Presence of a thermoregulatory hot spot in the prothorax of the large carpenter bee and the bumble bee

Abstract

In both the large carpenter bee (Xylocopa pubescens) and the bumblebee (Bombus terrestris), a hot spot was detected in the center of the prothorax on its dorsal-external aspect. In both cases, the temperature in this hot spot was found to be greater than the ambient temperature and that at the tip of the gaster. In B. terrestris, it was higher by 9-10 degrees C from that at the gaster tip and by 15-16 degrees C from the ambient temperature, while in X. pubescens the corresponding differences were 11-20 degrees C and 18-19 degrees C, respectively. The recorded thermal differences were not fixed but were rather variable, temporally as well as individually, but invariably all individuals measured showed these temperature differences. Furthermore, in none of the studied specimens was a hot spot detected in any part of the body other than the prothorax. From this hot spot in the prothorax, there is a cascade of temperatures in both directions, that is, anteriorly towards the head and posteriorly towards the gaster, with a graded drop in temperature in either direction. This article discusses possible reasons for the existence of such a hot spot in this particular location (the prothorax), its role or function, and its mode of operation. The authors speculate that it is a thermoregulatory center (for heating or cooling) that might be present in possibly all Hymenoptera that spend a considerable part of their life flying, regardless of whether they are social, parasocial, or solitary.

Diversity of Wild Bees along Elevational Gradient in an Agricultural Area in Central Java, Indonesia

“…This difference may be due to differences in the geographical region, climate zone, and range of elevational gradient. A commonly reported pattern in species richness along elevational gradients is a unimodal distribution with a mid-elevation peak [20]. In our study, peak species diversity occurred at middle elevations due to the presence of two species (Apis dorsata and Xylocopa caerulea) that began to appear above 442 m asl.…”

Large Carpenter Bees as Agricultural Pollinators

“…This heat tolerance suggests good heat regulation ability in carpenter bees, possibly controlled by a thermoregulatory center in the prothorax [51].…”

Ontogenesis of the Thermogenic Center in Hornets

“…Not surprisingly, in ants we failed to detect a hot spot. Of the insects examined for a hot spot by us, we need point out the Vespa orientalis (Galushko et al, 2004;Ishay et al, 2006a,b;Plotkin et al, 2005) as well as the solitary bee, Xylocopa pubescens, and the social bee, Bombus terrestris (Volynchik et al, 2006), and in all of these, a hot spot was detected. Apart from us, other investigators have also reported the presence of a hot spot in various insects, like the honeybee Apis mellifera (Stabentheiner, 2001;Stabentheiner et al, 2002;Underwood, 1991) and the solitary bee Anthophora and other solitary bee species in New Guinea (Stone, 1993).…”