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Estivation and hibernation of Pieris brassicae (L.) in southern Spain: synchronization of two complex behavioral patterns
Author(s) -
Spieth H. R.
Publication year - 2002
Publication title -
population ecology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.819
H-Index - 59
eISSN - 1438-390X
pISSN - 1438-3896
DOI - 10.1007/s101440200031
Subject(s) - aestivation , diapause , pieris brassicae , biology , hibernation (computing) , dormancy , phenology , pupa , photoperiodism , lepidoptera genitalia , pieridae , voltinism , ecology , zoology , larva , botany , state (computer science) , germination , algorithm , computer science
The large white butterfly, Pieris brassicae , has an unusually complex life‐history in its southernmost range in Western Europe. This complexity results (1) from two developmental rests, a short‐day induced hibernation and a long‐day induced estivation response, and (2) from the exceptionally early appearance of the first adult generation in January/February and a subsequent winter diapause in some of their progeny. It was found that in spring and autumn, different generations are faced with critical photophases which induce hibernation or estivation, with the consequence that in five out of six generations per year, only some develop directly whereas the others enter a dormancy phase. To assess the implications of this high number of optional responses on the generation succession, the development time was studied at various photoperiods and temperatures. The results showed that a threshold response determines the duration of estivation. With unchanged summer conditions (daylengths ≥15 h) estivation lasts on average 18–19 weeks, while with autumn conditions (daylengths ≤14 h) it lasts only 7 weeks. A change of photophases from ≥15 h to ≤14 h terminates estivation within about 3–5 weeks, slightly depending on the pupal exposure time in summer conditions. The duration of estivation is not affected by temperature or by the photophases experienced by the caterpillars. The winter diapause lasts 18–19 weeks on average with winter conditions (12°C/10.30 h light), but only 8–10 weeks with late spring conditions (21°C/15 h light). These results were used to assess the effects on the population phenology, with the finding that despite the different developmental pathways, a desynchronization of the generation succession is largely prevented. Estivation, hibernation, and direct development at different seasons are well adjusted to a common phenological pattern of a continuously reproducing population. This pattern of activity covers a cryptic dormant subpopulation, and could not have been deduced by field observations.