| 1. |
- Seppänen, J.T., et al.
(författare)
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Social information use is a process across time, space, and ecology, reaching heterospecifics
- 2007
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Ingår i: Ecology. - : Wiley. - 0012-9658 .- 1939-9170. ; 88:7, s. 1622-1633
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Tidskriftsartikel (refereegranskat)abstract
- Decision making can be facilitated by observing other individuals faced with the same or similar problem, and recent research suggests that this social information use is a widespread phenomenon. Implications of this are diverse and profound: for example, social information use may trigger cultural evolution, affect distribution and dispersal of populations, and involve intriguing cognitive traits. We emphasize here that social information use is a process consisting of the scenes of(1) event, (2) observation, (3) decision, and (4) consequence, where the initial event is a scene in such a process of another individual. This helps to construct a sound conceptual framework for measuring and studying social information use. Importantly, the potential value of social information is affected by the distance in time, space, and ecology between the initial observation and eventual consequence of a decision. Because negative interactions between individuals (such as direct and apparent competition) also depend on the distance between individuals along these dimensions, the potential value of information and the negative interactions may form a trade-off situation. Optimal solutions to this trade-off can result in adaptively extended social information use, where using information gathered some time ago, some distance away, and from ecologically different individuals is preferred. Conceivably, using information gathered from a heterospecific individual might often be optimal. Many recent studies demonstrate that social information use does occur between species, and the first review of published cases is provided here. Such interaction between species, especially in habitat selection, has important consequences for community ecology and conservation. Adaptively extended social information use may also be an important evolutionary force in guild formation. Complex coevolutionary patterns may result depending on the effect of information use on the provider of information.
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| 2. |
- Forsman, Jukka T., et al.
(författare)
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Competitor density cues for habitat quality facilitating habitat selection and investment decisions
- 2008
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 19:3, s. 539-545
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Tidskriftsartikel (refereegranskat)abstract
- The theory of species coexistence predicts avoidance between species that compete for similar resources. Recent studies, however, have suggested that facilitation is also possible if competitor density provides information about resources. Optimal solution to trade-off between competition and facilitation is predicted to occur at intermediate competitor densities. We tested this hypothesis by experimentally creating a density range of resident tit species (Parus spp.), and measured the response of a competitively subordinate migratory bird, the collared flycatcher (Ficedula albicollis) in terms of habitat preference (settlement order and density), offspring investment (clutch size and primary sex ratio of offspring), and reproductive success (number and condition of nestlings). We show that most habitat choice and investment decisions of flycatchers were unimodally related to tit density, whereas reproductive success decreased linearly with increasing density. Flycatchers thus made mismatched investment decisions at the artificial tit densities because manipulation disassociated the natural correlation between habitat quality and population density. Apparently low and high tit densities were perceived as indication of poor quality habitat in terms of low amount or quality of resources/high mortality risk and high costs of competition, respectively. This demonstrates that competitor density can be used in assessing overall habitat quality in habitat selection and offspring investment decisions, integrating information on resources and competition.
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| 3. |
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| 4. |
- Forsman, Jukka T., et al.
(författare)
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Experimental evidence for the use of density based interspecific social information in forest birds
- 2009
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 32:3, s. 539-545
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Tidskriftsartikel (refereegranskat)abstract
- Reproductive success and habitat preference are generally assumed to be negatively associated with densities of con- and heterospecific competitors. However, recent theoretical studies have suggested that in some cases habitat preference may have a nonlinear unimodal function in relation to con- or heterospecific competitor densities - intermediate densities being preferred. Such a pattern is expected if con- or heterospecific densities are used as a proximate cue in habitat selection, which may produce benefits by reducing searching costs and providing information about current habitat quality and costs of competition. At low density the use of such cues, and hence habitat selection, are hampered, whereas at high density costs of competition exceed the benefits of using cues, leading to avoidance. Here, we tested this hypothesis by examining whether arboreal migratory birds use the density of resident titmice (Parus spp.) in habitat selection decisions. Many migrants and titmice species share similar resource needs making titmice density a reliable source of information for migrants. At the scale of habitat patches, we experimentally created a range of titmice densities from low to very high and subsequently measured the density response of migrants. In contrast to the unimodal habitat preference hypothesis, the average species number and total density of migratory birds were positively and linearly correlated with manipulated titmice density. Thus, migrants probably use titmice density as a relative indicator of habitat quality (abundance or quality of food) because foliage gleaners that share similar food resource with titmice, but not ground foragers, showed a positive association with manipulated titmice density. These results emphasize the positive effect of interspecific social information on habitat choice decisions and diversity of migratory bird community.
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| 5. |
- Forsman, Jukka T., et al.
(författare)
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Mechanisms and fitness effects of interspecific information use between migrant and resident birds
- 2007
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 18:5, s. 888-894
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Tidskriftsartikel (refereegranskat)abstract
- Interactions with potential competitors are an important component of habitat quality. Due to the costs of coexistence with competitors, a breeding habitat selection strategy that avoids competitors is expected to be favored. However, many migratory birds appear to gain benefits from an attraction to the presence of resident birds, even though residents are assumed to be competitively dominant. Thus far the mechanisms of this habitat selection process, heterospecific attraction, are unknown, and the consequences for resident birds of migrant attraction remain untested. Through heterospecific attraction, migrants may gain benefits if the density or territory location of residents positively reflects habitat quality, and/or they gain benefits through increased frequency of social interactions with residents in foraging or predator detection. In this experiment, we examined the reciprocal effects of spatial proximity on fitness-related traits in migrant pied flycatcher (Ficedula hypoleuca) and resident great tit (Parus major) by experimentally forcing them to breed either alone or in close proximity to each other. Surprisingly, great tits bore all the costs of coexistence while flycatchers were unaffected, even gaining slight benefits. In concert with an earlier study, these results suggest that flycatchers use tits as information about good-quality nest-site locations while benefits from social interactions with tits are possible but less important. We suggest that utilizing interspecific social information may be a common phenomenon between species sharing similar resource needs. Our results imply that the effects of interspecific information use can be asymmetric and may therefore have implications for the patterns and consequences of species coexistence.
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| 6. |
- Hjernquist, Marten B., et al.
(författare)
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Sex allocation in response to local resource competition over breeding territories
- 2009
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Ingår i: Behavioral Ecology. - : Oxford University Press (OUP). - 1045-2249 .- 1465-7279. ; 20:2, s. 335-339
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Tidskriftsartikel (refereegranskat)abstract
- Sex allocation according to local resource competition suggests that investment and offspring sex ratio should be biased toward the dispersing sex to limit the competition among the natal philopatric sex. Conversely, when competition over resources is low, parents should allocate more resources toward the philopatric sex. In this study, this reciprocal scenario of sex allocation is tested. More specifically, the effect of breeding territory availability on primary sex ratio is studied in the collared flycatcher, a migratory passerine bird, where males are the natal philopatric sex. As predicted, primary sex ratios were biased toward males in areas where available territories were abundant (estimated from population growth). No relationship between sex ratio adjustment and adult phenotypes as well as date of first egg was found. We discuss potential explanation for the male-biased broods in areas with many vacant territories and low levels of competition. We suggest that sex ratio adjustment in relation to breeding territory quality and availability could be relatively common in birds.
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| 7. |
- Seppänen, Janne-Tuomas, et al.
(författare)
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Interspecific social learning : Novel Preference Can Be Acquired from a Competing Species
- 2007
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Ingår i: Current Biology. - : Elsevier BV. - 0960-9822 .- 1879-0445. ; 17:14, s. 1248-1252
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Tidskriftsartikel (refereegranskat)abstract
- Nongenetic transmission of behavioral traits via social learning allows local traditions in humans, and, controversially, in other animals [1], [2], [3] and [4]. Social learning is usually studied as an intraspecific phenomenon (but see [5], [6] and [7]). However, other species with some overlap in ecology can be more than merely potential competitors: prior settlement and longer residence can render them preferable sources of information [8]. Socially induced acquisition of choices or preferences capitalizes upon the knowledge of presumably better-informed individuals [9] and should be adaptive under many natural circumstances [10] and [11]. Here we show with a field experiment that females of two migrant flycatcher species can acquire a novel, arbitrary preference of competing resident tits for a symbol attached to the nest sites. The experiment demonstrates that such blind acquisition of heterospecific traits can occur in the wild. Even though genetic variation for habitat preferences exists in many taxa [12] and overlap between bird species likely induces costs [13], this result shows that interspecific social learning can cause increased overlap in nest-site preferences. Conventional, negative species interactions push ecological niches of species apart, but the use of competing species as a source of information counters that force and may lead to convergence.
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| 8. |
- Thomson, Robert L., et al.
(författare)
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Fear factor : prey habitat selection and its consequences in a predation risk landscape
- 2006
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Ingår i: Ecography. - : Wiley. - 0906-7590 .- 1600-0587. ; 29:4, s. 507-514
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Tidskriftsartikel (refereegranskat)abstract
- Predation risk influences prey use of space. However, little is known about how predation risk influences breeding habitat selection and the fitness consequences of these decisions. The nest sites of central-place foraging predators may spatially anchor predation risk in the landscape. We explored how the spatial dispersion of avian predator nests influenced prey territory location and fitness related measures. We placed 249 nest boxes for migrant pied flycatchers Ficedula hypoleuca, at distances between 10 and 630 in, around seven different sparrowhawk nests Accipiter nisus. After closely monitoring flycatcher nests we found that flycatcher arrival dates, nest box occupation rates and clutch size showed a unimodal relationship with distance from sparrowhawk nests. This relationship suggested an optimal territory location at intermediate distances between 330 and 430 in from sparrowhawk nests. Furthermore, pied flycatcher nestling quantity and quality increased linearly with distance from sparrowhawk nests. These fitness related measures were between 4 and 26% larger in flycatcher nestlings raised far from, relative to those raised nearby, sparrowhawk nests. Our results suggest that breeding sparrowhawk affected both flycatcher habitat selection and reproductive Success. We propose that nesting predators create predictable spatial variation in predation risk for both adult prey and possibly their nests, to which prey individuals are able to adaptively respond. Recognising predictable spatial variation in perceived predation risk may be fundamental for a proper understanding of predator-prey interactions and indeed prey species interactions.
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