Professor John Hunt
Professor of Evolutionary Genetics/ University Royal Society Fellow

Research

Research interests

I am an evolutionary biologist who predominantly uses insect models to test a variety of evolutionary theories. I use a combination of manipulative experiments in both the lab and field and quantitative genetic breeding designs to empirically test these theories.

Research projects

The ovoviparous cockroach, Nauphoeta cinerea
I have a number of projects currently running on sexual selection and the quantitative genetics of male sexual pheromones in N. cinerea. Most (but not all) projects focus on the central question of how genetic variance is maintained in these pheromone components in the face of strong sexual selection.

Balancing sexual selection and the maintenance of genetic variation
In N. cinerea, the three major structural components of a male’s pheromone profile (2-methylthiazolidine, 3-hydroxy-2-butanone & 4-ethyl-2-methoxyphenol) that makes a male more dominant in male-male competition is also known to make him less attractive to females. Thus, the selection imposed by each mechanism of sexual selection on male pheromones is opposing and therefore the potential exists for total sexual selection to be balancing in this species. Balancing selection is well known mechanism that preserves levels of genetic variation in phenotypic traits.

By experimentally constructing artificial pheromone profiles my research is examining the strength and form of linear and nonlinear sexual selection operating on male pheromones through male-male competition and female mate choice, as well as total sexual selection when these two mechanisms operate simultaneously.

Differential allocation as an Indirect Genetic Effect (IGE)
Indirect Genetic Effects (IGEs) occur whenever genes expressed by one individual have phenotypic effects in other (related or unrelated) individuals. Consequently, whenever individuals interact the potential exists for IGEs to influence phenotypic evolution. On such example occurs when females preferentially mate with an attractive male and differentially allocate more resources to his offspring.

In N. cinerea, females alter their reproductive investment depending on the pheromone profile of their mate. My research combines quantitative genetic breeding designs (half-sib breeding design and artificial selection) and multivariate selection analysis to examine how IGEs mediated through differential allocation influence the evolution of male pheromones.

The social environment and the release of genetic variance
The importance of genotype-by-environment interactions to the maintenance of genetic variation in phenotypic traits is well established in the evolutionary literature. However, most studies examine interactions with the physical environment (e.g. food, light, temperature). In contrast to this, many sexual traits depend on the social environment for their expression. Therefore, the potential exists for genotype-by-social environment interactions to both release and maintain genetic variance in male sexual traits.

In N. cinerea, a male’s pheromone profile is influenced by both his genes and the social environment provided by his competitor. By experimentally manipulating the pheromone profile of random competitor males (and hence their dominance status and that of the focal genetic male), my research is examining the importance of the social environment to the maintenance of genetic variation in male pheromone profiles.

The Australian field cricket, Teleogryllus commodus
The native Australian black field cricket Teleogryllus commodus occupies a wide geographic range across the southern coastline of Australia. Most of my genetic work has focused on a single population from Smiths Lake (NSW, Australia) but I now have 6 different geographically isolated populations successfully breeding in the lab (spanning 5 of the 8 states in Australia). These populations differ genetically (after common garden rearing) in the structure of the advertisement call (and how much time they spend broadcasting it) and female preference for this structure. We ask a range of evolutionary questions with T. commodus but most relate to male calling and female preference.

Condition dependence of male sexual advertisement
Male sexual traits are often condition dependent: that is, their expression is dependent on the male’s ability to acquire resources and allocate them to the sexual trait. My work with T. commodus has been combining quantitative genetics with life-history theory to examine whether there are ‘good genes‘ that make it beneficial for females to preferentially mate with certain males over others. In particular, if male sexual traits are condition dependent and resources fluctuate over space and time, are male sexual traits still able to reliably convey information about the male’s genetic quality?

Genetic constraint and the evolution of call structure
The genetic variance-covariance matrix (G) is central to quantitative genetic theory. Most models assume that it remains constant over evolutionary time. However, growing empirical evidence suggests that G is unlikely to remain stable. In fact, when subject to stabilizing selection G is expected to evolve to match the orientation of the fitness landscape.

In T. commodus from the Smith’s Lake population, we have used call manipulations to show that female mate choice exert strong stabilizing selection on male call structure. We have also shown that the structure of G has been shaped by this fitness surface: the vectors of G harbouring the most genetic variance have the weakest selection operating on them, while the vectors with the least genetic variation have the strongest selection operating on them. This not only shows how genetic variation can be maintained in some dimensions of G (and depleted in others) but also how genetic constraints can evolve. At present, we are estimating how G for call structure has evolved across populations that experience contrasting patterns of sexual selection.

Sexual selection and senescence
Reproduction is a costly, yet essential part of life. There is much current interest in the role that sexual selection plays in the rate of senescence in males and females. Previously, I have shown that males that invest more in calling, die sooner. Moreover, using artificial selection I have shown that this is due to negative pleiotropy between the genes governing calling and male longevity. My current work is examining the proximate mechanism that causes males to age more rapidly when calling more. In particular, I have started collaborations examining the importance of reactive oxygen species (ROS) to aging and how this relates to male calling effort and diet. I envisage using T. commodus to provide a comprehensive empirical test of the free radical theory of ageing.

The decorated cricket, Gryllodes sigillatus
A relatively new addition to our lab is the decorated cricket, G. sigillatus. 9 inbred lines (24 generations of brother-sister matings) have been imported from collaborators in the USA (Scott Sakaluk & Tracie Ivy) and will be used to examine the quantitative genetics of the male advertisement call, female mating preferences and sexual conflict over spermatophore retention time.

Research funding

BBSRC, “The genetic architecture and evolution of pleiotropy associated with evolutionary changes in developmental trajectories”, £613,000 (PI: Jason Wolf, CI: John Hunt, Gabriel Marroig and Andrew Ward) (2013 - 2016).

Royal Society University Fellowship, “Intralocus sexual conflict over nutrient intake and the evolution of ageing”, £421,900. (PI: John Hunt)(2013-2016).

Royal Society International Seminar Grant, “Nutrition and Ageing”.  £5,000. (PI: John Hunt)(2013).

Leverhulme Trust Visiting Professorship , “The gift of  love: The evolution of the chemical composition of insect food gifts”. £78,330. (PI: John Hunt)(2012-2013).

Royal Society Equipment Grant, “The scent of love: The evolution of insect cuticular hydrocarbons by sexual selection”.£60,000. (PI: John Hunt), (2010-2012).

European Science Foundation Workshop Grant, “The role of genotype by environment interactions in sexual selection”, €15,000. (PI: Dave Hosken, CI: John Hunt, CI: Nina Wedell and CI: Tom Tregenza)(2010).

NERC, “Sexual Selection and Constraints on Evolution: Insights from Field Crickets”. £478,210. (PI: John Hunt, CI: Tom Tregenza)(2010-2013).

NERC,“The Rapid Evolution of Male Genitalia”. £519,996. (PI: David Hosken, CI: John Hunt, Nina Wedell and Dave Hodgson)(2010-2013).

NERC, “Food, Sex and Death”. £35,261. (PI: John Hunt, CI: Nick Royle)(2009-2010).

Royal Society University Fellowship, “The stability of the G matrix over evolutionary time”, £692,171. (PI: John Hunt)(2008-2013).

Research networks

Mark Blows (University of Queensland)
Rob Brooks (University of New South Wales)
Luc Bussiere (University of Stirling)
Steve Chenoweth (University of Queensland)
Doug Emlen (University of Montana)
Tracie Ivy (University of Rochester)
Mike Jennions (Australian National University)
Erik Postma (University of New South Wales)
Scott Sakaluk (Illinois State University)
Leigh Simmons (University of Western Australia)
Jason Wolf (University of Bath)

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