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Data from: Temperature, size, reproductive allocation, and life-history evolution in a gregarious caterpillar

Citation

Pimentel, Carla; Santos, Marcia; Ferreira, Claudia; Nilsson, Jan-Åke (2011), Data from: Temperature, size, reproductive allocation, and life-history evolution in a gregarious caterpillar, Dryad, Dataset, https://doi.org/10.5061/dryad.8gt6m3m4

Abstract

The present study aimed to investigate the relation between growth rate, final mass and larval development, and how this relations influence the reproductive trade-offs in the context of a gregarious life-style and the need to keep an optimal group size. We use as model two sympatric populations of the pine processionary moth Thaumetopoea pityocampa, occurring in different seasons and thus experiencing different climatic conditions. T. pityocampa is a strictly gregarious caterpillar throughout the larval period, which occurs during winter in countries all over the Mediterranean Basin. However in 1997 a population, in which larval development occurs during the summer, was discovered in Portugal, being called Summer Population SP, as opposed to the normal Winter Population WP, which coexists in the same forest feeding on the same host during the winter. Both this populations were monitored during three years, with assessment of the length of the larval period and its relation with different climatic variables, final mass and adult size, egg size and number, colony size, and mortality in different life stages. The SP larval period was reduced due to development in the warmer part of the year, however reaching the same final mass and adult size as the WP. In spite of equal size at maturity, a trade-off between egg size and number was found between the two populations: SP produced less but bigger eggs than WP. This is the opposite of what is generally found in other Lepidoptera species, where development in colder environments leads to larger eggs at the expense of fecundity, but corroborates the trend found at a macro-geographic scale for T. pityocampa, with females from northern latitudes and colder environment, producing more and smaller eggs. Results point to the importance of number of eggs in cold environments due to an advantage of large colonies when gregarious caterpillars develop in such environments, and are discussed according to the major theories regarding size in animals.

Usage Notes

Location

8°57′W
Portugal
39°50′N
National Pine forest of Leiria