10.5061/DRYAD.CZ8W9GJ4W
Lindstedt, Carita
0000-0001-8176-3613
University of Helsinki
Bagley, Robin
The Ohio State University at Lima
Calhim, Sarah
University of Jyväskylä
Jones, Mackenzie
University of Kentucky
Linnen, Catherine
University of Kentucky
The impact of life stage and pigment source on the evolution of novel
warning signal traits
Dryad
dataset
2021
aposematism
Carotenoids
chemical defense
polytypic coloration
host adaptation
2021-12-25T00:00:00Z
2021-12-25T00:00:00Z
en
https://doi.org/10.5281/zenodo.5772251
6574848 bytes
3
CC0 1.0 Universal (CC0 1.0) Public Domain Dedication
Our understanding of how novel warning color traits evolve in natural
populations is largely based on studies of reproductive stages and
organisms with endogenously produced pigmentation. In these systems,
genetic drift is often required for novel alleles to overcome strong
purifying selection stemming from frequency-dependent predation and
positive assortative mating. Here, we integrate data from field surveys,
predation experiments, population genomics, and phenotypic correlations to
explain the origin and maintenance of geographic variation in a diet-based
larval pigmentation trait in the redheaded pine sawfly (Neodiprion
lecontei), a pine-feeding hymenopteran. Although our experiments confirm
that N. lecontei larvae are indeed aposematic—and therefore likely to
experience frequency-dependent predation—our genomic data do not support
a historical demographic scenario that would have facilitated the spread
of an initially deleterious allele via drift. Additionally, significantly
elevated differentiation at a known color locus suggests that geographic
variation in larval color is currently maintained by selection. Together,
these data suggest that the novel white morph likely spread via selection.
However, white body color does not enhance aposematic displays, nor is it
correlated with enhanced chemical defense or immune function. Instead,
the derived white-bodied morph is disproportionately abundant on a pine
species with a reduced carotenoid content relative to other pine hosts,
suggesting that bottom-up selection via host plants may have driven
divergence among populations. Overall, our results suggest that life stage
and pigment source can have a substantial impact the evolution of novel
warning signals, highlighting the need to investigate diverse aposematic
taxa to develop a comprehensive understanding of color variation in
nature.