Stereotypic behaviors in all animals are more often than not associated with poor welfare. Limited access to perform species specific behaviors is often a reason for the development of stereotypies. Elephants with their great intelligence and need of social contact, coupled with a destructive a behavior are especially difficult to house in captivity. To decrease the occurrence of stereotypic behaviors in elephants, environmental enrichment in form of food enrichment is a good option, since elephants have a great need of foraging. The aim of this study was to investigate if an extra supply of food enrichment could decrease the presence of stereotypic behaviors at night in three Asian elephants at Kolmården zoo. Already existing hay nets attached to wires in the roof were used and connected to a timer. The hay nets were lowered to vision trunk reach between 6:00 am and 6:30 am during five days and the frequencies of selected behaviors were compared with the frequencies of the same behaviors during five preceding baseline nights. The animals were filmed using mounted cameras with IR lights. There was a significant decrease of stereotypic behavior for one of the elephants, but all three showed an increase in foraging whereof the increases were significant for two of them. One of the elephants showed no stereotypic behaviors at all during the study. To keep in mind is that the elephants have different backgrounds and experiences which might have influenced the results.

In this thesis I investigate whether human sexual preferences develop through sexual imprinting. Sexual imprinting is the acquisition of sexual preferences through non-rewarded experiences with parents and siblings during an early sensitive period and it is known to exist in many other animals. Learning is often sex specific so that males, for instance, learn to prefer as sexual partners individuals that look like their mother, and avoid individuals that look like their father. First, sexual imprinting in animals and humans is reviewed and compared to prevailing evolutionary views presupposing genetically determined sexual preferences. Further, by means of web surveys, I have explored the relationship between childhood exposure to parents with certain natural and cultural traits and sexual attraction to these traits in a partner. Cultural traits were included because it is unlikely that preferences for them are genetically determined adaptations. Parental effects varied between traits. For instance, in heterosexual males, a positive effect of mother was found on attraction to smoking, but not glasses, while a negative paternal effect was found on attraction to glasses, but not smoking. However, when maternal and paternal effects were investigated for a large number of artificial and natural traits, including smoking and glasses, an overall positive effect of opposite sex parent emerged in both heterosexual males and females. Additionally, in the last study we explored a sexual preference for pregnant and lactating women. Results suggest that exposure to a pregnant and lactating mother had an effect if it occurred when the respondent was between 1,5 and 5 years old. In conclusion, these results suggest that human sexual preferences are the result of sex specific learning during a sensitive period. Sexual imprinting should therefore be recognised as a plausible explanation to human sexual preferences that deserves further scientific investigation. / At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 3: Manuscript. Paper 4: Manuscript.

The colour choice of spiders and the effects of competition on this phenomenon were examined in the laboratory using the sit-and-wait predator goldenrod crab spider (Misumena vatia, (Thomisidae)). This species can  be both white and yellow (could also change colour)  and it was here examined whether individuals preferred to sit on flowers which has the same colouration as their bodies. I found that M.vatia showed preference for flowers that matched their own body colour, but when competition was introduced this preference disappear. It seems, however, that position is a factor that can influences the substrate decisions of M. vatia, where the edge of the flower is preferred.

Si la sélection sexuelle proposée par Darwin fournit un cadre théorique satisfaisant pour expliquer l'évolution et le maintien des ornements sexuellement dimorphiques, le cas de l'ornementation mutuelle requiert l'emploi du cadre plus large offert par la sélection sociale. Dans de nombreux cas en effet, l'explication du maintien de l'ornementation mutuelle nécessite de considérer non seulement la compétition pour l'accès au partenaire de reproduction, mais également la compétition pour l'accès à d'autres types de ressources telles que la nourriture ou les emplacements pour nicher. Cependant, le maintien de l'ornementation mutuelle n'est encore que partiellement compris chez les oiseaux marins. Les travaux réalisés au cours de cette thèse s'inscrivent dans la continuité des recherches initiées depuis quelques années dans le but de comprendre le maintien de l'ornementation mutuelle chez le manchot royal, un oiseau exprimant un patch orange présentant un pic de réflectance ultraviolet de chaque côté de la mandibule, des patches auriculaires jaunes de chaque côté de la tête et un patch formant un dégradé allant du marron au jaune pâle sur le poitrail. Les travaux présentés dans ce manuscrit de thèse portent (i) sur les combats entre individus du même sexe pour accéder à un partenaire de reproduction, (ii) sur le rôle des ornements colorés dans le processus d'appariement, (iii) sur l'association entre le degré de développement des ornements et la position du territoire occupé au sein de la colonie, et enfin (iv) sur l'existence de variations interannuelles concernant le degré de coloration des ornements et le processus de choix de partenaire. Les résultats révèlent que : (i) les affrontements pour l'accès au partenaire sont beaucoup plus fréquents chez les mâles que chez les femelles ; (ii) l'ornementation mutuelle du bec pourrait être maintenu pas le processus de choix mutuel ; (iii) les individus occupant les territoires les plus centraux de la colonie expriment des patches auriculaires plus large et un patch de poitrine plus coloré ; (iv) les ornements présentent des variations notables entre deux années, tout comme le processus de choix de partenaire. Pris dans leur ensemble, ces résultats révèlent que le maintien de l'ornementation mutuelle du manchot royal est multifactoriel, et des pistes de recherches sont proposées pour affiner notre compréhension de ce phénomène complexe. / Darwin devised sexual selection theory in order to explain the evolution and maintenance of secondary sexual traits. In mutually ornamented species, however, the broader theoretical framework of social selection is needed. In many cases indeed, understanding the maintenance of mutual ornamentation requires to take into account competition for both sexual (i.e. mates) and non-sexual resources (e.g. food, nest sites). How mutual ornaments maintain and evolve is actually not well understood in seabirds species. The aim of the research program within which this Ph.D. thesis took place was to understand the maintenance of mutual ornamentation in king penguin, a bird exhibiting a ultraviolet and orange beak spot on each side of the mandible, two yellow auricular patches, and a patch on the breast that grade from brown to bright yellow. We studied (i) same-sex fight over mates; (ii) mate choice for color ornaments; (iii) the relationships between conspicuousness of ornaments and position of the territory within the colony; and finally (iv) the existence of inter-annual variations in color ornaments expression and mate choice process. Our results show that: (i) same-sex fights over mates are highly male-biased; (ii) color of the beak spots may be involved in mutual mate choice; (iii) central individuals exhibit larger auricular patches and more colorful breast patch; (iv) ornament conspicuousness as well as mate choice show inter-annual changes. Taken together, these results reveal that maintenance of king penguin mutual ornaments is multifactorial, and some research avenues are suggested for future researches.

Individuals engage in competitive and cooperative interactions with conspecifics. Furthermore, within any population of interacting individuals there are typically consistent differences among-individuals in behavioural traits. Understanding the importance of both these types of individual-specific behaviours allows us to understand why populations are structured as they are, why individuals show apparently limited behavioural flexibility, and how these elements link to population-level properties. I used extensive video camera monitoring of a population of wild field crickets (Gryllus campestris) to study the interactions and behaviours of uniquely identified individuals. I studied the shyness, activity and exploration of individuals of this population across contexts: from young to old and between captivity and the wild. This allowed me to confirm that individuals were relatively consistent across their adult lifetimes for all three traits, but only consistent between captivity and the wild for activity and exploration. I then found that high activity levels were positively related to high mating rates and short lifespans. Crucially, lifetime mating success was not related to activity level, indicating that the trade-off between lifespan and mating success was sufficient to allow variation in activity level to persist across generations. I also found that cricket social network structure is stable across generations despite the complete turnover of individuals every year. This social network structure influences sexual selection, with some male crickets heavily involved in networks of both pre- and post-copulatory competition, yet males are unable to use pre-copulatory competition to avoid post-copulatory competition. Additionally, positive assortment by mating rate between males and females may reduce the fitness of males with high mating rates, as they face stronger sperm competition. Finally, I used actor-based models to determine the factors predicting cricket social network structure and to test and reject the social-niche hypothesis for the maintenance of among-individual variation in behaviour. I also demonstrated that little else is needed in a stochastically changing network aside from positive assortment by mating rate to simulate a population with a similar skew in mating success to the one observed in the real cricket population. These results give insights into the importance of trade-offs and stochasticity in maintaining the extensive variation in the natural world.

Les traits ornementaux sont classiquement vus comme un attribut des mâles chez les espèces animales. Cette vision est liée à un rôle considéré historiquement comme très asymétrique des sexes, avec les mâles qui entrent en compétition (sélection intra-sexuelle) pour attirer les femelles qui choisissent (sélection intersexuelle) le meilleur partenaire. Cette idée fut développée en liaison avec l’asymétrie dans la production des gamètes mâles et femelles. Les femelles, qui produisent un nombre réduit de gamètes de grosse taille, maximisent la chance de survie de leurs descendants en investissant plus dans les soins parentaux ; elles deviennent ainsi le sexe limitant et choisissent les mâles qui entrent donc en compétition pour avoir accès à la reproduction. Tout trait ornemental qui augmente le succès d’appariement sera donc avantageux pour les mâles conduisant à des traits sexuels secondaires plus développés chez ce sexe. Si les traits ornementaux sont fréquents chez les mâles, il existe également de nombreux exemples chez les femelles, notamment chez les espèces socialement monogames à soins biparentaux. C’est seulement récemment que les biologistes évolutifs ont cherché à tester les processus expliquant l’apparition et le maintien des ornements femelles. Si le rôle de la corrélation génétique dans cette évolution est incontestable, et que la sélection sociale est aussi majeure, plusieurs études empiriques ont montré un choix mâle pour les ornements femelles et des modèles théoriques ont déterminé les paramètres conduisant à l’évolution du choix mâle. Par ailleurs, les approches phylogénétiques retraçant l’évolution des ornements ont montré une forte labilité des traits femelles, avec des apparitions et disparitions de traits ornementaux plus fréquentes chez les femelles que chez les mâles. Afin de mieux comprendre la relation entre la sélection sexuelle et l’évolution des ornements femelles, cette thèse s’est construite sur ces résultats précédemment acquis et a mené plusieurs approches pour mieux préciser le rôle de la sélection sexuelle dans l’évolution et le maintien de la coloration chez les femelles. Une approche comparative à l’échelle des passereaux a testé les paramètres déterminés comme conduisant à l’évolution du choix mâle par des modèles théoriques. En accord avec les modèles théoriques, les résultats mettent en avant l’importance de l’investissement du mâle dans les soins parentaux dans l’évolution de la coloration du plumage femelle. Ils montrent également comment l’investissement initial des femelles dans la reproduction limite l’évolution de la coloration femelle. Un autre axe de la thèse s’est focalisé sur la coloration chez une espèce monogame, la Mésange bleue Cyanistes caeruleus, en utilisant un vaste jeu de données à long terme avec10 ans de donnés dans quatre populations pour tester notamment(i) la force de la corrélation génétique, (ii) les liens entre indices de succès de reproduction et coloration et (iii) l’existence d’un appariement par homogamie chez cette espèce. Si les résultats principaux montrent une forte corrélation génétique et soulignent une très forte variation spatiotemporelle, l’application d’outils méta-analytiques a permis de déceler une relation entre les colorations des femelles et les indices de succès de reproduction ainsi qu’un patron faible mais positif d’appariement par homogamie pour les deux patchs étudiés (couronne et bavette). Les deux volets de la thèse représentent de nouveaux apports en faveur de l’évolution des ornements femelles. Ils soulignent la complexité associée à leur évolution et l’importance de prendre en compte la variation spatiotemporelle pour une compréhension étendue et une possibilité de généralisation. / Ornamental traits are classically associated with males in animal species. The asymmetrical view is related to sex roles, in which males are competing (intra-sexual selection) to attract females which chose the best mate (intersexual selection). This idea was developed with the concept of anisogamy, the asymmetry in the production of male and female gametes. Females producing few but large gametes maximize their offspring survival rate by investing more in parental care; they become the limiting sex and chose males which are thus competing for access to reproduction. Then, any ornamental trait increasing pairing success would become advantageous for males, leading to more developed secondary sexual traits in this sex. If ornamental traits are more frequent in males, there are also many examples with females, especially in socially monogamous species with biparental care. Evolutionary biologists have only started recently to test processes explaining the outbreak and maintenance of female ornaments. Genetic correlation is an unquestionable process involved in this evolution, and social selection is also a major process. Several empirical studies have also related male mate choice to female ornaments and theoretical models have defined key parameters driving the evolution of male mate choice. Furthermore, phylogenetical studies retracing the evolution of ornaments have showed a high lability in female traits, with more frequent gains and losses of ornamental traits in females compared to males. In order to link sexual selection to the evolution of female ornaments, this thesis was based on these previous achievements to develop different approaches to better understand the role of sexual selection in the evolution and maintenance of female colouration. Comparative methods in songbirds tested the key parameters defined by theoretical models as driving the evolution of male mate choice. In line with theoretical models, results highlight the importance of male investment in parental care in the evolution of female plumage colouration. They also show how female initial investment in reproduction limits this evolution. Another thesis axis focused on colouration in a monogamous species, the Blue tit Cyanistes caeruleus, using a large dataset across 10 years in four populations and tested in particular (i) the strength of genetic correlation, (ii) relations between proxies of reproductive success and colouration and (iii) the existence of assortative mating in this species. The main results highlight a strong genetic correlation and a wide spatiotemporal variation and the use of meta-analyses revealed correlation between female colouration and proxies of reproductive success as well as a weak but positive pattern of assortative mating on the two measured patches (crown and chest). Both sides of the thesis represent new insights in favour of the evolution of female ornaments. They also highlight the complexity associated with their evolution and the importance of considering spatiotemporal variation for extensive understanding and generalisation.

<p>Understanding and adequately protecting habitat is at the forefront of modern conservation concerns. Turtles are especially vulnerable to habitat loss, and are therefore a top priority for habitat research. To help meet this need, I used radio telemetry to collect microhabitat data from two imperiled species of turtles that occupy a military base in Michigan. Preliminary data exploration was carried out with principal components analysis (PCA). Microhabitat use was then modeled for each species using conditional logistic regression (CLR), with a generalized estimating equation (GEE) element to limit bias due to individual variation. Finally, I compared habitat use between sympatric Blanding’s and Wood Turtles using Mann-Whitney U tests and Mood’s median tests to investigate the degree of overlap in microhabitat use when these species occur in sympatry. Evidence for microhabitat selection in Blanding’s Turtles was weak, suggesting that they likely do not make habitat decisions at this level. Wood Turtles selected sites that were farther from water and had fewer trees, less overstory canopy cover, and more ground cover. Additionally, the two species differed in several aspects of microhabitat use; Wood Turtles were more terrestrial and more tolerant of tree cover than Blanding’s Turtles. Patterns of microhabitat use found in this study match previously observed behavior of turtles in high quality habitat, suggesting that managers should work to maintain the habitat currently available at Camp Grayling. Additionally, because both turtle species were associated with open canopy, selective logging could benefit turtles provided care is given to timing and methods. </p>

<p>This study monitored daily and seasonal locations of juvenile green turtles in three coastal bays of northwest Costa Rica, determining their home ranges and assessing their habitat use. My objective was to produce insights which might help future Pacific Ocean green turtle conservation efforts.</p> <p>I tracked 14 juvenile green turtles for 51-629 days using acoustic transmitters (VECOM v16) and 12 acoustic receivers (VECOM VR2Tx and VR2W) in 5 study area habitats: sandy areas, reef patches, macroalgae, rocky reefs, and mangroves. I divided these 14 turtles into large (equal to or larger than 65 cm CCL) and small (smaller than 65 cm CCL) size classes so I could highlight any changes as they grew toward adulthood. </p> <p>Both the large and small size turtles used habitats differently during the dry and rainy seasons. During the dry season, the large juveniles had a High Detection Rate (HDR) of 40% in the macroalgae area. During the rainy season, their HDR was 33% in the reef patch area. The small juveniles had their HDR in the reef patch area during both seasons: 33% in the dry season and 43% in the rainy season. The mean home range for the 14 turtles was 1.96 km²; their core use area was 0.19 km2. I saw no connection between body size and home range. The HDR findings suggest that juvenile green turtles preferred reef patches, rocky reefs, and macroalgae habitat types. The large juveniles prefer vegetation areas more as they grew; similar to that of adult green turtles. Some turtles moved between Matapalito Bay and Santa Elena Bay and along the coast to small bays east of Matapalito Bay. Travel speed varied between 0.23 km/h and 12.90 km/h with a mean of 1.57 km/h.  </p> <p>My findings highlight certain habitat areas preferred by Pacific juvenile green turtles. This can guide conservationists in identifying and protecting similar habitats in other inshore Pacific bays in Central America. By protecting habitat areas that are important for juvenile green turtles, this can help rebuild the green turtle population in the Pacific Ocean. </p>

The study of sex allocation is one of the most successful areas in evolutionary biology: its theoretical predictions have been supported by experimental, observational and comparative approaches. Here, I develop sex allocation theory as follows: (1) I use fertility insurance theory to predict the sex ratio strategy of the malaria parasite, in response to human medical interventions that increase mortality and decrease fertility of the parasite’s various sexual stages; (2) Haplodiploidy has been suggested as a driver of the evolution of eusociality, as under this genetic system a female may be more related to her sister than to her own offspring. I examine a model considering queen versus worker control over the sex ratio of the colony and show that haplodiploidy alone does not explain the evolution of helping; (3) I follow up this study of the haplodiploidy hypothesis by examining the idea that split-sex ratios may favour the evolution of eusociality in haplodiploid species. I study the two mechanisms of split sex ratios, that are found in natural populations and may have been important in the transition to eusociality: queen virginity and queen replacement. I focus on the impact of worker reproduction by considering the effect of woker producing a fraction of the colony offspring and by considering variation in the workers’ offspring sex ratio. My analysis shows that worker reproduction does not promote the evolution of helping in haplodiploid species; (4) I examine the evolution and function of a sterile soldier caste in parasitoid wasps from the genus Encyrtidae. Two main functions have been hypothesized for the emergence of soldiers: spiteful mediation of a sex ratio conflict in mixed-sex broods, and altruistic protection and 7 facilitation of the development of relatives. I develop a model considering variation in the oviposition behaviour of females, that may produce single-sex or mixed-sex broods. I show that, in accordance with previous theory, females are expected to produce more soldiers than males, under the sex ratio conflict hypothesis. I also show that one of the consequences of this costly conflict is that females are favoured to produce single-sex broods over mixed-sex broods.

Projet réalisé dans le cadre d'une cotutelle avec l'Université de Bourgogne (Dijon, France) / Dans cette enquête nous entreprenons d’explorer la notion de comportement animal telle que l’exprime une discipline contemporaine, l’écologie comportementale. Afin de procéder à l’examen d’une notion aussi complexe, positionnée dans un contexte étroit, nous développons et utilisons un outil d’investigation : l’épistémologie historique. De façon générale, cet outil consiste à intégrer en une seule démarche les perspectives d’investigation diachronique et synchronique sur un même thème. Ainsi, pour procéder à l’examen de la notion de comportement animal, nous puisons d’abord dans l’histoire récente de l’écologie comportementale. Nous nous intéressons plus particulièrement à sa filiation avec l’éthologie classique et, après avoir reconstitué la trame historique qui unit les deux disciplines, nous procédons à leur comparaison. Cette seconde étape de notre épistémologie contribue à mettre en évidence plusieurs différences critiques dans la conception du comportement animal qu’endosse chacune des disciplines. Ces distinctions, en faisant ressortir la spécificité de l’écologie comportementale, nous permettent ensuite de nous intéresser à la notion de comportement animal à travers les approches principales que cette discipline mobilise. Ultimement, nous élaborons deux définitions de la notion de comportement animal. La première reflète le statut ontologique du comportement dans la discipline, alors que la seconde correspond à la conception qui se dégage de la pratique des écologues. / In this inquiry I undertake to explore the notion of animal behaviour as it is expounded in a contemporary field of inquiry: behavioural ecology. In order to carry out an analysis of such a complex notion, localized in a very narrow context, I design and use a specific tool of investigation called “historical epistemology”. Simply understood, this tool consists in the integration of diachronic and synchronic perspectives of investigation into a single approach to investigate a circumscribed theme. So, in order to proceed to the analysis of the notion of animal behaviour, I first draw into the recent history of behavioural ecology. I take special interest in its filiation with classical ethology and, after having reconstructed the historical frame that links the two fields together, I proceed to compare them. This comparison, the second step of my epistemology, is used to highlight the characteristics of the animal behaviour conceptions put forward by the two scientific disciplines. These distinctions, bringing to the fore the specificity of behavioural ecology, then allow me to scrutinize the notion of animal behaviour as it is instantiated in the main approaches mobilized by the discipline (especially what I identifies as the “phenotypic adaptationist”, the “phenotypic structural”, the “comparative” and the “by reduction” approaches). Last, I design two definitions of the notion of animal behaviour. The first one reflects the ontological status of the notion in this field of investigation, whereas the second corresponds to the conception underlying behavioural ecologist practices.