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1.
Emeline Pettex Svein-H?kon Lorentsen David Grémillet Olivier Gimenez Robert T. Barrett Jean-Baptiste Pons Céline Le Bohec Francesco Bonadonna 《Marine Biology》2012,159(12):2743-2756
The survival of marine predators depends on behavioural plasticity to cope with changes in prey distribution. Variability in behaviour might predict plasticity and is easier to assess than plasticity. Using miniaturized GPS loggers over several breeding seasons in two Norwegian Northern gannet (Morus bassanus) colonies, we investigated if and how the variability within and between individuals, but also between colonies and years, affected foraging strategies. Results revealed strong individual variability (foraging trip durations, foraging effort and different foraging areas). Individuals from both colonies showed preferred commuting routes, flight bearings and feeding hotspots. Individuals from the largest colony used larger and more foraging areas than individuals from the small colony. Feeding hotspots and foraging ranges varied amongst years in the largest colony only. Our study demonstrated that gannets show flexibility by changing prey fields that are driven by shifting oceanographic conditions. 相似文献
2.
Summary Parent wheatears (Oenanthe oenanthe L.), foraging to meet their own needs and to provide food for a central place (CP, i.e. the nest), have to make decisions with respect to the configuration of foraging itineraries during round trips in the territory and to the directionality of their movements. These problems were studied in two pairs breeding in an agricultural area in central Swecen. All birds started a round trip by hunting from perches close to the CP and then moving to perches progressively further away in a roughly straight line until the first prey item was loaded. Loaded prey were either delivered singly (single prey loading: SPL) or with other prey (multiple prey loading: MPL). When the bird decided to return with several items to the CP, it abruptly changed the direction of its movements by making a left, right or backward turn and started to visit perches progressively nearer the CP, again following a roughly straight line. The decision to return continue loading was affected by the size of the prey as shown by the fact that prey carried singly was significantly larger than the first item in an MPL for all individuals. The distance to the CP also seemed to affect this decision as prey provisioned singly on average were collected significantly closer to the nest than the first item in an MPL by one pair. Both the size of prey loaded singly and load size of MPL increased with distance from the CP in one pair. The concentrated use of the territory in the other pair made any effect of distance difficult to detect. Great flexibility in foraging decisions was observed in cases when an individual, because of the size of the last prey captured, altered its decision to deliver an MPL and transported an SPL to the nest instead. On the basis of these results we propose a set of rules followed by predators such as wheatears when making decisions about delivering prey to a CP (Fig. 4). 相似文献
3.
Seasonally breeding predators, which are limited in the time available for provisioning young at a central location, and
by the fasting abilities of the young, are likely to maximize energy delivery to the young by maximizing the rate of energy
delivery averaged over the whole period of investment. Reduction in food availability or increased foraging costs will alter
the optimal behavior of individuals. This study examined the behavioral adaptations of a diving predator, the Antarctic fur
seal, to increased foraging costs during lactation. One group of mothers (n=5, treatment) was fitted with additional drag to increase the cost of transport in comparison with a control group (n=8). At the scales of the individual dives, the treatment group made more shorter, shallower (< 30 m) dives. Compensation for
slower swimming speeds was achieved by diving at a steeper angle. Overall, diving behavior conformed to several specific theoretical
predictions but there were also departures from theory, particularly concerning swimming speed during diving. Diving behavior
appears to be adjusted to maximize the proportion of time spent at the bottom of dives. At the scale of diving bouts, no difference
was observed between the treatment and control groups in terms of the frequency and duration of bouts and there was also no
difference between the two groups in terms of the proportion of time spent diving. At the scale of complete foraging cycles,
time taken to return to the pup was significantly longer in the treatment group but there was no difference in the rate of
delivery of energy (measured from pup growth rate) to the pups in each group. Since mothers in the treatment group did not
use significantly more body reserves, we conclude that behavioral adjustments at the scale of individual dives allowed mothers
in the treatment group to compensate for the additional foraging costs. Pup growth rate appears to be less sensitive to the
foraging conditions experienced by mothers than foraging trip duration.
Received: 14 June 1996 / Accepted after revision: 16 November 1996 相似文献
4.
Competition affects risk-sensitivity in foraging shrews 总被引:1,自引:0,他引:1
Summary Studies of risk-sensitive foraging have so far focused only on the effect of food demand on choice of feeding site. We suggest that competition is likely to be another factor influencing risksensitivity. A choice experiment with common shrews showed that, in the absence of competition, risk-aversion increased with increasing food intake relative to requirement. When apparent competitors were present, however, shrews were risk-indifferent regardless of their estimated requirement. The switch to risk-indifference in the presence of competitors appears to be an all-or-nothing rule of thumb which is not modified by experience with reward probability distributions. 相似文献
5.
Genetic determination of nectar foraging,pollen foraging,and nest-site scouting in honey bee colonies 总被引:2,自引:1,他引:1
Summary Allozyme analyses of honey bee workers revealed significant differences in the intracolonial subfamily composition of groups of nectar foragers, pollen foragers, and nest-site scouts. These differences demonstrate that colony genetic structure influences the division of labor among older foraging-age bees just as it does for younger workers. The maintenance of genetic variability for the behavior of individual workers and its possible effects on the organization of colonies are discussed. 相似文献
6.
Michael Simone-Finstrom Joel Gardner Marla Spivak 《Behavioral ecology and sociobiology》2010,64(10):1609-1617
Honeybees harvest and use plant resins in a mixture called propolis to seal cracks and smooth surfaces in the nest architecture.
Resins in the nest may be important in maintaining a healthy colony due to their antimicrobial properties. This study had
two main objectives: (1) Provide initial insight on the learning capabilities of resin foraging honeybees; (2) analyze the
sensitivity of resin foraging honeybees to tactile stimuli to elucidate its possible role as a mechanism behind resin foraging.
The first objective provides insight into the phenotype of these bees as compared to other forager types, while the second
creates a starting point for further work on behavioral mechanisms of resin foraging. Using tactile proboscis extension response
conditioning, we found that resin foragers learned to associate two different tactile stimuli, the presence of a gap between
two plates and a rough sandpaper surface, with a sucrose reward significantly better than pollen foragers. The results of
differential tactile conditioning exhibited no significant difference in the ability of resin foragers to discriminate between
smooth and rough surfaces as compared to pollen foragers. We also determined that the sucrose response thresholds (SRTs) of
returning resin foragers were lower compared to returning pollen foragers, but both resin foragers and pollen foragers learned
a floral odor equally well. This is the first study to examine SRTs and conditioning to tactile and olfactory stimuli with
resin foraging honeybees. The results provide new information and identify areas for future research on resin collectors,
an understudied foraging phenotype. 相似文献
7.
Chemical signals in bumble bee foraging 总被引:1,自引:0,他引:1
Sydney A. Cameron 《Behavioral ecology and sociobiology》1981,9(4):257-260
Summary Foraging bumblebees (Bombus vosnesenskii) deposit a substance on rewarding flowers which assists in discrimination between rewarding and nonrewarding flowers in a controlled laboratory environment. Discrimination occurs while the bee is on a flower; workers probe rewarding flowers as well as empty ones that have rewarded in the recent past, but they do not probe flowers that have had no reward. Recognition is not the result of honey contamination left on the flower by the bee during feeding. The deposit is only slightly soluble in water or ethyl alcohol but is very soluble in pentane. 相似文献
8.
Memory dynamics and foraging strategies of honeybees 总被引:6,自引:0,他引:6
Summary The foraging behavior of a single bee in a patch of four electronic flower dummies (feeders) was studied with the aim of analyzing the informational components in the choice process. In different experimental combinations of reward rates, color marks, odors and distances of the feeders, the behavior of the test bee was monitored by a computer in real time by several devices installed in each feeder. The test bee optimizes by partially matching its choice behavior to the reward rates of the feeders. The matching behavior differs strongly between stay flights (the bee chooses the feeder just visited) and shift flights (the bee chooses one of the three alternative feeders). The probability of stay and shift flights depends on the reward sequence and on the time interval between successive visits. Since functions describing the rising probability of stay flights with rising amounts of sucrose solution just experienced differ for the four feeders, it is concluded that bees develop feeder-specific memories. The choice profiles of shift flights between the three alternative feeders depend on the mean reward rate of the feeder last visited. Good matching is found after visits to the low-reward feeders and poor matching following departure from the high-reward feeders. These results indicate that bees use two different kinds of memories to guide their choice behavior: a transient short-term working memory that is not feeder-specific, and a feeder-specific long-term reference memory. Model calculations were carried out to test this hypothesis. The model was based on a learning rule (the difference rule) developed by Rescorla and Wagner (1972), which was extended to the two forms of memories to predict this operant behavior. The experiments show that a foraging honeybee learns the properties of a food source (its signals and rewards) so effectively that specific expectations guide the choice behavior.
Correspondence to: R. Menzel 相似文献
9.
Mathieu Lihoreau Jean-Louis Deneubourg Colette Rivault 《Behavioral ecology and sociobiology》2010,64(10):1577-1587
Group foraging by eusocial insects implies sophisticated recruitment processes that often result in collective decisions to
exploit the most profitable sources. These advanced levels of cooperation, however, remain limited to a small range of species,
and we still know little about the mechanisms underlying group foraging behaviours in the great mass of animals exhibiting
lower levels of social complexity. In this paper, we report, for the first time in a gregarious insect, the cockroach Blattella germanica (L.), a collective foraging decision whereby the selection of food sources is reached without requiring active recruitment.
Groups of cockroaches given a binary choice between identical food sources exhibited exploitation asymmetries whose amplitude
increases with group size. By coupling behavioural observations to computer simulations, we demonstrate that selection of
food sources relies uniquely on a retention effect of feeding individuals on newcomers without comparison between available
opportunities. This self-organised pattern presents similarities with the foraging dynamics of eusocial species, thus stressing
the generic dimension of collective decision-making mechanisms based on social amplification rules despite fundamental differences
in recruitment processes. We hypothesise that such parsimony could apply to a wide range of species and help understand the
emergence of collective behaviours in simple social systems. 相似文献
10.
Francis Strobbe Mark A. McPeek Marjan De Block Robby Stoks 《Behavioral ecology and sociobiology》2011,65(2):241-247
Despite the importance of foraging activity for the growth/predation risk trade-off, studies that demonstrated predator-induced
survival selection on foraging activity under semi-natural conditions are relatively rare. Here, we tested for fish-induced
selection for reduced foraging activity in two larval Enallagma damselflies using a field enclosure experiment. Fish imposed considerable mortality in both damselfly species and survival
selection on foraging activity could be detected in Enallagma geminatum. We did not detect selection in Enallagma hageni, probably because this species already was not eating very much in the absence of fish compared to E. geminatum. Both species responded strongly to the presence of predators by reducing their foraging activity. The documented survival
selection on foraging activity was detected despite the already low activity levels in fish lake prey species and despite
strong predator-induced plasticity in this trait. 相似文献
11.
1. | Five species of emballonurid bats (Rhynchonycteris naso, Saccopteryx leptura, Balantiopteryx plicata, Saccopteryx bilineata, and Peropteryx kappleri), were studied in Costa Rica and Trinidad. Stomach contents suggest that prey size generally increases for bat body size, but within these species there is considerable overlap. R. naso, S. leptura, and P. kappleri each appear to be specialized for foraging in a particular habitat type; B. plicata and S. bilineata are more opportunistic and feed over a variety of habitats during the year. While the other species feed in the proximity of surfaces, B. plicata is further separated from the other species by wing specializations favoring high altitude flight. |
2. | Foraging dispersion is more closely related to body size than it is to social structure at the roost: small bats group-forage while larger bats feed in solitary beats. In all of the species, food is spatially and temporally variable, and the location of foraging sites changes seasonally in accordance with these locally varying patterns of aerial insect abundance. In the case of S. bilineata, the locations of foraging sites were positively correlated with levels of phenological activity in the underlying plant communities. |
3. | Colony sizes ranged from small groups of 2–10 bats (S. leptura, P. kappleri), to intermediate colonies of 5–50 bats (R. naso, S. bilineata), to very large colonies with hundreds of bats (B. plicata). |
4. | R. naso, S. leptura, and S. bilineata colonies have colony-specific annual foraging ranges which are actively defended against conspecifics from other colonies. In most cases, all members of a given colony of one of these species will be found foraging in a common site at any time. In R. naso and S. bilineata, currently used foraging sites are partitioned socially. In the former species, adult breeding females occupy a central area and groupforage while younger non-breeding females and males occupy peripheral foraging areas in the colony territory. In S. bilineata, the colony foraging site is partitioned into individual harem territories defended by harem males and containing the individual beats of all current harem females. For this latter species, details of roost site subdivision are mapped directly onto foraging dispersions. In general, there is a close correlation between dayroost group membership and location of nocturnal foraging sites in all of the study species. |
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13.
Optimal foraging: Some simple stochastic models 总被引:5,自引:0,他引:5
Summary Some simple stochastic models of optimal foraging are considered. Firstly, mathematical renewal theory is used to make a general model of the combined processes of search, encounter, capture and handling. In the case where patches or prey items are encountered according to a Poisson process the limiting probability distribution of energy gain is found. This distribution is found to be normal and its mean and variance are specified. This result supports the use of Holling's disc equation to specify the rate of energy intake in foraging models. Secondly, a model based on minimization of the probability of death due to an energetic shortfall is presented. The model gives a graphical solution to the problem of optimal choices when mean and variance are related. Thirdly, a worked example using these results is presented. This example suggests that there may be natural relationships between mean and variance which make solutions to the problems of energy maximization and minimization of the probability of starvation similar. Finally, current trends in stochastic modeling of foraging behavior are critically discussed. 相似文献
14.
Summary Wintering black-capped chickadees (Paridae: Parus atricapillus) in northwestern Massachusetts showed a high degree of individual variation in foraging behavior. After accounting for the effects of different habitats and weather conditions, individual differences comprised 6–17% of the total observed variation in four measures of foraging location and rate of feeding. Differences between age and sex groups were not significant and explained comparatively little variation (0.0–1.4%). The chickadees did not fall into a few distinct behavioral categories but instead showed continuous variation on all measures of foraging behavior. It appeared that some variation among individuals was a consequence of behavioral convergence within social groups, since birds that were observed together were more similar in their foraging than expected by chance, after taking habitat differences into account. Our results therefore do not support the interpretation that individual variation in feeding behavior serves to reduce exploitation competition within social groups. 相似文献
15.
Shape and efficiency of wood ant foraging networks 总被引:2,自引:1,他引:1
Jerome Buhl Kerri Hicks Esther R. Miller Sophie Persey Ola Alinvi David J. T. Sumpter 《Behavioral ecology and sociobiology》2009,63(3):451-460
We measured the shape of the foraging trail networks of 11 colonies of the wood ant Formica aquilonia (Formica rufa group). We characterized these networks in terms of their degree of branching and the angles between branches, as well as
in terms of their efficiency. The measured networks were compared with idealized model networks built to optimize one of two
components of efficiency, total length (i.e., total amount of trail) and route factor (i.e., average distance between nest
and foraging site). The analysis shows that the networks built by the ants obtain a compromise between the two modes of efficiency.
These results are largely independent of the size of the network or colony size. The ants’ efficiency is comparable to that
of networks built by humans but achieved without the benefit of centralized control. 相似文献
16.
17.
A modelling framework for understanding social insect foraging 总被引:1,自引:0,他引:1
18.
Alasdair I. Houston 《Behavioral ecology and sociobiology》2011,65(3):525-535
The Darwinian approach to behavior generates models that are widely used by anthropologists and archeologists. In this paper,
I concentrate on a particular group of models based on cases in which a forager (or group of foragers) brings resources to
a location known as a central place. I examine two topics in detail: (1) the economics of transporting a load to the central
place, and (2) the extent to which items should be processed before they are brought back to the central place. In addition
to presenting new results and bringing out common themes in archeology and behavioral ecology, I discuss problems with some
of the models that have been used in archeology and offer suggestions for further work. 相似文献
19.