The quantitative genetics of physiological and morphological traits in an invasive terrestrial snail: additive vs. non‐additive genetic variation

Abstract

Summary1. The distribution of additive vs. non-additive genetic variation in natural populations represents a central topic of research in evolutionary/organismal biology. For evolutionary physiologists, functional or whole-animal performance traits ('physiological traits') are frequently studied assuming they are heritable and variable in populations. 2. Physiological traits of evolutionary relevance are those functional capacities measured at the whole-organism level, with a potential impact on fitness. They can be classified as capacities (or performances) or costs, the former being directly correlated with fitness and the latter being inversely correlated with fitness (usually assumed as constraints). 3. In spite of their obvious adaptive significance, the additive genetic variation in physiological traits, and its relative contribution to phenotypic variance (or narrow-sense heritability) in comparison with maternal, dominance or epistatic variance, is known only for a few groups such as insects and mammals. 4. In this study, we assessed the additive and maternal/non-additive genetic variation in a suite of physiological and morphological traits in populations of the land snail Cornu aspersum. 5. Except for dehydration rate (h 2 = 0Á32 AE 0Á15), egg mass (h 2 = 0Á82 AE 0Á30) and hatchling mass (h 2 = 1Á01 AE 0Á31; population = fixed effect), we found very low additive genetic variation. Large non-additive/maternal effects were found in all traits. Cage effects did not change the results, indicating low contribution of common environmental variance to our results. No differences were found between the phenotypic and non-additive genetic variance/covariance matrices. 6. Even though we compared populations across 1300 km in a common garden set-up, our results suggest an absence of physiological as well as morphological differentiation in these populations. 7. These results contrast with previous analyses in the original distributional range of this species, which found high additive genetic variation in morphological traits. These are intriguing results demanding further quantitative genetic studies in the original distributional range of this species as well as the history of colonization of this invasive species.

Energy expenditure and body size are targets of natural selection across a wide geographic range, in a terrestrial invertebrate

“…; Nespolo et al . ). This result, together with the fact that we did not find evidences of local adaptation, indicates that south imposes some severity to the reproductive schedule of these snails because of the short season.…”

“…We used four big cages per population (no crosses between populations were allowed, see details in Nespolo et al . ). The temperature and photoperiod for rearing conditions were 20 °C and 16 : 8 L : D. Water availability was maintained at high levels by sprinkling the interior of the cages with water daily.…”

“…; Nespolo et al . ). Hence, some population‐level processes are probably acting against local adaptation and/or differentiation.…”

Offspring development and life‐history variation in a water flea depends upon clone‐specific integration of genetic, non‐genetic and environmental cues

“…; Nespolo et al . ), this approach neglects the dynamic nature of such effects. Maternal effects on offspring vary according to a mother's environment (Plaistow et al .…”

Evaluation of Crosses Between Two Geographic Populations of Native Chinese and Introduced Thai Spotted Ivory Shell, Babylonia areolata, in Southern China

“…This was then followed by studies on abalones using crossbreeding of different geographic populations, H. diversicolor (You et al ) and H. discus hannai (Deng et al ), as well as interspecies hybridization, Haliotis laevigata × Hrubra rubra (Dang et al ; Botwright ), H. discus hannai × Haliotis gigantea (Luo et al ; Liang et al ), Haliotis rufescens × H. discus hannai (Lafarga‐de la et al , ), and H. discus hannai × Haliotis fulgens (You et al ). Genetic breeding of gastropods has also been performed in Physa acuta (Henry et al ), Melanoides tuberculata (Facon et al ), Lymnaea stagnalis (Coutellec and Caquet ), and Cornu aspersum (Nespolo et al ).…”