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The question 'why do females mate with lots of males?' is a major issue for evolutionary biology. We need to understand female mating behaviour because it has very broad implications for things like understanding competition between males, mate choice and why males typically produce such huge numbers of tiny sperm.

Male promiscuity is easy to explain - every mating means potential new offspring for males. Females are limited by their ability to produce offspring, and typically get more sperm than they could ever use from just one mating - so why do females of nearly all species mate with more than one partner?

Recently it has been suggested that females may mate repeatedly as a way of choosing between males. The idea is that females might be able to choose sperm from males with whom they are genetically compatible or invest more in the offspring of such males . This way, even if females don't have any choice over their mates, they may be able to tell during mating whether a male is a suitable mate, or may be able to tell afterwards from the properties of the males' sperm. This might provide females with a benefit of promiscuity - an opportunity to choose the father of their offspring even if they can't choose their mates. I am investigating this question using insect model systems, particularly, field crickets Gryllus bimaculatus. My work has shown that female crickets who mate with more than one male have increased offspring viability . A recent study, in which I mated females to related and unrelated males reveals that inbreeding reduces offspring viability, but that females mating with both siblings and non-siblings have offspring viability as high as if they'd never mated with a related male . This indicates that polyandry reduces the costs of inbreeding.

Insect model systems provide opportunities to test some basic predictions of sexual selection theory, and to examine conflicts of interest between the sexes. Nina Wedell and myself have used field crickets to demonstrate that fathers successful in gaining mates have sons who are also successful . I am collaborating with Rolando Rodríguez-Muñoz in using field crickets to address issues such as the heritability of mating success, and coinheritance of preferences and traits.

The origin of species remains one of the big questions facing evolutionary biology. To test hypotheses for what drives divergence and reproductive isolation between populations I have studied populations of the meadow grasshopper Chorthippus parallelus. In collaboration with Roger Butlin and Vicky Pritchard we have used the approach of measuring divergence in phenotypic traits and premating and postmating reproductive isolation between populations, and then comparing observed patterns with the predictions of the existing hypotheses. Our approach allows comparison of the contributions to reproductive isolation of different ecological and demographic factors. Likelihood analysis reveals that long periods of allopatry are associated with postmating reproductive isolation, but not premating isolation, which is more strongly associated with range expansion. Neither premating nor postmating isolation is higher between populations differing in potential environmental selection pressures. Interestingly, there are only weak correlations between patterns of genetic divergence and phenotypic divergence and no correlation between premating and postmating isolation. This suggests that the potential for mate choice in animals may affect the types of factor that promote speciation.

I'm collaborating with Mark Norman of the museum of Victoria, Melbourne in studying dynamic mimicry in cephalopods. The unique abilities of octopuses, squids and cuttlefish to rapidly change their shape, colour and texture is unrivaled in the animal kingdom and promises new insights into the evolution of mimicry. Our work on giant cuttlefish in Spencer Gulf, South Australia revealed the first example of males facultatively mimicking females in order to avoid the attentions of competitors.

The mimic octopus in its lair, a banded sea snake, and the octopus mimicking this species.

Our new observations of the as yet undescribed 'mimic octopus' provide the best and arguably the first examples of anti-predator mimicry in a cephalopod . The mimic octopus is able to produce an astonishing range of forms and movement patterns, resembling at least 3 poisonous animals in its habitat, including banded soles and lionfish. Quicktime video footage shows the octopus foraging , impersonating a flounder and a sea snake . Recently we have also recorded the first encounter with a live male blanket octopus - a species in which the female is 40,000 times larger than the male - the highest degree of sexual dimorphism in any animal larger than a few cm.

Scientists are judged more and more according to how much they publish and how many times their publications are cited. We all take an interest in indices such as the impact factor of the journals we submit to [sic], but are these indices reliable? and do biases lurk in the mechanisms that generate them? I have investigated factors such as whether author gender or nationality affects manuscript acceptance rates and citation rates . I've also made the bizarre finding that authors with initals later in the alphabet are less likely to have their work cited ...