Phenotypic plasticity allows some animals to change their behavioural, morphological, performance, and life history traits in response to changes in environmental conditions such as the presence of predators. These changes can enhance survival, but come at a cost. Some of these phenotypic changes are predator and diet specific. I examined the effects of predator diet on the performance, life-history, and morphology of developing Northern Leopard Frog (Lithobates pipiens) tadpoles. Tadpoles were either exposed to cues from fish free water, cues from Brown Bullhead (Ameiurus nebulosus) fed a diet of trout pellets, or cues from A. nebulosus fed a L. pipiens tadpoles diet. Tadpoles exposed to predatory fish cues had smaller bodies, deeper tail fins, slower growth and development rates, and better rotational performance than tadpoles that were not exposed to predatory fish cues. Moreover, tadpoles appeared to differentiate between predatory fish diet and produced diet-specific responses in tail morphology and activity, although the latter effect was only marginally significant. Hatching, metamorphosis rates, and linear performance were not affected by the treatments. These results suggest that A. nebulosus can induce phenotypic changes in L. pipiens tadpoles, with some of these changes being diet specific.

Phenotypic plasticity allows some animals to change their behavioural, morphological, performance, and life history traits in response to changes in environmental conditions such as the presence of predators. These changes can enhance survival, but come at a cost. Some of these phenotypic changes are predator and diet specific. I examined the effects of predator diet on the performance, life-history, and morphology of developing Northern Leopard Frog (Lithobates pipiens) tadpoles. Tadpoles were either exposed to cues from fish free water, cues from Brown Bullhead (Ameiurus nebulosus) fed a diet of trout pellets, or cues from A. nebulosus fed a L. pipiens tadpoles diet. Tadpoles exposed to predatory fish cues had smaller bodies, deeper tail fins, slower growth and development rates, and better rotational performance than tadpoles that were not exposed to predatory fish cues. Moreover, tadpoles appeared to differentiate between predatory fish diet and produced diet-specific responses in tail morphology and activity, although the latter effect was only marginally significant. Hatching, metamorphosis rates, and linear performance were not affected by the treatments. These results suggest that A. nebulosus can induce phenotypic changes in L. pipiens tadpoles, with some of these changes being diet specific.

Phenotypic plasticity allows some animals to change their behavioural, morphological, performance, and life history traits in response to changes in environmental conditions such as the presence of predators. These changes can enhance survival, but come at a cost. Some of these phenotypic changes are predator and diet specific. I examined the effects of predator diet on the performance, life-history, and morphology of developing Northern Leopard Frog (Lithobates pipiens) tadpoles. Tadpoles were either exposed to cues from fish free water, cues from Brown Bullhead (Ameiurus nebulosus) fed a diet of trout pellets, or cues from A. nebulosus fed a L. pipiens tadpoles diet. Tadpoles exposed to predatory fish cues had smaller bodies, deeper tail fins, slower growth and development rates, and better rotational performance than tadpoles that were not exposed to predatory fish cues. Moreover, tadpoles appeared to differentiate between predatory fish diet and produced diet-specific responses in tail morphology and activity, although the latter effect was only marginally significant. Hatching, metamorphosis rates, and linear performance were not affected by the treatments. These results suggest that A. nebulosus can induce phenotypic changes in L. pipiens tadpoles, with some of these changes being diet specific.

Velvet ants are a group of parasitic wasps that are well known for a suite of defensive adaptations including bright coloration and a formidable sting. While these adaptations are presumed to function in antipredator defense, observations between potential predators and this group are lacking. We conducted a series of experiments to determine the risk of velvet ants to a host of potential predators including amphibians, reptiles, birds, and small mammals. Velvet ants from across the United States were tested with predator's representative of the velvet ants native range. All interactions between lizards, free-ranging birds, and a mole resulted in the velvet ants survival, and ultimate avoidance by the predator. Two shrews did injure a velvet ant, but this occurred only after multiple failed attacks. The only predator to successfully consume a velvet ant was a single American toad (Anaxyrus americanus). These results indicate that the suite of defenses possessed by velvet ants, including aposematic coloration, stridulations, a chemical alarm signal, a hard exoskeleton, and powerful sting are effective defenses against potential predators. Female velvet ants appear to be nearly impervious to predation by many species whose diet is heavily derived of invertebrate prey.

Small mammals have often been utilised as indicators of past environments. Before palaeoecological assessments can be made, investigations into the origin and mode of deposition are carried out. Many small mammal accumulations are predator-derived, and in order to take account of predatory bias in these deposits, it is necessary to identify the predator. Several methodologies have catalogued patterns of bone modification from dietary waste of modern predators, for comparison with taphonomic features found on archaeological assemblages of small mammals. The majority of this research has concentrated only on the adult age range from these predators. However, data from owls have shown that younger individuals are often responsible for more extensive bone modification. To investigate this difference associated with the age of predators and bone modification, two modern Tyto alba roost samples and three modern Tyto alba nest samples were analysed to provide evidence of bone modification from adult and baby owls. Significant differences were found between these two groups, with higher rates of bone digestion associated with the nest samples, To test whether these taphonomic patterns could be identified in archaeological deposits, small mammal assemblages from four archaeological sites (The Old Vicarage at Tadcaster, Filey Roman Signal Station, Fox Hole Cave and Carsington Pasture Cave) were analysed. At one of these sites, bone digestion matched that of the Tyto alba nest sites. Bone digestion at the other three sites was higher than that recorded in this study for either Tyto alba adults or their young. This study has shown that it is possible to recognise owl nests in the archaeological record, and concludes that analysis of these assemblages can elucidate not only the origin of specific predator deposits, but can also be used to investigate the nature of human occupation, usage and abandonment of these sites.

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Predators may play an important role in affecting the fitness of preys. Many organisms have thus evolved strategies to prevent predation. Recognition of predator presence may be achieved by vision, olfaction, tactile sense or detection of water motion. Some organisms sense predators directly; others associate the injuries of victims to the presence of predators. There are many brittlestars (Ophiocoma scolopendrina) at the intertidal zone of Kenting, southern Taiwan and they suffer high frequencies of injuries in the wilds. Since their predators are likely to be diverse, we want to know if O. scolopendrina has the ability to sense the presence of predators, indirectly. We have two hypotheses: firstly, the avoidance behavior is elicited specifically in response to predators, secondly, the avoidance behavior is a general response to unfamiliar elements in the water mass. Our experiments revealed that the tested individuals would avoid conspecific viscera liquids and also that of other echinoderms¡¦. They are more likely to respond to conspecific viscera liquids. And O. scolopendrina hardly respond to solutions prepared from other organisms, e.g., fish, pork, macroalgae, freshwater. This behavior may help brittlestars reduce the probability of encountering predators. The results are compatible with the first hypothesis only. The effect of tide was also explored by testing in different times, but the frequencies of avoidance responses were independent of the tide. Furthermore, the subtidal species Ophiocoma dentata was also tested for the behavior. They escaped from conspecific viscera liquid as well as that of O. scolopendrina. This species, however, could not distinguish the liquids from the two brittlestar species. In conclusion, the avoidance behaviors of the ophiocomid brittlestars are adaptations for avoiding predators, not for avoiding unfamiliar environments.

No description available.

No description available.