Our research

We are interested in arthropod ecology and evolution – particularly reproductive strategies and life histories.  We are especially interested in how animals’ nutritional ecology affects (and is affected by) the evolution of sociality and parental care. 

Some of our research interests

Acacia thrips

Nutrition and cooperation  

Despite nearly fifty years of research and debate about theoretical conditions that might favour the evolution of sociality, we still know little about the kinds of environments that select for social behaviour in nature. We aim to address a fundamental, long-standing gap in our knowledge about the evolution of social behaviour: the idea that inadequate nutrition limits opportunities for individuals to breed independently, favouring social living. This knowledge gap has existed because the model systems that are most informative about evolutionary transitions to sociality (socially plastic species, i.e. which are able both to breed alone and in social groups) have proven to be intractable when it comes to manipulating nutrition. I am testing this principle in the field, using species that can both be social or solitary – for example Acacia thrips (Dunatothrips spp.), Halictine bees (Halictus rubicundus) and socially plastic spiders (Anelosimus spp.). We are using the nutritional geometry approach to test firstly whether social behaviour occurs more often on nutritionally imbalanced food, and secondly whether experimentally imbalancing nutrients causes solitary breeders to decide instead to cooperate. This will open up a paradigm much theorized but never rigorously tested.

Halictus rubicundus - a socially plastic sweat bee. (Photo: Julien Mangelsdorf)
Halictus rubicundus – a socially plastic sweat bee. (Photo: Julien Mangelsdorf)

 

Collaborators:

Dr Laurence A Mound, CSIRO, Canberra.

Prof. Jeremy Field, University of Sussex

Dr Lena Grinsted, University of Sussex

 

 

Evolution of parental care in insects

Male Rhinocoris tristis guarding eggs. (Photo: JDJ Gilbert)
Male Rhinocoris tristis guarding eggs

Some insects, like dung beetles, supply offspring with food. These species show highly unusual, mammal-or-bird-like life histories (Gilbert & Manica 2010). Parental care may therefore explain the unusual life history patterns we observe in birds and mammals. Most evolutionary origins of insect parental care involve female parents, but repeated origins of male parental care occur predictably from a state of no care (Gilbert & Manica 2015).  In male-caring assassin bugs (Rhinocoris tristis) males benefit by caring for eggs, because females are highly abundant, available and show preference for caring males (Gilbert et al, 2010). Excitingly, this leads to a novel sexual conflict: due to female choice, males benefit by caring conspicuously, but females prefer hiding eggs from parasites (Gilbert & Manica, 2009).

 

 

Platycleis affinis, with dissected testes

Mating strategies

Male bushcrickets have the world’s largest testes at 14% of body mass! These allow repeated matings, rather than more sperm (Vahed, Parker & Gilbert, 2010). As a substitute for a nuptial gift, cerci modified into “handcuffs, spikes and traps” can allow them to hold on to females after mating to protect ejaculates (Vahed, Gilbert, et al, 2014). Male genital “titillators” allow mate assessment (Vahed, Lehmann, Gilbert & Lehmann, 2011).

Collaborators:

Prof. Karim Vahed (Univ. of Derby), Drs Gerlind & Arne Lehmann (Humboldt Univ., Berlin)

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