Alternative Mating Tactics and Their Impact on Survival in Adult Male Alpine Ibex (Capra ibex ibex)

Effects of local versus global competition on reproductive skew and sex differences in social dominance behaviour

Social hierarchies are often found in group-living animals. The hierarchy position can influence reproductive success (RS), with a skew towards high-ranking individuals. The amount of aggression in social dominance varies greatly, both between species and between males and females within species. Using game theory we study this variation by taking into account the degree to which reproductive competition in a social group is mainly local to the group, emphasizing within-group relative RS, or global to a larger population, emphasizing an individual's absolute RS. Our model is similar to recent approaches in that reinforcement learning is used as a behavioural mechanism allowing social-hierarchy formation. We test two hypotheses. The first is that local competition should favour the evolution of mating or foraging interference, and thus of reproductive skew. Second, decreases in reproductive output caused by an individual's accumulated fighting damage, such as reduced parenting ability, will favour less intense aggression but should have little influence on reproductive skew. From individual-based simulations of the evolution of social dominance and interference, we find support for both hypotheses. We discuss to what extent our results can explain observed sex differences in reproductive skew and social dominance behaviour.

Reproductive skew, fighting costs, and winner-loser effects in social-dominance evolution

1. Social hierarchies are often found in group-living animals and can be formed through pairwise aggressive interactions. The dominance rank can influence reproductive success (RS) with a skew towards high-ranking individuals. 2. Using game theory we investigate how the opportunity for differently ranked individuals to achieve RS influences the costs of hierarchy formation and the strength of winner and loser effects. 3. In our model, individuals adjust their aggressive and submissive behaviour towards others through reinforcement learning. The learning is based on rewards and penalties, which depend on relative fighting ability. From individual-based simulations we determine evolutionary equilibria of traits such as learning rates. We examine situations that differ in the extent of monopolisation of contested RS by dominants and in the proportion of total RS that is contested. 4. The model implements two kinds of fighting costs: a decrease in effective fighting ability from damage (loss of condition), and a risk of mortality that increases with the total accumulated damage. Either of these costs can limit the amount of fighting. 5. We find that stable dominance hierarchies form, with a positive correlation between dominance position and fighting ability. The accumulated costs differ between dominance positions, with the highest costs paid by low or intermediately ranked individuals. Costs tend to be higher in high-skew situations. 6. We identify a 'stay-in, opt-out' syndrome, comprising a range from weaker (stay-in) to stronger (opt-out) winner-loser effects. We interpret the opt-out phenotype to be favoured by selection on lower-ranked individuals to opt out of contests over social dominance, because it is more pronounced when more of the total RS is uncontested. 7. We discuss our results in relation to field and experimental observations and argue that there is a need for empirical investigation of the behaviour and reproductive success of lower-ranked individuals.

Targeted strategies for the management of wildlife diseases: the case of brucellosis in Alpine ibex

The management of infectious diseases in wildlife reservoirs is challenging and faces several limitations. However, detailed knowledge of host-pathogen systems often reveal heterogeneity among the hosts' contribution to transmission. Management strategies targeting specific classes of individuals and/or areas, having a particular role in transmission, could be more effective and more acceptable than population-wide interventions. In the wild population of Alpine ibex (Capra ibex-a protected species) of the Bargy massif (French Alps), females transmit brucellosis (Brucella melitensis) infection in ~90% of cases, and most transmissions occur in the central spatial units ("core area"). Therefore, we expanded an individual-based model, developed in a previous study, to test whether strategies targeting females or the core area, or both, would be more effective. We simulated the relative efficacy of realistic strategies for the studied population, combining test-and-remove (euthanasia of captured animals with seropositive test results) and partial culling of unmarked animals. Targeting females or the core area was more effective than untargeted management options, and strategies targeting both were even more effective. Interestingly, the number of ibex euthanized and culled in targeted strategies were lower than in untargeted ones, thus decreasing the conservation costs while increasing the sanitary benefits. Although there was no silver bullet for the management of brucellosis in the studied population, targeted strategies offered a wide range of promising refinements to classical sanitary measures. We therefore encourage to look for heterogeneity in other wildlife diseases and to evaluate potential strategies for improving management in terms of efficacy but also acceptability.

Reproductive effort affects subsequent horn growth in sexually dimorphic male ungulates

Trade-offs between reproductive effort and subsequent growth in males are not well explored, despite their relevance in questions of individual energy allocation. Regarding the growth of sexual secondary characters in polygynous breeding male mammals, indeed, no conclusive studies exist. We investigated in male Alpine ibex (Capra ibex) the relationship between their behavioral reproductive effort, current horn size, and subsequent horn growth. While controlling for age, no evidence was found for male behavioral reproductive effort during the rut being affected by their horn size. On the other hand, reproductive effort significantly decreased age-specific horn growth during the following summer. Our study provides evidence that growth of secondary sexual characters is traded against behavioral investments in reproduction in a male mammal. It bears important implications for the understanding of energy allocation between various life-history components and the evolutionary ecology of secondary sexual characters.

Determinants and long-term costs of early reproduction in males of a long-lived polygynous mammal

In long-lived polygynous species, male reproductive success is often monopolized by a few mature dominant individuals. Young males are generally too small to be dominant and may employ alternative tactics; however, little is known about the determinants of reproductive success for young males. Understanding the causes and consequences of variability in early reproductive success may be crucial to assess the strength of sexual selection and possible long-term trade-offs among life-history traits. Selective pressures driven by fluctuating environmental conditions may depend on age class. We evaluated the determinants of reproduction in male bighorn sheep (Ovis canadensis) aged 2-4 years using 30 years of individual-level data. These young males cannot defend estrous ewes and use alternative mating tactics. We also investigated how the age of first detected reproduction was correlated to lifetime reproductive success and longevity. We found that reproductive success of males aged 3 years was positively correlated to body mass, to the proportion of males aged 2-4 years in the competitor pool, and to the number of females available per adult male. These results suggest that reproductive success depends on both competitive ability and population age-sex structure. None of these variables, however, had significant effects on the reproductive success of males aged 2 or 4 years. Known reproduction before the age of five increased lifetime reproductive success but decreased longevity, suggesting a long-term survival cost of early reproduction. Our analyses reveal that both individual-level phenotypic and population-level demographic variables influence reproductive success by young males and provide a rare assessment of fitness trade-offs in wild polygynous males.

Weather stochasticity and alternative reproductive tactics in Northern chamois, Rupicapra rupicapra

In polygynous ungulates, male breeding success is often achieved through alternative reproductive tactics (ARTs). The maintenance of ARTs in this taxon is largely explained by condition-dependent selection, a decision rule in which individuals switch their breeding behaviour on the basis of internal factors such as ageing (status-dependent selection), or external factors such as weather conditions during the rut (environment-dependent selection). In some species, however, ARTs are fixed during the mating season, and other forms of selective pressures rather than environment-dependent selection may contribute to the evolutionary maintenance of male types within populations. Assuming female vicinity as a proxy of mating opportunity, we explored the effect of snow depth variations on the elevational overlap between females, and territorial and non-territorial male chamois, Rupicapra rupicapra, in three consecutive rutting seasons. In snow-free periods, females overlapped with non-territorial males, but not with territorial ones. With increasing snow depth, females and territorial males progressively occupied similar elevations. Our results suggest that snow cover variations may impose changes in the spatial distribution of males and females. In turn, weather stochasticity over multiple ruts, rather than within-rut environment-dependent selection, may impose variations in mating opportunities of ARTs, possibly contributing to the coexistence of different phenotypes within populations.

Sexual size dimorphism and sexual selection in artiodactyls

Sexual size dimorphism is biased toward males in most mammalian species. The most common explanation is precopulatory intramale sexual selection. Large males win fights and mate more frequently. In artiodactyls, previous tests of this hypothesis consisted of interspecific correlations of sexual dimorphism with group size as a surrogate for the intensity of sexual selection (Is). However, group size is not a proper measure of sexual selection for several reasons as is largely recognized in other mammalian taxa. I conducted an interspecific test on the role of sexual selection in the evolution of sexual dimorphism using the variance in genetic paternity as a proxy for the Is. I reviewed the literature and found 17 studies that allowed estimating Is= V/(W2), where V and W are the variance and mean number of offspring per male, respectively. A phylogenetic generalized least squares analysis indicated that dimorphism (Wm/Wf) showed a significant positive regression with the intensity of sexual selection but not group size (multiple r2= 0.40; F3,17= 12.78, P = 0.002). This result suggests that sexual selection may have played a role in the evolution of sexual size dimorphism in Artiodactyla. An alternative hypothesis based on natural selection is discussed.

The Sonar Model for Humpback Whale Song Revised

Why do humpback whales sing? This paper considers the hypothesis that humpback whales may use song for long range sonar. Given the vocal and social behavior of humpback whales, in several cases it is not apparent how they monitor the movements of distant whales or prey concentrations. Unless distant animals produce sounds, humpback whales are unlikely to be aware of their presence or actions. Some field observations are strongly suggestive of the use of song as sonar. Humpback whales sometimes stop singing and then rapidly approach distant whales in cases where sound production by those whales is not apparent, and singers sometimes alternately sing and swim while attempting to intercept another whale that is swimming evasively. In the evolutionary development of modern cetaceans, perceptual mechanisms have shifted from reliance on visual scanning to the active generation and monitoring of echoes. It is hypothesized that as the size and distance of relevant events increased, humpback whales developed adaptive specializations for long-distance echolocation. Differences between use of songs by humpback whales and use of sonar by other echolocating species are discussed, as are similarities between bat echolocation and singing by humpback whales. Singing humpback whales are known to emit sounds intense enough to generate echoes at long ranges, and to flexibly control the timing and qualities of produced sounds. The major problem for the hypothesis is the lack of recordings of echoes from other whales arriving at singers immediately before they initiate actions related to those whales. An earlier model of echoic processing by singing humpback whales is here revised to incorporate recent discoveries. According to the revised model, both direct echoes from targets and modulations in song-generated reverberation can provide singers with information that can help them make decisions about future actions related to mating, traveling, and foraging. The model identifies acoustic and structural features produced by singing humpback whales that may facilitate a singer's ability to interpret changes in echoic scenes and suggests that interactive signal coordination by singing whales may help them to avoid mutual interference. Specific, testable predictions of the model are presented.

Social dominance affects the development of sexual behaviour but not semen output in yearling bucks

Goats are polygynous seasonal mammals that establish dominant-subordinate relationships, especially in bucks. The aims of this study were to: 1) compare the reproductive development of dominant and subordinate young bucks allocated in dyads, and 2) determine if their previous dominant position affect their response to grouping. Twenty-four young bucks were allocated in dyads when they were 4 mo old, and the dominance position (DP) [dominant (DB) or subordinate buck (SB)] was determined with a test of competition for food. Body weight, scrotal circumference, semen quality and sexual behaviour toward an oestrous ewe were weekly determined during 8 weeks beginning when the bucks were 8 mo old. Body weight, scrotal circumference, and seminal parameters were not affected by DP. Dominant bucks tended to begin sexual courtship earlier than SB bucks (P = .09), but displayed less flehmen (P = .0008) and tended to display less ano-genital sniffings (P = .053). However, DB bucks displayed more lateral approaches (P = .019), attempted to mount, mounted, and mated the oestrous doe more times (P < .0001, P = .0002 and P < .0001, respectively) than SB bucks. In the 9th week, all the bucks were grouped, cortisol and testosterone serum concentrations were measured, and agonistic and sexual behaviour between bucks were recorded during the first day. Semen was collected and evaluated 4 and 9 days after grouping. Cortisol concentration increased (P = .037), but testosterone decreased (P < .0001), after grouping the animals, without differences according to their DP. The DB tended to display more lateral approaches toward other bucks than SB bucks (P = .06), but there were no effects of DP in any other behaviour. Sperm concentration and the total number of sperm in the ejaculate decreased after grouping (P = .01 and P = .009 respectively. In conclusion, in the conditions of this study, dominance relationships affected sexual behaviour but not body or testicular size or semen output in young bucks allocated in dyads. Dominant bucks were more effective displaying sexual consummatory behaviours. Grouping all the bucks together displayed a strong stress response that affected testosterone secretion and sperm output which was of similar magnitude in bucks that were dominant or subordinate individuals before.

Sociospatial structure explains marked variation in brucellosis seroprevalence in an Alpine ibex population

In a context of (re)emerging infectious diseases with wildlife reservoirs, understanding how animal ecology shapes epidemiology is a key issue, particularly in wild ungulates that share pathogens with domestic herbivores and have similar food requirements. For the first time in Europe, brucellosis (Brucella melitensis), a virulent zoonosis, persisted in an Alpine ibex (Capra ibex) population and was transmitted to cattle and humans. To better understand disease dynamics, we investigated the relationships between the spatial ecology of ibex and the epidemiology of brucellosis. Combining home range overlap between 37 GPS-collared individuals and visual observations of 148 visually-marked individuals monitored during the 2013-2016 period, we showed that females were spatially segregated in at least 4 units all year round, whereas males were more prone to move between female units, in particular during the rutting period. In addition to ibex age, the spatial structure in females largely contributed to variation in seroprevalence in the whole population. These results suggest that non-sexual routes are the most likely pathways of intraspecific transmission, crucial information for management. Accounting for wildlife spatial ecology was hence decisive in improving our ability to better understand this health challenge involving a wildlife reservoir.

Temporal variation in the operational sex ratio and male mating behaviours in reindeer (Rangifer tarandus)

In polygynous species, sexual selection is mostly driven by male ability to monopolize access to females in oestrous. In ungulates, the operational sex ratio (OSR), i.e. the proportion of males to individuals ready to mate, varies throughout the peak rut, resulting from the temporal variation in the number of females in oestrous. But the way males adjust their mating tactics to maximise their access to females in oestrous (i.e. as OSR varies) is yet to be investigated. Using 15 years of behavioural observations in reindeer (Rangifer tarandus), we compared the relative importance of time within the rutting season (days to the peak-rut) and the OSR to explain the variation in the propensity (i.e. the frequency after controlling for the potential number of encounters) of young and adult dominant males to engage in four mating tactics: herding females, chasing other males, investigating female reproductive status, and courting females. Male-male agonistic behaviour was the most frequent mating behaviour, followed by herding. As predicted, dominant male mating tactics changed over the rutting season: first herding, then chasing other males, and finally investigating and courting females. In contrast to our prediction, we did not find support for the OSR theory. We noted some discrepancies in how young and adult dominant males adjusted their tactics during the mating season, adults being more efficient in timing and in performing their behaviour to maximise access to females in oestrous. The reported sequence of mating tactics may be more efficient than a static mating tactic to monopolize females in oestrous, regardless of the population composition.

Seasonal dynamics of agonistic displays in territorial and non-territorial males of goitered gazelle

Aggression serves a great variety of social functions, one of which is protection of individual territories from intruders. Territorial males of many antelope species show aggressive noncontact displays, and only rarely fight. It has been suggested that ungulate males tend to have more frequent and longer aggressive interactions with rivals of similar age or social status than with males of dissimilar status. In the present paper, we test whether territorial and non-territorial males behave in a similar manner and avoid fights, and whether or not they preferentially direct aggressive and longer agonistic interactions towards males of similar age or social status, rather than towards other classes of males. We found that territorial males usually avoided straight fights with peers, and instead mainly used noncontact displays in aggressive interactions. In contrast, non-territorial males used fights considerably more often, especially during the onset of territoriality in April to May, when these males had their most frequent aggressive interactions. Territorial bucks aggressively interacted most frequently with non-territorial males and significantly less often with other territorial males, but agonistic noncontact displays between territorial males lasted the longest. In contrast, non-territorial males addressed their aggressive noncontact displays and fights most often to peers and less frequently to sub-adults. Asymmetry in the social status of territorial vs. non-territorial males was likely responsible for the distinctively different agonistic behaviors shown by the two types of males, which in turn are likely due to the different costs and benefits each male can accrue from these aggressive interactions.

Patterns of spatial overlap in a monogamous large rodent, the crested porcupine

The crested porcupine Hystrix cristata is a large rodent which pairs for life. We studied the space use of 17 female and 9 male radio-tracked porcupines in an evergreen coastal woodland ("macchia", EW) and in an agricultural estate (AE), with special reference to the use of cultivations. Home range sizes of male porcupines (4.72-323.40) ranged around 114ha (median) during the warm period (April-September) and 162ha during the cold one (October-March). Home ranges of females (2.48-323.40) were c. 91ha during the warm period and c. 143ha during the cold one. Habitat composition and selection changed from the cold to the warm months, with porcupines being present in agricultural areas especially in the latter. Home range overlap between members of the same pair varied from 57% to 97% (median, 75%). Habitat selection was analyzed at the second (within study area) and at the third (within home range) order of selection. Within study areas, porcupines avoided cultivations and selected habitats with dense vegetation, providing cover and food. Within home ranges, in the warm period, porcupines selected agricultural areas in EW, where this habitat represented a minor portion of the study site. In that season, the Mediterranean "macchia" is a poor source of food, forcing porcupines to travel long distances to reach feeding sites. No significant difference of habitat selection within home ranges was detected between members of the same pair. Cultivations may play a key-role for porcupine survival, especially in poor habitats, as they provide abundant food resources in the warm period.

Influences of mating group composition on the behavioral time-budget of male and female Alpine Ibex (Capra ibex) during the rut

During the rut, polygynous ungulates gather in mixed groups of individuals of different sex and age. Group social composition, which may vary on a daily basis, is likely to have strong influences on individual's time-budget, with emerging properties at the group-level. To date, few studies have considered the influence of group composition on male and female behavioral time budget in mating groups. Focusing on a wild population of Alpine ibex, we investigated the influence of group composition (adult sex ratio, the proportion of dominant to subordinate males, and group size) on three behavioral axes obtained by Principal Components Analysis, describing male and female group time-budget. For both sexes, the first behavioral axis discerned a trade-off between grazing and standing/vigilance behavior. In females, group vigilance behavior increased with increasingly male-biased sex ratio, whereas in males, the effect of adult sex ratio on standing/vigilance behavior depended on the relative proportion of dominant males in the mating group. The second axis characterized courtship and male-male agonistic behavior in males, and moving and male-directed agonistic behavior in females. Mating group composition did not substantially influence this axis in males. However, moving and male-directed agonistic behavior increased at highly biased sex ratios (quadratic effect) in females. Finally, the third axis highlighted a trade-off between moving and lying behavior in males, and distinguished moving and female-female agonistic behavior from lying behavior in females. For males, those behaviors were influenced by a complex interaction between group size and adult sex ratio, whereas in females, moving and female-female agonistic behaviors increased in a quadratic fashion at highly biased sex ratios, and also increased with increasing group size. Our results reveal complex behavioral trade-offs depending on group composition in the Alpine ibex, and emphasize the importance of social factors in influencing behavioral time-budgets of wild ungulates during the rut.

Consequences of snowy winters on male mating strategies and reproduction in a mountain ungulate

Alternative mating tactics (AMTs) are intrasexual variants in mating behaviour of several species ranging from arthropods to mammals. Male AMTs coexist between and within populations. In particular, male ungulates rarely adopt just one tactic throughout their lifetime. Tactics commonly change according to internal factors (age, body size, condition) and external conditions (weather, resources, predation, animal density). However, the influence of weather has not yet been investigated in upper vertebrates. Such influence may be relevant in species whose rutting period occurs late in fall or in winter, when environmental conditions and the snow cover in particular may vary considerably. We detected two AMTs in Alpine ibex (Capra ibex) males: older and full-grown males mainly adopted the tending tactic, while younger males usually pursued an alternative one (coursing tactic). Weather was found to influence the use of AMTs by males: in snowy mating seasons, the coursing tactic was no longer used due to difficulties in moving through deep snow. In snowy rutting periods, males appeared to delay or even avoid mating activities and a decrease of births was reported in the second part of the following birth season. Snow cover may have a negative effect on population dynamics by reducing the recruitment and on population genetic variability, as a consequence of poorer mating opportunities. Studies on factors affecting mating behaviour and leading to a reduced availability of mates and a decrease in female productivity are especially relevant in species, like Alpine ibex, whose genetic variability is low.

A novel approach for choosing summary statistics in approximate Bayesian computation

The choice of summary statistics is a crucial step in approximate Bayesian computation (ABC). Since statistics are often not sufficient, this choice involves a trade-off between loss of information and reduction of dimensionality. The latter may increase the efficiency of ABC. Here, we propose an approach for choosing summary statistics based on boosting, a technique from the machine-learning literature. We consider different types of boosting and compare them to partial least-squares regression as an alternative. To mitigate the lack of sufficiency, we also propose an approach for choosing summary statistics locally, in the putative neighborhood of the true parameter value. We study a demographic model motivated by the reintroduction of Alpine ibex (Capra ibex) into the Swiss Alps. The parameters of interest are the mean and standard deviation across microsatellites of the scaled ancestral mutation rate (θ(anc) = 4N(e)u) and the proportion of males obtaining access to matings per breeding season (ω). By simulation, we assess the properties of the posterior distribution obtained with the various methods. According to our criteria, ABC with summary statistics chosen locally via boosting with the L(2)-loss performs best. Applying that method to the ibex data, we estimate θ(anc)≈ 1.288 and find that most of the variation across loci of the ancestral mutation rate u is between 7.7 × 10(-4) and 3.5 × 10(-3) per locus per generation. The proportion of males with access to matings is estimated as ω≈ 0.21, which is in good agreement with recent independent estimates.

The cost of trying: weak interspecific correlations among life-history components in male ungulates

Life-history trade-offs are well known in female mammals, but have seldom been quantified for males in polygynous species. I compared age-specific mass, weapon size, survival, and reproductive success of males in eight species of ungulates, and found weak interspecific correlations among life-history traits. Young males tended to have higher reproductive success in rapidly-growing than in slow-growing species, and in species where horns or antlers reached near-asymptotic size over the first few years of life. There was no clear interspecific trade-off between early reproduction and early survival. Reproductive senescence was evident in most species. Generation length, calculated as the mean age of fathers, was negatively correlated with the reproductive success of young males and positively with life expectancy of 3-year-olds, but not with early mortality. The main determinant of male reproductive success in polygynous ungulates is the ability to prevail against competing males. Consequently, the number and age structure of competitors should strongly affect an individual’s ability to reproduce, making classic trade-offs among life-history traits very context-dependent. Most fitness costs of reproduction in male ungulates likely arise from energy expenditure and injuries sustained while attempting to mate. Individual costs may be weakly correlated with fitness returns.

Does a temperate ungulate that breeds in summer exhibit rut-induced hypophagia? Analysis of time budgets of male takin (Budorcas taxicolor) in Sichuan, China

Mammals maximize fitness by optimizing time and energy allocation between reproduction and survival. Describing time budgets is a way to understand a species' constraints in energy allocation. We describe a time budget for male takin (Budorcas taxicolor) in Tangjiahe Nature Reserve, China, to better understand rut-induced hypophagia, which is frequently observed in temperate ungulates that breed in autumn or in winter. Observations generally occurred at two elevations (1200-1600m and 2600-3200m), using 20-min focal animal scan sampling from 2007 to 2009. Feeding behaviors accounted for the majority in takin's time budget (61.1%) during daylight hours, relative to the other observed behaviors, such as rest (14.1%), alert behavior (10.2%) and locomotion (6.8%). We found a negative correlation between feeding behavior and rutting behavior during the rutting season. A ratio of feeding time to resting time increased from pre-rut to rut, while resting behavior did not change significantly across seasons. These results suggest the "energy saving" hypothesis could explain reduced foraging in male takin during the rut, but aspects of the species biology suggest that hypotheses for rut-induced hypophagia developed for other temperate ungulates do not apply to takin. We suggest that the unusual summer rutting season of takin releases males from the energy constraints encountered by temperate ungulates that breed in the autumn and has other benefits for offspring survival. Further research should be conducted on ungulates that exhibit rut during the summer and tropical ungulates that might not experience limited food availability following the mating season to improve our understanding on rut-induced hypophagia.

Coprological analyses on apparently healthy Alpine ibex (Capra ibex ibex) from two Swiss colonies

To provide baseline parasitological data for health surveillance in free-ranging Alpine ibex (Capra ibex ibex), we assessed the endoparasite population and level of parasitism in apparently healthy ibex. Faecal samples from 148 ibex were collected between 2006 and 2008 in two different Swiss ibex colonies. They were analysed by coprology, including combined sedimentation/flotation method, sedimentation method, Baermann funnel technique and Ziehl-Neelsen staining. Gastrointestinal parasites and lungworms were identified in 100% and 81.8% of the examined animals, respectively. Highest prevalences were recorded for gastrointestinal strongylids other than Nematodirus/Marshallagia spp. (100%), Eimeria spp. (100%), Muellerius spp. (79.8%) and Nematodirus/Marshallagia spp. (79.0%). We report for the first time Cryptosporidium sp. in free-ranging Alpine ibex and Cystocaulus spp. in free-ranging ibex from Switzerland. On average, ibex were infected with 3.9 different parasites taxa (range: 1-8). Parasite prevalence and diversity varied significantly between sexes, study sites and seasons. Parasite egg output was low in 95.7% and moderate in 5.3% of the samples. Overall, the results indicate that Alpine ibex are widely infected with endoparasites and suggest that multiple infections are very common in apparently healthy populations. Furthermore, our data underline the potential influence of factors such as sex, study site and season on parasitological findings.