Outbreaking herbivore escapes parasitoid by attaining only a small body size

摘要: The reason why parasitoids are often unable to control insect herbivores during outbreak years has remained unclear modern ecologists. Here I show that the blue willow beetle (Phratora vulgatissima) can escape (Perilitus brevicollis) by reaching only a small body size increased competition which coincides with outbreaks. Different phases of outbreaks were simulated allowing leaf-beetle larvae develop at different densities on willow. denser herbivore populations, smaller sizes they attained. In field too, decreased when level defoliation increased. clearly limited size, exhibiting reduced survival in parallel decreasing none them surviving beetles from reared highest density. results demonstrate how bottom-up becomes more important as intensify, while top-down gradually less and ...