Adaptation of Aphis gossypii (Homoptera: Aphididae) on cotton and melon

Cotton or melon aphid, Aphis gossypii, is an extremely polyphagous aphid species, including cotton and cucurbits. Long-term selective regimes may lead to differences in fitness on different host. In this study, we transferred the winged adults collected from cotton to melon and vice versa. The aphids that collected from either host plant fed with nothing (in empty Petri dishes) were used as an untreated control. We found that newly-emerged adults from cotton had similar longevity and fecundity to those fed nothing, whereas those of 24 h old lived longer and reproduced more offspring than those fed nothing. Newly emerged adults from melon had longer longevity and reproduced more than those fed nothing; whereas those of 24 h old from melon lived longer than those fed on cotton, but reproduced similar number of offspring to those fed nothing. The nymphs reproduced by the adults from cotton could not survive on melon, and similarly, those from melon could not survive on cotton