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Title: BOLL WEEVIL REPRODUCTIVE DEVELOPMENT RESPONSES TO CROWDING AND VARIATIONS IN HOST QUALITY

Author
item Spurgeon, Dale
item Raulston, Jimmy

Submitted to: National Cotton Council Beltwide Cotton Conference
Publication Type: Proceedings
Publication Acceptance Date: 1/11/1996
Publication Date: N/A
Citation: N/A

Interpretive Summary: Eradication of boll weevils from subtropical regions of the U.S. requires a better understanding of their ability to overwinter. It has been suggested that boll weevil overwintering strategies in the subtropics may be different than in temperate areas. A thorough understanding of diapause, or the dormancy associated with successful overwintering, in the subtropics sis needed. Diapause is indicated by accumulation of fat and poorly developed reproductive organs. We dissected weevils to examine the effects of food quality and crowding on the ability of boll weevils to reproduce or enter diapause. Low quality food and crowding decreased egg development and increased fat accumulation and occurrence of diapause in females but did not influence mating. Development of reproductive organs resumed when food quality improved and crowding decreased. The influence of these factors on diapause occurrence in males was different than for females. Food quality and crowding influenced fat accumulation in males but did not affect development of reproductive organs or mating. The methods currently used to detect diapause may not be valid. If these methods are valid, control of diapause is different between boll weevil sexes. Resumption of reproductive development with improving host and crowding conditions supports previous assertions that dormancy in subtropical boll weevils is not a true diapause.

Technical Abstract: Impacts of crowding and host quality on boll weevil reproductive development and occurrence of diapause characters were investigated under controlled environmental conditions. Crowding and poor host quality influenced fat accumulation, reproductive commitment, and diapause status of females, but did not influence mating activity. Moderation of crowding and improvement in host quality tended to be accompanied by increased reproductive commitment and decreased diapause incidence. Crowding and host quality influenced fat accumulation in males, but did not appear to influence gonadal or seminal vesicle condition. Experimental conditions influenced diapause status of males, but effects were different than for females. Implications of the results to other diapause studies and control programs are discussed.