Open AccessLife history reaction norms to time constraints in a damselfly: differential effects on size and mass
Author(s) -
STROBBE FRANCIS,
STOKS ROBBY
Publication year - 2004
Publication title -
biological journal of the linnean society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.906
H-Index - 112
eISSN - 1095-8312
pISSN - 0024-4066
DOI - 10.1111/j.1095-8312.2004.00379.x
Subject(s) - damselfly , biology , constraint (computer aided design) , constant (computer programming) , larva , life history , exponential growth , neglect , ecology , mathematics , computer science , medicine , mathematical analysis , geometry , nursing , programming language
Optimality models predict that, under a time constraint, organisms should accelerate development, and preferably so by increasing growth rate, to keep size at emergence constant. Unfortunately, most tests did neglect genetic constraints and interchanged mass with body size which may explain mixed support for some of the models’ predictions. We imposed time constraints on full sibling larvae of the damselfly Enallagma cyathigerum by manipulating day length regimes. Under a time constraint, larval development and growth rate based on size indeed were faster. This made it possible to keep size at emergence constant, despite the shorter development time. Interestingly, under a time constraint, growth rate based on mass was not increased and larvae had a lower mass at emergence. We see two reasons for this difference between body mass and size. First, size is fixed at emergence, while mass can still increase in many insects. Secondly, genetic constraints may have contributed to different responses for size and mass. In general, our results strongly suggest discriminating between size and mass when testing life history responses. © 2004 The Linnean Society of London, Biological Journal of the Linnean Society , 2004, 83 , 187–196.