Egg parasitoids of Thaumetopoea pityocampa (Den. & Schiff.) (Lep., Thaumetopoeidae) and their impact in SW Turkey

Abstract

Egg parasitoids (Hym., Chalcidoidea) and egg parasitism were studied in 132 egg batches of the pine processionary moth collected from stands of Pinus nigra Arnold and P. brutia Ten. in SW Turkey, at four places in heights of 800-1010 m a.s.l. in October 1998, beyond the caterpillarsÕ hatch. The egg batches deposited on P. nigra were high-significantly smaller than those found on P. brutia. In this mountainous regions, Baryscapus servadeii (Dom.) and Ooencyrtus pityocampae (Mercet) were the most abundant egg parasitoids of Thaumetopoea pityocampa (Den. & Schiff.). Considering the different sampling places, Trichogramma sp. was found maximally in 3.1% of the parasitized eggs. Additionally, the hyper-parasitoid Baryscapus ransversalis Graham (mean infestation 1.8%) and Pediobius bruchicida (Rond.) (0.1%), both occurring in both sexes, and Anastatus bifasciatus (Fonsc.) (0.1%), only females, were established. The primary parasitoid O. pityocampae dominantly parasitized the eggs placed near the top of the batches, and B. servadeii was found mainly in eggs near the base. The rate of parasitism of the egg batches was very variable. The impact of egg parasitoids and predators varied from 24 to 35.9% depending on the sampling place. The hatching rate of the caterpillars was reduced to 50.7-65.6%. Under laboratory conditions, the emergence dynamics of the parasitoids showed a peak of B. tranversalis in December of the year, in which the host eggs were laid. Baryscapus servadeii emerged mainly in March-May of the following year, when the second part of O. pityocampae appeared. A large part of both parasitoids emerged before sampling of the batches. In O. pityocampae 1.65% and in B. servadeii 2.23% males developed under laboratory conditions. A rate of 15.7% of O. pityocampae and 7.9% of B. servadeii died in the eggs. The polyembryonic Trichogramma sp. (see also Tsankov et al., 1996a) attacked 1.8% of the eggs. Up to 20 (mean 12) dead pupae were found in one egg. Minor parts of eggs were undeveloped (2.9%) and 0.6% totally empty.Zusammenfassung: Eiparasitoide und Eiparasitierung wurden bei 132 Gelegen des Pinienprozessionsspinners untersucht, die in Forsten von Pinus nigra Arnold und Pinus brutia Ten. in der SW Tu¨rkei gesammelt wurden. Die Eigelege wurden an vier Orten in Ho¨hen von 800-1010 m im Oktober 1998 nach dem Schlupf der Raupen entnommen. Die von P. nigra erhaltenen Eigelege waren hochsignifikant kleiner als jene an P. brutia gefundenen. In den Gelegen von Thaumetopoea pityocampa (Den. & Schiff.) aus den untersuchten montanen Regionen waren Baryscapus servadeii (Dom.) und Ooencyrtus pityocampae (Mercet) die am ha¨ufigsten vertretenen Eiparasitoide. An den verschiedenen Lokalita¨ten parasitierte Trichogramma sp. maximal 3.1% der Eier. Zusa¨tzlich wurden der Hyperparasitoid Baryscapus transversalis Graham (mittlerer Befall 1.8%) und Pediobius bruchicida (Rond.) (0.1%) in beiden Geschlechtern nachgewiesen. Von Anastatus bifasciatus (Fonsc.) wurden nur wenige Weibchen gefunden. Der Prima¨rparasitoid O. pityocampae befi...

Egg mortality in the pine processionary moth: habitat diversity, microclimate and predation effects

“…Predation was the major cause of mortality (approximately 22%), accounting for twice as many deaths as abortion (approximately 12%), with a negligible level of egg parasitism (< 1%). The 12% mortality recorded for eggs fully protected against natural enemies is similar to the abortion rates previously reported by Mirchev et al (), which varied from 9.1 to 13.4%. However, the contribution of abiotic factors to abortion may be overestimated because some of the aborted eggs may have died from viral or bacterial infections.…”

Eggmass Structure and Parasitism of Thaumetopoea wilkinsoni (Lepidoptera: Thaumetopoeidae) in Lebanon

“…The number of eggs was comparable for the two locations as none of the pine in the locations was subject to any treatment and as the weather conditions were mild during the previous years. The mean number of eggs per batch was slightly lower in Jeita than Qnat and more similar to the numbers found for T. pityocampa in SW Turkey [11]. However lower number of eggs per batch were found for the PPM in Israel [14].…”

“…As for most of defoliating Lepidoptera, the eggs of PPM, are subject to the action of numerous natural enemies more particularly that of parasitoids that have a significant incidence in the control of host populations [10,11]. The highest incidence of egg parasitoids was found in egg masses on Pinus halepensis Miller followed by those on Pinus pinaster Aïton and in decreasing order on Pinus pinea Linnaeus and on Pinus insignis D.Don which are as the pine species least preferred by egg parasitoids [12].…”

Tendency and consequences of superparasitism for the parasitoid Ooencyrtus pityocampae (Hymenoptera: Encyrtidae) in parasitizing a new laboratory host, Philosamia ricini (Lepidoptera: Saturniidae)

“…The fi tness of females is mainly dependent on their ability to fi nd hosts, and evaluating their life-history entails examining traits such as the percentage of eggs parasitized and percentage parasitoid emergence, development time, sex ratio and longevity (Bigler et al, 1991;Fournet et al, 2001;Perera & Hemachandra, 2014). The solitary synovigenic egg parasitoid Ooencyrtus pityocampae can be utilized in the biological control of the pine processionary moth due to its biological characteristics, which are as follows: it is successful in parasitizing this host both in the laboratory and the fi eld, has a short development time, long adult longevity, is able to successfully overwinter as a diapausing female and can locate its host by responding to its sex pheromone (Biliotti, 1958;Battisti et al, 1990;Tiberi, 1990;Tsankov et al, 1996Tsankov et al, , 1999Schmidt et al, 1997Schmidt et al, , 1999Mirchev et al, 2004). For this reason, successful mass and laboratory rearing of this parasitoid is very important.…”