Hughes Lab

Study systems

Social insects. We use social insects as our main study organisms. As one of the pinnacles of sociality, social insects are amongst the most important models for understanding, for example, how work can be efficiently organised in complex societies, how cooperation evolves and why it is maintained in the face of the apparent advantages that can be obtained by cheating. Their societies range from simple to complex, and, unlike multicellular organisms, can be broken apart and put back together with relative ease, allowing us to investigate the importance of the constituent parts. They are faced with many of the same problems of disease as our own societies, but appear to be much more successful than us at dealing with them. And they exhibit the full range and extremes of sex, from queens of the giant Asian honeybee mating with over 100 drones in just a couple of hours to the lifetime monogamy shown by termites. Social insects are also of tremendous ecological and economic importance, including both pests and beneficial species. Understanding how their societies are organised, their defences against parasites, and their need for different amounts of sex can help suggest improved ways of controlling species which are pests, and inform our conservation of those that are beneficial. Our main study species leaf-cutting ants from the Neotropics, honeybees and bumblebees, but we also work with pharaoh’s ants, red ants, slave-maker ants and their slaves, weaver ants, army ants, and ‘primitively eusocial’ ponerine ants.

Symbionts. Much of our research has utilised ‘obligate killer’ fungal parasites of insects, either specialists (Metarhizium, Ascosphaera) or opportunists (Aspergillus), as well as the Nosema microsporidian parasites of bees. These parasites make excellent model species because they are experimentally tractable, allowing us to give controlled doses of the parasite to individual insects, to give them single or mixed infections of parasites to study within-host competition, and to then measure the fitness of the parasites and host very easily. We also work with Wolbachia and other cryptic bacterial or viral symbionts, which we detect using PCR and qPCR, and most recently by metagenomic sequencing.

White sharks. As well as being charismatic animals of conservation concern, white sharks are in fact an excellent model species for investigating animal personalities. Unusually for a large apex predator, they can be found in relatively high densities (in certain areas!), can be readily observed in the field, individually identified and respond nicely to controlled stimuli. Working with collaborators in South Africa, we are interested in establishing the extent to which the sharks show ‘personalities’ and behavioural syndromes, and investigating both the proximate basis and implications of these.

Mealybugs. Mealybugs at first sight may seem a rather strange and uninteresting choice of study organism. Admittedly they include many important pest species so studying them is of applied relevance, but they don’t move around much or show obviously interesting behaviours. The reason (from our perspective) they’re so interesting is because of what they have inside them. Mealybugs host not one, but two obligate mutualistic symbionts. The mealybugs host β-proteobacteria in special cells within them, and remarkably these β-proteobacteria have within them a γ-proteobacteria. Both of the bacterial symbionts are essential for the mealybugs to be able to survive on the nutritionally-poor diet of plant sap on which they feed. In addition, there are other facultative symbionts within the mealybugs, and the mealybugs themselves are farmed by ants, making them an ideal group for investigating the evolutionary biology of symbiotic and mutualistic relationships.