Ontogenesis of honey bees (Apis mellifera) under the influence of temperature stress

Abstract

The productivity of bee colonies mostly depends on the influence of exogenous factors. The most significant ones include: the presence of a honey base, climatic conditions, environmental temperature, etc. The stability of microclimate indicators in the nest significantly affect the growth of families and nest. The vital temperature range in the post-embryonic period ranges from 30–38 °С. For normal brood development, the incubation temperature should be 34–35 °С. The intensity of growth during this period is largely determined by the influence of climatic conditions, including temperature. As a result of decrease in temperature, there is a densification of the placement of bees, which are more concentrated in the central, breeding part of the nest. Under these conditions, hypothermia of individual areas of the brood, located on the peripheral parts of the honeycombs, beyond the healthy temperature range, is sometimes noted. This is manifested by a sharp drop in the ambient temperature, when there is a numerous brood in the family, or if the nest is not expanded properly. In order to study the influence of cold stress on the development of offspring, two groups were formed. The group incubated at a temperature of 35 ºС was considered the control group. The experimental group was a group which was grown at a temperature of 32 ºС. After the brood was sealed, pupae were selected every 2 days. At the same time, their mass, the content of total lipids and the ratio of their individual classes were determined. It was found that under the influence of cold stress during brood development, the duration of the incubation period increases by 35–42 hours. It has been established that the adaptation of bees to cold includes a complex of physiological and biochemical processes, among which changes in the mass and composition of lipids play a significant role. The dynamics of triacylglycerides under optimal and stressful conditions of incubation were studied. Taking into account their functional purpose as the main element of energy supply of metabolic pathways, such dynamics indicate profound changes in the processes of energy exchange. When studying the mechanisms of adaptation to cold, a change in the ratio of phospholipid classes, the expression of which is induced by the effect of cold, was revealed. The results of this study bring a deeper understanding of the adaptation mechanisms of honeybees' response to changes in brood incubation temperature. They expand data on the biology of bees during critical periods of growth and development.