Genetic and maternal effects on tail spine and body length in the invasive spiny water flea (Bythotrephes longimanus).

Andrea L J Miehls,Andrew G Mcadam,Scott D Peacor

doi:10.1111/j.1752-4571.2011.00221.x

Abstract

Interest in the evolution of invasive species has grown in recent years, yet few studies have investigated sources of variation in invasive species traits experiencing natural selection. The spiny water flea, Bythotrephes longimanus, is an invasive zooplankton in the Great Lakes that exhibits seasonal changes in tail spine and body length consistent with natural selection. Evolution of Bythotrephes traits, however, depends on the presence and magnitude of quantitative genetic variation, which could change within or across years. Clonal analysis of wild-captured Bythotrephes indicated that variance components for distal spine length were variable among but not within years. Spine length was always heritable but was not always influenced by maternal effects. In contrast, variance components for body length varied both within and among years, but likewise body length was always heritable and not always influenced by maternal effects. Results indicate that important Bythotrephes traits have heritable variation comparable to native species and other invasive species that would enable an evolutionary response to natural selection. This evolutionary capacity could contribute to the widespread success and dramatic effects of Bythotrephes invasion in systems with diverse biotic and abiotic conditions.

Highlights

Invasive species are considered one of the leading threats to biodiversity and ecosystem function
We found significant genetic variation in Bythotrephes distal spine length in 2007, 2008 and 2010 (Table 2; Fig. 3), corresponding to CVg estimates of 15.0, 8.1, and 4.1 respectively, and H2 estimates of 0.76, 0.48 and 0.27, respectively (Table 2)
We found that the two traits considered to have the greatest effect on food web interactions with fish, namely Bythotrephes distal spine and body length, both had significant genetic and maternal variation and exhibited moderate-to-high coefficients of genetic variation, broad-sense heritabilities and maternal effects (Table 2)

Summary

Introduction

Invasive species are considered one of the leading threats to biodiversity and ecosystem function. Mooney and Cleland 2001; Lee 2002; Cox 2004; Lambrinos 2004; Strayer et al 2006) This growing body of research suggests invasive species often evolve upon introduction into new environments because of novel selection pressures, population bottlenecks, founder effects and hybridization with related species in the invaded range, as well as freedom from selection pressures in the native range (Lambrinos 2004; Bossdorf et al 2005). There is growing evidence that evolution of invasive species may play a key role in their pronounced ecological effects (Mooney and Cleland 2001; Lambrinos 2004; Strayer et al 2006). The few studies that have addressed quantitative genetic variation suggest no consistent pattern in the amount of genetic variation in invasive species traits;

Methods

Results

Conclusion