Studies on the importance of nest temperature of Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae)¹

Abstract

The thermoeconomy of nests of the 5th instar larvae of Tbaumetopoea pityocampa was studied under laboratory conditions. Measurements over a period of several days showed an up and down in the inner temperature corresponding to the activities of the caterpillars: As the animals left the nest, the temperature inside the nest decreased quickly below than that of the surroundings, which is explained as an effect of transpiration. When the cater illars returned to the nest, the temperature increased to a maximum value of about 1.5"C over that ofthe surroundings. This rise in temperature is contributed by the biogenic heat production.Using an infrared lamp as light and heat source, the inner temperature of the nest was measured which rose very high. Although the nest temperature was above 32 "C neither the caterpillars came out nor a higher mortality could be observed. After switching the lamp off, as contributed by the web insulation and the aggregation of caterpillars, a storing of thermal energy could be recorded for several hours.As evidenced by the present and earlier studies, a great role of web thickness and solar energy on the development of pine processionary caterpillar could be revealed.

Habitat Complexity, Spatial Interference, and “Minimum Risk Distribution”: A Framework for Population Stability

“…Larger groups of late stage larvae may enhance the effectiveness of nest web construction (, Tsubaki 1981), and aggregative defense (Itô and Miyashita 1968, Morimoto 1976, , Brown and Cameron 1979, Lawrence 1990). Breuer and Devkota (1990) found that the larval nest of Thaumetopoea pityocampa (Den. and Schiff.…”

Arthropod diversity sheltered in Thaumetopoea pityocampa (Lepidoptera: Notodontidae) larval nests

“…Nests are believed to afford protection against predation, parasitism and adverse weather conditions, while improving larval thermoregulation and nest temperatures (e.g. Breuer & Devkota, 1990). Additionally, they may enclose food sources to the advantage of the primary shelter maker, co‐existing organisms and secondary users (e.g.…”

Current insect extinctions

“…Such a case of social behavior was found by Ruf and Fiedler (2000) in the caterpillars of the insect Eriogaster lanestris (Lepidoptera, Lasiocampidae). The same behavior was found in the tents of the pine processionary caterpillar T. pityocampa (Breuer and Devkota 1990). An increase in ambient temperature, such as the one predicted by global warming scenarios is going to have unpredictable consequences to the survival of the insect and its natural enemies.…”