| 55561. |
- Paquet, Matthieu
(författare)
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Maternal allocation in relation to weather, predation and social factors in a colonial cooperative bird
- 2021
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 90, s. 1122-1133
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Tidskriftsartikel (refereegranskat)abstract
- Females may adjust prenatal allocation in relation to ecological conditions that affect reproductive success, such as weather conditions or predation risk. In cooperative breeders, helpers might also influence reproductive success, and previous studies suggest that females can lay smaller eggs or larger clutches when breeding with more helpers. Although recent work suggests that helper effects can vary according to climatic variables, how social and ecological factors interact to shape prenatal allocation is poorly understood.Here, we examine how ecological and social components of the breeding environment covary with egg mass and clutch size, using as a model the sociable weaver Philetairus socius, a colonial, cooperatively breeding passerine. The study spanned 9 years and included over 1,900 eggs from over 550 clutches. Our analyses combined natural variation in weather conditions (rainfall before each reproductive event) with a nest predator-exclusion experiment and continuous monitoring of the mother's social environment, allowing us to estimate how individual females adjust allocation to reproduction as their number of helpers varies.We found that egg mass varied consistently within females and did not clearly differ in relation to rainfall or predation risk. Contrary to previous studies, there was no evidence for plastic adjustments as females gained and lost helpers, and egg mass was instead better predicted by mother size and identity.Females laid larger clutches when breeding in environments where predation risk was experimentally reduced and after higher rainfall levels. Yet, there was no evidence for increasing clutch size as the number of helpers increased, nor for an interaction between helper effects and ecological factors.We conclude that while sociable weaver females can vary their clutch size, they show high individual consistency in egg mass. In addition, we found no evidence that females may maximize fitness through plastic prenatal allocation in relation to the number of helpers, or that the presence/absence of helper effects is modulated by rainfall levels or predation risk. These results challenge our current knowledge on some of the possible benefits of breeding with helpers and call for more long-term analyses on reproductive allocation adjustments in other cooperative systems.
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| 55562. |
- Paquet, Matthieu
(författare)
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Offspring are predisposed to beg more towards females in the burying beetle Nicrophorus vespilloides
- 2018
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Ingår i: Animal Behaviour. - : Elsevier BV. - 0003-3472 .- 1095-8282. ; 141, s. 195-201
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Tidskriftsartikel (refereegranskat)abstract
- In species with biparental care, begging offspring may preferentially associate with or beg more towards one of their parents. Such preferences may reflect that the benefits of begging vary with the parent's sex given that females and males often differ in the amount of care they provide and/or in their responsiveness to begging levels. Alternatively, they may reflect the outcome of sexual conflict over care as females may deposit compounds into eggs tha tatter offspring begging behaviour such that it increases male contributions towards care. For example, females might use male presence during egg laying as a cue for whether they might receive male assistance in care. Here, we studied offspring begging behaviour towards male and female parents in the burying beetle Nicrophorus vespilloides by manipulating male presence or absence during egg laying and providing larvae with a simultaneous choice between an unfamiliar female and male adult beetle. We then recorded begging behaviour of (1) naive newly hatched larvae that had no prior experience of a parent and (2) larvae after 24 h of care by foster parents. Larvae showed a clear preference for associating with and begging towards females both when naive and after 24 h of care. We found no evidence for prenatal maternal effects on larval begging behaviour. Our study reveals that offspring are predisposed to preferentially beg towards females independently of prior experiences with parents and highlights the importance of considering responses of begging offspring to parental attributes, such as the parent's sex, for our understanding of family conflicts. (C) 2018 The Association for the Study of Animal Behaviour. Published by Elsevier Ltd. All rights reserved.
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| 55563. |
- Paquet, Matthieu, et al.
(författare)
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Quantifying the links between land use and population growth rate in a declining farmland bird
- 2019
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Ingår i: Ecology and Evolution. - : Wiley. - 2045-7758. ; 9, s. 868-879
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Tidskriftsartikel (refereegranskat)abstract
- Land use is likely to be a key driver of population dynamics of species inhabiting anthropogenic landscapes, such as farmlands. Understanding the relationships between land use and variation in population growth rates is therefore critical for the management of many farmland species. Using 24 years of data of a declining farmland bird in an integrated population model, we examined how spatiotemporal variation in land use (defined as habitats with Short and Tall ground vegetation during the breeding season) and habitat-specific demographic parameters relates to variation in population growth taking into account individual movements between habitats. We also evaluated contributions to population growth using transient life table response experiments which gives information on contribution of past variation of parameters and real-time elasticities which suggests future scenarios to change growth rates. LTRE analyses revealed a clear contribution of Short habitats to the annual variation in population growth rate that was mostly due to fledgling recruitment, whereas there was no evidence for a contribution of Tall habitats. Only 18% of the variation in population growth was explained by the modeled local demography, the remaining variation being explained by apparent immigration (i.e., the residual variation). We discuss potential biological and methodological reasons for high contributions of apparent immigration in open populations. In line with LTRE analysis, real-time elasticity analysis revealed that demographic parameters linked to Short habitats had a stronger potential to influence population growth rate than those of Tall habitats. Most particularly, an increase of the proportion of Short sites occupied by Old breeders could have a distinct positive impact on population growth. High-quality Short habitats such as grazed pastures have been declining in southern Sweden. Converting low-quality to high-quality habitats could therefore change the present negative population trend of this, and other species with similar habitat requirements.
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| 55564. |
- Paquet, Matthieu, et al.
(författare)
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Why we should care about movements: Using spatially explicit integrated population models to assess habitat source-sink dynamics
- 2020
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790 .- 1365-2656. ; 89, s. 2922-2933
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Tidskriftsartikel (refereegranskat)abstract
- Assessing the source-sink status of populations and habitats is of major importance for understanding population dynamics and for the management of natural populations. Sources produce a net surplus of individuals (per capita contribution to the metapopulation > 1) and will be the main contributors for self-sustaining populations, whereas sinks produce a deficit (contribution < 1). However, making these types of assessments is generally hindered by the problem of separating mortality from permanent emigration, especially when survival probabilities as well as moved distances are habitat-specific. To address this long-standing issue, we propose a spatial multi-event integrated population model (IPM) that incorporates habitat-specific dispersal distances of individuals. Using information about local movements, this IPM adjusts survival estimates for emigration outside the study area. Analysing 24 years of data on a farmland passerine (the northern wheatearOenanthe oenanthe), we assessed habitat-specific contributions, and hence the source-sink status and temporal variation of two key breeding habitats, while accounting for habitat- and sex-specific local dispersal distances of juveniles and adults. We then examined the sensitivity of the source-sink analysis by comparing results with and without accounting for these local movements. Estimates of first-year survival, and consequently habitat-specific contributions, were higher when local movement data were included. The consequences from including movement data were sex specific, with contribution shifting from sink to likely source in one habitat for males, and previously noted habitat differences for females disappearing. Assessing the source-sink status of habitats is extremely challenging. We show that our spatial IPM accounting for local movements can reduce biases in estimates of the contribution by different habitats, and thus reduce the overestimation of the occurrence of sink habitats. This approach allows combining all available data on demographic rates and movements, which will allow better assessment of source-sink dynamics and better informed conservation interventions.
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| 55565. |
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| 55566. |
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| 55567. |
- Parachnowitsch, Amy L., et al.
(författare)
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Evolutionary ecology of nectar
- 2019
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Ingår i: Annals of Botany. - : Oxford University Press. - 0305-7364 .- 1095-8290. ; 123:2, s. 247-261
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Forskningsöversikt (refereegranskat)abstract
- Background: Floral nectar is an important determinant of plant–pollinator interactions and an integral component of pollination syndromes, suggesting it is under pollinator-mediated selection. However, compared to floral display traits, we know little about the evolutionary ecology of nectar. Combining a literature review with a meta-analysis approach, we summarize the evidence for heritable variation in nectar traits and link this variation to pollinator response and plant fitness. We further review associations between nectar traits and floral signals and discuss them in the context of honest signalling and targets of selection.Scope: Although nectar is strongly influenced by environmental factors, heritable variation in nectar production rate has been documented in several populations (mean h2 = 0.31). Almost nothing is known about heritability of other nectar traits, such as sugar and amino acid concentrations. Only a handful of studies have quantified selection on nectar traits, and few find statistically significant selection. Pollinator responses to nectar traits indicate they may drive selection, but studies tying pollinator preferences to plant fitness are lacking. So far, only one study conclusively identified pollinators as selective agents on a nectar trait, and the role of microbes, herbivores, nectar robbers and abiotic factors in nectar evolution is largely hypothetical. Finally, there is a trend for positive correlations among floral cues and nectar traits, indicating honest signalling of rewards.Conclusions: Important progress can be made by studies that quantify current selection on nectar in natural populations, as well as experimental approaches that identify the target traits and selective agents involved. Signal–reward associations suggest that correlational selection may shape evolution of nectar traits, and studies exploring these more complex forms of natural selection are needed. Many questions about nectar evolution remain unanswered, making this a field ripe for future research.
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| 55568. |
- Parachnowitsch, Amy L.
(författare)
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Interpreting local adaptation studies
- 2013
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Ingår i: Ideas in Ecology and Evolution. - : Queen's University Library. - 1918-3178. ; 6:1, s. 37-39
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Tidskriftsartikel (refereegranskat)
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| 55569. |
- Parachnowitsch, Amy L., et al.
(författare)
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Neighbours matter : natural selection on plant size depends on the identity and diversity of the surrounding community
- 2014
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Ingår i: Evolutionary Ecology. - : Springer Science and Business Media LLC. - 0269-7653 .- 1573-8477. ; 28:6, s. 1139-1153
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Tidskriftsartikel (refereegranskat)abstract
- Plant diversity can affect ecological processes such as competition and herbivory, and these ecological processes can act as drivers of evolutionary change. However, surprisingly little is known about how ecological variation in plant diversity can alter selective regimes on members of the community. Here, we examine how plant diversity at two different scales (genotypic and species diversity) impacts natural selection on a focal plant species, the common evening primrose (Oenothera biennis). Because competition is frequently relaxed in both genotypically and species rich plant communities, we hypothesized that increasing diversity would weaken selection on competitive ability. Changes in plant diversity can also affect associated arthropod communities. Therefore, we hypothesized that diversity would alter selection on plant traits mediating these interactions, such as herbivory related traits. We grew 24 focal O. biennis genotypes within four different neighbourhoods: genotypic monocultures or polycultures of O. biennis, and species monocultures or polycultures of old-field species that commonly co-occur with O. biennis. We then measured genotypic selection on nine plant traits known to be ecologically important for competition and herbivory. Focal O. biennis plants were smaller, flowered for shorter periods of time, had lower fitness, and experienced greater attack from specialist predispersal seed predators when grown with conspecifics versus heterospecifics. While neither conspecific nor heterospecific diversity altered trait means, both types of diversity altered the strength of selection on focal O. biennis plants. Specifically, selection on plant biomass was stronger in conspecific monocultures versus polycultures, but weaker in heterospecific monocultures versus polycultures. We found no evidence of selection on plant traits that mediate insect interactions, despite differences in arthropod communities on plants surrounded by conspecifics versus heterospecifics. Our data demonstrate that plant genotypic and species diversity can act as agents of natural selection, potentially driving evolutionary changes in plant communities.
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| 55570. |
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