Evolutionary theory successfully explains how and when organisms should vary their reproductive strategies in order to maximise transmission of their genes to the next generation (fitness). Our understanding of the evolution of reproductive strategies comes primarily from theory developed for multicellular taxa such as birds, mammals and insects - taxa in which reproductive behaviours were often already well understood.
Testing whether evolutionary theory is general enough to apply to unicellular organisms, such as malaria parasites, is an important challenge for evolutionary biology. Furthermore, research at the interface between biomedicine and evolutionary ecology offers huge potential advances to both fields.
Above left: a male gamete attached to the remains of his male gametocyte, which is adhered to an uninfected red blood cell. Above right: elongate and banana shaped ookinetes at 20 hours post fertilisation and spherical female gametes or gametocytes that were not fertilised, from a genetically transformed reference line that constitutively expresses green fluorescent protein (GFP) throughout its life cycle. Photos by Sinclair Stammers
We test evolutionary theory in a biomedical context to investigate an obligate part of the life cycle of malaria parasites. Our aim is to understand the life-history strategies that malaria (and related protozoan) parasites have evolved to maximise their transmission to new hosts. This requires understanding the reproductive strategies that malaria parasites have evolved to transmit from vertebrate hosts to insect vectors. These parasites have high medical, veterinary and conservation importance therefore understanding and predicting their reproductive biology is important from both theoretical and applied perspectives. More on the biology of malaria parasites.
Current research topics are focused on asking questions about:
(1) Investment into sexual reproduction and sex allocation
(2) Variation within infections in investment into sexual reproduction and sex allocation
(3) Timing of co-ordinated parasite behaviours [more to come]
(4) Programmed cell death of parasite stages (ookinetes) that infect vectors [more to come]
(5) Reproductive strategies in mixed-species infections
Our approach is largely experimental and we develop new theory through collaborations. In experiments, we use recent developments in cell and molecular biology, GM, immunology and imaging techniques in an evolutionary framework. A brief summary of findings so far can be found here.
Information on opportunities, including PhD projects, can be found here
In addition to malaria parasites, we are interested in social evolution more generally and also use an unusual species of parasitoid wasp (Melittobia acasta) to understand life-history decisions in the context of co-operation and conflict. This is in collaboration with Stu West. In the past we have dabbled in sex allocation strategies in Nasonia (parasitoid wasps) and Callasobruchus (bean beetles), as well as temperature sex determination in Chelonia (sea turtles).
Images, clockwise from left: Melittobia acasta males fighting; Nasonia vitripennis emerging; Chelonia mydas hatchling; Callosobruchus maculatus adult.
