Assortative mating and maternal effects in red-billed queleas
Red-billed quelea males display either a red or yellow body-plumage and either a black or white face-mask. In wild queleas, the correlation between father and son plumage coloration is so high that it suggests that there is either 1) strong assortative mating for male breeding plumage coloration genotype, even though females do not express the male breeding plumage phenotype, or 2) mothers influence their son's future adult phenotype through manipulating embryonic exposure to maternal hormones deposited in the egg. In this study, I am using both descriptive and experimental approaches on captive and wild queleas in order to determine 1) whether assortative mating for plumage genotype occurs in queleas, 2) the role maternal effects (i.e. egg hormones) might have on adult phenotype, and 3) the mechanistic basis to the expression of sexually dimorphic ornamentation in this species.
Silke Laucht (PhD Student) Department of Behavioural Ecology & Evolutionary Genetics Max Planck Institute for Ornithology PO Box 1564 D-82305 Starnberg (Seewiesen) Germany tel: +49 8157 932-320 e-mail: laucht@orn.mpg.de
Dynamics in testosterone and its relationship to ornaments in male House Sparrows
Currently there is widespread interest in the nature of testosterone and its relationship to ornamentation. However it is still unknown how testosterone titers vary within individuals over different points in time, and how this variation is related to ornament development. I am currently studying the variability of testosterone and its relationship to male ornaments in a population of approximately 150 captive House Sparrows (Passer domesticus) through the course of a year. Questions I am focusing on include: 1) how does testosterone change throughout the course of a year? 2) how does testosterone change throughout the course of a day? 3) how consistent is relative testosterone levels within individuals throughout the year? 4) how is testosterone influenced by social group dynamics? and 5) what is the nature of the relationship between testosterone and male ornamentation in this species?
Ariane Mutzel (Masters Student) Department of Behavioural Ecology & Evolutionary Genetics Max Planck Institute for Ornithology PO Box 1564 D-82305 Starnberg (Seewiesen) Germany tel: +49 8157 932-324 e-mail: mutzel@orn.mpg.de
Personalities in house sparrows
Historically, personality research has focused on humans and primates. However more recently, interest has grown around understanding consistent individual differences in personality in more diverse taxa, such as non-primate mammals, birds, fish and insects. So far the vast majority of studies on avian personalities have focused on great tits and surprisingly there are very few studies looking at the relationship between personalities and hormonal profile, even though hormones are known to have a strong influence on behaviour. For my Diplomearbeit thesis (Masters) I am testing how personality is related with testosterone profiles as measured with point-sample plasma testosterone assays and bill colouration and badge size - well-known t-dependent ornaments in this species. I have tested the personalities of 115 captive male house sparrows using two different 30 min assays performed once with each individual. First, exploratory behaviour was tested by placing males in an unfamiliar aviary with 10 different objects and monitoring how many objects the males investigated. Second, curiosity (or bold/shyness) was measured as the reaction towards a novel object introduced in a familiar environment.
