Department of Ecology and Evolution, University of Lausanne, CH 1015 Lausanne, Switzerland.
Nat Commun. 2013;4:1789. doi: 10.1038/ncomms2744.
Hunting live prey is risky and thought to require specialized adaptations. Therefore, observations of predatory cannibalism in otherwise non-carnivorous animals raise questions about its function, adaptive significance and evolutionary potential. Here we document predatory cannibalism on larger conspecifics in Drosophila melanogaster larvae and address its evolutionary significance. We found that under crowded laboratory conditions younger larvae regularly attack and consume 'wandering-stage' conspecifics, forming aggregations mediated by chemical cues from the attacked victim. Nutrition gained this way can be significant: an exclusively cannibalistic diet was sufficient for normal development from eggs to fertile adults. Cannibalistic diet also induced plasticity of larval mouth parts. Finally, during 118 generations of experimental evolution, replicated populations maintained under larval malnutrition evolved enhanced propensity towards cannibalism. These results suggest that, at least under laboratory conditions, predation on conspecifics in Drosophila is a functional, adaptive behaviour, which can rapidly evolve in response to nutritional conditions.
捕食活体猎物具有风险，被认为需要专门的适应。因此，在其他非肉食性动物中观察到捕食性同类相食行为，引发了对其功能、适应意义和进化潜力的疑问。在这里，我们记录了黑腹果蝇幼虫对较大同种个体的捕食性同类相食行为，并探讨了其进化意义。我们发现，在拥挤的实验室条件下，年幼的幼虫经常攻击和消耗“游荡阶段”的同种个体，形成由受攻击受害者释放的化学信号介导的聚集。通过这种方式获得的营养可能非常重要：仅以同类相食为食的饮食足以使卵正常发育为有生育能力的成虫。这种同类相食的饮食还诱导了幼虫口器的可塑性。最后，在 118 代的实验进化中，在幼虫营养不良条件下维持的复制种群进化出了对同类相食的更高倾向。这些结果表明，至少在实验室条件下，黑腹果蝇对同种个体的捕食是一种功能性的、适应性的行为，可以根据营养状况迅速进化。
