Migratory birds likely evolved from residents as a consequence of intraspecific competition for limiting resources followed by dispersal of such individuals to novel sites that had previously not been occupied by migr...
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Migratory birds likely evolved from residents as a consequence of intraspecific competition for limiting resources followed by dispersal of such individuals to novel sites that had previously not been occupied by migrant conspecifics(Alerstam and Hogstedt 1982).
Wood frog Lithobates sylvaticus tadpoles develop in temporary wetlands where high population densities can force tadpoles into aggregations that intensify competition and can lead to cannibalism. However, chemical ala...
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Wood frog Lithobates sylvaticus tadpoles develop in temporary wetlands where high population densities can force tadpoles into aggregations that intensify competition and can lead to cannibalism. However, chemical alarm cues released from injured conspecifics could also dissuade cannibalism. The purpose of this study was to test mechanisms that may influence can- nibalistic behaviour. We tested whether the tendency of tadpoles to consume conspecifics would increase with the presence of competition and/or cues of profitable diets. Tadpoles placed in 1L experimental containers were tested for feeding initiation times of multiple diets, including conspecific tissues and conspecific tissues combined with chemical cues from the alternative diets (brine shrimp and comrneal). Tadpoles were tested in the presence and absence of a competitor, and at multiple times over the course of the study. Tadpoles exhibited an altered response to diets over time; however the presence of a competitor reduced re- sponse times to all diets including conspecific tissues. Similarly, the presence of specific diets also reduced the response time of tadpoles to conspecific tissues. These results suggest competition among feeding tadpoles could result in aggressive behaviour leading to indiscriminate predation and cannibalism [Current Zoology 60 (5): 571-580, 2014 ].
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