STORAGE PROTEINS IN WINTER HONEY BEES

Abstract

Honey bee colonies in temperate climates begin brood rearing in late winter before floral resources are available. Protein required for brood rearing comes from pollen stored in combs as well as proteins stored internally in the bees' bodies. We studied the changes in amounts of several proteins that could serve as internal storage compounds in fall-emerging bees that contributed to the wintering population. Vitellogenin, a known storage protein, increased from none in newly emerged bees to ~60 (range: 10-200)ug/abdomen in winter bees (60-day-old bees sampled in late November). Probable jelly proteins from bee heads were present in minor amounts. A third previously unreported protein from adult honey bee abdomens was a six-unit storage protein, probably arylphorin. Like vitellogenin, it was nonexistant in newly emerged bees and reached an average of 75 ug/bee by late November. Although the two hives from which we sampled bees were randomly selected, there were highly significant colony-related differences in amounts of protein in the bees. Bees from one colony consistently had higher levels of all proteins studied. We have demonstrated the existence of a previously unknown storage protein in wintering bees that is probably arlyphorin. Although wintering bees have significantly elevated amounts of vitellogenin and arylphorin, the amounts of protein present in the bodies of wintering bees are not sufficient to rear large amounts of brood. We suggest that their primary function may be to allow colonies to continue brood rearing when extremely cold periods prevent bees from leaving the cluster to feed on pollen. Other possible functions are suggested.