Estelle Roux

Person

1996 -1999 study of biology at Saint Jérôme University of Aix-Marseille, France.
1998: summer project at the chemical communication unit of the CNRS, Marseille: "Cuticular profiles in hierarchy of the lobster cockroach" (supervisors Dr. L. Sreng, Dr. E. Provost)
1999: ERASMUS year at Manchester University, UK: "Sexual selection in Fruit flies" (supervisor: Prof. R.J. Wood)
2000: master project at INRA, research center of Versailles, on "Mate recognition system in the green sting bug: is pheromone use for population discrimination by females?" (supervisor Dr. M. Renou)
Since nov. 2000: PhD at the University of Regensburg, Biology 1, accomplished in 2004:
"Role of soldiers in the basal termite Cryptotermes secundus" (supervisor: Dr. J. Korb)

Research Project :

PLUG AND DIE … is that the function of dry-wood termite soldiers?

In the basal termite Cryptotermes secundus (Kalotermitidae) only one sterile caste is found: the soldier caste. It differs from the other colony members morphologically. The head is heavily sclerotised and pigmented and the mandibles are more developed than in helpers (i.e. individuals that assume the role of workers before they develop into reproductives). Besides, soldiers of the Kalotermitid family have a peculiar flat front head, almost as large as the galleries that they inhabit. This characteristic allows them to block a gallery with their head and act as living plug.

My project investigates the function of this particular caste in order to elucidate why the soldier caste is maintained. The absence of non-social Isoptera prevents us to directly investigate the origin of the evolution of this caste.

To answer this main question I am looking at:

1. What is the advantage of being a soldier?

A set of experiment has been set up in the mangroves of Darwin (Australia) the natural habitat of this species, in order to measure fitness parameters of soldiers. This will tell us if soldiers gain indirect fitness by assuring a higher survival rate of the colony and also if they confer a better production rate of sexuals.

2. Are there some peculiar pressures that favour the presence of soldiers?

In the field I have been looking at the presence of potential predators and competitors. No specific predators could be identified, even if ants are common they didn't show particular agonistic behaviour towards the termites. As colonies of this termite never exploit new food sources, wood-borer beetle larvae are our best inter-specific candidate as competitors with high impact on colony survival.

3. How do soldiers behave towards intruders?

The proximate function of soldier is investigated with a series of behavioural experiments. First, the behaviour of soldiers and its colony is recorded in presence of a jewel beetle larvae. Second, intraspecific encounters will investigate the impact of direct competition and how this species deals with it.

This project is supported by the DFG grant KO 1895/2-1
Additional links:

Check list of termites (and more)

A lot on Jewel Beetles