Compensatory growth strategies are affected by the strength of environmental time constraints in anuran larvae
- 484 Downloads
Organisms normally grow at a sub-maximal rate. After experiencing a period of arrested growth, individuals often show compensatory growth responses by modifying their life-history, behaviour and physiology. However, the strength of compensatory responses may vary across broad geographic scales as populations differ in their exposition to varying time constraints. We examined differences in compensatory growth strategies in common frog (Rana temporaria) populations from southern and northern Sweden. Tadpoles from four populations were reared in the laboratory and exposed to low temperature to evaluate the patterns and mechanisms of compensatory growth responses. We determined tadpoles’ growth rate, food intake and growth efficiency during the compensation period. In the absence of arrested growth conditions, tadpoles from all the populations showed similar (size-corrected) growth rates, food intake and growth efficiency. After being exposed to low temperature for 1 week, only larvae from the northern populations increased growth rates by increasing both food intake and growth efficiency. These geographic differences in compensatory growth mechanisms suggest that the strategies for recovering after a period of growth deprivation may depend on the strength of time constraints faced by the populations. Due to the costs of fast growth, only populations exposed to the strong time constraints are prone to develop fast recovering strategies in order to metamorphose before conditions deteriorate. Understanding how organisms balance the cost and benefits of growth strategies may help in forecasting the impact of fluctuating environmental conditions on life-history strategies of populations likely to be exposed to increasing environmental variation in the future.
KeywordsAdaptive plasticity Climate change Food intake Growth efficiency Growth rates Time constraints
We thank Frank Johansson and Alfredo Nicieza for comments on a previous draft of the manuscript. The animals were collected with the permissions from the county authorities and the experiment was approved by the Ethical Committee for Animal Experiments in Uppsala County (C70/8). Our research was supported by Fundación Caja Madrid, Fundación Ramón Areces, Helge Ax:son Johnsons Stiftelse and Stiftelsen Oscar och Lili Lamms Minne (G.O.), Stiftelsen för Zoologisk Forskning (E.D.), and the Swedish Research Council (A.L.).
- Finch CE, Kirkwood TBL (2000) Change, development, and ageing. Oxford University Press, OxfordGoogle Scholar
- Gasc JP (1997) Atlas of amphibians and reptiles in Europe. Societas Europaea Herpetologica and Muséum National d′Histoire Naturelle (IEGB/SPN), ParisGoogle Scholar
- Gosner KL (1960) A simplified table for staging anuran embryos and larvae with notes on identification. Herpetologica 16:183–190Google Scholar
- Kapoor BC, Smith H, Verighina IA (1975) The alimentary canal and digestion in teleosts. Adv Mar Biol 13:109–239Google Scholar
- Lima SL (1998) Stress and decision making under the risk of predation: recent developments from behavioral, reproductive, and ecological perspectives. In: Moller AP, Milinski M, Slater P (eds) Advances in the study of behaviour, vol 27., Stress and behavior. Academic, London, pp 215–290Google Scholar
- Mangel M, Stamps J (2001) Trade-offs between growth and mortality and maintenance of individual variation in growth. Evol Ecol Res 3:583–593Google Scholar
- Metcalfe NB, Bull CD, Mangel M (2002) Seasonal variation in catch-up growth reveals state-dependent somatic allocations in salmon. Evol Ecol Res 4:871–881Google Scholar