A good deal of research has recently focused on people's commitment to biodiversity conservation by investigating their "willingness-to-pay" (WTP). Because of the public's self-reported preferences for species that are more charismatic or similar to humans, conservation programs are often biased toward these species. Our study aimed to explore the determinants of WTP among 10 066 participants in a zoo conservation program. The program aims to raise money to support conservation programs and involves donating a sum of money to "adopt" an animal in the zoo. We explored whether participants were influenced by particular scientific characteristics of the animal (IUCN conservation status and phylogenetic distance from humans) or by more affect-related characteristics, such as the charisma of the animal. We found that participants did not choose an animal to adopt because of the endangered status of the species, and did not donate more to endangered species than to other species. Instead, they were more likely to choose a charismatic species. However, surprisingly, those who chose a less charismatic species gave more money on average to the program than those who adopted more charismatic species, suggesting a higher level of commitment among the former. These results therefore suggest that this type of conservation program may not be an effective way of reconnecting people with conservation issues related to endangered species. We therefore advise zoos to communicate more strongly on the level of threat to species and to increase the ratio of endangered over charismatic species in their animal adoption programs.

Evolutionary theories of ageing posit that increased reproductive investment occurs at the expense of physiological declines in later life. Males typically invest heavily in costly sexual ornaments and behaviour, but evidence that the expression of these traits can cause senescence is lacking. Long-lived houbara bustards (Chlamydotis undulata) engage in extravagant sexual displays to attract mates and here we show that males investing most in these displays experience a rapid senescent deterioration of spermatogenic function at a younger age. This effect is sufficiently large that the expected links between male 'showiness' and fertility reverse in later life, despite 'showy' males continuing to display at near maximal levels. We show that our results cannot be explained by the selective disappearance of competitive phenotypes and that they are instead consistent with an early vs. late life trade-off in male reproductive competence, highlighting the potential significance of sexual selection in explaining rates of ageing.

The evolution of multiple sexual traits remains controversial and poorly understood in evolutionary biology. In many bird species, males exhibit complex courtships involving feather ornaments and behavioral display. Multiple traits may convey information on the genetic and phenotypic quality of males. In particular, fixed characters, such as feather ornaments (produced once a year during the annual molt in many bird species) might convey information about past male condition (at the time of trait development); whereas flexible traits such as behavioral displays should be sensitive to present condition. Here we show that both flexible behavioral displays and fixed feather ornaments of peacocks, used by females to choose a mate, honestly reflect health status. Correlative data showed that peacocks with high display rate (the number of behavioral displays per hour) and a large number of tail eyespots had low levels of circulating heterophils, suggesting better health status. Experimental activation of the immune system, through LPS injection, significantly reduced display rate compared to a control group. However, the sensitivity of a male display rate to the immune challenge was dependent on the number of tail eyespots: males with higher number of tail eyespots were better able to cope with the experimental immune challenge, and maintained their display rate at levels closer to the levels performed before the immune activation. These results are consistent with the idea that multiple signaling might enhance information reliability

Habitat selection is a hierarchical process where the distribution of individuals is constrained by environmental factors acting from the landscape scale to specific microhabitats such as breeding sites. However, interactions between conspecifics might greatly influence bird distribution and habitat use, especially in lekking birds. In the lekking Houbara bustard Chlamydotis undulata undulata, we investigated the respective role of environmental and social constraints on the distribution of nests and display sites. We measured environmental variables around 69 nests and 70 display sites at different spatial scales: the landscape, the breeding range, and the display and nest site scale. The variables were compared to those measured at 50 random plots to determine whether environmental features are actively selected. Social variables were included by studying spatial relationships between displaying male density, nests and female movements throughout the year. At the landscape scale, human presence acted as a limiting factor for the establishment of nest and display sites. At the breeding range scale, habitat requirements differed between sexes. Breeding females used a heterogeneous complex of habitats provided by the network of wadis (water courses) crossing the reg (gravel plain) covered by tall perennial plants. In contrast, display males looked for conspicuousness and courtship ability by selecting the reg with short perennials, and used temporarily flooded areas for feeding. Males aggregated on traditional display site where they experienced the greatest female density. This result supported the hotspot model in the evolution of leks in the Houbara bustard. It underlies an overriding effect of female attraction on male settlement in the individual habitat selection process.

This paper presents observations of Houbara Bustard Chlamydotis undulata undulata homerange, in the semi-desert steppe of eastern Morocco. Home-ranges were calculated from radiotagged birds using the fixed kernel method (LSCV). The mean annual home-range of males (17 km 2 ) was smaller than that of females (146 km 2 ; P < 0.001). The majority of male home-ranges had a unimodal distribution (86%), whereas 67% of female home-ranges were multimodal. Consequently, the amplitude of female movements was larger (mean: 44 km/13 km; P < 0.002). In spring, male home-ranges decreased in size around display sites (8 km 2 ) and many of them overlapped considerably. Display sites show an aggregative distribution ( P < 0.001) and a single female reproductive range may contain the display sites of several males. The data fulfil the definition of an exploded lek social structure. In our study, C. u. undulata appears to be sedentary with relatively limited home-ranges. Successive years of fidelity to home-ranges indicate that adults are not nomadic.

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Theory of Mind (ToM), i.e. the ability to understand others' mental states, endows humans with highly adaptive social skills such as teaching or deceiving. Candidate evolutionary explanations have been proposed for the unique sophistication of human ToM among primates. For example, the Machiavellian intelligence hypothesis states that the increasing complexity of social networks may have induced a demand for sophisticated ToM. This type of scenario ignores neurocognitive constraints that may eventually be crucial limiting factors for ToM evolution. In contradistinction, the cognitive scaffolding hypothesis asserts that a species' opportunity to develop sophisticated ToM is mostly determined by its general cognitive capacity (on which ToM is scaffolded). However, the actual relationships between ToM sophistication and either brain volume (a proxy for general cognitive capacity) or social group size (a proxy for social network complexity) are unclear. Here, we let 39 individuals sampled from seven non-human primate species (lemurs, macaques, mangabeys, orangutans, gorillas and chimpanzees) engage in simple dyadic games against artificial ToM players (via a familiar human caregiver). Using computational analyses of primates' choice sequences, we found that the probability of exhibiting a ToM-compatible learning style is mainly driven by species' brain volume (rather than by social group size). Moreover, primates' social cognitive sophistication culminates in a precursor form of ToM, which still falls short of human fully-developed ToM abilities.

Animal communication involves a multitude of signals ranging from morphological to behavioural traits. In spite of the diversity of traits used in animal signalling, most studies of sexual selection have focused on single male traits. Moreover, the two forces of sexual selection (male-male competition and female preference) may target different traits and favour the diversification of male signalling. Still, little is known on the combined effects of intra-and intersexual selection on the evolution of multiple signals. The peacock is often cited as one of the best examples of the strength of sexual selection in producing exaggerated traits. Here, we investigated traits under intra-and intersexual selection in a population of free-ranging common peafowl. Peacocks with longer trains and tarsi were more likely to establish a display territory in a central position within the lek and had a higher number of intrusions and agonistic interactions. These traits appeared therefore to be under intrasexual selection. Female selection was assessed as the number of copulations. Mating success was positively correlated with behavioural traits (display activity) and with train ornamentation (number and density of ocelli) suggesting that females use multiple cues during mate selection. Therefore, intraand intersexual selection seem to operate on different sets of traits. Overall, our results stress the role of multiple receivers on the evolution of multiple signals.