Endothermic warm-up in two species of sphecid wasp and its relation to behaviour

Autor: P. G. Willmer, J. Ghazoul
Rok vydání: 1994
Předmět:
Zdroj: Physiological Entomology. 19:103-108
ISSN: 1365-3032
0307-6962
Popis: The ability of two sphecid wasps, Bembix rostrata and B.tonata (Hymenoptera: Sphecidae), to warm up endothennically is demonstrated under laboratory conditions. Mean warm-up rates of B.rostrata are comparable to bees of similar weight. Despite endothermic ability, field observations reveal that B. rostrata are not active below 22°C. From observations at the nectar-foraging site (clumps of Thymus vulgaris flowers) it is calculated that the energy resources available to wasps are sufficient to power endothermic warm-up at low tem- peratures. Alternative explanations for the absence of wasp activity at low temperatures, such as the risk of parasitism, are suggested. Endothermy may be used periodically to increase flight efficiency in response to added load, such as prey carried by females, and mates by males. Key words. Endothermy, Sphecidae, thermal conductance, pubescence, foraging, wing loading. Introduction While all species of insect are probably capable of behav- ioural thermoregulation, only a limited range have the ability to raise body temperatures by metabolic means, using the flight musculature to generate heat (Adams & Heath, 1964; Heinrich, 1971). Endothermy in the Apoidea has been well documented (e.g.
Databáze: OpenAIRE
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