| 181. |
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| 182. |
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| 183. |
- Ekman, J, et al.
(författare)
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Queuing for preferred territories: delayed dispersal of Siberian jays
- 2001
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Ingår i: JOURNAL OF ANIMAL ECOLOGY. - : BLACKWELL SCIENCE LTD. - 0021-8790. ; 70:2, s. 317-324
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Tidskriftsartikel (refereegranskat)abstract
- 1. Siberian jays (Perisoreus infaustus) can acquire breeding status along two routes. Some offspring dispersed in their first summer of life, but one-third of birds ringed as nestlings (39 of 117,40 broods) postponed dispersal beyond their first winter an
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| 184. |
- Ferraguti, Martina, et al.
(författare)
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Ecological determinants of avian malaria infections : An integrative analysis at landscape, mosquito and vertebrate community levels
- 2018
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790. ; 87:3, s. 727-740
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Tidskriftsartikel (refereegranskat)abstract
- Vector and host communities, as well as habitat characteristics, may have important but different impacts on the prevalence, richness and evenness of vector-borne parasites. We investigated the relative importance of (1) the mosquito community composition, (2) the vertebrate community composition and (3) landscape characteristics on the prevalence, richness and evenness of avian Plasmodium. We hypothesized that parasite prevalence will be more affected by vector-related parameters, while host parameters should be also important to explain Plasmodium richness and evenness. We sampled 2,588 wild house sparrows (Passer domesticus) and 340,829 mosquitoes, and we performed vertebrate censuses at 45 localities in the Southwest of Spain. These localities included urban, rural and natural landscapes that were characterized by several habitat variables. Twelve Plasmodium lineages were identified in house sparrows corresponding to three major clades. Variation partitioning showed that landscape characteristics explained the highest fraction of variation in all response variables (21.0%-44.8%). Plasmodium prevalence was in addition explained by vector-related variables (5.4%) and its interaction with landscape (10.2%). Parasite richness and evenness were mostly explained by vertebrate community-related variables. The structuring role of landscape characteristics in vector and host communities was a key factor in determining parasite prevalence, richness and evenness, although the role of each factor differed according to the parasite parameters studied. These results show that the biotic and abiotic contexts are important to explain the transmission dynamics of mosquito-borne pathogens in the wild.
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| 185. |
- Fiksen, O., et al.
(författare)
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Multiple predators in the pelagic: modelling behavioural cascades
- 2005
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Ingår i: Journal of Animal Ecology. - 0021-8790. ; 74:3, s. 423-429
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Tidskriftsartikel (refereegranskat)abstract
- 1. The behaviour of predators is rarely considered in models of predator-prey interactions, nor is it common to include multiple predators in models of animal behaviour. 2. We introduce a model of optimal diel vertical migration in zooplankton prey facing predation from two functionally different predators, fish and other zooplankton. Zooplankton predators are themselves subject to predation from larger zooplankton, and all zooplankton face the classical trade-off between increasing growth rate and predation risk from fish towards the surface. Prey are most vulnerable to zooplankton predators at small sizes, but become more visible to fish as they grow. However, by habitat selection prey continuously manage their exposure to different sources of risk. 3. We analyse situations with cascading behavioural interactions of size-structured predator-prey interactions in the pelagic. In particular, we explore how vertical gradients in growth rates and relative abundance of fish and zooplankton predators affect optimal distribution patterns, growth and mortality schedules. 4. A major model prediction is that prey susceptibility to one functional predator type depends on the abundance of the other predator. Higher abundance of zooplankton predators leads to risk enhancement from fish, minor increases in predation rate from zooplankton and unchanged prey growth rates. Increasing abundance of fish does not alter the risk from zooplankton predators, but reduces growth and development rates. Such asymmetric emergent effects may be common when prey and predators share the same spatial refuge from a common top predator.
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| 186. |
- Hegemann, Arne, et al.
(författare)
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A mimicked bacterial infection prolongs stopover duration in songbirds—but more pronounced in short- than long-distance migrants
- 2018
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Ingår i: Journal of Animal Ecology. - : Wiley. - 0021-8790. ; 87:6, s. 1698-1708
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Tidskriftsartikel (refereegranskat)abstract
- Migration usually consists of intermittent travel and stopovers, the latter being crucially important for individuals to recover and refuel to successfully complete migration. Quantifying how sickness behaviours influence stopovers is crucial for our understanding of migration ecology and how diseases spread. However, little is known about infections in songbirds, which constitute the majority of avian migrants. We experimentally immune-challenged autumn migrating passerines (both short- and long-distance migrating species) with a simulated bacterial infection. Using an automated radiotelemetry system in the stopover area, we subsequently quantified stopover duration, “bush-level” activity patterns (0.1–30 m) and landscape movements (30–6,000 m). We show that compared to controls, immune-challenged birds prolonged their stopover duration by on average 1.2 days in long-distance and 2.9 days in short-distance migrants, respectively (100%–126% longer than controls, respectively). During the prolonged stopover, the immune-challenged birds kept a high “bush-level” activity (which was unexpected) but reduced their local movements, independent of migration strategy. Baseline immune function, but not blood parasite infections prior to the immune challenge, had a prolonging effect on stopover duration, particularly in long-distance migrants. We conclude that a mimicked bacterial infection does not cause lethargy, per se, but restricts landscape movements and prolongs stopover duration, and that this behavioural response also depends on the status of baseline immune function and migration strategy. This adds a new level to the understanding of how acute inflammation affect migration behaviour and hence the ecology and evolution of migration. Accounting for these effects of bacterial infections will also enable us to fine-tune and apply optimal migration theory. Finally, it will help us predicting how migrating animals may respond to increased pathogen pressure caused by global change.
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| 187. |
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| 188. |
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| 189. |
- Hulthén, Kaj, et al.
(författare)
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Finotypic plasticity : Predator-induced plasticity in fin size, darkness and display behaviour in a teleost fish
- 2024
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Ingår i: Journal of Animal Ecology. - 0021-8790. ; 93:8, s. 1135-1146
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Tidskriftsartikel (refereegranskat)abstract
- Fish fins are remarkable devices of propulsion. Fin morphology is intimately linked to locomotor performance, and hence to behaviours that influence fitness, such as foraging and predator avoidance. This foreshadows a connection between fin morphology and variation in predation risk. Yet, whether prey can adjust fin morphology according to changes in perceived risk within their lifetime (a.k.a. predator-induced plasticity) remains elusive. Here, we quantify the structural size of five focal fins in crucian carp (Carassius carassius) following controlled manipulations to perceived predation risk (presence/absence of pike Esox lucius). We also assess if crucian carp respond to increased predation risk by shifts in dorsal fin colouration, and test for differences in how fish actively use their dorsal fins by quantifying the area of the fin displayed in behavioural trials. We find that crucian carp show phenotypic plasticity with regards to fin size as predator-exposed fish consistently have larger fins. Individuals exposed to perceived predation risk also increased dorsal fin darkness and actively displayed a larger area of the fin to potential predators. Our results thus provide compelling evidence for predator-induced fin enlargement, which should result in enhanced escape swimming performance. Moreover, fin-size plasticity may evolve synergistically with fin colouration and display behaviour, and we suggest that the adaptive value of this synergy is to enhance the silhouette of deep-bodied and hard-to-capture prey to deter gape-limited predators prior to attack. Together, our results provide new perspectives on the role of predation risk in development and evolution of fins.
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| 190. |
- Kenward, RE, et al.
(författare)
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Demographic estimates from radio-tagging: models of age-specific survival and breeding in the goshawk
- 1999
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Ingår i: JOURNAL OF ANIMAL ECOLOGY. - : BLACKWELL SCIENCE LTD. - 0021-8790. ; 68:5, s. 1020-1033
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Tidskriftsartikel (övrigt vetenskapligt/konstnärligt)abstract
- 1. Age-specific survival and breeding (ASSAB) models were developed with data from 318 goshawks (Accipiter gentilis L.) fitted during 1980-7 on the Baltic island of Gotland with tail-mounted radio-tags. 2. Comparisons with recaptures and recoveries of 238
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