Temperature and the pollinating activity of social bees

Abstract

1. Thermal constraints on flight acivity limit the pollinating effectiveness of bees. Each species of social bee has a microclimatic 'window' within which foraging flight can be sustained.2. To predict whether a given species of social bee is worth testing as a pollinator in a given climate, it is useful to know at least the lower limits of that microclimatic 'window'. We consider how information from a series of bee counts through a day can be used to characterize a bee species in terms of activity/microclimate relations as a basis for predicting the diel pattern of foraging activity of a bee introduced into a new climate as a pollinator.3. We discuss the relative merits of bee counts at a foraging patch and counts based on hive traffic as indices of the proportion of bees active. 4.We suggest that the activity/microclimate relations of a species be expressed in terms of the lower threshold black globe temperature for flight activity. Black globe temperature, T,, is easily measured with inexpensive equipment, and can substitute for measurements of ambient temperature and radiation as a predictor of diel patterns of bee activity. 5.We use examples of field data to explore the relationship between microclimate and activity for the honeybee Apis mellifera and several species of bumblebee, Bombus. Regression analysis is used to relate activity to T, and to identify the lower temperature threshold for activity from field bee counts.6. In field studies analysed here, the bumblebees Bombus terrestrisllucorum, B.pascuorum and B . hortarum began foraging at lower temperatures than honey-bees or B. lapidarius.

Increased density of honeybee colonies affects foraging bumblebees

“…This contention is supported by the higher density of grey honeybees compared to yellow honeybees early in the morning, even though the A. m. ligustica colonies were located directly at the Phacelia field. Thus, landscape features probably prevented the bumblebee workers from profiting from their lower temperature thresholds (Corbet et al, 1993(Corbet et al, , 1995.…”

“…If increased honeybee densities could be achieved by increasing the number of colonies, we assumed we would observe a "temporal avoidance strategy" (i.e. bumblebees forage earlier in the morning or later in the evening, Corbet et al, 1993Corbet et al, , 1995Williams and Christian, 1991). We further assumed that spatial displacement from the mass resource Phacelia tanacetifolia due to exploitative competition should mainly affect short-tongued and abundant species of the B. terrestris-group that have a foraging strategy similar to that of honeybees.…”

Foraging behavior of Melipona rufiventris Lepeletier (Apinae; Meliponini) in Ubatuba, SP, Brazil

“…The main climatic conditions that affect the flight and foraging behavior of bees are temperature, light intensity and relative humidity (Kleinert-Giovannini, 1982;Corbet et al, 1993). Foraging can be hampered by rain and wind speed; continuous rainfall can cause a reduction in flight activity which, on the other hand, is not particularly disturbed by mild rain (Sommeijer et al, 1983).…”

Por que Melipona scutellaris (Hymenoptera, Apidae) forrageia sob alta umidade relativa do ar?

“…Mesmo sem considerar eventuais mecanismos fisiológicos espécie-específicos (CORBET et al, 1993), o tamanho é um bom previsor da capacidade passiva de termorregulação, através de trocas de calor por condução (PEREBOOM & BIESMEIJER, 2003): espécies grandes aquecem mais, num mesmo período de tempo de exposição a altas temperaturas, e também resfriam mais lentamente do que espécies pequenas.…”