Trait correlations and landscape fragmentation jointly alter expansion speed via evolution at the leading edge in simulated range expansions

Theoretical Ecology, Journal Year: 2021, Volume and Issue: 14(3), P. 381 - 394

Published: Feb. 27, 2021

Language: Английский

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When complex movement yields simple dispersal: behavioural heterogeneity, spatial spread and parasitism in groups of micro-wasps

Movement Ecology, Journal Year: 2023, Volume and Issue: 11(1)

Published: March 1, 2023

Understanding how behavioural dynamics, inter-individual variability and individual interactions scale-up to shape the spatial spread dispersal of animal populations is a major challenge in ecology. For biocontrol agents, such as microscopic Trichogramma parasitic wasps, an understanding movement strategies also critical predict pest-suppression performance field. We experimentally studied propagation groups parasitoids their patterns parasitism. investigated whether population density-dependent, it affected by presence hosts, distribution parasitism (dispersal kernel) can be predicted from observed individuals. Using novel experimental device high-throughput imaging techniques, we continuously tracked over large temporal scales (8 h; 6 m, ca. 12,000 body lengths). could thus study density, hosts impacted rate spread, individuals during expansion, overall kernel (position events). Higher density accelerated but only transiently: reverted low values after 4 h, "tortoise-hare" effect. Interestingly, suppressed this transiency permitted sustained high spread. Importantly, found that did not obey classical diffusion, involved dynamical switches between resident explorer modes. Population was therefore Gaussian, though surprisingly was. Even homogenous asexual insects develop heterogeneities few hours, latter control Behavioural switching states determined distribution, density-dependence dispersal. A simple Gaussian reflect rather interplay several non-linearities at level. These results highlight need take into account behaviour heterogeneity understand animals.

Language: Английский

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

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2021, Volume and Issue: unknown

Published: March 4, 2021

A bstract 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 continuum going from pulled dynamics, in which low-density edge populations provide the “fuel” for advance, to pushed dynamics high-density rear “push” expansion forward. While theory suggests that evolution during range could lead become time, empirical comparisons phenotypic divergence vs. contexts are lacking. In previous experiment using Trichogramma brassicae wasps model, we showed were more when connectivity was lower. Here used descendants these experimental landscapes look at how process and interact shape evolution. Interestingly, found no clear consistent shifts, whether along gradients between reference low replicates, focused trait expression. However, evidence changes density-dependence, particular regarding dispersal: went positive negative density-dependent dispersal edge, but only high. leads expansions, our results confirm predictions may pulled, add nuance by showing landscape conditions slow down cancel this process. This shows need jointly consider context accurately predict consequences.

Language: Английский

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

Peer Community Journal, Journal Year: 2022, Volume and Issue: 2

Published: Jan. 4, 2022

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

Language: Английский

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Individual variation in dispersal, and its sources, shape the fate of pushed vs. pulled range expansions

bioRxiv (Cold Spring Harbor Laboratory), Journal Year: 2022, Volume and Issue: unknown

Published: Jan. 13, 2022

Abstract Ecological and evolutionary dynamics of range expansions are shaped by both dispersal population growth. Accordingly, density-dependence in either or growth can determine whether pulled pushed, i.e. expansion velocities genetic diversity mainly driven recent, low-density edge populations, older populations closer to the core. Despite this despite abundant evidence evolution during expansions, impact density-dependent its on remains understudied. Here, we used simulation models examine influence individual trait variation capacity density- dependence how it impacts position pulled-pushed continuum. First, found that knowing about at greatly improve our ability predict an is (more) pushed pulled. Second, costs sources (genetic non-genetic, versus dependence) evolve. Among other scenarios, tended become more with time only when was highly heritable, were low could not When, hand, had no basis, but evolve, then time, More generally, results show trying using information from non-expanding regions may be problematic, play a key role determining stays environmental context (here costs) cannot neglected. Those simulations suggest new avenues research explore, terms theoretical studies regarding ways empirically study vs. expansions.

Language: Английский

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