Consistency and Variation in Phenotypic Selection Exerted by a Community of Seed Predators

Smith, Julie W.; Maier, Monika; Hansen, L.; Talluto, Matthew V.

doi:10.1111/j.1558-5646.2012.01736.x

Cited by 29 publications

(44 citation statements)

References 56 publications

(205 reference statements)

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“…The arms race between predators and prey Natural selection by selective removal of prey can have a profound influence on prey behavior, morphology, and physiology (Genovart et al 2010, Benkman et al 2013, Vedder et al 2014. Under the selection pressures imposed by predators, prey continuously evolve behavioral, morphological, and physiological defense mechanisms (Dawkins and Krebs 1979).…”

Section: Depletion Of Cockle Densities and Community Effectsmentioning

confidence: 99%

Natural selection by pulsed predation: survival of the thickest

Bijleveld

Twietmeyer

Piechocki

et al. 2015

Ecology

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Abstract. Selective predation can lead to natural selection in prey populations and may alleviate competition among surviving individuals. The processes of selection and competition can have substantial effects on prey population dynamics, but are rarely studied simultaneously. Moreover, field studies of predator-induced short-term selection pressures on prey populations are scarce. Here we report measurements of density dependence in body composition in a bivalve prey (edible cockle, Cerastoderma edule) during bouts of intense predation by an avian predator (Red Knot, Calidris canutus). We measured densities, patchiness, morphology, and body composition (shell and flesh mass) of cockles in a quasiexperimental setting, i.e., before and after predation in three similar plots of 1 ha each, two of which experienced predation, and one of which remained unvisited in the course of the short study period and served as a reference. An individual's shell and flesh mass declined with cockle density (negative density dependence). Before predation, cockles were patchily distributed. After predation, during which densities were reduced by 78% (from 232 to 50 cockles/m 2 ), the patchiness was substantially reduced, i.e., the spatial distribution was homogenized. Red Knots selected juvenile cockles with an average length of 6.9 6 1.0 mm (mean 6 SD). Cockles surviving predation had heavier shells than before predation (an increase of 21.5 percentage points), but similar flesh masses. By contrast, in the reference plot shell mass did not differ statistically between initial and final sampling occasions, while flesh mass was larger (an increase of 13.2 percentage points). In this field study, we show that Red Knots imposed a strong selection pressure on cockles to grow fast with thick shells and little flesh mass, with selection gradients among the highest reported in the literature.

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Section: Depletion Of Cockle Densities and Community Effectsmentioning

confidence: 99%

Natural selection by pulsed predation: survival of the thickest

Bijleveld

Twietmeyer

Piechocki

et al. 2015

Ecology

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“…Cones that were not identifiable in this manner were treated as missing data and ignored for analysis. The rate of disappearance between intervals is an appropriate measure of the predation rate from red squirrels because no other organism removes cones from lodgepole pine (due to extreme defense requiring specialized predators), and cones do not generally fall from branches (even after they have opened) (21,25). Because survival of serotinous cones is likely to vary as the cone ages, we analyzed survival as a function of the degree of weathering, with separate estimates for green (first-year), brown (likely 1-to 5-y-old), and gray (>5-y-old) cones.…”

Section: Methodsmentioning

confidence: 99%

“…Postdispersal seed predation may be another mechanism favoring the evolution of serotiny if delayed and synchronous seed release limits the abundance of postdispersal predators (7,20). However, escape from postdispersal predation may come at the expense of extreme losses to predispersal predators that can easily access the canopy seed bank (21, 22), potentially exerting selection favoring increased allocation to seed defense (21,(23)(24)(25). …”

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confidence: 99%

Conflicting selection from fire and seed predation drives fine-scaled phenotypic variation in a widespread North American conifer

Talluto

2014

Proc. Natl. Acad. Sci. U.S.A.

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Recent work has demonstrated that evolutionary processes shape ecological dynamics on relatively short timescales (eco-evolutionary dynamics), but demonstrating these effects at large spatial scales in natural landscapes has proven difficult. We used empirical studies and modeling to investigate how selective pressures from fire and predispersal seed predation affect the evolution of serotiny, an ecologically important trait. Serotiny is a highly heritable key reproductive trait in Rocky Mountain lodgepole pine (Pinus contorta subsp. latifolia), a conifer that dominates millions of hectares in western North America. In these forests, the frequency of serotiny determines postfire seedling density with corresponding community-and ecosystem-level effects. We found that serotinous individuals have a selective advantage at high fire frequencies and low predation pressure; however, very high seed predation shifted the selective advantage to nonserotinous individuals even at high fire frequencies. Simulation modeling suggests that spatial variation in the frequency of serotiny results from heterogeneity in these two selective agents. These results, combined with previous findings showing a negative association between the density of seed predators and the frequency of serotiny at both landscape and continental scales, demonstrate that contemporary patterns in serotiny reflect an evolutionary response to conflicting selection pressures from fire and seed predation. Thus, we show that variation in the frequency of a heritable polygenic trait depends on spatial variation in two dominant selective agents, and, importantly, the effects of the local trait variation propagate with profound consequences to the structure and function of communities and ecosystems across a large landscape.Greater Yellowstone Ecosystem | geographic selection mosaics | genes to ecosystems R ecent work has attempted to unify processes acting across spatiotemporal scales by connecting smaller-scale (e.g., individuals, patches) ecological processes to large-scale (e.g., ecosystems, landscapes) patterns via evolutionary mechanisms (1, 2). When heritable traits in foundation species have important community and ecosystem effects, ecological drivers that exert natural selection on these traits can propagate to largescale patterns in community and ecosystem function, resulting in landscape heterogeneity driven by small-scale ecological variation (1, 3). Although there is a clear conceptual link between selection acting on individuals and landscape-scale patterns, making mechanistic connections across these very different scales has proven challenging (refs. 4 and 5; but see ref. 6). Forested ecosystems in particular are difficult to study, because long generation times prevent direct observations of any response to selection. Nevertheless, attempts to elucidate the connections between individual-level genetic variation and ecosystem and landscape structure are imperative, especially given the unprecedented pace of global change.Here, we integrate empiric...

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“…Divergence in morphology has been a dominating theme of coevolutionary studies (for recent examples see e.g. Benkman et al 2012;Pauw et al 2009; Toju et al 2011), but studies of chemical diversification increasingly have shown that coevolution is just as often about attractants, repellents, toxic compounds, and counter responses to those compounds (Berenbaum and Zangerl 2006;Brodie and Ridenhour 2003;Ehrlich and Raven 1964;Foitzik et al 2003;Hanifin et al 2008;Johnson et al 2010;Raguso 2008;. Attractants are a particularly intriguing class of compounds in coevolving interactions, because they actively attract mutualists but may simultaneously attract enemies (Theis and Adler 2012).…”

Section: Introductionmentioning

confidence: 99%

Floral Scent Contributes to Interaction Specificity in Coevolving Plants and Their Insect Pollinators

et al. 2014

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Chemical defenses, repellents, and attractants are important shapers of species interactions. Chemical attractants could contribute to the divergence of coevolving plant-insect interactions, if pollinators are especially responsive to signals from the local plant species. We experimentally investigated patterns of daily floral scent production in three Lithophragma species (Saxifragaceae) that are geographically isolated and tested how scent divergence affects attraction of their major pollinator-the floral parasitic moth Greya politella (Prodoxidae). These moths oviposit through the corolla while simultaneously pollinating the flower with pollen adhering to the abdomen. The complex and species-specific floral scent profiles were emitted in higher amounts during the day, when these day-flying moths are active. There was minimal divergence found in petal color, which is another potential floral attractant. Female moths responded most strongly to scent from their local host species in olfactometer bioassays, and were more likely to oviposit in, and thereby pollinate, their local host species in no-choice trials. The results suggest that floral scent is an important attractant in this interaction. Local specialization in the pollinator response to a highly specific plant chemistry, thus, has the potential to contribute importantly to patterns of interaction specificity among coevolving plants and highly specialized pollinators.

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Consistency and Variation in Phenotypic Selection Exerted by a Community of Seed Predators

Cited by 29 publications

References 56 publications

Natural selection by pulsed predation: survival of the thickest

Natural selection by pulsed predation: survival of the thickest

Conflicting selection from fire and seed predation drives fine-scaled phenotypic variation in a widespread North American conifer

Floral Scent Contributes to Interaction Specificity in Coevolving Plants and Their Insect Pollinators

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