Adaptive phenotypic plasticity in a clonal invader.

Area of Science:

• Evolutionary Biology
• Ecology
• Genetics

Background:

• Potamopyrgus antipodarum, an ovoviviparous freshwater snail, exhibits significant trait variability and wide habitat distribution.
• This species has successfully invaded aquatic ecosystems globally since the mid-19th century.
• Asexual invasive populations of P. antipodarum possess low genetic diversity compared to native mixed populations.

Purpose of the Study:

• To investigate adaptive phenotypic variation in invasive P. antipodarum populations.
• To determine the contributions of genetic factors versus environmental influences (phenotypic plasticity) on shell morphology.
• To assess the relationship between shell morphology, environmental parameters, and reproductive fitness (brood size).

Main Methods:

• Surveyed 425 snails from 21 localities across northwest Europe.
• Analyzed shell geometric morphometrics and brood size (fitness proxy).
• Genotyped snails for SNPs and mtDNA haplotypes to control for genetic background.

Main Results:

• Lineage primarily influenced shell shape, while environmental factors affected both shape and size.
• Physicochemical parameters, particularly stream flow rate, significantly impacted shell morphology and its relation to brood size.
• Larger shells were associated with stronger stream flow, suggesting adaptation to faster currents.

Conclusions:

• Phenotypic plasticity in shell size and genetic control of shell shape contribute to the invasive success of P. antipodarum.
• Differential control of shell morphology components allows adaptation to diverse environmental conditions.
• The ability to modify shell morphology is a key factor in the colonization of novel habitats by this invasive species.