Studies on the remnants of the parasitoid larvae of Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), in the galls collected in two places in Italy for determining parasitism level and type of parasitoids

Abstract : 

In several parts of the world almost 69 species of parasitoids/hyperparasitoids) of Dryocosmus kuriphilus Yasumatsu (Hymenoptera: Cynipidae), were obtained by several works conducted in the galls collected in the spring. Aims of the studies on remnants of larvae in the galls of D. kuriphilus, collectedin autumn, 2014 sent from two places, Italy were: (1) for determining parasitism level of Torymus sinensis; (2) parasitism type of parasitoids in the galls. As study materials 135 galls collected in September, 2014 from Trehago (VR) Italy Se Hembre, and 185 galls, collected October, 2014 from Crespano del Grappa (TV) were send by Drs. Andrea Battisti and Fernanda Colombori, Padova University, Italy. From each group 10 galls were taken and dissecting for determining parasitism level of T. sinensis and parasitism type of parasitoids in the galls. For obtaining parasitism level, larvae of D. kuriphilus (dead ones)and T. sinensis (alive ones) were taken off from the galls, boiled in 10% KOH for 5 minutes, dissected, cleaned from fat-body and slide-mounted in Canada balsam for determining the shape of head structures, mainly mandibles, and spiracles. The other groups of galls were put into vials separately, and kept in room conditions, about 20-250 C and 50-70% relative humidity. If galls have holes, the holes were signed by red pencil, in order to identify the new holes on the galls from which any hymenopterous adult will come out in the future. When adult comes out from gall, it was identified by following keys of several works. The gallery following hole of the adult was dissected for reaching to growing-chamber of adult(s) developed. The remnant of adults were taken off, and slide-mounted in Canada balsam, and figured them by using of Leica DM 500 microscopes with a digital Leica ICC 50 camera attached to it. The mandibles and spiracles of the species were identified. Types of parasitism were determined by the following ways: if one type of mandible was found in the gall, it would be D. kuriphilus, having two-teethed mandible; if two different mandibles were found in galls, the adult come out is the parasitoid and the other one is its host. By this way, In Trehago (VR) Italy Se Hembre the parasitism by T. sinensis was about 65.3% and 3.3% dead adult/lar. of ACGW, and 25.7% of its associates+ACGW (larvae+adults), 1.0% E. annulatus and 5.0% of Pyemotes, and in Crespano del Grappa (TV) the parasitism by T. sinensis was about 62.6% and from the galls 14.4% of dead adult/lar. of ACGW, and 23.0% of its associates +ACGW (larvae /adults),and 4.8% of Pyemotes (2.4 on D. kuriphilus and 2.4 on T. sinensis) were obtained from galls collected in Autumn. The characters of the mandibles and spiracles of D. kuriphilus, T. sinensis, Eupelmus annulatus Nees, Eurytoma pistacina Rondani were figured and discussed

Keyword : 

Cynipidae, parasitoid, galls, gall wasp

Author(s) : , M. Doğanlar
Downloads : 768

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