Evolutionary determinants of population differences in population growth rate × habitat temperature interactions in Chironomus riparius
- 448 Downloads
Little is known about intraspecific variation in fitness performance in response to thermal stress among natural populations and how this relates to evolutionary aspects of species ecology. In this study, population growth rate (PGR; a composite fitness measure) varied among five natural Chironomus riparius populations sampled across a climatic gradient when subjected to three temperature treatments reflecting the typical range of summer habitat temperatures (20, 24 and 28 °C). The variation could be explained by a complex model including effects of genetic drift, genetic diversity and adaptation to average temperature during the warmest month, in addition to experimental temperature. All populations suffered a decrease in PGR from 20 to 28 °C and ΔPGR was significantly correlated with the respective average habitat temperature in the warmest month—populations from warmer areas showing lower ΔPGR. This implies that long-term exposure to higher temperatures in the warmest month (the key reproductive period for C. riparius) is likely to be a key selective force influencing fitness at higher temperatures. A comparison of phenotypic divergence and neutral genetic differentiation revealed that one phenotypic trait—the number of fertile egg masses per female—appeared to be under positive selection in some populations. Our findings support a role for response to temperature selection along a climatic gradient and suggest population history is a key determinant of intraspecific fitness variation. We stress the importance of integrating different types of data (climatic, experimental, genetic) in order to understand the effects of global climate change on biodiversity.
KeywordsChironomidae Adaptation potential Climate Change Life cycle experiments Genetic drift
This work was supported by the research funding programme LOEWE (Landes-Offensive zur Entwicklung Wissenschaftlich-ökonomischer Exzellenz) of the Hesse Ministry of Higher Education, Research, and the Arts. We appreciate the assistance of Miriam Imo and Joao Barateiro Diogo in field sampling and experiments.
- Armitage PD, Cranston PS, Pinder LCV (1995) The Chironomidae: biology and ecology of non-biting midges. Chapman & Hall, LondonGoogle Scholar
- Belkhir K, Borsa P, Chikhi L, Raufaste N, Bonhomme F (1996–2004) GENETIX 4.05, logiciel sous Windows TM pour la génétique des populations. In: Laboratoire génome, populations, interactions. CNRS UMR 5000, Université de Montpellier II, MontpellierGoogle Scholar
- Hommen U (2005) Ableitung von Populationswachstumsraten aus Lebensdatenstudien mit Chironomus riparius. Frauenhofer Institut für Molekularbiologie und angewandte Ökologie, SchmallenbergGoogle Scholar
- Lynch M (2007) The origins of genome architecture, 1st edn. Sinauer, Massachusetts Google Scholar
- MacIsaac HJ, Hebert PDN, Schwartz SS (1985) Inter- and intraspecific variation in acute thermal tolerance of Daphnia. Physiol Zool 58:350–355Google Scholar
- OECD (2004) Sediment-water chironomid toxicity test using spiked water. OECD guidelines for the testing of chemicals (original guideline 219, adopted 13 April 2004)Google Scholar
- Vogt C, Belz D, Galluba S, Nowak C, Oetken M, Oehlmann J (2007a) Effects of cadmium and tributyltin on development and reproduction of the non-biting midge Chironomus riparius (Diptera)—baseline experiments for future multi-generation studies. J Environ Sci Health Part A-Toxic/Hazard Subst Environ Eng 42:1–9. doi: 10.1080/10934520601015255 CrossRefGoogle Scholar