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ŠUMARSKI LIST 1-2/2015 str. 72     <-- 72 -->        PDF

to the Forest Research Institute in Sofia for further observations of parasitoid emergence. Every egg batches were placed singly in test tubes plugged with cotton stoppers, after some measurements had been taken. Then, they were preserved in laboratory conditions at room temperature (20–22 ºC). Daily observations were made and the emerged egg parasitoids were removed immediately and separated in plastic capsules for further determination.
B. transversalis was identified by the key of Graham (1991) and confirmed by Dr. E. Yegorenkova (Ulyanovsk State Pedagogical University, Ulyanovsk, Russia). A part of biological material is deposited in her entomological collection.
Results
Rezultati
In this study B. transversalis was recorded for the first time in Bosnia and Herzegovina and is therefore a new member for the fauna of this country. In laboratory conditions, 80 specimens of the species emerged from 8.515 eggs out of 38 pine processionary moth egg batches.
The emerging period of B. transversalis ended in 20 days (Graph. 1), between 3 and 22 November 2013.
In the eggs of T. pityocampa both males and females of B. transversalis developed. From 80 specimens emerged, 60 were females and 20 males – i.e. sex ratio (♀♀:♂♂) was 3:1.
Discussion
Diskusija
Dautbašić (2015) reported three species only as egg parasitoids of pine processionary moth in Bosnia and Herzegovina: Baryscapus servadeii, Ooencyrtus pityocampae and Anastatus bifasciatus (Geoffroy, 1785) (Hymenoptera: Eupelmidae).
As a general rule, the hyperparasitism does not increase the parasitoid impact but the effectiveness of primary parasitoids is reduced. Therefore, the record of the hyperparasitoid B. transversalis in Bosnia and Herzegovina is very important. Percentage of B. servadeii and O. pityocampae in the host eggs attacked by the hyperparasitoid in more reports were from 0.5–3.0% (Tsankov et al. 1996; Schmidt et al. 1997) to 8–12 % (Mirchev et al. 1998a), and in a site in Albania reached up to 23.6% (Mirchev et al. 2000).
After the first description of B. transversalis (Graham 1991), it was found again in Greece (Schmidt et al. 1997; Tsankov et al. 1999; Mirchev et al. 2010) and in other countries of Balkan Peninsula: Bulgaria (Tsankov et al. 1996, 1998; Mirchev et al. 1998a, 1998b, 2012) and Albania (Mirchev et al. 2000).
Studies of the life cycle of B. transversalis show that the reproduction period lasted from spring to autumn when the primary parasitoids are in diapause as mature larvae (Bellin 1995). The developmental period from egg to adult lasted about 5 weeks, and the adults did not survive more than 5 weeks. A sex ratio of 2:1 to 1:1 (females to males) was found. Males arise from arrhenotocal parthenogenesis. Tsankov et al. (1996) pointed out that B. transversalis is less successful in larvae of O. pityocampae than in those of B. servadeii.
In the present study, the established flight period of B. transversalis was very short –more than 50% of individuals emerged in the first day, and 80% – for three days (Graph. 1). The emerging period of other egg parasitoids of T. pityocampa lasted more than eight and a half months from 3 November 2013 to 21 July 2014 (unpublished data).
Other studies reported that B. transversalis always emerge before the mass flight of its host, the primary parasitoids, O. pityocampae and B. servadeii (Tsankov et al. 1996; Schmidt et al. 1997; Mirchev et al. 2000, 2004).
In most localities of B. transversalis both sexes of the species were established. In Bulgaria, the sex ratio varies from about equal numbers at Marikostino (Tsankov et al. 1998) to 10 times more of females at Ploski (Tsankov et al. 1996). Females were 2 times more in the sample from the island of Hydra (Greece) (Schmidt et al. 1997), and as the average for all surveyed sites in Turkey (Mirchev et al. 2004), in Albania – 1.2 times more (Mirchev et al. 2000). In Bulgaria in Kurtovo and Kardzhali higher participation of males was registered – 83.3% and 55.8%, respectively (Mirchev et al. 1998a).
The present finding of B. transversalis increase the strength of entomofauna of Bosnia and Herzegovina and enhance knowledge on parasitoid complex of T. pityocampa in this country.