Image: Anoplocnemis curvipes (giant coreid bug) ©Georg Goergen/IITA Insect Museum, Cotonou, Benin 

Sexual selection and the role of host plant

Supervisor: Professor Christine Miller 

Across taxa, mating decisions are often shaped by past and present ecological contexts. In plant-feeding insects, mating decisions commonly are made using pheromones, and pheromone composition can be heavily influenced by the host plants upon which the male and female have fed. Differences in mating decisions can change the growth and evolutionary trajectory of populations. A better understanding of mating behaviour will help advance strategies for pest management. This project will test the extent to which mate choice is influenced by an individual’s developmental host plant and that of their potential mates. We will assess mate choice using olfactometers, and we will assess male fighting behaviours as they compete for territories on host plants.

For this position, a student should enjoy watching animals and studying their behaviour. You should also be comfortable with international travel, building collaborations with African scientists, and working in hot and humid conditions.

Type of work 

We have applied for funding that would allow the student to travel to Benin in West Africa for two months to rear insects and study their behaviour in an olfactometer and in fighting arenas. We will return with the specimens to Cambridge for morphological measurements, analysis, and writing. It will be valuable to know if applicants would like to travel to Benin (all expenses paid) as part of this MPhil, or if they would rather work on-site at Cambridge for the entire year.

Importance of the area of work concerned

This project will examine the effects of ecologically relevant variation in nutrition on three leaf-footed bug pests of cowpea in Africa, Clavigralla tomentosicollis, Riptortus dentipes, and Anoplocnemis curvipes. These insects will be raised on two cultivated pulses and a wild host, and we will look at consequences for mate choice. We may find, for example, that insects prefer mates raised on the species of plant they were raised on, which could lead to host-race formation and speciation under some circumstances.

References

Miller CW, Kimball RT & Forthman M (2024). The evolution of multi-component weapons in the superfamily of leaf-footed bugs. Evolution 78: 635–651.

McCullough E, Miller CW, and Emlen DE (2016). Why sexually-selected weapons are not ornaments. Trends in Ecology and Evolution. 31: 742-751. DOI: 10.1016/j.tree.2016.07.004.

Woodman TE, Chen S, Emberts Z, Wilner D, Federle W & Miller CW.  Developmental nutrition affects the structural integrity of a sexually selected weapon. Integrative and Comparative Biology 61: 723-735. 

Joseph PN, Emberts Z, Sasson DA, & Miller CW (2018). Males that drop a sexually-selected weapon grow larger testes. Evolution. 72: 113–122. DOI: 10.1111/evo.13387.

Miller CW, McDonald G, & Moore AJ (2016). The tale of the shrinking weapon: seasonal changes in nutrition affect weapon size and sexual dimorphism, but not contemporary evolution. Journal of Evolutionary Biology. 29: 2266-2275.