American Entomologist (2010) 56, 100-105

Allan T. Showler (2010)
Do boll weevils really diapause?
American Entomologist 56 (2), 100-105
Abstract: Boll weevil, Anthonomus grandis grandis Boheman, diapause has been poorly understood since the term was first applied 50 yr ago to the pest's winter dormancy in temperate regions. In this literature-based study, I found that low temperatures and changes in photoperiod are the boll weevil diapause-induction factors most often referred to by scientists. Studies to test the influences of those factors, however, commonly rely on weak or erroneous assumptions about selected criteria for determining diapause that have been widely, and perhaps too quickly, accepted. Although declining temperatures are associated with reduced metabolic and locomotory activity and, under field conditions, with seeking shelter, the capacity of temperature to induce diapause status in boll weevils is contentious largely because of confusing, sometimes contradictory, experimental findings. Results for assessing the influence of photoperiod on diapause induction are also confounded by the same weak diapause characteristics. Other studies have shown that egg production does not cease under any photoperiod regime, and that active subtropical winter populations reproduce. Diapause as an overwintering modality for boll weevils may have been claimed prematurely and preserved in dogma. Rather, boll weevil dormancy during temperate winters appears to comprise a temperature-related slowing of metabolism and locomotion until a threshold is reached for quiescence. The tropical origin of the boll weevil and high overwinter mortality in temperate regions suggest that it did not evolve to endure cold winters and thus may not have developed a true diapause response.
(The abstract is excluded from the Creative Commons licence and has been copied with permission by the publisher.)
Link to article at publishers website
Database assignments for author(s): Allan T. Showler

Research topic(s) for pests/diseases/weeds:
general biology - morphology - evolution

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Pest and/or beneficial records:

Beneficial	Pest/Disease/Weed	Crop/Product	Country	Quarant.
	Anthonomus grandis