Evolution of Dynamic Anti-predator Behaviour of Insects
Predation is a potent selection pressure that has driven the evolution of diverse anti-predator defences. Anti-predator defences refer to a select set of traits that help potential prey avoid detection, recognition, subjugation, or consumption by predators and thus, increase their chances of survival when encountering a potential enemy. These adaptations range from morphological traits including weapons such as spines, or armour-like exoskeletons, to physiological traits such as chemical secretions and behavioural defence mechanisms such as fleeing and playing dead.
Termites (Blattodea: Isoptera) are a diverse group of eusocial insects that employ a wide range of specialised anti-predator traits to aid in colony protection. Due to their spatially concentrated high abundance and biomass, termites are particularly susceptible to predation, and as such have evolved a variety of mechanisms to thwart predator attacks. Termite weaponry is incredibly diverse and includes a range of mechanical and chemical adaptations. From mandibular snapping to the ejection of viscous, toxic substances from specialised rostra, termites are well-adapted to defend themselves from a variety of predators. Isolated aspects of morphological and chemical termite defences are well studied but the defence system as a whole is not well understood with behavioural aspects of defence often being neglected.
We currently do not fully understand the relationship between weapon morphology and defensive behaviours of termites, nor do we have in-depth knowledge into what has driven the evolution of such a wide range of defensive traits. Thus, my research aims to unravel the complex evolutionary history of morphological, chemical, and behavioural antipredator defences in a phylogenetic framework, and how these traits have co-evolved and vary across the landscape, using termites as a model before narrowing down to the species level and examining the antipredator defences of an Australian nasute termite species.
The key aims of my PhD are to: i) map the evolution of antipredator strategies in termites, ii) explore the evolutionary relationships of behaviour, morphology and chemistry with regards to soldier defence in Australian representatives of Nasutitermitinae, iii) conduct a comprehensive comparative analysis of nasute termites to quantify variation in defensive traits and iv) describe the antipredator defence strategies of an economically significant Australian nasute species, Nasutitermes exitiosus.
Dr Kate Umbers, A/Prof Markus Riegler, Prof Nathan Lo (USYD)