A system for characterizing reproductive and diapause morphology in the boll weevil (Coleoptera: Curculionidae)

Authors: Spurgeon, Dale; Sappington, Thomas; Suh, Charles

Submitted to: Annals of the Entomological Society of America
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/16/2002
Publication Date: 1/15/2003
Citation: Spurgeon, D.W., Sappington, T.W., Suh, C.P. 2003. A system for characterizing reproductive and diapause morphology in the boll weevil (Coleoptera: Curculionidae). Annals of the Entomological Society of America. 96:1-11.

Interpretive Summary: One of the keys to the boll weevil's success at infesting and damaging U.S. cotton has been its ability to survive the winter in a state of dormancy. Although this dormancy has been extensively studied, earlier results have been inconsistent and the dormancy remains poorly understood. One possible reason for the differences among the results of earlier studies is that the characters identifying dormant weevils were not used consistently. Through our previous studies and observations we have documented the different stages of development of boll weevil fat reserves and reproductive organs. We present illustrated descriptions of these stages, with a discussion of their meaning in relation to reproduction or dormancy. These descriptions provide clearer and more extensive guidelines for identifying dormant weevils than were previously available. We also propose a set of characters for use in identifying dormant weevils. This set of characters will allow future studies of the dormancy to use more standardized methods, and they provide a clear baseline for comparison with the identification methods used by other researchers.

Technical Abstract: Diapause in the boll weevil, Anthonomus grandis Boheman, has been extensively studied but remains poorly understood. In particular, results of diapause induction studies have been inconsistent, and the body of published literature does not clearly indicate the factors or cues responsible for induction. A likely contributor to this variability may be the differences among studies in the criteria used to distinguish diapause. We present illustrated descriptions of the stages of male and female reproductive development, and of the fat body types and conditions associated with reproductive and diapausing weevils. These descriptions provide clearer and more extensive guidelines for the classification of reproductive and diapausing boll weevils than were previously available. We also propose criteria for distinguishing diapause based on specific characters of the fat body and male and female reproductive organs. These criteria provide a means of standardizing diapause assessments in future studies, or at least a baseline for comparison when describing alternate criteria, and should serve to clarify these descriptions in future reports.