Rapid evolution of increased dispersal at the edge of a range expansion can accelerate invasions. However, populations expanding across environmental gradients often face challenging environments that reduce fitness of dispersing individuals. We used an eco‐evolutionary model to explore how environmental gradients influence dispersal evolution and, in turn, modulate the speed and predictability of invasion. Environmental gradients opposed evolution of increased dispersal during invasion, even leading to evolution of reduced dispersal along steeper gradients. Counterintuitively, reduced dispersal could allow for faster expansion by minimizing maladaptive gene flow and facilitating adaptation. While dispersal evolution across homogenous landscapes increased both the mean and variance of expansion speed, these increases were greatly dampened by environmental gradients. We illustrate our model's potential application to prediction and management of invasions by parameterizing it with data from a recent invertebrate range expansion. Overall, we find that environmental gradients strongly modulate the effect of dispersal evolution on invasion trajectories.
- Award ID(s):
- 0448827
- PAR ID:
- 10337048
- Date Published:
- Journal Name:
- Evolution
- Volume:
- 65
- Issue:
- 8
- ISSN:
- 0014-3820
- Page Range / eLocation ID:
- 2229 to 2244
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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Abstract Aim The Hemiptera is the fifth‐largest insect order but among non‐native insect species is approximately tied with the Coleoptera as the most species‐rich insect order (Hemiptera comprise 20% more species than in world fauna). This over‐representation may result from high propagule pressure or from high species invasiveness. Here, we assess the reasons for over‐representation in this group by analysing geographical, temporal and taxonomic variation in numbers of historical invasions.
Location Global.
Method We assembled lists of historical Hemiptera invasions in 12 world regions, countries or islands (Australia, Chile, Europe, New Zealand, North America, South Africa, South Korea, Japan and the Galapagos, Hawaiian, Okinawa and Ogasawara Islands) and border interception data from nine countries (Australia, Canada, European Union, United Kingdom, Hawaii, Japan, New Zealand, South Korea, USA mainland and South Africa). Using these data, we identified hemipteran superfamilies that are historically over‐represented among established non‐native species, and superfamilies that are over‐represented among arrivals (proxied by interceptions). We also compared temporal patterns of establishments among hemipteran suborders and among regions.
Results Across all regions, patterns of over‐ and under‐representation were similar. The Aphidoidea, Coccoidea, Aleyrodoidea, Cimicoidea and Phylloxeroida were over‐represented among non‐native species. These same superfamilies were not consistently over‐represented among intercepted species indicating that propagule pressure does not completely explain the tendency of some Hemiptera to be over‐represented among invasions. Asexual reproduction is common in most over‐represented superfamilies and this trait may be key to explaining high invasion success in these superfamilies.
Conclusions We conclude that both propagule pressure and species invasiveness are drivers of high invasion success in the Sternorrhyncha suborder (aphids, scales, whiteflies) and this group plays a major role in the exceptional invasion success of Hemiptera in general. The high historical rates of invasion by Sternorrhyncha species provide justification for biosecurity measure focusing on exclusion of this group.
- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1111/j.1558-5646.2011.01308.x
