Phenotypic plasticity is an important mechanism allowing adaptation to new environments and as such it has been suggested to facilitate biological invasions. Under this assumption, invasive populations are predicted to exhibit stronger plastic responses than native populations. Drosophila suzukii is an invasive species whose males harbor a spot on the wing tip. In this study, by manipulating developmental temperature, we compare the phenotypic plasticity of wing spot size of two invasive populations with that of a native population. We then compare the results with data obtained from wild-caught flies from different natural populations. While both wing size and spot size are plastic to temperature, no difference in plasticity was detected between native and invasive populations, rejecting the hypothesis of a special role of plasticity in the invasion success. In contrast we observed a remarkable stability in the spot-to-wing ratio across temperatures, as well as among geographic populations. This stability suggests either that the spot relative size is under stabilizing selection, or that its variation might be constrained by a tight developmental correlation between spot size and wing size. Our data show that this correlation was lost at high temperature, leading to an increased variation in the relative spot size, particularly marked in the two invasive populations. This suggests (i) that D. suzukii’s development is impaired by hot temperatures, in agreement with the cold-adapted status of this species; (ii) that the spot size can be decoupled from wing size, rejecting the hypothesis of an absolute constraint and suggesting that the wing color pattern might be under stabilizing (sexual) selection; (iii) that such sexual selection might be relaxed in the invasive populations. Finally, a subtle but consistent directional asymmetry in spot size was detected in favor of the right side in all populations and temperatures, possibly indicative of a lateralized sexual behavior.

Within this dataset you can find the analyses run in the paper.

First, ./Sizes esimation shows the Python 3 script to infer spot and wing sizes from the pictures

Then, in ./R analyses you can find the R reports (with the analyses included) showing the particular
commands used for the analyses. Versions in .Rmd and .pdf are attached.

Here you can find data and scripts used in the article:

Drosophila suzukii wing spot size is robust to developmental temperature

Before having a look at the files, please consider two things:

1) I've tried to upload the minimum amount of information neccesary to run all the analyses, in
order to make the replication as simple as possible and avoid possible sources of confusion.

However, during this effort I might have left out something important unintendedly. If that's the case,
or if you struggle to understand something, please don't hesitate to contact me.

2) In the plasticity analyses you might find a population with a different name: Sokol. This is the name
the people collecting the samples gave to the population obtained in Dayton (Oregon). Because I learnt this
some time after I started the project I left the former name in these files, although I used to correct
place name in the manuscript. Sorry about that.