Neonicotinoids and Varroa mites force the extending of longevity in a bee colony during overwintering to forget

Abstract

A mathematical model that can estimate the apparent longevity of bee-colony proposed by the authors to clarify that the longevity normally changes with seasons as follows: The longevity maintains almost constant from at 20 to 30 days from late spring to late autumn, thereafter, it continues to extend till late spring up to 160 to 200 days. Immediately after overwintering, the longevity is shortened almost vertically from one sixth to one tenth. Such normal seasonal changes in longevity are shown when a pesticide-free food is administered to the bee-colony and when pesticide-containing sugar syrup is. However, abnormal seasonal changes in longevity, which does not extend even if winter approaches, are shown for the bee-colony ingesting neonicotinoid-containing pollen and for the colony infested with Varroa mites. Judging from the fact that pollen is the main food for the bee-brood, that mites parasitize larvae and pupae, and that the vital functions and organs of honeybees are created during the larval and pupal stages, it can be inferred that a neonicotinoid-containing pollen paste and parasitic mites cause serious damage to the bee ability to detect the arrival of winter. Such dysfunction in the larval and pupal stages probably interferes with extending the longevity of adult bees even as winter approaches.