Seventh International Congress of Hymenopterists

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7 th International Congress of Hymenopterists 20-26 June 2010, Kszeg Hungary _____________________________________________________________________________________________________ previously inferred for their gallwasp hosts. However, coalescent-based estimates of the ages of population divides are much more recent (coinciding with the Eemian interglacial) than nodal ages of single gene trees for C. fungosa and other species. Our results suggest that similar methods could be applied to multiple species to test alternative models of parasitoid assemblage evolution. ____________________________________ The almond seed wasp, Eurytoma amygdali Enderlein (Hymenoptera: Eurytomidae) of Iran, morphological and molecular aspects Hosseinali Lotfalizadeh 1 *, Gerard Delvare 2 & Jean-Yves Rasplus 2 1 Agricultural Research Centre of Azarbaijan-e-Sharghi, Department of Plant Protection, Tabriz, Iran; lotfalizadeh2001@yahoo.com 2 UMR INRA CIRAD IRD AGROM. Centre de Biologie et de Gestion des Populations (CBGP), Campus International de Baillarguet, 34398 Montpellier Cedex 5, France The systematic studies of the almond seed wasp, Eurytoma amygdali Enderlein (Hymenoptera: Eurytomidae) were performed using morphological and molecular methods. Two different morphological types were identified, which appeared to be fitted with E. amygdali and E. schreineri characteristics. Two genetic markers COI and ITS2 were used. However, the molecular studies reject specific value of the second form and show two types belonged to E. amygdali. ____________________________________ Host manipulation by spider parasitoids of the Polysphincta group (Pimplinae, Ichneumonidae) Rikio Matsumoto Osaka Museum of Natural History, Nagai Park 1-23, Higashisumiyoshi-ku, Osaka, 546-0034, Japan; rikio@mus-nh.city.osaka.jp The Polysphincta group is a monophyletic lineage of Ephialtini of Pimplinae and comprises koinobiont ectoparasitoids of active spiders. The female wasp stings and paralyzes the host spider and lays an egg on it. The spider recovers shortly after and continues normal life. The parasitoid larva remains on the host body, consuming body fluids of the host. In some species, it is known that the host spider weaves a modified “cocoon web” of quite different structure to the normal web when the parasitoid larva reaches its penultimate instar. As the web modifications do not occur until the parasitoid reaches the penultimate instar, and the parasitoid larvae are on active hosts at this stage, the modified webs are considered to be formed by the spider under the manipulation of the parasitoid larva. Three types of host manipulation have been detected. 1) Weaving a modified web with durability: the larva of Hymenoepimecis argyraphaga induces its orb-weaving host, Leucauge argyla, to build a highly modified web with only radii and lines connecting them at the hub and lacking circular hub lines and sticky spirals, shortly before it kills the host. Similar modification in web structure of hosts has been observed for Reclinervellus spp. on Cyclosa spp., where the disappearance of most of the sticky spiral is recognized. The same kind of modification was observed in Cyclosa fililineata attacked by Polysphincta janzeni. Another modification providing durability for the web is also known in a parasitoid of the linyphiid spider, Neolinyphia fusca, forming a hammock-like sheet web between twigs. The cocoon of 42
7 th International Congress of Hymenopterists 20-26 June 2010, Kszeg Hungary _____________________________________________________________________________________________________ Longitibia sp. is found in a modified web whose sheet is lost, and surrounded by densely and irregularly spun thick threads. 2) Weaving a modified web resistant against predators and scavengers: in the case of Brachyzapus nikkoensis, a parasitoid of Agelena limbata forming a funnel web, when the parasitoid larva is a penultimate instar, veils of very fine and dense threads covering the spider and parasitoid larva were observed in the tunnel of the funnel web. Removal of the veil indicated that penultimate instar larvae and pupae were more likely to fail to emerge in manipulated webs compared to the controls. The modified web seems resistant against predators and scavengers such as ants. 3) Arresting the growth of the host and detaining it in a more concealed site: the dome-like sheet webs of an immature Turinyphia yunohamensis, (Linyphiidae) are small and formed under leaves of the undergrowth. When the spiders mature, they move out to more exposed spaces to form larger webs. If the spider bears a larva of Zatypota sp., the growth and molt of the spider is arrested and the spider remains immature even when unattacked spiders become adults. Although reinforcement of webs was not detected in this species, this action of the parasitoid on the spider seems potentially adaptive for the parasitoid, which spins a cocoon on the web, because such small hidden webs are possibly resistant to damage. ____________________________________ Impact of secondary-parasitoids on population density of Psyllaephagus pistaciae in pistachio plantations of Iran M. Reza Mehrnejad Pistachio Research Institute, P.O. Box 77175.435, Rafsanjan, Iran; reza_mehrnejad@hotmail.com The specific, solitary endoparasitoid, Psyllaephagus pistaciae Ferrière (Hymenoptera, Encyrtidae), is the most widely distributed biological control agent of the common pistachio psyllid, Agonoscena pistaciae Burckhardt & Lauterer (Hemiptera: Psylloidea), in Iran. The appearance of the first adult parasitoid in the field tended to coincide with the first psyllid nymphs emerging on the pistachio leaves. Thereafter, the parasitoid normally has no difficulty in finding its host, as all psyllid nymphal instars are available throughout the pistachio growing season. The parasitism rate of A. pistaciae was found low throughout spring, summer and early autumn, ranging from 1 to 5%, rising to about 11% in November, in orchards where chemical sprays were applied for pest control as usual each year. However, in orchards where no chemical was used for several years, the parasitism rate is also low from May through to September but increased to 65% in November. Of the 6159 wasps emerging from psyllids mummies, 26.6% were P. pistaciae, and the remaining 73.6% represented six species of hymenopterous hyperparasitoids, Chartocerus kurdjumovi (Nikol’skaja), Marietta picta (André), Pachyneuron aphidis (Bouché), Pachyneuron muscarum (Linnaeus), Psyllaphycus diaphorinae (Hayat) and Syrphophagus aphidivorus (Mayr). Syrphophagus aphidivorus was found as the dominant secondary parasitoid for the common pistachio psyllid. The presence of shared hyperparasitoids attacking both A. pistaciae and weed-infesting aphids in pistachio orchards was verified. The braconid wasp, Lysiphlebus fabarum Marshall, the parasitoid of Aphis gossypii Glover and Aphis craccivora Koch present on weeds was found to be an alternative host for three major hyperparasitoids of A. pistaciae. Syrphophagus aphidivorus was the most abundant hyperparasitoid for aphids in pistachio orchards. It is widely distributed in pistachio plantation areas. The weed-infesting aphids, along with their primary parasitoid, can act as a reservoir of A. pistaciae secondary parasitoids. Therefore, parasitized aphids allow populations of secondary parasitoids to increase and consequently to apply 43
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Seventh International Congress of Hymenopterists

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