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Mother knows best: maternal effects on climate change adaptation in a disease vector

Mother knows best: maternal effects on climate change adaptation in a disease vector

Supervisor: Dr Sinead English

Co-supervisors: Prof Rebecca Kilner (Zoology), John Hargrove (Stellenbosch University) and John Terblanche (Stellenbosch University)

Importance of the area of research:

A major concern about climate change is the increased risk of vector borne disease, yet specific predictions are hampered by a lack of understanding of vector ecology in the wild. Populations can respond to environmental change through several mechanisms: from slow genetic change through to rapid behavioural response. A growing focus is the role of parents in facilitating such adaptation: parents pass on both genes and information to their offspring based on their own experiences of the environment. Such parental effects are likely to be particularly strong in the live-bearing tsetse fly, sole vector of human and animal African trypanosomiases, which pose major problems for public health and agricultural development across sub-Saharan Africa. Developing improved models of how tsetse respond to climate change is thus imperative to predict and respond to these diseases.

Project summary:

This project will investigate how mothers facilitate their offspring's response to warming temperatures in a live-bearing disease vector, the tsetse fly, using field experiments and simulation models. Unlike most flies, tsetse have a unique breeding biology: females give birth to live young who emerge as large as their mother. Previous research has found that nutrient transfer by mothers has major effects on offspring survival, particularly under hot temperatures when there is strong selection against small size. It is unknown whether mothers strategically adjust their investment depending on their offspring's predicted conditions, which will be the focus of this project. 

What the student will do:

The student will investigate maternal effects in tsetse using a combination of field experiments and simulation models. Fieldwork will be conducted at a well-established tsetse research centre in the Zambezi Valley, Zimbabwe. The student will use a recently developed method of artificial warthog burrows to catch mothers and the offspring they have just produced, to measure the correlation between maternal and offspring phenotype. The student will use meteorological recording equipment to quantify the specific microhabitat conditions experienced by pupae in burrows in different habitats. The student will then experimentally manipulate offspring environment by transferring pupae between burrows with contrasting microclimates, to ascertain if maternal effects are adaptive. Finally, the student will use simulation models – parameterized based on outcomes of the field studies – ­to predict how tsetse populations will respond under various climate change scenarios.

References: 

English, S., Cowen, H., Garnett, E. & Hargrove, J.W. 2016 Maternal effects on offspring size in a natural population of the viviparous tsetse fly. Ecol. Entomol., vol. 41, pp.618-626, DOI:10.1111/een.12333

Moore, S., Shrestha, S., Tomlinson, K. W., & Vuong, H. 2012. Predicting the effect of climate change on African trypanosomiasis: integrating epidemiology with parasite and vector biology. J. Roy. Soc. Interface, vol. 9., pp. 817-830. DOI:10.1098/rsif.2011.0654

Badyaev, A.V., &  Uller, T. 2009. Parental effects in ecology and evolution: mechanisms, processes and implications. Phil. Trans. Roy. Soc. B, vol. 364, pp.1169-1177. DOI: 10.1098/rstb.2008.0302

Funding:

Applicants may apply to the NERC DTP for funding for this project.