| Flight activity for the alfalfa weevil, Hypera postica Gyllenhal, was evaluated in relation to development, degeneration, and regeneration of the indirect flight muscles. Muscle conditions were determined from flight tests and dissections. The dorsolongitudinal muscle condition perceived to be fully developed was highly correlated (P {dollar}<{dollar} 0.001) with flight capability.; A dichotomous key, based upon the condition of the muscles and gonads, was developed, and used to differentiate among physiological stages of adults found: teneral, prediapause, diapause, and postdiapause, with and without flight capability. The key also was used to determine the frequency of such adults in samples collected from alfalfa and aestivation sites.; Samples were collected weekly during April, May, and June, in northwest Arkansas over a four year period (1986-1989). Adults were collected from alfalfa fields following larval peaks that occurred in March or April. Prediapause adults with fully developed muscles increased from {dollar}<{dollar}10% in April, peaked at 40% in May and declined in June to 23%. Postdiapause adults with fully developed muscles made up 63% of samples in April. This declined to 10% by June. Percentages of males declined more rapidly than females. Few (8%) postdiapause reproductive adults with degenerate muscles were found.; Adults in diapause were most common in June, but percentages were highly variable from year to year. All the above physiological stages of adults were found during these months in alfalfa.; Dissections and flight tests with weevils of known ages indicated that young adults required about a week for indirect flight muscle development. These muscles were retained for 1-2 weeks. Flight tests and survey data suggested that these prediapause adults exited the field promptly and many aggregated in aestivation sites by 1 June. All weevils found in these sites had degenerate muscles from June to September. |
