Pj. Mccall et al., AGGREGATED OVIPOSITION IN THE SIMULIUM-DAMNOSUM COMPLEX IS MEDIATED BY EGGS IN A LABORATORY BIOASSAY, Medical and veterinary entomology, 8(1), 1994, pp. 76-80
The phenomenon of aggregated oviposition in blackflies (Diptera: Simul
iidae) was investigated under controlled laboratory conditions, using
wild-caught females of the Simulium damnosum complex in Sierra Leone.
A method was developed for inducing Simulium females to lay eggs, and
used as a bioassay to measure the responses of gravid S. damnosum s.l.
to freshly laid eggs of the same species complex. In a series of two-
choice tests, significantly more ovipositing flies chose substrates al
ready containing eggs over control substrates (P = 0.004). The time fr
om introduction of flies into the oviposition system to the onset of e
gg-laying was significantly less when eggs were already present (P = 0
.049). Flies responded more quickly when more eggs were present and th
e relationship between egg-batch number and the time of this response
was curvilinear (P = 0.012). Ecological advantages and disadvantages o
f such aggregation behaviour and the possible role of semiochemicals i
n its mediation are discussed.