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

Pimentel, Carla; Santos, Marcia; Ferreira, Claudia and Nilsson, Jan-Åke LU (2012) In Biological Journal of the Linnean Society 105(2). p.340-349
Abstract
The present study aimed to investigate the relationship between growth rate, final mass, and larval development, as well as how this relationship influences reproductive trade-offs, in the context of a gregarious life-style and the need to keep an optimal group size. We use as a model two sympatric populations of the pine processionary moth Thaumetopoea pityocampa, which occur in different seasons and thus experience different climatic conditions. Thaumetopoea 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, namely the summer... (More)
The present study aimed to investigate the relationship between growth rate, final mass, and larval development, as well as how this relationship influences reproductive trade-offs, in the context of a gregarious life-style and the need to keep an optimal group size. We use as a model two sympatric populations of the pine processionary moth Thaumetopoea pityocampa, which occur in different seasons and thus experience different climatic conditions. Thaumetopoea 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, namely the 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 populations were monitored over 3 years, with an assessment of the length of the larval period and its relationship with different climatic variables, final mass and adult size, egg size and number, colony size, and mortality at different life stages. The SP larval period was reduced as a result of development in the warmer part of the year, although it reached the same final mass and adult size as the WP. Despite an 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 contrasts with the findings obtained 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-geographical scale for T. pityocampa, with females from northern latitudes and a colder environment producing more (and smaller) eggs. The results demonstrate the importance of the number of eggs in cold environments as a result of an advantage of large colonies when gregarious caterpillars develop in such environments, and these findings are discussed in accordance with the major theories regarding size in animals. (C) 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 340349. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
adaptive, clutch size, egg, development time, Lepidoptera, phenology, social insects, Thaumetopoea pityocampa
in
Biological Journal of the Linnean Society
volume
105
issue
2
pages
340 - 349
publisher
Linnean Society of London
external identifiers
  • wos:000298983700007
  • scopus:84855802178
ISSN
0024-4066
DOI
10.1111/j.1095-8312.2011.01794.x
language
English
LU publication?
yes
id
0d163bf3-5b62-4cd8-8c64-854876d66713 (old id 2355293)
date added to LUP
2012-02-24 08:52:26
date last changed
2017-07-02 03:11:55
@article{0d163bf3-5b62-4cd8-8c64-854876d66713,
  abstract     = {The present study aimed to investigate the relationship between growth rate, final mass, and larval development, as well as how this relationship influences reproductive trade-offs, in the context of a gregarious life-style and the need to keep an optimal group size. We use as a model two sympatric populations of the pine processionary moth Thaumetopoea pityocampa, which occur in different seasons and thus experience different climatic conditions. Thaumetopoea 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, namely the 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 populations were monitored over 3 years, with an assessment of the length of the larval period and its relationship with different climatic variables, final mass and adult size, egg size and number, colony size, and mortality at different life stages. The SP larval period was reduced as a result of development in the warmer part of the year, although it reached the same final mass and adult size as the WP. Despite an 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 contrasts with the findings obtained 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-geographical scale for T. pityocampa, with females from northern latitudes and a colder environment producing more (and smaller) eggs. The results demonstrate the importance of the number of eggs in cold environments as a result of an advantage of large colonies when gregarious caterpillars develop in such environments, and these findings are discussed in accordance with the major theories regarding size in animals. (C) 2011 The Linnean Society of London, Biological Journal of the Linnean Society, 2012, 105, 340349.},
  author       = {Pimentel, Carla and Santos, Marcia and Ferreira, Claudia and Nilsson, Jan-Åke},
  issn         = {0024-4066},
  keyword      = {adaptive,clutch size,egg,development time,Lepidoptera,phenology,social insects,Thaumetopoea pityocampa},
  language     = {eng},
  number       = {2},
  pages        = {340--349},
  publisher    = {Linnean Society of London},
  series       = {Biological Journal of the Linnean Society},
  title        = {Temperature, size, reproductive allocation, and life-history evolution in a gregarious caterpillar},
  url          = {http://dx.doi.org/10.1111/j.1095-8312.2011.01794.x},
  volume       = {105},
  year         = {2012},
}