Dispersal and reproductive properties of sugarcane bugs,Cavelerius saccharivorus

Summary

The distribution of sugarcane bugs,Cavelerius saccharivorus is remarkably patchy at time of the peak emergence of the first generation adult in early summer. In population near carrying capacity 70% of adults become macropterous, and they move to sparse populations or vacuum areas.

The experiment on the reproductive difference between females from field populations with different densities, showed that the overcrowding restricted their oviposition. On the further experiment it was shown that reproductive ability of macropterous adults or dispersers was not much inferior to that of brachypterous from sparse populations. Overcrowding at time of the peak emergence is reduced by the dispersal. Hence the intraspecific competition is a transient condition. The oviposition is at first restricted in residents of dense populations as compared with brachypterous adults of sparse populations, but the difference becomes small as the former density decreases by the emigration.

The last section considers the relation of the reproductive rate and dispersal risk to the rate of dispersal with the simple model, which explains the characteristic dispersal of this species.