Diglyphus isaea Walker (Hymenoptera: Eulophidae) is an important ectoparasitic wasp of many leaf miners. Ability of D. isaea to find hosts placed in artificial mines and for its larvae to pupate when the larva is not in a mine was studied. Artificial mines consisted of slits cut in index card sandwiched between two cover slips. Almost 80% of the neonate larvae of D. isaea located host larvae in artificial mines compared to only 50% of those not in a mine. Mature larvae removed from mines did not construct normal pupal chambers. Nonetheless, they pupated and emerged successfully. Larvae of Liriomyza sativae Blanchard (Diptera: Agromyzidae) in mines are more likely to be attacked than those not in mines. Moreover, when close to a host larva this parasitoid can use vibrational cues to locate the larva in a mine. In addition, this parasitoid also did not always use volatile and gustatory cues for short range location of hosts. However, adult females of D. isaea more quickly located L. sativae larvae in the presence of the odour of juice extracted from an uninfested host plant. We conclude by proposing that the host mine is the medium by which the vibrations generated by the host larva are transmitted, which are probably the most important cue used by female D. isaea searching for hosts. That is this parasitoid first perceives mines not host larvae. These results will be helpful for developing techniques for the mass rearing of D. isaea in the future., De Yu Zou, Hong Yin Chen, Li Sheng Zhang., and Obsahuje seznam literatury
Electroantennogram responses of the polyphagous leafminer Liriomyza sativae and its generalist parasitoid Diglyphus isaea to host and non-host plant odours of L. sativae were investigated. The odours of healthy leaves can elicit distinct EAG responses in L. sativae. The EAG responses to the odours of the host plants, bean and tomato, were stronger than to non-host plants, Chinese rose and morning glory. Neither healthy host nor non-host plants of the leafminer elicited distinctive EAG responses in the parasitoid, D. isaea. Odours of physically damaged leaves, no matter whether of host or non-host plants, increased strongly the EAG responses of the leafminer and its parasitoid. We compared the EAG responses of D. isaea to bean leaves of different status. The odour of mined leaves elicited distinct EAG responses, which were weaker than those of physically damaged ones. No differences were detected in the EAG response to leaves with empty mines, healthy leaves or an air control. The role of plant odours in host location of the leafminer and its parasitoid is discussed.