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Late autumn eclosion in the winter moth Operophtera brumata: compromise of selective forces in life‐cycle timing
Author(s) -
Peterson Nancy A.,
Nilssen Arne. C.
Publication year - 1998
Publication title -
ecological entomology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.865
H-Index - 81
eISSN - 1365-2311
pISSN - 0307-6946
DOI - 10.1046/j.1365-2311.1998.00155.x
Subject(s) - biology , pupa , diapause , phenology , population , ecology , zoology , predation , larva , demography , sociology
. 1. In eclosion experiments at constant temperatures (6, 9, 12, 15, 18, 21, and 25 °C), Operophtera brumata (L.) pupae were found to respond nonlinearly to temperature, with 9 °C giving the highest developmental rate. 2. Pupal development rate decreased and mortality increased at the highest and lowest temperatures. No pupae eclosed at 6, 21, or 25 °C. 3. Exposing pupae to periods of cold did not enhance their rate of development consistently, indicating that no pupal diapause occurred. Light did not affect the length of the pupal period significantly. 4. Variation in mean developmental rates across temperatures was modelled both for data in the present study (northern Norway) and for a previously published German study (20° further south). The German population had a longer pupal period at all temperatures than the northern population (mean difference of 88 days). The difference is assumed to be genetically based, and hence an adaption to (and not a consequence of) differences in phenology between the two sites. 5. The diversity of the life cycle of O. brumata is discussed. Timing of eclosion can be explained by the selective forces of predation by birds on the one hand and mortality due to early snowfall on the other.