Fewer invited talks by women in evolutionary biology symposia.

Lower visibility of female scientists, compared to male scientists, is a potential reason for the under-representation of women among senior academic ranks. Visibility in the scientific community stems partly from presenting research as an invited speaker at organized meetings. We analysed the sex ratio of presenters at the European Society for Evolutionary Biology (ESEB) Congress 2011, where all abstract submissions were accepted for presentation. Women were under-represented among invited speakers at symposia (15% women) compared to all presenters (46%), regular oral presenters (41%) and plenary speakers (25%). At the ESEB congresses in 2001-2011, 9-23% of invited speakers were women. This under-representation of women is partly attributable to a larger proportion of women, than men, declining invitations: in 2011, 50% of women declined an invitation to speak compared to 26% of men. We expect invited speakers to be scientists from top ranked institutions or authors of recent papers in high-impact journals. Considering all invited speakers (including declined invitations), 23% were women. This was lower than the baseline sex ratios of early-mid career stage scientists, but was similar to senior scientists and authors that have published in high-impact journals. High-quality science by women therefore has low exposure at international meetings, which will constrain Evolutionary Biology from reaching its full potential. We wish to highlight the wider implications of turning down invitations to speak, and encourage conference organizers to implement steps to increase acceptance rates of invited talks.

Why care? Inferring the evolution of complex social behaviour.

Phylogenetic comparative analyses of complex traits often reduce the traits of interests into a single (or a few) component variables. Here, we show that this may be an over-simplification, because components of a complex trait may evolve independently from each other. Using eight components of parental care in 400 bird species from 89 avian families that represent the relative contribution of male vs. female to a particular type of care, we show that some components evolve in a highly correlated manner, whereas others exhibit low (or no) phylogenetic correlation. Correlations were stronger within types of parental activity (brooding, feeding, guarding) than within stages of the breeding cycle (incubation, prefledging care, post-fledging care). A phylogenetically corrected cluster analysis identified two groups of parental care components that evolved in a correlated fashion: one group included incubation and brooding, whereas the other group comprised of the remaining components. The two groups of components provide working hypotheses for follow-up studies to test the underlying genetic, developmental and ecological co-evolutionary mechanism between male and female care. Furthermore, the components within each group are expected to respond consistently to different ambient and social environments.

Genetic relatedness in wintering groups of house sparrows (Passer domesticus).

Social behaviour of group-living animals is often influenced by the relatedness of individuals, thus understanding the genetic structure of groups is important for the interpretation of costs and benefits of social interactions. In this study, we investigated genetic relatedness in feeding aggregations of free-living house sparrows (Passer domesticus) during the nonbreeding season. This species is a frequent model system for studies of social behaviour (e.g. aggression, social foraging), but we lack adequate information on the kin structure of sparrow flocks. During two winters, we ringed and observed sparrows at feeding stations, and used resightings to identify stable flock-members and to calculate association indices between birds. We genotyped the birds using seven highly polymorphic microsatellite loci, and estimated pairwise relatedness coefficients and relatedness categories (close kin vs. unrelated) by maximum likelihood method. We found that most birds were unrelated to each other in the flocks (mean +/- SE relatedness coefficient: 0.06 +/- 0.002), although most individuals had at least a few close relatives in their home flock (14.3 +/- 0.6% of flock-mates). Pairwise association between individuals was not significantly related to their genetic relatedness. Furthermore, there was no difference between within-flock vs. between-flock relatedness, and birds had similar proportions of close kin within and outside their home flock. Finally, relatedness among members of different flocks was unrelated to the distance between their flocks. Thus, sparrow flocks were not characterized by association of relatives, nevertheless the presence of some close kin may provide opportunity for kin-biased behaviours to evolve.

Lean birds in the city: body size and condition of house sparrows along the urbanization gradient.

1. Urbanized habitats differ from natural ones in several ecological features, including climate, food availability, strength of predation and competition. Although the effects of urbanization on avian community composition are well known, there is much less information about how individual birds are affected by these human-generated habitat differences. 2. In this study we investigated the relationships between the morphological characteristics and the degree of habitat urbanization in house sparrows, Passer domesticus (Linne 1758) . We collected data for more than 1000 non-breeding adult birds in Hungary between 1997 and 2006, from seven sites including farmlands, suburban areas and city centres. 3. We found that the body mass, tarsus length and body condition of free-living sparrows differed among the sites: birds in more urbanized habitats were consistently smaller and in worse condition than birds in more rural habitats. A composite measure of habitat urbanization (based on building density, road density and vegetation cover) explained over 75% of variance between sites in the studied traits, after we controlled for the effects of sex, year, season and time of capture. 4. The difference in body mass between rural and urban sparrows was significant when birds were kept in aviaries under identical conditions, with constant ad libitum food availability. It is therefore unlikely that the reduced body size and condition of urban sparrows are a consequence of reduced access to food for adults (e.g. due to strong competition), or their short-term responses to high food predictability (e.g. by strategic mass regulation). 5. We suggest that habitat differences in nestling development or adaptive divergence of sparrow populations due to distinct environmental conditions (such as differing predation pressure) may account for the differences along the urbanization gradient.

Parental conflict in birds: comparative analyses of offspring development, ecology and mating opportunities.

Parents often conflict over how much care to provide to their offspring. This conflict is expected to produce a negative relationship between male and female parental care, the strength of which may be mediated by both ecological and life-history variables. Previous studies have observed such trade-offs, but it is not known how generally they occur. Traditional views of sexual conflict place great importance on ecological factors in determining levels of parental care, whereas alternative views propose that the key determinant is mating opportunity. We carried out a broad-scale comparative study of parental conflict using 193 species from 41 families of birds. Using phylogenetic comparative analysis, we establish the generality of intersexual parental care conflict. We also show that parental conflict, as indicated by the disparity in care between the male and the female, depends on offspring development and mating opportunities, since in precocial species both males and females responded to increased mating opportunities. Altricial birds, however, failed to show these relationships. We also found little influence of breeding climate on parental conflict. Taken together, our results suggest that sexual conflict is a key element in the evolution of parental care systems. They also support the view that the major correlates of the intersexual conflict are mating opportunities for both sexes, rather than the breeding environment.

Methamphetamine-induced stereotypies in newly-hatched decerebrated domestic chicks.

Metamphetamine in high dose has been reported to induce stereotypic behavior of abnormal form in the pigeon and domestic chick. A number of reports suggested that the target of metamphetamine was the paleostriatal complex, the highest motor center of the avian brain. The present study tested this hypothesis by treating newly-hatched domestic chicks with high dose of metamphetamine (10 mg/kg b.w.) after complete decerebration or sham operation. Stereotypic mandibulations were observed both in sham-operated and in decerebrated birds in similar form following methamphetamine treatment. The results suggested that brainstem pattern generators remain responsive to dopaminergic stimuli in the absence of the main telencephalic (striatal) targets.

Aggression among female lapwings, Vanellus vanellus

Social monogamy is the most common pair bond in birds and one hypothesis for its prevalence is that already mated females ('residents') prevent other females from establishing a pair bond with their mates ('competition for male parental care' hypothesis). To investigate this hypothesis we experimentally induced aggressive behaviour in resident female lapwings by presenting a female dummy conspecific, and a male dummy as control, near their nests. Females attacked both dummies. However, the female dummy was attacked more often than the male during the 5-min trials. Attacks on the female dummy were mostly on the ground (88%, N=27 resident females) whereas the male dummy was attacked either by aerial dives (53%) or on the ground (47%, N=24 resident females). Frequency of attacks on the female dummy decreased over the incubation period, whereas there was no such trend with the male dummy. These results suggest that female lapwings attempt to prevent their mates from attracting a new mate and thus try to monopolize their parental care. Other competing hypotheses for the explanation of aggressive behaviour in female lapwings are also discussed but were not supported by our data.1997The Association for the Study of Animal Behaviour