Predation by the three-spined stickleback (Gasterosteus aculeatus L.): the influence of hunger and experience.

摘要: [Predatory behaviour in a small fish, the three-spined stickleback (Gasterosteus aculeatus L.), has been analyzed quantitatively by continuous observation of individual fishes searching for food (generally one Tubifex worm) large maze during experiments 40 min. Properties environment and prey (e.g. their number size) were kept as constant possible, order to study effects on risk changes internal state predator, viz. its hunger experience with type question. By variation length foregoing deprivation time under specified conditions temperature, day, feeding-deprivation schedule, kind eaten before — sticklebacks brought into well defined states. A elements feeding found increase decrease feeding, respectively. These parallel fluctuations different independently measured argue common mechanism, which may be called stickleback. Hunger, then, anyone these fluctuating parallel. Hunger severely affected prey. Risk is destroyed per unit predator density. Higher hungers caused higher risks both swimming activity proportions complete responses discovered (viz. greater grasped eaten). Encountering efficiency (i.e. ratio encountered distance swum or cells visited) proved independent hunger. It increased all used (though extent) growing increasing ability explore it more systematically, was achieved turning less. The chance an primarily fish approached it. This at given dependent visual acuity only very low levels hunger, not normally reached min.-experiments Prey according larger. Nearly able get satiated towards end minutes, having ingested then about 5% body weight. As much less weight than capacity, larger got slower rate smaller ones. dependence size could explained differences decay. At density did eat more. inversely proportional became faster largely explain observed relationship between risk. Introduction new after some delay rapid "searching image formation" occurred if question judged sufficiently palatable. Palatability proportion During formation component risk, discovered, consistently affected. Responsiveness inedible objects, looked like prey, conspicuously raised same time. Sticklebacks are polyphagic. Once known, presence negatively alternative Larvae Drosophila, nearly palatable worms, latters mere (expressed units) themselves would do. Addition highly pieces Enchytraeus had drastic consequences : activity. Nevertheless, decreased dramatically selective inhibition this type. Some evidence points learning process, involving refusal worms high expectation Enchytraeus. characteristics stickleback's predatory have compared premises various mathematical models predator-prey interactions. concluded that existing should modified essential represent characteristic traits predators stickleback., Predatory stickleback.]