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Intrinsic prey suitability in specialist and generalist H armonia ladybirds: a test of the trade‐off hypothesis for food specialization
Author(s) -
Noriyuki Suzuki,
Osawa Naoya
Publication year - 2012
Publication title -
entomologia experimentalis et applicata
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.765
H-Index - 83
eISSN - 1570-7458
pISSN - 0013-8703
DOI - 10.1111/j.1570-7458.2012.01288.x
Subject(s) - predation , biology , aphid , predator , generalist and specialist species , ecology , botany , habitat
The trade‐off hypothesis posits that increased performance on a given resource comes at the cost of decreased performance on other resources, and that this trade‐off is a driving force of food specialization in both predators and herbivores. In this study, we examined larval survival and performance in two sibling ladybird species, H armonia yedoensis T akizawa and H armonia axyridis P allas ( C oleoptera: C occinellidae), fed on one of four prey species. H armonia yedoensis is a specialist predator that preys mostly on pine aphids in the field, whereas H . axyridis is a generalist predator with a broad prey range. We experimentally showed in the laboratory that larval survival and performance were not higher when H . yedoensis was fed on pine aphids, compared with the other prey species. Rather, prey suitability was similar in both ladybird species, and H . yedoensis larvae developed as well or even better on prey species that they never utilize in nature. These results suggest that the host range in H . yedoensis may not be limited by the intrinsic suitability of the aphid species per se. Moreover, as shown by our previous study, the pine aphid is a highly elusive prey that is difficult for small ladybird hatchlings to capture, which means that the cost of utilizing this prey is high. Therefore, we conclude that some factor other than prey suitability is responsible for the observed food specialization in H . yedoensis .