Shifts from pulled to pushed range expansions caused by reduction of landscape connectivity

Dahirel, Maxime; Bertin, Aline; Haond, Marjorie; Blin, Aurélie; Lombaert, Éric; Calcagno, Vincent; Fellous, Simon; Mailleret, Ludovic; Malausa, Thibaut; Vercken, Elodie

doi:10.1101/2020.05.13.092775

Cited by 11 publications

(25 citation statements)

References 90 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In this context, we revisit a previous study of experimental range expansions using Trichogramma parasitic wasps as a model (Dahirel et al, 2020), in which we showed that reducing landscape connectivity led to increased “pushiness”. We this time examine the phenotypic changes that have occurred in space and time depending on the type of expansion.…”

Section: Introductionmentioning

confidence: 89%

Landscape connectivity alters the evolution of density-dependent dispersal during pushed range expansions

Dahirel¹,

Bertin²,

Calcagno³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

As human influence reshapes communities worldwide, many species expand or shift their ranges as a result, with extensive consequences across levels of biological organization. Range expansions can be ranked on a continuum going from pulled dynamics, in which low-density edge populations provide the "fuel" for the advance, to pushed dynamics in which high-density rear populations "push" the expansion forward. While theory suggests that evolution by spatial sorting, a common feature of range expansions, could lead pushed expansions to become pulled with time, empirical comparisons of phenotypic divergence in pushed vs. pulled contexts are lacking. In a previous experiment using Trichogramma brassicae wasps as a model, we showed that expansions were more pushed when connectivity was lower. Here we used descendants from these experimental landscapes to look at how the range expansion process and connectivity interact to shape phenotypic evolution. Interestingly, we found no clear and consistent phenotypic shifts, whether along expansion gradients or between treatments, when we focused on low-density trait expression. However, we found evidence of changes in density-dependence, in particular regarding dispersal: populations went from positive to negative density-dependent dispersal at the expansion edge, but only when connectivity was high. As positive density-dependent dispersal leads to pushed expansions, our results confirm predictions that evolution during range expansions may lead pushed expansions to become pulled, but add nuance by showing environmental context may slow down or cancel this process. This shows we need to jointly consider evolution and ecological context to accurately predict range expansion dynamics and their consequences.

show abstract

Section: Introductionmentioning

confidence: 89%

Landscape connectivity alters the evolution of density-dependent dispersal during pushed range expansions

Dahirel¹,

Bertin²,

Calcagno³

et al. 2021

Preprint

Self Cite

View full text Add to dashboard Cite

show abstract

“…The variability of the counting processes can furthermore be quantified and formally taken into account in statistical analyses if needed (see e.g. Dahirel et al 2020). This approach has already been used in several projects with satisfying performance, and there is still ample room for improvement.…”

Section: Discussionmentioning

confidence: 99%

Up and to the light: intra- and interspecific variability of photo- and geo-tactic oviposition preferences in genusTrichogramma

Perez

Burte

Ayed

et al. 2021

Preprint

View full text Add to dashboard Cite

Trichogramma are parasitic microwasps much used as biological control agents. The genus is known to harbor tremendous diversity, both inter- and intra-specific. The successful selection of appropriate strains rests on a careful evaluation of this diversity at the phenotypic level, especially regarding oviposition performance and behavior. Oviposition preferences in relation to environmental cues such as light and gravity, although suspected to play an important role in microhabitat selection and oviposition patterns, have received little attention so far in this group, either alone or in combination. The extent of their variability is thus virtually unknown. Here we use a novel experimental approach relying on automatic image analysis to characterize the oviposition preferences in relation to light, gravity, and their interaction, in 25 populations of Trichogramma from five species. We show that most Trichogramma populations and species harbour preferences for light and preferences for elevated parts. However, the two trait harbor significant inter and intraspecific variation. The effects of light and gravity on oviposition patterns were found to be almost perfectly additive overall, with two exceptions. Oviposition preference patterns were not static but very plastic in time: preferences tended to relax over consecutive days, and the strongest preferences relaxed the fastest, presumably because of the density-dependent effect of resource depletion. A correlation of oviposition patterns with the vegetation stratum at which populations were sampled suggests that different species/populations may be associated with different strata with corresponding differentiation in light- and gravity-related oviposition preferences.

show abstract

“…As these invasion waveforms can themselves undergo evolutionary transitions (Gandhi et al 2016;Erm and Phillips 2020), the underlying DDD patterns are expected to shift rapidly as well. In fact, DDD has been recently proposed as a putative mechanism for these transitions (Dahirel et al 2020), highlighting yet another important way in which DDD and dispersal evolution interact with each other.…”

Section: Discussionmentioning

confidence: 99%

Dispersal evolution diminishes the negative density dependence in dispersal

2020

View full text Add to dashboard Cite

In many organisms, dispersal varies with the local population density. Such patterns of density‐dependent dispersal (DDD) are expected to shape the dynamics, spatial spread, and invasiveness of populations. Despite their ecological importance, empirical evidence for the evolution of DDD patterns remains extremely scarce. This is especially relevant because rapid evolution of dispersal traits has now been empirically confirmed in several taxa. Changes in DDD of dispersing populations could help clarify not only the role of DDD in dispersal evolution, but also the possible pattern of subsequent range expansion. Here, we investigate the relationship between dispersal evolution and DDD using a long‐term experimental evolution study on Drosophila melanogaster. We compared the DDD patterns of four dispersal‐selected populations and their non‐selected controls. The control populations showed negative DDD, which was stronger in females than in males. In contrast, the dispersal‐selected populations showed DDD, where neither males nor females exhibited DDD. We compare our results with previous evolutionary predictions that focused largely on positive DDD, and highlight how the direction of evolutionary change depends on the initial DDD pattern of a population. Finally, we discuss the implications of DDD evolution for spatial ecology and evolution.

show abstract

Shifts from pulled to pushed range expansions caused by reduction of landscape connectivity

Cited by 11 publications

References 90 publications

Landscape connectivity alters the evolution of density-dependent dispersal during pushed range expansions

Landscape connectivity alters the evolution of density-dependent dispersal during pushed range expansions

Up and to the light: intra- and interspecific variability of photo- and geo-tactic oviposition preferences in genusTrichogramma

Dispersal evolution diminishes the negative density dependence in dispersal

Contact Info

Product

Resources

About