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51.
Adjustment of parental effort to manipulated foraging ability in a pelagic seabird,the thin-billed prion Pachyptila belcheri 总被引:6,自引:0,他引:6
Henri Weimerskirch Olivier Chastel Luc Ackermann 《Behavioral ecology and sociobiology》1995,36(1):11-16
An experiment was designed to examine in a long-lived seabird, the thin-billed prion (Pachyptila belcheri), how adults adjust their food provisioning strategy when their foraging abilities are reduced and when the chick's needs are increased. To reduce the foraging abilities of adults we impaired their flying ability by removing some flight feathers (handicapped), and to increase the food needs of the chick one parent was retained (single). Birds made either short foraging trips lasting 1–3 days, or long trips lasting 5–9 days. Control birds alternated long and short trips whereas single birds or handicapped birds made several successive short trips and thereafter a long trip. In each treatment, food loads tended to be heavier after long trips than after short trips, and single birds tended to bring heavier loads than control or handicapped birds. Birds in the three treatments lost similar amounts of mass after short trips and gained similar amounts of mass after long trips. However, the mass of handicapped birds declined through the experiment, while that of control and single birds remained stable. Although the proportion of chicks that died during the experiment was similar among the three treatments, the chicks fledged by a single bird were lighter than those in control nests. The results of the experiment suggest that thin-billed prions adjust their breeding effort differently to decreased flying ability or increased food demand by the chick. Single birds increase foraging effort without allowing their condition to deteriorate. Conversely, handicapped birds are unable to maintain their body condition while sustaining the chick at the same rate as control birds. It is suggested that in this long-lived seabird, adults probably adjust their breeding effort so that they do not incur the risk of an increased mortality, this risk being monitored by the body condition. 相似文献
52.
Divergent evolution of feeding substrate preferences in a phylogenetically young species flock of pupfish (Cyprinodon spp.) 总被引:1,自引:0,他引:1
A fundamental question in sympatric speciation is how trophic divergence is achieved. We used an extremely young (<8,000 years)
species flock of pupfish (Cyprinodon spp.) from Laguna Chichancanab in south-eastern Mexico to examine divergent evolution of preferences for different feeding
substrates. In a test aquarium, we presented four feeding substrates (sand, gravel, a plastic plant, and blank bottom), but
no actual food was offered. The four feeding substrates were chosen to mirror the most common substrate types in Laguna Chichancanab.
Previous studies demonstrated that benthic food items prevail in the diet of most Cyprinodon species. C. beltrani preferred sand, whereas C. labiosus preferred gravel. F1 hybrids of both species showed intermediate preferences. C. maya searched for food equally at all substrates. As the test fish were reared under identical laboratory conditions (i.e., in
the absence of feeding substrates), the species-specific preferences appear to be genetically fixed, suggesting rapid divergent
evolution of feeding behaviors. 相似文献
53.
Evidence of a maternal foraging cycle resembling that of otariid seals in a small phocid,the harbor seal 总被引:1,自引:0,他引:1
Summary Lactation strategies in the two largest families of seals have been characterized as a phylogenetic dichotomy, with sea lions and fur seals (Otariidae) exhibiting foraging cycles and true seals (Phocidae) a strategy of fasting. We show that a lactating phocid, the harbor seal, Phoca vitulina, has a foraging cycle similar to that of otariids. Time-depth recorders attached to lactating harbor seal mothers revealed that 9 of 11 females began bouts of diving, averaging 12–40 m, by mid-lactation (12 days). During the remainder of lactation, females made an average of seven diving trips, lasting about 7 h. They returned to the rookery during the interval between successive bouts to nurse their pups. Diving was more frequent during daylight than at night and diving bouts increased in duration as lactation progressed. The diving behavior of females that had weaned their pups and previously collected data from stomach lavage, suggest that the bouts of diving represent successful foraging. We propose that the lactation strategy of the harbor seal is intermediate to that of the otariids and other phocids studied. The harbor seal has a foraging cycle like the otariids, but typically resembles other phocids in length of lactation, rate of mass gain in pups, and in milk fat content. As harbor seals are among the smallest phocids, and only slightly larger than most otariids, it seems likely that maternal size constrains the amount of stored energy harbor seal females can bring to the rookery, forcing them to start feeding during the lactation period.Correspondence to: D.J. Boness 相似文献
54.
Fungus gardening ants make clear choices among fungal substrates (food for their fungus). It has been proposed, but never
demonstrated, that these ants are collecting the best for their symbiotic fungus and the production of ant biomass (fitness).
The goal of this study was to determine whether preferred substrates lead to higher fitness in the attine, Trachymyrmex septentrionalis. Preferences exhibited by foragers were established. Colonies were fed a single substrate or a mixture of substrates during
the entire course of the experiment, which ended when sexual offspring appeared in the nest. The response variables were numbers
and weights of ant offspring and the chitin content of fungus gardens. Preference was not strongly related to fitness. The
preferred oak catkins produced the highest amounts of ant and fungal biomass, but the ants collected much more material than
needed, which indicates that forager activity is decoupled from fitness. The preferred caterpillar feces were rejected shortly
after the feedings began. The unpreferred oak leaves were just as effective at producing ant and fungal biomass as catkins.
Leaves are possibly unpreferred because they are expensive to cut. The unpreferred huckleberry flowers were inferior but did
not cause rejection behavior. The mixed diet was just as productive as catkins or leaves. This study indicates that foragers
possess a default mechanism to prefer catkins and frass, which can be quickly changed if substrates are bad. In contrast,
there does not appear to be a similar mechanism causing substrates to become preferred quickly. 相似文献
55.
Knowing how far away animals can detect food has important consequences for understanding their foraging and social behaviors.
As part of a broader set of field experiments on primate foraging behavior, we set out artificial feeding platforms (90 × 90 cm
or 50 × 50 cm) throughout the home range of one group of 22 brown capuchin monkeys, at sites where they had not seen such
platforms previously. Whenever the group approached such a new platform to within 100 m, we recorded the group's direction
and speed of approach, and the identity and distance from the platform of the group member that detected the platform or came
closest to it without detecting it. We used logistic regression on these data to examine the effects of group movement speed,
platform size and height, and focal individual age and sex on the probability of detecting the platform as a function of distance.
Likelihood of detecting a platform decreased significantly at greater distances – the probability of detecting a platform
reached 0.5 at 41 m from the group's center and 25.5 m from the nearest group member. These results show that detectability
of platforms by the entire group (9 adults, 13 juveniles) was less than twice that for single group members. Detectability
at a given distance decreased severely as the group moved faster; at their fastest speed, individuals had to approach a platform
to within less than 10 m to find it. The large platforms were significantly more likely to be detected than the small ones,
suggesting that increased use of larger food patches by wild primates may not necessarily reflect foraging preferences.
Received: 20 May 1996 / Accepted after revision: 5 April 1997 相似文献
56.
Leaf surface compound fromBrassica oleracea (Cruciferae) induces oviposition byPieris brassicae (Lepidoptera: Pieridae) 总被引:4,自引:0,他引:4
Joop J. A. van Loon Anton Blaakmeer Frans C. Griepink Teris A. van Beek Louis M. Schoonhoven Aede de Groot 《Chemoecology》1992,3(1):39-44
Summary Chemicals present on the surface of cabbage (Brassica oleracea L.) leaves were extracted by dipping these leaves for 3 s in dichloromethane followed by a 3 s dip in methanol. When offered in dual choice bioassays using green paper cards as a substrate, the methanol extract stimulated oviposition activity byPieris brassicae L. (Lepidoptera: Pieridae) females. The oviposition stimulant was isolated using medium pressure liquid chromatography, reversed-phase HPLC, ion-pair HPLC and ion exchange chromatography. Using1H-NMR spectroscopy, the stimulant could be identified as glucobrassicin (3-indolyl-methyl-glucosinolate). When pure glucobrassicin was offered at a dose identical to that in the crude methanol extract, butterflies did not discriminate between these two substrates in a dual choice test. It is argued that a high sensitivity for indole glucosinolates as host recognition factors may confer an adaptive value for these specialist crucifer feeders. The nutritional significance of their precursor tryptophan and the non-volatile nature of the aglycones formed upon enzymic hydrolysis in damaged tissues are proposed as properties of indole glucosinolates that contribute to this possible adaptive advantage. 相似文献
57.
Behavioral responses to a novel predator and competitor of invasive mosquitofish and their non-invasive relatives (Gambusia sp.) 总被引:1,自引:0,他引:1
J. Schöpf Rehage Beverly K. Barnett Andrew Sih 《Behavioral ecology and sociobiology》2005,57(3):256-266
Attributes of the recipient community may affect the invasion success of arriving non-indigenous organisms. In particular, biotic interactions may enhance the resistance of communities to invasion. Invading organisms typically encounter a novel suite of competitors and predators, and thus their invasiveness may be affected by how they cope with these interactions. Behavioral plasticity may help invaders to respond appropriately to novelty. We examined the behavioral responses of highly invasive mosquitofish to representative novel competitors and predators they might encounter as they spread through North America. We compared the behavior of invasive Gambusia holbrooki and G. affinis to that of two close relatives of lower invasive potential (G. geiseri and G. hispaniolae) in order to elucidate whether responses to novelty related to invasiveness. In short-term assays, female Gambusia were paired with a novel competitor, Pimephales promelas, and a novel predator, Micropterus dolomieu. Behavioral responses were measured in terms of foraging success and efficiency, activity, refuge use, predator inspections, and interspecific aggression. Contrary to a priori predictions, invasive and non-invasive responses to novel interactions did not differ consistently. In response to novel competition, both invasive species increased foraging efficiency, but so did G. geiseri. In response to novel predation, only G. holbrooki decreased consumption and activity and increased refuge use. No antipredator response was observed in G. affinis. We found consistent differences, however, between invasives and non-invasives in foraging behavior. Both in the presence and absence of the competitor and the predator, invasives foraged more efficiently and consumed more prey than non-invasives.Communicated by P. Bednekoff 相似文献
58.
William A. H. Ellis Alistair Melzer Fred B. Bercovitch 《Behavioral ecology and sociobiology》2009,63(8):1181-1188
Animal movement patterns and use of space depend upon food and nonfood resources, as well as conspecific and heterospecific
interactions, but models of habitat use often neglect to examine multiple factors and rarely include marsupials. We studied
habitat use in an Australian population of koalas (Phascolarctos cinereus) over a 6-year period in order to determine how koalas navigate their environment and partition limited patchy food and nonfood
resources. Tree selection among koalas appears to be mediated by folar chemistry, but nonfood tree selection exerts a major
impact on home range use due to thermoregulatory constraints. Koalas moved on a daily basis, during both day and night, but
daytime resting site was not necessarily in the same location as nighttime feeding site. Koalas had substantial home range
overlap in the near absence of resource sharing with less than 1% of trees located in areas of overlap used by multiple koalas.
We suggest that koala spatiotemporal distribution and habitat use are probably based upon a community structure of individuals,
with a checkerboard model best describing overlap in home range area but not in resource use. Nonfood refugia and social networks
should be incorporated into models of animal range and habitat use. 相似文献
59.
Correlated evolution of prey chemical discrimination with foraging, lingual morphology and vomeronasal chemoreceptor abundance in lizards 总被引:3,自引:0,他引:3
William E. Cooper 《Behavioral ecology and sociobiology》1997,41(4):257-265
Comparative data from ten families of lizards suggest that correlated evolution has occurred between the ability to identify
prey chemicals and several aspects of lingual function and morphology, abundance of vomeronasal chemoreceptor cells, and foraging
behavior. Ability to discriminate prey chemicals from control substances was measured experimentally and correlated with other
variables by Felsenstein's method. This ability increased with evolutionary increases in degree of lingual protrusion during
tongue-flicking, which may reflect the tongue's ability to reach substrates to be sampled. It increased with deepened lingual
forking and greater lingual elongation, which may be important for scent-trailing and sampling ability, respectively. Discriminatory
ability also increased with abundance of vomerolfactory chemoreceptors, which presumably reflects some aspects of analytical
capacities of the vomeronasal system. Prey chemical discrimination increased with degree of active foraging. Natural selection
for improved vomerolfactory sampling and analysis of prey chemicals by active, but not ambush, foragers appears to account
for the observed relationships. In active foragers that use vomerolfaction to locate prey, natural selection favors increased
abilities to lingually sample chemicals from environmental substrates, analyze the samples for prey chemicals, and respond
appropriately if prey chemicals or possible prey chemicals are detected. Such selection can account for the observed relationships
among the sampling device and its movements, the sense, the discriminations, and variations in foraging ecology.
Received: 13 February 1997 / Accepted after revision: 12 June 1997 相似文献
60.
Faced with an intermittent but potent threat, animals exhibit behavior that allows them to balance foraging needs and avoid predators and over time, these behaviors can become hard-wired adaptations with both species trying to maximize their own fitness. In systems where both predator and prey share similar sensory modalities and cognitive abilities, such as with marine mammals, the dynamic nature of predator-prey interactions is poorly understood. The costs and benefits of these anti-predator adaptations need to be evaluated and quantified based on the dynamic engagement of predator and prey. Many theoretic models have addressed the complexity of predator-prey relationships, but few have translated into testable mechanistic models. In this study, we developed a spatially-explicit, geo-referenced, individual-based model of a prototypical adult dusky dolphin off Kaikoura, New Zealand facing a more powerful, yet infrequent predator, the killer whale. We were interested in two primary objectives, (1) to capture the varying behavioral game between a clever prey and clever predator based on our current understanding of the Kaikoura system, (2) to compare evolutionary costs vs. benefits (foraging time and number of predator encounters) for an adult non-maternal dusky dolphin at various levels of killer whale-avoidance behaviors and no avoidance rules. We conducted Monte Carlo simulations to address model performance and parametric uncertainty. Mantel tests revealed an 88% correlation (426 × 426 distance matrix, km2) between observed field sightings of dusky dolphins with model generated sightings for non-maternal adult dusky dolphin groups. Simulation results indicated that dusky dolphins incur a 2.7% loss in feeding time by evolving the anti-predator behavior of moving to and from the feeding grounds. Further, each evolutionary strategy we explored resulted in dolphins incurring an additional loss of foraging time. At low killer whale densities (appearing less than once every 3 days), each evolutionary strategy simulated converged towards the evolutionary cost of foraging, that is, the loss in foraging time approached the 2.7% loss experienced by evolving near shore-offshore movement behavior. However, the highest level of killer whale presence resulted in 38% decreases in foraging time. The biological significance of these losses potentially incurred by a dusky dolphin is dependent on various factors from dolphin group foraging behavior and individual energy needs to dolphin prey availability and behavior. 相似文献