Reproductive Status and Survival of Alfalfa Weevil1 Adults: Effects of Certain Foods and Temperatures

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Abstract
The reproductive status of female alfalfa weevils, Hypera postica (Gyllenhal) (Coleoptera: Curculionidae), and the survival of both sexes were found to be increased by reducing the storage temperature from 24 to 1.7°C, and also to be improved by increasing food quality and quantity at 7 and 24°C. After 16 weeks of storage, the best weevil survival and reproductive condition resulted from storage at 1.7°C with alfalfa bouquets or a 2% sucrose solution as food. Survival of parasites (Microctonus spp.) in diapause inside the host weevils was not affected by the various cold storage treatments tested but was reduced by feeding sucrose to the weevils at 24°C. The sexual regression of female weevils induced by certain of the storage conditions was corrected by feeding them alfalfa bouquets for 4–6 weeks after the cold storage period had ended. The poststorage and certain of the storage procedures markedly increased the yield of reproductive weevils, which was necessary for more economical production of the parasite Microctonus aethiops (Nees). Weevils were able to feed on alfalfa foliage and to deposit fertile eggs during extended storage periods at 1.7°C, but mating was not observed at temperatures below 7°C. Measurements of ovarioles and testes of New Jersey weevils showed that measurements alone were not a reliable index of reproductive status.

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