Abstract
Infestations of Anthonomus grandis Boheman (Coleoptera, Curculionidae) were found on staminate Hampea nutricia Fryxell (Malvaceae) trees throughout central Tabasco, Mexico. Pistillate fruiting forms were sometimes punctured although not infested. Staminate flower buds acceptable for oviposition (> 4 mm diameter) were available for about 3 months during the rainy season, with 3 to 4 weeks variation between sites and years. Weevils destroyed 30% of staminate buds in 1981 and 60% in 1982. Infestation rates were initially high, then declined until peak bloom, rising again with decreasing bud population density and increasing numbers of adult weevils. All adult weevils were reproductive until peak bloom, but decreased relative to non-reproductive weevils with declining bud population density. Non-reproductive weevils appeared to accumulate fat at the expense of reproductive structures. In the laboratory, eggs were 94% viable, and mean oviposition rate was 12.5 eggs/day over an average of 38 days. Ovipositing females avoided frass-sealed punctures so that no more than one egg was deposited per bud. Bud abscission occurred early in the third larval stadium, and development was completed on the ground. Median age at adult eclosion was 11.5 days in the laboratory, but 18.5 days in the field, because of delayed hatching in living buds. Net reproductive rate (R0) was 278, and the innate capacity for increase (r) was 0.197 in the laboratory and 0.154 with delayed hatching. Mortality of immatures was 54% on the tree and 78% of the remainder on the ground after abscission. Fire ants, Solenopsis geminata F., caused 56% irreplacable mortality of the average cohort on the ground as determined by exclusion experiments. Removal of cadavers and parasitized larvae by the ants resulted in underestimation of other mortality factors. In spite of 90% mortality to immatures, weevil populations continued to grow (r = .086). Mortality and reduced fecundity associated with food limitation at the end of the season eventually caused population decline. The 9 month host-free period is probably a critical part of the weevil's life cycle, since the next-year's generation is initiated by relatively few individuals.
Stansly, Philip A. (1985). Life history and ecology of the boll weevil on a native host plant in Southeastern Mexico. Texas A&M University. Texas A&M University. Libraries. Available electronically from
https : / /hdl .handle .net /1969 .1 /DISSERTATIONS -446669.