Four individually paint-marked paper wasps share a prey caterpillar that one of them has brought back to the nest

Professor Jeremy Field
Professor of Evolutionary Biology

Profile

Broad research specialisms

I study the evolution and ecology of social behavior, using insect societies as model systems. Most people are familiar with large-colony social insects such as ants and the domesticated honeybee, but it is the so-called primitively social species living in much smaller colonies, like paper wasps and sweat bees, that give us the best chance of understanding why sociality evolved in the first place. Why is this? While individual honeybees and ants have lost the ability to nest independently, worker paper wasps, sweat bees and other small-colony species hardly differ morphologically from their queens, and are still quite capable of independent reproduction. This means that by comparing females that nest independently with females living in groups, we can measure the advantages and disadvantages of sociality directly, and thus understand the conditions under which it could have evolved. And because groups are so small in primitively social species – often just a handful of workers with their queen – and colonies are relatively short-lived – it is also feasible to track every individual in every group and measure their lifetime reproductive success in a matter of weeks or months. Not only that, but wasps and bees can be socially polymorphic. In a socially polymorphic species, some populations are social, with nests containing queens and workers, while other populations of the same species are non-social, with each individual having its own nest and reproducing on its own. This polymorphism provides particularly good raw material for our over-arching aim, which is to understand fundamental features of social evolution at both behavioural and genomic levels.

Our work involves a combination of innovative, large-scale manipulative field experiments to test theoretical predictions; mathematical modelling; and molecular work using transcriptomics to look at gene expression and microsatellite markers to estimate genetic relatedness and assign offspring to parents. Our study organisms include (1) socially polymorphic sweat bees that nest in burrows in the ground (Halictus, Lasioglossum, UK and Europe); (2) primitively social wasps that construct open air nests using paper, mud or silk paper-wasps (Polistes, Spain), hover wasps (Liostenogaster, Malaysia) and silk wasps (Microstigmus, neotropics); as well as (3) non-social digger wasps (Ammophila, UK). We have used these diverse study systems to make some key discoveries about how and why insect sociality evolves. We have demonstrated that the typical life-history of wasps and bees, where mothers are unlikely to live long enough to bring their helpless offspring through to adulthood, was probably a major driver towards group living (see our paper in Nature). We also showed how this somewhat paradoxical life-history may have evolved in the first place in ancestral non-social species, perhaps pre-adapting them for sociality (see our paper in Nature). The main paradigm used to explain why individuals give up their own chance of reproduction to become workers is that they are working for a genetically related queen: by boosting the reproduction of a relative who carries copies of their own genes, workers effectively reproduce indirectly. In our paper wasp (Polistes) study system, however, many workers are completely unrelated to the queen, providing a challenge to traditional theory. Surprisingly, we found that worker paper wasps in fact produce enough offspring of their own - by laying occasional eggs themselves, or by eventually taking over the queen position - to make group-living, even with non-relatives, a more profitable option than nesting alone (see our paper in Science). The possibility of inheriting the queen position differs for each individual, and this leads to major differences in behaviour. Remarkably, in the Malaysian hover wasps we study, there is an age-based queue to become the queen. It is always the oldest female in the group who is queen, and if we remove her, the next-oldest female takes her place (a 'gerontocracy'). Older workers, nearer to the front of the queue, have more to lose and are correspondingly more risk-averse. Not wanting to jeopardize their bright futures as potential queens, these older workers are lazier, and spend less time foraging away from the safety of their nests (see our paper in Nature).

As well as understanding why social behaviour might have been favoured by natural selection, we are interested in how it evolved mechanistically. It remains unclear how a single mother queen can produce such very different classes of offspring: short-lived specialized foragers (workers), but also long-lived egg-laying machines (new queens). We are currently using transcriptomics to investigate how genetic constraints preventing the evolution of queen and worker castes can be overcome during evolution. One of the keys to this may be social plasticity, exemplified by socially polymorphic sweat bees. For example, northern populations of the sweat bee Halictus rubicundus are non-social, with each bee reproducing independently in its own nest. In contrast, nests in southern populations are usually social, with queens and workers. By transplanting queens from a northern to a southern field site, we can directly induce a transition from non-sociality to sociality within the same species (see our paper in Current Biology). The implication is that transitions may often represent condition-sensitive plasticity, or selection at just a few key developmental switch loci, rather than repeated evolutionary gains and losses of large suites of traits.

We are always keen to host young researchers who are interested in fundamental questions about social evolution. If you would like to explore the possibility of applying for a fellowship to join our group, and need help with your application, contact Prof Jeremy Field.

Qualifications

1987 PhD in Zoology (University of Cambridge)
1982 First Class BA (Hons.) in Zoology (University of Cambridge)

Career

2017-present: Professor of Evolutionary Biology, Centre for Ecology and Conservation, University of Exeter (Penryn Campus)

2007-2016: Professor, School of Life Sciences, University of Sussex
        
1995-2007: Lecturer/Senior Lecturer/Professor, Department of Biology, University College London

1994-1995: Huxley Research and Teaching Fellowship, Department of Ecology & Evolutionary Biology, Rice University, Houston, Texas

1991-1993: Postdoctoral Research Associate, Department of Zoology, University of Cambridge

1989- 1990: Postdoctoral Research Fellowship, Department of Biology, University of York

1987- 1989: Postdoctoral Research Fellowship, Department of Pure & Applied Biology, Imperial College at Silwood Park

Contact details


Email
Tel+44 (0) 1326 253770
AddressDaphne du Maurier Building
University of Exeter
Penryn Campus
Penryn
Cornwall
TR10 9FE
UK
Office3038

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