| 1. |
- Roth, Allison M., et al.
(författare)
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Sexual selection and personality : Individual and group-level effects on mating behaviour in red junglefowl
- 2021
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 90:5, s. 1288-1306
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Tidskriftsartikel (refereegranskat)abstract
- Despite increasing evidence of the importance of repeatable among-individual differences in behaviour (animal personality) in ecology and evolution, little remains known about the role of animal personalities in sexual selection. Here, we present an investigation of the hypothesis that the personalities of individuals and their sexual partners play a role in different episodes of sexual selection, and the extent to which these effects are modulated by the social environment. We first examined how two repeatable behaviours-exploration and boldness-are associated with pre- and postcopulatory sexual selection in male red junglefowl Gallus gallus, using replicate groups across three experimental sex ratio treatments. We further explored how the social environment modulates relationships between male personality and mating performance, and whether mating is assortative or disassortative with respect to exploration or boldness. Finally, we examined behavioural mechanisms linking personality with mating performance. Across all sex ratios, the fastest and slowest exploring males courted females proportionally less, and faster exploring males associated with females more and received more sexual solicitations. In female-biased groups, the fastest and slowest exploring males experienced the highest mating success and lowest sperm competition intensity. Faster exploring males also obtained more mates in female-biased groups when their competitors were, on average, slower exploring, and the proportion of matings obtained by fast-exploring males decreased with the proportion of fast-exploring males in a group, consistent with negative frequency-dependent sexual selection. While boldness did not predict mating performance, there was a tendency for individuals to mate disassortatively with respect to boldness. Collectively, our results suggest that male exploration can play a role in sexual selection, and that sexual selection on personality is complex and contingent on the social environment.
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| 2. |
- Dingemanse, Niels J., et al.
(författare)
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Individual variation in age-dependent reproduction: Fast explorers live fast but senesce young?
- 2020
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Ingår i: Journal of Animal Ecology. - : WILEY. - 0021-8790 .- 1365-2656. ; 89:2, s. 601-613
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Tidskriftsartikel (refereegranskat)abstract
- Adaptive integration of life history and behaviour is expected to result in variation in the pace-of-life. Previous work focused on whether risky phenotypes live fast but die young, but reported conflicting support. We posit that individuals exhibiting risky phenotypes may alternatively invest heavily in early-life reproduction but consequently suffer greater reproductive senescence. We used a 7-year longitudinal dataset with amp;gt;1,200 breeding records of amp;gt;800 female great tits assayed annually for exploratory behaviour to test whether within-individual age dependency of reproduction varied with exploratory behaviour. We controlled for biasing effects of selective (dis)appearance and within-individual behavioural plasticity. Slower and faster explorers produced moderate-sized clutches when young; faster explorers subsequently showed an increase in clutch size that diminished with age (with moderate support for declines when old), whereas slower explorers produced moderate-sized clutches throughout their lives. There was some evidence that the same pattern characterized annual fledgling success, if so, unpredictable environmental effects diluted personality-related differences in this downstream reproductive trait. Support for age-related selective appearance was apparent, but only when failing to appreciate within-individual plasticity in reproduction and behaviour. Our study identifies within-individual age-dependent reproduction, and reproductive senescence, as key components of life-history strategies that vary between individuals differing in risky behaviour. Future research should thus incorporate age-dependent reproduction in pace-of-life studies.
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| 3. |
- Sorato, Enrico, et al.
(författare)
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The price of associating with breeders in the cooperatively breeding chestnut-crowned babbler: foraging constraints, survival and sociality
- 2016
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Ingår i: Journal of Animal Ecology. - : WILEY-BLACKWELL. - 0021-8790 .- 1365-2656. ; 85:5, s. 1340-1351
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Tidskriftsartikel (refereegranskat)abstract
- 1. Understanding the costs of living with breeders might offer new insights into the factors that counter evolutionary transitions from selfish individuals to cooperative societies. While selection on early dispersal is well understood, it is less clear whether costs are also associated with remaining with family members during subsequent breeding, a prerequisite to the evolution of kin-based cooperation. 2. We propose and test the hypothesis that living in groups containing breeders is costly and that such costs are exacerbated by increasing group size. For example, in group-living central- place foragers, group members might suffer from resource depletion when foraging in a restricted area during breeding and significant costs of repeatedly travelling between foraging patches and the site of offspring. 3. Using the cooperatively breeding chestnut-crowned babbler (Pomatostomus ruficeps), for which grouping during breeding is obligatory, we show that reproduction is associated with substantially reduced foraging areas and evidence of resource depletion, particularly in larger groups. Such effects largely persisted from the onset of incubation through to offspring independence 4-5 months later. All group members, irrespective of their breeder or helper status, lost significant body mass over this period, and, in males, mass loss was associated with reduced interannual survival. 4. Although babblers are constrained from living outside of breeding groups due to high risks of predation and the poor success of breeding without helpers, we suggest that the effects we describe may generally select against group living during breeding attempts in species where constraints to independent breeding and costs of dispersal are less acute.
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| 4. |
- Cirtwill, Alyssa R., et al.
(författare)
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Species motif participation provides unique information about species risk of extinction
- 2024
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Ingår i: Journal of Animal Ecology. - : WILEY. - 0021-8790 .- 1365-2656.
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Tidskriftsartikel (refereegranskat)abstract
- Loss of species in food webs can set in motion a cascade of additional (secondary) extinctions. A species' position in a food web (e.g. its trophic level or number of interactions) is known to affect its ability to persist following disturbance. These simple measures, however, offer only a coarse description of how species fit into their community. One would therefore expect that more detailed structural measures such as participation in three-species motifs (meso-scale structures which provide information on a species' direct and indirect interactions) will also be related to probability of persistence. Disturbances affecting the basal resources have particularly strong effects on the rest of the food web. However, how disturbances branch out and affect consumer persistence depends on the structural pattern of species interactions in several steps. The magnitude, for example, the proportion of basal resources lost, will likely also affect the outcome. Here, we analyse whether a consumer's risk of secondary extinction after the removal of basal resources depends on the consumer's motif participation and how this relationship varies with the severity of disturbance. We show that consumer species which participate more frequently in the direct competition motif and less frequently in the omnivory motif generally have higher probability of persistence following disturbance to basal resources. However, both the strength of the disturbance and the overall network structure (i.e. connectance) affect the strength and direction of relationships between motif participation and persistence. Motif participation therefore captures important trends in species persistence and provides a rich description of species' structural roles in their communities, but must be considered in the context of network structure as a whole and of the specific disturbance applied. Like degree and trophic level, a species' participation in meso-scale motifs can affect its persistence after disturbance. We show that these relationships also depend strongly on the strength of disturbance.image
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| 5. |
- Berlow, E.L., et al.
(författare)
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Interaction strengths in food webs : Issues and opportunities
- 2004
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 73:3, s. 585-598
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Forskningsöversikt (refereegranskat)abstract
- 1. Recent efforts to understand how the patterning of interaction strength affects both structure and dynamics in food webs have highlighted several obstacles to productive synthesis. Issues arise with respect to goals and driving questions, methods and approaches, and placing results in the context of broader ecological theory. 2. Much confusion stems from lack of clarity about whether the questions posed relate to community-level patterns or to species dynamics, and to what authors actually mean by the term 'interaction strength'. Here, we describe the various ways in which this term has been applied and discuss the implications of loose terminology and definition for the development of this field. 3. Of particular concern is the clear gap between theoretical and empirical investigations of interaction strengths and food web dynamics. The ecological community urgently needs to explore new ways to estimate biologically reasonable model coefficients from empirical data, such as foraging rates, body size, metabolic rate, biomass distribution and other species traits. 4. Combining numerical and analytical modelling approaches should allow exploration of the conditions under which different interaction strengths metrics are interchangeable with regard to relative magnitude, system responses, and species identity. 5. Finally, the prime focus on predator-prey links in much of the research to date on interaction strengths in food webs has meant that the potential significance of nontrophic interactions, such as competition, facilitation and biotic disturbance, has been largely ignored by the food web community. Such interactions may be important dynamically and should be routinely included in future food web research programmes.
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| 6. |
- Ebenman, Bo
(författare)
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Response of ecosystems to realistic extinction sequences
- 2011
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Ingår i: Journal of Animal Ecology. - Malden, MA, USA : Wiley-Blackwell. - 0021-8790 .- 1365-2656. ; 80:2, s. 307-309
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- Recent research suggests that effects of species loss on the structure and functioning of ecosystems willcritically depend on the order with which species go extinct. However, there are few studies of theresponse of natural ecosystems to realistic extinction sequences. Using an extinction scenario basedon the International Union for Conservation of Nature (IUCN) Red List, de Visser et al. sequentiallydeleted species from a topological model of the Serengeti food web. Under this scenario, large-bodiedspecies like top predators and mega-herbivores go extinct first. The resulting changes in the trophicstructure of the food web might affect the robustness of the ecosystem to future disturbances.
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| 7. |
- Eklöf, Anna, 1976-, et al.
(författare)
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Species loss and secondary extinctions in simple and complex model communities
- 2006
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Ingår i: Journal of Animal Ecology. - : Wiley InterScience. - 0021-8790 .- 1365-2656. ; 75:1, s. 239-246
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Tidskriftsartikel (refereegranskat)abstract
- The loss of a species from an ecological community can trigger a cascade of secondary extinctions. Here we investigate how the complexity (connectance) of model communities affects their response to species loss. Using dynamic analysis based on a global criterion of persistence (permanence) and topological analysis we investigate the extent of secondary extinctions following the loss of different kinds of species.We show that complex communities are, on average, more resistant to species loss than simple communities: the number of secondary extinctions decreases with increasing connectance. However, complex communities are more vulnerable to loss of top predators than simple communities.The loss of highly connected species (species with many links to other species) and species at low trophic levels triggers, on average, the largest number of secondary extinctions. The effect of the connectivity of a species is strongest in webs with low connectance.Most secondary extinctions are due to direct bottom-up effects: consumers go extinct when their resources are lost. Secondary extinctions due to trophic cascades and disruption of predator-mediated coexistence also occur. Secondary extinctions due to disruption of predator-mediated coexistence are more common in complex communities than in simple communities, while bottom-up and top-down extinction cascades are more common in simple communities.Topological analysis of the response of communities to species loss always predicts a lower number of secondary extinctions than dynamic analysis, especially in food webs with high connectance.
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| 8. |
- Mueller, Johann P, et al.
(författare)
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Ingredients for protist coexistence: competition, endosymbiosis and a pinch of biochemical interactions
- 2012
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Ingår i: Journal of Animal Ecology. - : Wiley-Blackwell. - 0021-8790 .- 1365-2656. ; 81:1, s. 222-232
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Tidskriftsartikel (refereegranskat)abstract
- 1. The interaction between mutualism, facilitation or interference and exploitation competition is of major interest as it may govern species coexistence. However, the interplay of these mechanisms has received little attention. This issue dates back to Gause, who experimentally explored competition using protists as a model [Gause, G.F. (1935) Verifications experimentales de la theorie mathematique de la lutte pour la vie. Actualites Scientifiques et Industrielles, 277]. He showed the coexistence of Paramecium caudatum with a potentially allelopathic species, Paramecium bursaria. less thanbrgreater than less thanbrgreater than2. Paramecium bursaria hosts the green algae Chlorella vulgaris. Therefore, P. bursaria may benefit from carbohydrates synthesised by the algae. Studying endosymbiosis with P. bursaria is possible as it can be freed of its endosymbiont. In addition, C. vulgaris is known to produce allelochemicals, and P. bursaria may benefit also from allelopathic compounds. less thanbrgreater than less thanbrgreater than3. We designed an experiment to separate the effects of resource exploitation, endosymbiosis and allelopathy and to assess their relative importance for the coexistence of P. bursaria with a competitor that exploits the same resource, bacteria. The experiment was repeated with two competitors, Colpidium striatum or Tetrahymena pyriformis. less thanbrgreater than less thanbrgreater than4. Results show that the presence of the endosymbiont enables the coexistence of competitors, while its loss leads to competitive exclusion. These results are in agreement with predictions based on resource equilibrium density of monocultures (R*) supporting the idea that P. bursarias endosymbiont is a resource provider for its host. When P. bursaria and T. pyriformis coexist, the density of the latter shows large variation that match the effects of culture medium of P. bursaria. Our experiment suggests these effects are because of biochemicals produced in P. bursaria culture. less thanbrgreater than less thanbrgreater than5. Our results expose the hidden diversity of mechanisms that underlie competitive interactions. They thus support Gausess speculation (1935) that allelopathic effects might have been involved in his competition experiments. We discuss how a species engaged both in competition for a resource and in costly interference such as allelopathy may counterbalance these costs with a resource-provider endosymbiont.
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