The boll weevil, Anthonomus grandis grandis Boheman (Coleoptera: Curculionidae), once the dominant pest of cotton (Gossypium spp.) in the United States, is now the most serious pest of South American cotton. Despite eradication efforts in the United States, intractable populations in southern Texas and northern Mexico remain a threat to adjoining regions. A key to eliminating this pest from the subtropics may lie in better understanding mechanisms facilitating survival through the non–cotton season. We examined the diapause response to diet regimes by evaluating the influences of food type (square, boll), size, and replacement interval, under photoperiod (13:11 [L:D] h) and temperature conditions (29.4°C) considered to suppress diapause. Female weevils exhibited diapause characters earlier than did males on all diets, and physiological status was not reliably evaluated until adults were 9 d old. When squares fed to groups of weevils were replaced thrice weekly, most weevils responded with symptoms of starvation instead of diapause. In other feeding regimes, incidence of diapause increased with increasing food development, which may reflect the weevil perception of host maturity. These results are consistent with accounts of seasonality of diapause and host utilization in the subtropics and tropics, as well as accounts of lateseason weevil ecology in temperate regions prior to the widespread adoption of mechanized harvest and determinant cotton cultivars. These findings, combined with earlier demonstrations of extended host-free longevity and lack of a photoperiod response, identify food characteristics as important determinants of boll weevil reproductive diapause irrespective of other environmental cues.
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