Overlapping oviposition and chemical defense of eggs in two co-occurring species of ladybird predators of aphids

Citation
Bk. Agarwala et H. Yasuda, Overlapping oviposition and chemical defense of eggs in two co-occurring species of ladybird predators of aphids, J ETHOL, 19(1), 2001, pp. 47-53
Citations number
43
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences
Journal title
JOURNAL OF ETHOLOGY
ISSN journal
0289-0771 → ACNP
Volume
19
Issue
1
Year of publication
2001
Pages
47 - 53
Database
ISI
SICI code
0289-0771(2001)19:1<47:OOACDO>2.0.ZU;2-9
Abstract
Oviposition behavior in two co-occurring species of predatory ladybirds of aphids were investigated. The two species of beetles often shared the same aphid colonies in bean plants in space and time and showed a similar ovipos ition pattern in response to aphid abundance. Overlapping oviposition prese nts potential risks of interspecific predation of eggs in unstable aphid co lonies. Eggs in clusters by two ladybird species, Menochilus sexmaculatus a nd Coccinella transversalis, were defended from reciprocal predation and th e defense was found to be chemical. Eggs occurring singly were found to be highly vulnerable to predation. Strength of chemical defense significantly increased from single eggs to eggs in mixed clusters and eggs in pure clust ers. Results are not only consistent with the hypothesis that eggs in clust ers are better protected from natural enemies but also extend the ambit of the hypothesis that coexisting ladybird predators have evolved to avoid the risks of heterospecific predation of eggs in a patch.