APPARENT TRANSGENERATIONAL EFFECTS OF HOST-PLANT IN THE LEAF BEETLE OPHRAELLA-NOTULATA (COLEOPTERA, CHRYSOMELIDAE)

The natural host of Ophraella notulata is Iva frutescens (Asteraceae); its close relative feeds on a related plant, Ambrosia artemisiifolia. We reared beetles on both plants, obtained progeny from the four poss ible crosses (two sexes X two parental hosts), and reared the progeny on both plant species. Survival to the imaginal stage of progeny reare d on Iva varied with both maternal and paternal host. Hatchling feedin g response to both plants showed a maternal host X paternal host inter action. Consumption of Ambrosia by adult beetles was, counter to expec tation, higher for progeny of Iva-reared males than Ambrosia-reared ma les. Oviposition response, although based on too few data to be defini tive, was peculiar: parental host did not affect oviposition on Ambros ia; on Iva daughters of Iva-reared males laid significantly more eggs than did daughters of Ambrosia-reared males, but only if they had been reared on Iva; those reared on Ambrosia displayed the reverse pattern . We discuss the possibility that nongenetic paternal transmission of host plant effects may explain these results, but offer a somewhat unc omfortable hypothesis of selection as a preferable explanation. An imp ortant outcome of the experiment is that it provided no evidence of ma ternal effects of host plant on offspring feeding or oviposition.