ISSN:
1439-5444
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
Notes:
Abstract Behavioural thermoregulation of 3Pieris butterfly species,P. rapae, P. melete andP. napi, was examined in relation to the intensity of solar radiation. To evaluate solar radiation intensity, the temperature (Twr) was measured with a mercury thermometer whose bulb was covered with white cloth and exposed to direct sunlight. On clear days, the diurnal air temperature was between 16 and 28°C. The Twt varied between 18 and 45°C, while the temperature in the shade was under 25°C. When the Twt was under 28°C, the body temperatures (Th) of butterflies closely coincided with it. Butterflies with Tb's under 26°C were resting, while those with Tb's between 26 and 28°C were basking. When Twr was between 28 and 40°C, the butterflies were active and their Tb's were always lower than Twr, never exceeding 36°C, though body temperatures could be artificially elevated easily up to the level of Twr. When Twr exceeded 40°C, butterflies showed species-specific heat-avoiding behaviour.P. rapae, whose habitat resources exist in the sun, intercepted solar radiation by closing the wings over the body.P. melete andP. napi, however, whose main habitat resources exist in the shade, moved into the shade. Strictly speaking, it is concluded that both butterflies, in many cases, leave shaded habitats for sunny habitats to elevate their Tb rather than enter the shaded habitats for heat-avoiding.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF02348247
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