This study was carried out on trees of the host plant Hibiscus pernambucensis Arruda (Malvaceae), to evaluate the potencial benefits gained from maternal care in Antiteuchus sepulcralis (Fabricius). Three kinds of sleeve cages were used: with no access to natural enemies (=control); with access only to parasitoids, and with access to all natural enemies (predators and parasitoids). A fourth treatment consisted of complete exposure, with no cage. For all treatments, there was a condition in which the egg mass was protected by the mother and one in which the mother was removed. This experiment was repeated 15 times on different dates. Egg masses were also collected in the field to assess the parasitism rates under natural conditions. The predation rate in unprotected egg masses was 100% in less than 24h, whereas no egg was fed upon when the mother was present. Parasitism rates in the sleeve cage treatments, caused exclusively by Phanurospis semiflaviventris Girault (Hymenoptera: Scelionidae), were 41.6% and 69.5% in egg masses protected and not protected by the mother, respectively. Under natural conditions, parasitism rates were 66.4%, 20.1%, and 62.2% in the periods of December/96-March/97, August-October/97, and November/97-February/98, respectively. Eggs located on the outside edge of the egg mass experienced higher levels of parasitism than the internal ones. These results show that the female defense is highly effective against predators, but not so effective against the parasitoid P. semiflaviventris. The adaptive value of the maternal care in A. sepulcralis (trade-off between benefits and costs) as a strategy for offspring survival is discussed.
Insecta; parasitism; Phanuropsis semiflaviventris; predation; subsocial behavior
