Evol Ecol Res 6: 541-553 (2004)     Full PDF if your library subscribes.

Temperature-induced responses of a permanent-pond and a temporary-pond cyclopoid copepod: a link to habitat predictability?

Dagmar Frisch1* and Barbara Santer2

1Institut für Biologie, Freie Universität Berlin, Königin-Luise-Str. 1–3, 14195 Berlin and  2Max-Planck-Institut für Limnologie, Postbox 165, 24302 Plön, Germany

Address all correspondence to Dagmar Frisch, Institut für Biochemie und Biologie, Universität Potsdam, Maulbeerallee 2, 14469 Potsdam, Germany.
e-mail: dfrisch@sistern.net


Temporary-pond species can be expected to use environmental cues to predict the onset of adverse conditions, while permanent-pond species may be insensitive to such cues. Temperature is such a potential cue in temporary waterbodies, as it fluctuates more widely with decreasing pond size than in deeper permanent ponds. We compared the temperature-induced response of a permanent-pond and a temporary-pond cyclopoid copepod focusing on juvenile development duration, diapause induction and survival during diapause. Non-linear regression analysis suggested a stronger effect of temperature on the duration of juvenile development in the temporary-pond species. This species also showed a higher and temperature-dependent variation in development duration (highest coefficient of variation 26%) compared with the permanent species, for which variation was lower and similar at all temperatures (maximal coefficient of variation 6%). Temperature significantly influenced the induction of diapause in the temporary-pond species, where the percentage of individuals entering diapause increased from 0% at 5°C and 10°C to 63% at 15°C and 91% at 20°C. In the permanent-pond species, diapause induction was independent of temperature and was induced in 100% of experimental specimens. This suggests an obligatory diapause in the permanent-pond species, a type of dormancy that has not been described previously for cyclopoid copepods. Survival during diapause in both species was higher when the diapausing copepodid stage was reached at lower temperatures. At higher temperatures, the temporary-pond species survived longer than the permanent-pond species. These results suggest different temperature optima of the two species. The strategy displayed by the permanent-pond species might be selected for in more stable habitats and may preclude the colonization of temporary ponds. Higher flexibility in life-history traits and the use of temperature as an environmental cue in the temporary-pond species could be favoured in unpredictable habitats.

Keywords: Cyclops insignis, Cyclops strenuus, developmental plasticity, diapause, ephemeral habitats, juvenile development.

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        © 2004 Dagmar Frisch. All EER articles are copyrighted by their authors. All authors endorse, permit and license Evolutionary Ecology Ltd. to grant its subscribing institutions/libraries the copying privileges specified below without additional consideration or payment to them or to Evolutionary Ecology, Ltd. These endorsements, in writing, are on file in the office of Evolutionary Ecology, Ltd. Consult authors for permission to use any portion of their work in derivative works, compilations or to distribute their work in any commercial manner.

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