem badan bylo uzyskanie danych dotyczących dynamiki liczebności, rozrodu, śmiertelności, przezywalności oraz struktury wieku i plci. Na podstawie zebranych danych sporządzono bilans ilościowy populacji
Article
A botanical analysis was made of food contents taken from the rumen of 125 roe deer Capreolus capreolus (Linnaeus, 1758), obtained during the hunting season in an experimental field area. The roe deer's food over the annual cycle is formed by 85 plant species, but six species of cultivated plants are of basic importance.
Article
Studies were made over a period of several years of basic population processes in a group of roe deer inhabiting a small wood situated in fields. The purpose of this studies was to determine to what extent this community differs from roe deer living in fields surrounding the wood. It was found that the density of roe deer in the wood is several times greater than in the extensive area of fields surrounding it.
Article
Przeprowadzone eksperymeny mialy na celu wyjaśnienie wplywu stresora na cyklicznośc poroza jeleniowatych. Do doświadczen uzyto 13 sztuk jeleniowatych, w tym 5 sztuk dwukrotnie. Doświadczenia przeprowadzono w warunkach hodowli zagrodowej.
Article
In open landscapes, grass leaves provide an abundant resource for ruminants, with potentially high nutritional value. However, their extensive digestion requires a long fermentation time, achieved through large rumen and the stratification of the rumen content. Due to anatomical and physiological differences, ruminants differ in their ability to process grass leaves. Particularly, the small roe deer, with its viscous saliva and unstratified rumen content, is generally classified as a strict browser. We hypothesised that roe deer may be able to use grass leaves in some circumstances, notably when the availability of other resources declines and when the quality of grass leaves is high. We expected that (1) grass leave consumption should be higher in open landscapes than in forest habitat because grasses are more widely available and more nutritious in open landscapes and (2) grass leave consumption should increase in winter when the availability of other resources declines. We assessed grass consumption by microscopic analysis of roe deer faecal pellets collected monthly both in forest habitat and in the surrounding open landscape. We found that both the occurrence and the proportion of grass leaves in the faeces were higher in the open landscape (predicted mean proportion 0.31) than in the forest (predicted mean proportion 0.05). In addition, the proportion of grass leaves in the faeces was higher in winter and lower in spring in both forest and open landscape. We suggest that roe deer are able to use grass leaves with unusually high nutritional quality in winter in this mild climate area. This involves a certain level of digestive plasticity to efficiently digest high quality grasses and may confer nutritional benefit to individuals feeding in an open landscape.
Article
The rate of wear of ruminant teeth may vary according to diet, habitat, and individual tooth characteristics. This variation may cause error in estimating the age of wild ungulates from patterns of tooth wear. We tested the ability of 10 observers to accurately estimate age from observation of tooth wear in a large sample of jaws of known-age roe deer (Capreolus capreolas) from three populations.. Although the average error was not large (+/-1.02 years), maximum error ranged from -5 to +6 years for jaws of animals between 1 and 7 years old, with observers generally overestimating the age of young animals and underestimating the age of old animals. We found significant differences among observers in estimation error. When a "jaw-board" of known-age reference specimens was provided, this observer effect was largely controlled for, but accuracy was not improved. Error was partly due to variation in tooth wear, both within and among populations. Initial cusp height of the first molar was lower, but tooth wear tended to be slower in one population than in the other two populations,possibly reflecting differences in diet and (or) habitat. Individual variation in tooth wear within populations was observed, possibly reflecting variation in tooth characteristics (e.g., enamel mineralisation), which was a source of error in age estimation from observation. Observers tended to underestimate the age of jaws with a relatively low degree of wear and vice versa. These results show that estimating the age of roe deer from observation of tooth wear produces biased results, severely limiting its application in population studies of this species.
Article
Fluctuating asymmetry (FA) has been suggested as a measure of the sensitivity of development to a wide array of genetic and environmental stresses. It has been also suggested that antlers in red deer could be important during social and rutting displays. We used antler measurements of 51 males that were measured over subsequent seasons, from 3–8 years of age, and analysed three antler traits: antler weight, length, and the number of antler tines (antler size). We calculated absolute and relative FA. All three size traits were highly significantly intercorrelated. By contrast to this, the FA of the three traits, did not show such relationships. With increasing age, antler size and FA also increased. When testing the repeatability of FA and antler size, there was a principal difference in the pattern between FA and antler size, with the latter being much more consistent than the former. This suggests that antler size, not FA, may be a good predictor of the bearer’s quality in mate selection. This fits well with the good-genes hypothesis that the development of extravagant secondary sexual characters can be an honest advertisement of heritable male quality. © 2007 The Linnean Society of London, Biological Journal of the Linnean Society, 2007, 91, 215–226.
Article
The rate of wear of ruminant teeth may vary according to diet, habitat, and individual tooth characteristics. This variation may cause error in estimating the age of wild ungulates from patterns of tooth wear. We tested the ability of 10 observers to accurately estimate age from observation of tooth wear in a large sample of jaws of known-age roe deer (Capreolus capreolus) from three populations. Although the average error was not large (±1.02 years), maximum error ranged from -5 to +6 years for jaws of animals between 1 and 7 years old, with observers generally overestimating the age of young animals and underestimating the age of old animals. We found significant differences among observers in estimation error. When a "jaw-board" of known-age reference specimens was provided, this observer effect was largely controlled for, but accuracy was not improved. Error was partly due to variation in tooth wear, both within and among populations. Initial cusp height of the first molar was lower, but tooth wear tended to be slower in one population than in the other two populations, possibly reflecting differences in diet and (or) habitat. Individual variation in tooth wear within populations was observed, possibly reflecting variation in tooth characteristics (e.g., enamel mineralisation), which was a source of error in age estimation from observation. Observers tended to underestimate the age of jaws with a relatively low degree of wear and vice versa. These results show that estimating the age of roe deer from observation of tooth wear produces biased results, severely limiting its application in population studies of this species.
Article
Reviews evidence for 5 functional explanations of the evolution of antlers in male cervids. 1) There is extensive evidence that antlers are used in fights between competing males. Fights are regular during the breeding season and can be damaging. Antlers have proved to be effective weapons of defence and offense, and there is no systematic evidence to support the suggestion that antler-less males (hummels) are more successful in competition for females than antlered stags. 2) Though male deer sometimes use their antlers in defence against predators, the absence of antlers in females of most species suggests that this is not their principal function. 3) Nor does it seem likely that antlers evolved as heat-regulating mechanisms. 4) There is no conclusive evidence that males assess each other by their relative antler size, most measures of antler size and shape are not closely correlated with dominance or fighting ability. 5) Nor is there firm evidence that females selectively mate with large-antlered males. Antlers thus evolved as weapons and are retained by selection because of their function in intra-specific combat. -from Author
Article
En poblaciones naturales las anormalidades morfológicas se pueden asociar con la depresión por cruzamiento consanguíneo o la heredabilidad. Exploramos una base genética para las deformidades de cuerno y de pedú nculo (base del cuerno) documentadas en una población reintroducida del alce (Cervus elaphus) en la Hualapai Indian Reservation en el noroeste de Arizona. Usamos 12 loci de microsatélites para comparar la heterozigosidad individual de mú ltiples loci (IH) y parentesco interno (IR) entre alces adultos machos con malformaciones (n = 23) e individuos que presentaron formación normal de cuerno (n = 17). Adicionalmente, utilizamos 3 coeficientes de parentesco pareados para determinar si los machos con cuernos deformados estuvieron más estrechamente relacionados entre sí que los machos con cuernos normales. La media de IH y la media de IR no fueron significativamente más altas para el grupo de cuernos deformados. Asimismo, la relación entre las malformaciones de cuerno y los coeficientes de parentesco pareados tampoco fue significativa, lo que sugiere que los machos deformados no comparten esta característica entre sí debido a una relación genética más cercana. Otras causas, como factores nutricionales o ambientales, podrán estar asociadas con estas deformidades. Se necesita investigación adicional para determinar las causas fundamentales de las malformaciones de cuerno y de pedúnculo documentadas en el grupo de alces introducidos en el norte de Arizona.
Article
Summary1. Females should adjust their reproductive effort prior to substantial investment. For roe deer, due to delayed implantation, this adjustment may occur at ovulation/fertilization during the summer rut, or at implantation in mid-winter. We investigated the effects of climate and maternal phenotype (mass, condition, age) on potential litter size (number of fertilized ovulations) and implantation failure (number of fertilized ovulations less number of fetuses) of 818 individual roe does from nine populations across Britain.2.Potential litter size varied from 1 to 4, with 0–100% of does per population polyovulating. Among prime-aged does, 16.7–54.5% subsequently failed to implant at least one blastocyst.3.Individual fecundity was determined by the combined effects of maternal phenotypic quality and age, but acting at different stages of the reproductive process: potential litter size increased with increasing maternal body mass; implantation failure was independent of phenotypic quality, but varied in relation to maternal age, being lowest for prime-aged does, somewhat higher for yearlings, but higher still for senescent females.4.Implantation failure increased with increasing initial potential litter size, perhaps related to physiological malfunction. Implantation was often an all-or-nothing process, with females either implanting all or failing to implant any of their fertilized blastocysts.5.Climatic factors were not consistently correlated with individual female fecundity within populations, but between populations implantation failure increased with climatic severity.6.For species such as roe deer, where females rely on food intake rather than fat reserves for reproduction, we suggest that a two-step process shapes patterns of reproductive output: body mass first sets an upper limit to potential litter size at conception, then reproductive output is limited mainly by senescence and climatic severity through implantation failure.
Article
Annual variation in two sexually selected male traits, carcass mass and number of antler points, was studied in 2,862 moose (Alces alces) collected during the autumn hunting season in northern Norway during 23 years. Yearling males grew larger during cool and dry summers, but a decrease in mean carcass mass of adult males was best predicted from the decline in sex ratio. However, because population density was significantly correlated with sex ratio, the two effects were difficult to separate. Males were smaller when population density was high and the male: female ratio was low. Carcass mass in female moose was unaffected by density or sex ratio, except in the case of yearlings. The cohort effect of large size of yearling only persisted for 1 year among males. Antler size did not change during the study despite the decline in body mass of males; this implies that the costs of bearing antlers of a given size increased. Variation in sexually selected characters in males may be understood by considering them to be life-history traits.
Article
Information on genetic and environmental sources of variation that control antler development in white-tailed deer (Odocoileus virginianus) is needed to develop harvest management programs. We estimated genetic and environmental components of variance for antler development traits collected from deer born from 1977 to 1993 in a captive population. Antler traits were incidence of spikes versus forks, number of points, maximum inside spread, total mass, main beam circumference, and main beam length. In 1.5-year-old males, the degree of additive genetic determination, or heritability (h(2)), was low (range = 0.00-0.13) for incidence of spikes versus forks, number of points, maximum inside spread, total mass, and main beam length, and was moderate for main beam circumference (h(2) = 0.25). The relatively large carryover influence of the dam as a source of variation was more important than heritability. In 2.5-year-old males, antler-trait heritabilities were low to moderate (0.08-0.39), whereas heritability ranged from 0.03 to 0.43 in mature males (3.5-7.5 years old) with repeated antler-trait records. Permanent and residual effects caused by nonadditive genetic and environmental factors accounted for most of the variation in antler traits expressed by mature males. Our results do not support the use of yearling antler records as criteria for selective breeding management or harvest schemes to alter the genetic quality of a white-tailed deer population.
Article
Body size of large herbivores is a crucial life history variable influencing individual fitness-related traits. While the importance of this parameter in determining temporal trends in population dynamics is well established, much less information is available on spatial variation in body size at a local infra-population scale. The relatively recent increase in landscape fragmentation over the last century has lead to substantial spatial heterogeneity in habitat quality across much of the modern agricultural landscape. In this paper, we analyse variation in body mass and size of roe deer inhabiting a heterogeneous agricultural landscape characterised by a variable degree of woodland fragmentation. We predicted that body mass should vary in relation to the degree of access to cultivated meadows and crops providing high quality diet supplements. In support of our prediction, roe deer body mass increased along a gradient of habitat fragmentation, with the heaviest deer occurring in the most open sectors and the lightest in the strict forest environment. These spatial differences were particularly pronounced for juveniles, reaching >3 kg (ca 20% of total body mass) between the two extremes of this gradient, and likely have a marked impact on individual fates. We also found that levels of both nitrogen and phosphorous were higher in deer faecal samples in the more open sectors compared to the forest environment, suggesting that the spatial patterns in body mass could be linked to the availability of high quality feeding habitat provided by the cultivated agricultural plain. Finally, we found that adults in the forest sector were ca 1 kg lighter for a given body size than their counterparts in the more open sectors, suggesting that access to nutrient rich foods allowed deer to accumulate substantial fat reserves, which is unusual for roe deer, with likely knock-on effects for demographic traits and, hence, population dynamics.
Article
Abstract Good-genes hypotheses predict that development of secondary sexual characters can be an honest advertisement of heritable male quality. We explored this hypothesis using a cervid model (adult, male white-tailed deer, Odocoileus virginianus) to determine whether antler development could provide an honest signal of a male's genetic quality and condition to adversaries. We compared antler, morphometric, hormonal, and parasitic data collected from hunter-harvested deer to characteristics of the Mhc-DRB (Odvi), the most widely studied gene of the major histocom-patibility complex (MHC) in Artiodactyla. We detected associations between genetic characteristics at Odvi-DRB and antler development and body mass, suggesting that antler development and body mass may be associated with pathogen resistance in deer and thus may be an honest signal of genetic quality. We also detected associations between Odvi-DRB characteristics and serum testosterone during the breeding season, suggesting that certain MHC characteristics may help deer cope with stresses related to breeding activity. In addition, we observed a negative relationship between degree of antler development and overall abundance of abomasal helminths. Our observations provide support for the hypothesis that antler development in white-tailed deer is an honest signal of quality.
Article
Abstract We present estimates of the selection on and the heritability of a male secondary sexual weapon in a wild population: antler size in red deer. Male red deer with large antlers had increased lifetime breeding success, both before and after correcting for body size, generating a standardized selection gradient of 0.44 (±0.18 SE). Despite substantial age- and environment-related variation, antler size was also heritable (heritability of antler mass =0.33 ±0.12). However the observed selection did not generate an evolutionary response in antler size over the study period of nearly 30 years, and there was no evidence of a positive genetic correlation between antler size and fitness nor of a positive association between breeding values for antler size and fitness. Our results are consistent with the hypothesis that a heritable trait under directional selection will not evolve if associations between the measured trait and fitness are determined by environmental covariances: In red deer males, for example, both antler size and success in the fights for mates may be heavily dependent on an individual's nutritional state.
Article
Fluctuating asymmetry (FA) refers to small random differences that occur between the right and the left sides of bilateral characters. Under the hypothesis that the degree of FA in secondary sex traits reflects the ability of males to cope with environmental stress, and consequently reflects individual quality, a negative relationship is expected between FA and the trait size. Additionally, selective mortality acting preferentially on individuals in poor condition, presumably more asymmetric, should lead to a decrease in FA with age. We tested these hypotheses on roe deer (Capreolus capreolus) antlers, analysing the FA pattern in antler size from individuals culled over 18 years in a single population. Absolute asymmetry significantly decreased with age, and tended to decrease with antler size, at constant carcass mass, within age classes. Moreover, increase in the population density negatively affected carcass mass and antler size, and resulted in a significant increase in the degree of asymmetry in antlers. These results suggest that antler development in roe deer represents a reliable signalling of individual quality. Moreover, due to the deciduous nature of antlers, asymmetry in antler size appears to be a valuable indicator of the current environmental conditions encountered by populations.
Article
The significance of adult buck aggression as a proximate factor driving yearling male dispersal in roe deer, Capreolus Capreolus, was studied in Sweden during the dispersal season (April–June) in 1988–1991. In roe there is a well established positive correlation between yearling antler size and dispersal tendency. I tested the prediction that yearlings with large antlers will experience more agonism from adult bucks than those with smaller antlers. Additionally, I studied the relationship between antler size and level of sexual maturity, by recording date of velvet shedding, and sampling testes weights from culled yearlings during the breeding season. The amount of agonism experienced by yearlings was positively correlated with the size of their antlers during April and May, whereas in June no such relationship was found. Aggression towards all yearlings tended to increase as the season progressed. A positive correlation between antler size and testes weight was evident, and the larger the antlers of yearlings the earlier the velvet shedding occured. These results indicate: firstly, that adult buck agonism is an important proximate factor underlying yearling male dispersal; and secondly, that agonism is mainly directed towards the sexually most mature yearlings. This, in turn, suggests mate competition to be the ultimate cause of male-male agonism, and thus male dispersal in this species.
Article
Time- and sex-specific summer survival of roe deer fawns was estimated using capture-mark-recapture methods in two enclosed populations living in contrasting conditions. The population of Trois Fontaines (eastern France) was roughly constant in size throughout the study period, while in Chizé (western France), the population experienced frequent summer droughts and numbers decreased continuously during the study. Early survival of fawns was low and highly variable over the years at both Chizé and Trois Fontaines, and demonstrated marked variations between cohorts that need to be taken into account when modelling roe deer population dynamics. In Trois Fontaines, fawn survival was positively correlated with early body growth and total rainfall in May and June. In Chizé, fawn survival decreased with increasing density and tended to increase with increasing rainfall in May and June and adult female body mass. These factors explained more than 75% of the variability in early survival observed in both populations. Variation between cohorts had different consequences for the two populations. At Trois Fontaines, cohort variation was limited to a numerical effect on early survival. However at Chizé, cohort variation was long-lasting and affected the phenotypic quality of survivors at later ages, and thereby future survival and breeding abilities (both numerical and quality effects). Male and female fawns had similar survival over their first summer in both populations. This result contrasts with the lower survival of young males often observed in ungulates. Two ultimate causes can be proposed to account for the low and variable survival of roe deer fawns over the first summer: the high energy expenditures incurred by does during each breeding attempt and/or the low absolute body size of newborn roe deer fawns.
Article
After about 50 years of research on fluctuating asymmetry (FA) as a reliable indicator of both individual quality and environmental stress, the enthusiasm is beginning to decline. The findings of many studies are inconsistent and the relationship between FA and stress appears both weaker and more complex than first thought. To provide clarification of the debate, new studies should use more efficient and unified statistical protocols, large sample sizes and joint analysis of several related traits. In addition, fitness–FA associations should be tested at the individual level, in different populations and under different environmental conditions. To achieve these criteria, we describe a 9-year study in which we measured six antler traits of 3 000 Iberian red deer, Cervus elaphus hispanicus, from three study areas in southwest Spain. Males were harvested during hunting activities and measured, weighed and aged post mortem. We found evidence of correlations between traits in FA, an association between asymmetry and stress conditions and a weak but significant negative relationship between FA and fitness surrogates (body mass and antler size), thus supporting some assumptions of the FA hypothesis. As also predicted by theory, antler traits of less functional importance were more asymmetric and more sensitive to stress than those directly used in fighting behaviour. The relationship between age and antler asymmetry was U-shaped, suggesting an effect of sexual selection on antler development in favour of larger and more symmetrical antlers during prime age.
Article
compared with other vertebrate taxa, mammals possess a very limited capacity for appendage regeneration. The antlers of deer are an exception in that they are periodically lost and fully regenerated throughout the life of an individual. Objective: in this paper we compare certain aspects of antler regeneration with regenerative processes in other vertebrates. review of the literature. recent studies suggest that antler regeneration is a stem cell-based process and that these stem cells are located in the pedicle periosteum. There is evidence that signaling pathways known to operate during appendage regeneration in other vertebrates are also activated during antler regeneration. There are, however, also differences between antlers and other systems of epimorphic regeneration. Thus, contrary to amphibian limb regeneration, signaling from the wound epidermis appears not to be of crucial importance for antler regeneration. Healing of the casting wound typically involves no or only minor scarring, making antlers interesting subjects for researchers attempting to reduce scar formation during wound healing in humans. The fact that despite their enormous growth rate the antlers of intact and castrated deer appear to be resistant to malignant transformation furthermore offers research opportunities for cancer biology. studying antler renewal as an example of mammalian appendage regeneration may provide crucial information for regenerative medicine to achieve its ultimate goal of stimulating limb regeneration in humans. A deeper understanding of the developmental mechanisms involved in antler renewal can also be useful for controlling induced regeneration processes in mammals.
Article
Heritabilities for two body weights and five antler characteristics were estimated for a captive white-tailed deer (Odocoileus virginianus) herd maintained by the Texas Parks and Wildlife Department. Single male breeding pens with 10-14 female deer were used for five consecutive generations. To minimize selection and maintain a broad genetic base, different sets of sires and as many different dams as possible were randomly assigned as breeders each generation. All deer were accurately predigreed by sire and dam and, except for birth weight, traits were measured at 1.5 years of age. Heritabilities were estimated utilizing (1) sire and within-sire components of variance, and (2) regression of male progeny performance on sire performance. Theoretically, these procedures estimate the amount of additive genetic variance present in a population without indication of non-additive genetic (dominance and epistasis) and maternal effects. Heritabilities ranged from 0.00-0.17 (birth weight), 0.58-0.64 (body weight), 0.22-0.56 (antler points), 0.47-0.70 (main beam length), 0.03-0.43 (antler spread), 0.80-0.89 (basal circumference) and 0.71-0.86 (antler weight). These heritabilities, except for birth weight, suggest that substantial genetic change could be expected from individual selection if realistic selection differentials were used.
Article
Secondary sexual characters have been hypothesized to signal male quality and should demonstrate a negative relationship between the size of the trait and degree of fluctuating asymmetry because they are costly to produce. We collected morphometric and antler data from 439 white-tailed deer (Odocoileus virginianus) in Oklahoma, USA, in order to determine whether measures of antler asymmetry follow the patterns predicted for sexually selected characters. Relative fluctuating asymmetry was negatively related to antler size for all deer and within age groups up to five and a half years of age. We did not detect an association between asymmetry and antler size among deer that were six and a half years or older. When categorizing deer by antler size, we found that deer with small antlers (< or = 33rd percentile) had greater levels of relative asymmetry than deer with large antlers (< or = 67th percentile). The relative asymmetry of antlers was negatively related to age and was greatest in deer that were one and a half years old. Relative asymmetry was also negatively related to carcass mass, inside spread, skull length and body length. These data suggest that asymmetry in the antlers of white-tailed deer may be a reliable signal of quality and, as such, may be important in maintaining honesty in intrasexual advertisements during the breeding season.