Our group works on a wide range of topics in the field of behavioural ecology and conservation of invertebrates. We typically work with non-model organisms, including pepeke nguturoa (giraffe weevils), fishing spiders and harvestmen – but the astounding diversity and beauty of Aotearoa New Zealand’s invertebrate fauna makes it easy to be distracted by new potential study species.

Evolution of Exaggerated Traits

We are intrigued by the diversity of exaggerated traits displayed by males across the animal kingdom, especially those used as weapons. We explore the role of sexual selection in driving the evolution of weaponry using an integrated approach that combines morphology, ecology, behaviour and physiology. Current projects include comparative approaches to understanding weapon evolution and allometry in brentine weevils and long-legged harvestmen, and single-species projects focussing in on evolutionary oddities such as pepeke nguturoa and the ribbonwood fungus weevil.

Interaction Between Pre- and Post-copulatory Selection

Weapons can help male animals to gain mating opportunities by winning fights for females, but getting to mate is only part of what determines reproductive success. When females mate multiple times, male sperm must compete to fertilise her eggs. We know little about the relative importance of sexual selection operating before (pre-copulatory) and after (post-copulatory) mating, and how these two modes of sexual selection interact to maintain variation in reproductive success among males. In particular, few studies have quantified sexual selection among wild populations, despite this being crucial for understanding how mating systems evolve. Using classic field observations, molecular parentage analysis and social network theory we are investigating the interaction between pre- and post-copulatory traits in pepeke nguturoa (the New Zealand giraffe weevil), the males of which bear an enormously elongated rostrum used as a weapon.

Evolution of Monogyny & Extreme Male Mating Behaviours

Animal mating systems are highly diverse and understanding the evolutionary pathways that lead towards different mating systems remains an intriguing research avenue. In collaboration with Eileen Hebets, Matjaz Kuntner and Dion O’Neale, we are exploring the evolutionary route to monogyny, where males mate with a single female in their lifetime. Dolomedes spiders (often called fishing, raft, water, or nursery web spiders) provide a fantastic model to use in a comparative systems approach, because species vary dramatically in their mating behaviour, morphology and ecology. Aotearoa New Zealand is home to four endemic Dolomedes spiders, including the threatened Rangatira spider, restricted to several predator-free islands in the Rēkohu/Wharekauri/Chatham Island archipelago. We are currently describing the mating systems, ecology and morphology of these species to contribute to our global comparative study. You can check out our recent review of the wonderful Dolomedes fishing spiders here. This work is funded by a Marsden Fast Start.

Chemical Communication in a Changing World

To cope with ever-changing environmental conditions, insects produce cuticular hydrocarbons
(CHCs), waxy lipids secreted onto their cuticle that prevent desiccation. However, these CHCs also
act as pheromones crucial for communication during mating and contests. Given that CHCs
function both as a barrier between an insect and its environment and to convey messages during
social interactions, they provide an ideal trait to investigate the interaction between natural and
sexual selection. How these selective forces interact to shape the evolution of CHCs is poorly
known, especially under climate change. Using pepeke nguturoa, we are investigating the role of CHCs in sexual signalling and the trade-off between desiccation resistance and communication using behavioural experiments and analytical chemistry. Ultimately, this research will explore the resilience of NZ insects to anthropogenic change and how an animal’s ability to show plasticity in response to environmental stress may interfere with or enhance its ability to communicate via reliable sexual signalling. This work is funded by a Mana Tūānuku Research Leader Fellowship and University of Waikato Strategic Research Fund, and is in collaboration with Megan Grainger, Florian Menzel and Leigh Simmons.

Invertebrate Conservation

Invertebrates comprise the majority of biodiversity on earth and are critical to ecosystem function. We contribute to the conservation of invertebrates through our passion for understanding a species natural history, our field-based approach which focusses on wild populations, and our outreach activities. We acknowledge our privilege of working on Waikato-Tainui land, home to many endemic Aotearoa New Zealand invertebrates. We welcome collaborations with iwi, community groups, councils and other stakeholders interested in undertaking invertebrate conservation research. In a current project, we are collaborating with the Chatham Island Black Robin recovery group to investigate the diet and invertebrate food availability in the Chatham Islands.

Check out our roadmap paper on the conservation and recovery of insects.

Honeybee Behaviour & Ecology

We work closely with our colleagues at Plant & Food Research, including Ashley Mortensen, to explore fundamental questions about the behaviour and ecology of honeybees. Our group has investigated the impacts of parasites and pathogens at mating sites, competitive interactions between native bees and honey bees on mānuka flowers, and the impact of population density on reproductive investment and physiology.