His research interests lie in the ecology and evolution of species interactions, and he is particularly interested in how intimate symbiosis influences the biology of the species involved. Pollinators are a special interest and his current research focuses mainly on insect pollinator communities and their role in pollination of horticultural crops. He is also an expert on specialist pollination systems, such as the classic mutualism between fig trees and wasps, while another research priority centres on insects and their endosymbiotic bacteria.