Sexual Conflicts in a monogamous arctic bird. Sexual conflicts over copulation, hatching failure and brood reduction

The season 2011 finished at the end of August 2011. All our projects went smoothly and we managed to perform all the planned experiments and observations. The IPEV programme 1162 focuses on sexual behaviour of a pan arctic seabird, the kittiwake. Sub topics are Sexual conflicts about multiple copulations, Sexual selection and brood reduction,. Hormones and behaviour, Sexual behaviour and genetic distance among partners, and sex-allocation. During the two next years the project will focus on Sex allocation as it is the topic of Thomas Merkling’s PhD. His preliminary results, which are submitted to Behavioral Ecology, suggest that kittiwakes can manipulate the sex ratio of their progeny according to their own condition. This project benefited from external funding from the CNRS (MIE program) including salaries and molecular material (kits etc).

Campaign 2012

Year 1/2

We recently submitted a paper, investigating hatchlings sex ratio variation in relation to the parents’ feeding treatment (fed / unfed). Results (1) clearly show that the kittiwake is particularly relevant for studying sex allocation patterns and (2) strongly suggest clear directions for future research. These are the core of the next field season. One of our main goals is to focus on the role of relative condition, i.e. relative to the condition of other members of the colony. Some preliminary experiments have been carried out in 2011. In particular, this allowed us to make sure that birds that were not fed the previous year could get used to it. This worked and about 70 % accepted to be fed within few days. Next year, we will go on with this investigation in creating a gradient of density of neighbors of a given treatment (fed or unfed) surrounding focal pairs of the opposite treatment, paying particular attention to spatial organization (distances between nests etc…). We expect unfed pairs to produce less males than fed pairs, and this to be all the more pronounced that the fed neighbours density increases (the opposite being expected for fed pairs). This prediction of a role of relative condition is particularly difficult to test in nature and to our knowledge it has never been tested before. Birds are good model species because the spatial constraint of the nest allows us to clearly account for space. In this context, the MDO tower provides a uniquely favorable setting to test that prediction on a wild species. We will further study the role of environmental condition, assessed by different proxies related to population performance and nutritional status, on chick sex variation according to feeding treatment, over the long term (at least 8 years of data already collected). At an individual level, parental ability to care will be assessed using innovative proxies, such as genetic similarity between mates or partners’ coloration, and studied in relation to chick sex. Finally, the frequency and intensity of aggression between sibs as well as growth and mortality rates and parental behavior will be studied in relation to chick sex, rank (with B chicks experimentally older than A chicks), age difference (experimentally controlled for) and body weight / size differences between sibs and parental feeding treatment.