Dr Nina Wedell


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Graduated from the University of Stockholm in 1984, where she also did a Masters in 1986. After working as a research assistant on various projects she did a PhD, also at Stockholm, examining the evolution and function of nuptial gifts in bushcrickets. A large part of her work was carried out in Australia collecting a comparative data-set on several species, many of them undescribed. She also did collaborative work on sexual selection in butterflies with her colleagues in Stockholm during this time. Following her PhD in 1993, Nina moved to Prof. G.A. Parkerís lab in Liverpool for a 3 year post-doc, working on sexual selection and sperm competition in butterflies and crickets. She was awarded a Research Fellowship in 1996 from the Swedish Natural Science Research Council, and returned to Stockholm to continue working on sexual selection in insects. During this time she has worked extensively in Leeds in the Ecology and Evolution group, and also spent a year at the University of Melbourne, Australia. In 2000 she was awarded a Royal Society University Research Fellowship, which she holds at the University of Exeter, Cornwall Campus.

Research Topics

My research is mainly focused on sexual selection and sexual conflict using various insect model systems (bushcrickets, crickets, butterflies, bugs and flies). I am specifically interested in what determines female mating frequencies. Why do females mate as many or as few times as they do, and what consequences does this have for male mating decisions? Males and females often disagree over when and how often to mate and amount of resources invested in offspring. I am exploring the consequences and possible resolutions to this conflict, in particular the relationship between cost and benefits of female mating frequency and male adaptations to reduce female remating.

Paternal Investment and Paternity Assurance

Males of many species provide the female with nutrient donations at mating that she converts into more eggs. How does a maleís paternity assurance affect how much resources he will invest in offspring, and is it influenced by female mating status and potential fecundity? I am also examining the effect of variation in the quality of male donations on female mating frequency, and the femaleís own investment in offspring.

Ejaculate Tailoring

Sperm competition and female quality and encounter rates are expected to influence males sperm delivery strategies. Competition between ejaculates has affected evolution of sperm number and form, resulting in increased ejaculate expenditure with increasing degree of sperm competition. Increased costs of sperm production promote prudent sperm allocation by males, at times resulting in sperm limitation for females. The question is: how sensitive are males to variation in female quality and risk of sperm competition in terms of number of sperm delivered at mating.

Sperm Polymorphism

Males of many species produce different sperm types, some of them unable to fertilise the femaleís eggs. I am investigating the function of these non-fertile sperm in butterflies, where they appear to play a role in sperm competition. Does the proportion of non-fertile sperm change in relation to female mating frequency, and is male fertilisation success affected by the number of non-fertile sperm produced? I am Examining the function of different sperm morphs in butterflies and moths (Lepidoptera), bugs (Heteroptera) and flies (Diptera).

Selfish Genetic Elements and Sexual Selection

Selfish genetic elements and sexual selection - Females may mate multiply to avoid using sperm from males carrying selfish genetic elements ( SGEs), by promoting sperm competition as a means to swamp SGE-carrying sperm. I am examining this possibility in flies: Drosophilapseudoobscura (X-linked meiotic driver genes causing female biased sex ratios) and D. melanogaster and D. simulans (the cytoplasmic maternally inherited bacterium Wolbachia causing reduced hatching success). I am also investigating the consequences of male-killing Wolbachia on the mating system in the butterfly Hypolimnas bolina across Pacific Islands , which vary in frequency of male killers in collaboration with Greg Hurst (UCL).

Email: n.wedell@exeter.ac.uk