Submitted to: Journal of Economic Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 30, 2005
Publication Date: June 14, 2005
Citation: Greenberg, S.M., Spurgeon, D.W., Sappington, T.W., Setamou, M. 2005. Size-dependent feeding and reproduction by the boll weevil (Coleoptera: Curculionidae). Journal of Economic Entomology. 98:749-756. Interpretive Summary: The boll weevil is an important cotton pest that damages cotton by puncturing and laying eggs in flower buds and small fruit. Research is needed to determine the effects of weevil body weight on feeding and reproductive activity. Heavier male and female weevils produced more punctures than did lighter weevils. Female weevils that weighed more than 10 mg lived longer, laid more eggs, and produced more offspring than lighter females. Even the smallest weevils produced offspring. Because light body weight reduces weevil reproduction and survival, crop management that promotes production of small adult weevils may be used to limit weevil population growth. Better knowledge of the biological relationships between weevils and cotton plants will lead to the development of environmentally-safe and efficient pest management strategies.
Technical Abstract: It is widely known that the boll weevil, Anthonomus grandis grandis Boheman, exhibits considerable variation in adult size, but the influences of adult size on reproduction and population dynamics are not known. We examined the relationship between the size of boll weevils and their feeding and oviposition. Weevils weighed to the nearest milligram were grouped into five categories based on pupal weight: </= 5 mg, 6-10 mg, 11-15 mg, 16-20 mg, and < 20 mg. Numbers of lifetime punctures tended to increase with pupal weight for both females and males. Boll weevil females with pupal weights > 10 mg produced progeny with significantly higher survival to adulthood, and also produced a higher percentage of female progeny, than those with pupal weights </= 10 mg. The growth indices of progeny from females having pupal weights > 10 mg averages 1.8-fold higher than those of females weighing </= 10 mg. Survivorship of boll weevil females also tended to increase with pupal weight. The percentage of females laying eggs on any given day averaged 2.1 times higher when their pupal weights were > 10 mg than when their pupal weights were </= 10 mg. Although small size negatively affected female reproductive potential, even extremely small females produced some viable offspring. However, the penalties of small adult size, in terms of longevity and reproductive potential, suggest that cultural practices that result in the production of small adults may be used to impact weevil populations.