Johanna Liljestrand Rönn, Fil Dr

Kontakt

Adress
Dept of Animal Ecology
Evolutionary Biology Centre (EBC)
Uppsala University
Norbyvägen 18 D
SE-752 36 Uppsala
SWEDEN

Telefon
+46 18 471 2662

Telefax
+46 18 471 6484

Denna information finns endast på engelska.

Male-female coevolution in Bruchid beetles

Background

Males and females of many taxa are known to coevolve, such that evolution in one sex is matched by evolution in the other. In many cases, the same trait is involved in both sexes (e.g. body size). However, coevolution may also involve distinct traits in the two sexes (e.g. secondary sexual morphologies in males and mating behaviors in females). Intersexual coevolution is at the heart of biology, as it can be a driving force in speciation by accelerating differentiation in behavior and morphology. The pattern of intersexual coevolution is relatively well established in several taxa. Yet, our understanding of the processes responsible for male-female coevolution remains incomplete.

Study species

I use several species of Bruchid beetles belonging to the genus Callosobruchus as a model system. We currently host six Callosobruchus species in the laboratory. These beetles are highly amenable to experimental research and also very easy to keep in laboratory conditions (easily stored in simple containers, they are robust and easy to transport). Another advantage of using Callosobruchus as a research organism is the fact that they have fairly short lifecycles (3-5 weeks). Furthermore, it is an economically important group (as pests on stored food) around the world, and new populations are fairly easy to obtain.

PhD thesis

The primary aim of my PhD was to establish a robust molecular phylogeny of the genus Callosobruchus. This project was done in collaboration with Prof. Midori Tuda, Faculty of Agriculture, Kyushu University, Japan. I was then able to use this phylogeny as a basis to conduct comparative studies on a number of traits. During the last two decades comparative methods have gone through a revolutionary development. These changes incorporate the development of new statistical models that include phylogenetic relationships between species. By employing comparative methods based on robust phylogenies, more complete pictures can be presented and results from comparative studies and laboratory experiments can be put into broader contexts.

I have taken measurements of a suite of morphological traits in both sexes, including body size, genital morphology, morphology of the genital tract, and antennal morphology. I use these data to quantify morphological variation across species. I have also quantified reproductive behavior in a series of standardized laboratory experiments. I have compiled a large data set on parameters such as mating behavior, the cost of mating, egg production and ejaculate size.

I will defend my thesis in spring 2009.