Osservazioni sull’attività degli oofagi di Lymantria dispar (Lepidoptera Lymantriidae) in sugherete meridionali

During investigations of the population dynamics of the Lepidoptera Lymantriidae Lymantria dispar Linnaeus, we examined the role of oophagous parassitoids and predators in a cork oak forest in the Iblei Mountains, where the defoliating moth faces periodic pullulations. On 79 egg masses collected in field and periodically isolated in laboratory, parasitization of the encyrtid Ooencyrtus kuwanae Howard was on average 12%. Traces of predation by Coleoptera Dermestidae Globicornis bifasciata (Perris) and Trogoderma versicolor (Creutzer), were present in 53 egg masses. A further 60 egg masses, identified as one of those just laid, were examined in situ and photographed to assess the level of deterioration as well as the apparent predation and parasitization. The number of integrate egg masses progressively diminished starting from the first observation and, in the second ten days of November, all the egg masses had been attacked at the same time the number of egg masses completely destroyed increased and in total were 37. Also, in 20 out of the 23 egg masses removed, there were traces of predation by G. bifasciata and T. versicolor, as well as emergence holes from O. kuwanae. The oophagous predatory activity was therefore important to containing Lymantriidae populations if one considers that it affected 95% of the 60 egg masses marked, of which it directly or indirectly eliminated 52.6% of eggs, thereby favouring, with the destruction of the egg masses, the parasitic activity of O. kuwanae.