BA (1st Class Hons) Biological Sciences, 2005,
Keble College, University of Oxford, UK;
DPhil. The Molecular Evolution of Strepsiptera. 2010,
St Hugh's College, University of Oxford, UK.
I am interested in the diverse selection pressures that act on and between closely associated individuals, from co-evolutionary arms races operating between sexes, to the close interplay between hosts and parasites. How do these relationships drive evolution, and what is their subsequent role in speciation?
For most host-parasite systems, single interactions are an unrealistic representation of the natural living environment. Such systems are better interpreted as overlapping communities of hosts and intermittently shared parasite populations.
Honey bees are host to at least 18 viruses, 2 microsporidian (fungal) intracellular pathogens, parasitic flies (e.g. Braula coeca), trypanosomes (e.g. Crithidia mellificae), ectoparasitic mites (e.g. Varroa destructor); and a number of bacterial and fungal pathogens such as Paenibacillus larvae and Ascosphaera apis (causative agents of American Foulbrood and Chalkbrood respectively). I am interested in how interactions are shaped by this wider community. Do parasites enter into conflicting or co-operative relationships when they co-infect the same host? Does this result in raised or reduced virulence (impact on host), and does this depend on host variables (such as species, age, caste etc.), or other factors such order of parasite arrival, dose or other types of environmental variation?
Several non-native pests and pathogens of high impact (e.g. Varroa destructor, Nosema ceranae) have also recently emerged as problems in honey bees. Has their presence affected the life history trade-offs of other naturally occurring parasites, honey bee hosts, or other secondary host pollinator species (such as bumble bees)? I am addressing some of these questions through a UK government Insect Pollinator Initiative (IPI): "Impact and mitigation of emergent diseases on major UK insect pollinators".
McMahon, D.P., Hayward, A., Kathirithamby, J. (2011). The first molecular phylogeny of Strepsiptera (Insecta) reveals an early burst of molecular evolution correlated with the transition to endoparasitism. PLoS ONE, 6: e21206.
McMahon, D.P., Hayward, A., Kathirithamby, J. (2011). Quick Guide: Strepsiptera. Current Biology, 21: R271-R27.
Hayward, A.*, McMahon, D.P.*, Kathirithamby, J. (2011). Cryptic diversity and host specificity in a parasitoid where the sexes utilize hosts from separate orders. Molecular Ecology, 20: 1508-1528.
Kathirithamby, J., Hatting, J.L., McMahon, D.P. (2010). First host record and description of female Halictophagus calcaratus Pasteels (Strepsiptera: Insecta) from South Africa. African Entomology, 18: 322-327.
McMahon, D.P., Hayward, A., Kathirithamby, J. (2009). The mitochondrial genome of the 'twisted-wing parasite' Mengenilla australiensis (Insecta, Strepsiptera): a comparative study. BMC Genomics, 10: 603.
Kathirithamby, J., Hayward, H., McMahon, D.P. et al. (2009). Conspecifics of a heterotrophic heteronomous species of Strepsiptera (Insecta) are matched by molecular characterization. Systematic Entomology, 35: 234-242.
Pod Academy: In Search of Lost Bees. A podcast about our first summer season of honey bee radar tracking.
McMahon, D.P. (2009). Silver-fish, solitary bees, and Strepsiptera: encounters with peculiar parasites in the Carpathian basin. Genetics Society News, 60: 39-40.