The roles of phenotypic plasticity and adaptation in morphology and performance of an invasive species in a novel environment

Authors: JARDELEZA, M - Colorado State University; Koch, Jonathan; PEARSE, IAN - Us Geological Survey (USGS); GHALAMBOR, CAMERON - Colorado State University; HUFBAUER, RUTH - Colorado State University

Submitted to: Ecological Entomology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 8/18/2021
Publication Date: 9/15/2021
Citation: Jardeleza, M.G., Koch, J., Pearse, I., Ghalambor, C., Hufbauer, R.A. 2021. The roles of phenotypic plasticity and adaptation in morphology and performance of an invasive species in a novel environment. Ecological Entomology. 47(1):25-37. https://doi.org/10.1111/een.13087.
DOI: https://doi.org/10.1111/een.13087

Interpretive Summary: The spotted-wing drosophila, Drosophilla suzukii, has rapidly invaded diverse habitats, where it is a major pest of fleshy crops and native fruits. We studied how population density and body size of individuals varied over an elevational gradient and conducted a reciprocal temperature experiment to evaluate how temperature influenced fitness correlates of D. suzukii from low and high elevation in Hawai'i. We observed an elevational cline in wing size where individuals from higher elevation sites were larger and abundant. In the reciprocal temperature experiment, flies emerged faster in the warm low elevation temperature and developed larger wings at cool high elevation temperature. Contrastingly, flies from high and low elevation sites produced more offspring in the opposing temperature and less offspring in their home temperature. We hypothesize that opposing selection pressures, the high vagility of flies, and extreme plasticity in body size constrain adaptation to the different temperature regimes. While successful invasive species such as D. suzukii often exhibit local adaptation, our data suggests that local adaptation to different temperatures is not crucial to its success. This study is evidence that even ‘successful’ species can remain maladapted in its environment. Documenting D. suzukii’s plasticity and population-level variation will be important in predicting future effects and invasion zones.

Technical Abstract: When a species is introduced to a novel environment, they may be maladapted, but may also survive through phenotypic plasticity, adaptation, or both. In four decades, the spotted-wing drosophila, Drosophilla suzukii, has rapidly invaded diverse habitats, where it is a major pest of fleshy crops and native fruits. This provides the opportunity to examine plastic and adaptive, or maladaptive, responses of invasive species to different environments. We studied how population density and body size of individuals varied over an elevational gradient and conducted a reciprocal temperature experiment to evaluate how temperature influenced fitness correlates of D. suzukii from low and high elevation. We observed an elevational cline in wing size where individuals from higher elevation sites were larger and abundant. In the reciprocal temperature experiment, flies emerged faster in the warm low elevation temperature and developed larger wings at cool high elevation temperature. Contrastingly, flies from high and low elevation sites produced more offspring in the opposing temperature and less offspring in their home temperature. We suggest that opposing selection pressures, the high vagility of flies, and extreme plasticity in body size constrain adaptation to the different temperature regimes. While successful invasive species such as D. suzukii often exhibit local adaptation, we show that local adaptation to different temperatures is not crucial to its success. This study is evidence that even ‘successful’ species can remain maladapted in its environment. Documenting D. suzukii’s plasticity and population-level variation will be important in predicting future effects and invasion zones.