The influence of initial age structure on predator–prey interaction

Hance, T.; Impe, Georges Van

doi:10.1016/s0304-3800(98)00148-3

Cited by 19 publications

(8 citation statements)

References 17 publications

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“…Twenty‐five weeks from the start of the experiment ( c . 12 generations under the experimental conditions; Hance & Van Impe, ), we collected individuals from all the different patches to quantify whether relevant ecological traits had evolved in response to metapopulation connectedness. We quantified performance and dispersal in adult females that were raised for one generation under common garden conditions (see further).…”

Section: Methodsmentioning

confidence: 99%

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

Masier

Bonte

2019

Ecology Letters

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Dispersal evolution impacts the fluxes of individuals and hence, connectivity in metapopulations. Connectivity is therefore decoupled from the structural connectedness of the patches within the spatial network. Because of demographic feedbacks, local selection also drives the evolution of other life history traits. We investigated how different levels of connectedness affect trait evolution in experimental metapopulations of the two‐spotted spider mite. We separated local‐ and metapopulation‐level selection and linked trait divergence to population dynamics. With lower connectedness, an increased starvation resistance and delayed dispersal evolved. Reproductive performance evolved locally by transgenerational plasticity or epigenetic processes. Costs of dispersal, but also changes in local densities and temporal fluctuations herein are found to be putative drivers. In addition to dispersal, demographic traits are able to evolve in response to metapopulation connectedness at both the local and metapopulation level by genetic and/or non‐genetic inheritance. These trait changes impact the persistence of spatially structured populations.

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Section: Methodsmentioning

confidence: 99%

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

Masier

Bonte

2019

Ecology Letters

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“…However, the behavioural mechanisms involved in collective dispersal in overcrowded conditions remain poorly understood. Tetranychus urticae (also called the two-spotted spider mite) has a very rapid population growth, short developmental time, a high birth rate and long adult survival [10] – [11] . This, together with the use of agricultural plants as a food source (more than 900 plants including field crops, horticultural crops, green house vegetables and ornamental plants [12] ), has made this species a major pest.…”

Section: Introductionmentioning

confidence: 99%

The Formation of Collective Silk Balls in the Spider Mite Tetranychus urticae Koch

et al. 2011

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Tetranychus urticae is a phytophagous mite that forms colonies of several thousand individuals. These mites construct a common web to protect the colony. When plants become overcrowded and food resources become scarce, individuals gather at the plant apex to form a ball composed of mites and their silk threads. This ball is a structure facilitating group dispersal by wind or animal transport. Until now, no quantitative study had been done on this collective form of migration. This is the first attempt to understand the mechanisms that underlie the emergence and growth of the ball. We studied this collective behaviour under laboratory conditions on standardized infested plants. Our results show that the collective displacement and the formation of balls result from a recruitment process: by depositing silk threads on their way up to the plant apex, mites favour and amplify the recruitment toward the balls. A critical threshold (quorum response) in the cumulative flow of mites must be reached to observe the emergence of a ball. At the beginning of the balls formation, mites form an aggregate. After 24 hours, the aggregated mites are trapped inside the silk balls by the complex network of silk threads and finally die, except for recently arrived individuals. The balls are mainly composed of immature stages. Our study reconstructs the key events that lead to the formation of silk balls. They suggest that the interplay between mites' density, plant morphology and plant density lead to different modes of dispersions (individual or collective) and under what conditions populations might adopt a collective strategy rather than one that is individually oriented. Moreover, our results lead to discuss two aspects of the cooperation and altruism: the importance of Allee effects during colonization of new plants and the importance of the size of a founding group.

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“…Due to its small dimensions (≈0.5mm), it is possible to raise very large populations in relatively small spaces; at the same time, it is still big enough to allow for individual-based census and analysis. The generation time is around 15 days at 30 °C [79]. The base population of spider mites we initialized the experiment with was randomly sampled from a stock of T.urticae belonging to the "LS-VL" strain.…”

Section: Study Species and Experiments Descriptionmentioning

confidence: 99%

Individual heterogeneity and its importance for metapopulation dynamics

Masier

Dahirel

Mortier

et al. 2020

Preprint

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Habitat fragmentation reduces the area of habitat patches and their connectedness in the landscape. It is well established that the level of connectedness impacts connectivity and metapopulation dynamics, and is therefore a central tenet in conservation biology. Connectedness equally generates sorting of phenotypes within the spatial network and therefore impacts local and regional eco-evolutionary dynamics. Paradoxically, recommendations for species conservation rely on principles derived from theory that neglects any individual phenotypic heterogenety and spatial organization.By creating experimental metapopulations using the model species Tetranychus urticae (two-spotted spider mite) with three levels of landscape connectedness and by regularly removing phenotypic structure in a subset of these populations, we tested the degree to which regional and local population dynamics are determined both by network connectedness and the phenotypic spatial organization.Our results show that some aspects of metapopulation dynamics can be attributed to the evolution of dispersal. More importantly, we find self-organization of phenotypic spatial structure to equalize the effects of reduced connectedness on metapopulation dynamics. These changes were all in the direction of improved metapopulation persistence. Contrary to expectations, the most connected local patches showed an overall reduced local population size, possibly originating from a faster depletion of resources from immigrants or transiting individuals.This experiment shows how metapopulation dynamics can significantly deviate from theoretical expectations if individual heterogeneity is considered, and more importantly that disruption of this phenotypic self-structuring may drive metapopulation dynamics towards higher risks of extinction.Significance StatementChanges in connectedness impact metapopulation dynamics but also the spatial organization of individual phenotypic heterogeneity. The extent to which metapopulation dynamics depend on this phenotypic structuring is unknown, despite the fact metapopulation theory is at the heart of conservation biology. By using experimental metapopulations and a randomization treatment, we demonstrate that the emerging spatial organization of individuals (both genetically and phenotypically) is a major driver of metapopulation dynamics. This spatial organization may be important as it may equalize all variation in metapopulation dynamics across a gradient of connectivity. This potentially rescuing effect stemming from the self-organization of phenotypes in metapopulations is of uttermost importance for conservation and translocation actions.

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The influence of initial age structure on predator–prey interaction

Cited by 19 publications

References 17 publications

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

Spatial connectedness imposes local‐ and metapopulation‐level selection on life history through feedbacks on demography

The Formation of Collective Silk Balls in the Spider Mite Tetranychus urticae Koch

Individual heterogeneity and its importance for metapopulation dynamics

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