Evolution of conditional male dimorphism

Currently, my main research interest is male dimorphism, a phenomenon that often reflects alternative reproductive tactics among males: the large male morphs typically guard females or reproductive territories and have more elaborate weaponry; the small male morphs sneak copulations and have reduced weaponry. Male dimorphism is particularly common among arthropods, and usually results from a polyphenism: the differential expression of alternative phenotypes from a single genotype depending upon environmental conditions. I have been investigating several questions about polyphenic male dimorphism with  experiments using mites, harvestmen, and dung beetles.

The environmental-threshold model: a hypothesis to explain threshold traits such as earwigs' forceps

Behavioral ecology in insects and arachnids

Moreover, I am also interested in the behavioral ecology of insects and arachnids, especially their reproductive biology. My  research includes the evolution of parental care, mating systems, sperm competition, and social behavior.

A multiple-male amplexus of the quacking frog (Crinia georgiana) with four males competing for the fertilization of eggs from a single female

My current fellowship at UWA

In 2015 I started a three year fellowship from the Australian Research Council, the competitive Discovery Early Career Researcher Award (DECRA). This fellowship has been funding my research project entitled “The development, ecology and evolution of alternative phenotypes”, which includes experiments on conditional male dimorphism in dung beetles, bulb mites and harvestmen (arachnids from the order Opiliones). At the moment I am fairly busy with artificial selection experiments in bulb mites, investigating whether selection imposed in one male morph generates correlated evolutionary responses in the other morph.

A major male of the gonyleptid harvestman
Arthrodes xanthopygus

Phenotypic plasticity and polyphenisms

My interest in the evolution of alternative mating tactics and male dimorphism led me into the topic of phenotypic plasticity. Therefore, in the last 5 years, part of my research has focused on threshold traits (polyphenisms), usually from a quantitative genetics perspective.

A female of the gonyleptid harvestman
Serracutisoma proximum laying eggs

Pre and post-copulatory sexual selection

During the 2013-2014 period, I was employed under the ARC Discovery Project entitled "Testing new theoretical models of sperm allocation: does competition for mates compromise male fertility?", by professors Leigh Simmons and J. Dale Roberts. My main role in this project was to investigate the trade-off between pre and postcopulatory investment in Crinia georgiana, a frog with simultaneous polyandry in the form of multiple-male amplexus. Males of this species vary greatly in their investment in arm muscles, which are used in male-male fights and in the multiple-male amplexi. Interestingly, males also present alternative reproductive tactics (calling vs sneaking) associated with the girth of their arms.

A fighter (left) and a scrambler (right) male of the male dimorphic  bulb mite Rhizoglyphus echinopus. Note the thickened third pair of legs (red arrow) of the fighter.