Potential natural enemy complex of Lymantria dispar L. in the eastern Andalucía

Abstract: Cork oak (Quercus suber L.) is the dominant tree species across a fourth of the dehesa surface in Andalucía (Southern Spain), with the gipsy moth (Lymantria dispar L.) being the major cork oak defoliator all over its geographical range. The main purpose of this work was to study the entomological diversity in two areas of Andalucía (Cádiz and Granada provinces; Spain) with different infestation levels by L. dispar, focusing on orders that include potential candidate natural enemies of this defoliator. For this purpose 10 experimental plots were studied: eight plots in 2010 (four plots per province) and two plots in 2011 (located in Cádiz). We also wanted to determine the influence of the infestation level by L. dispar on both the abundance and diversity of potential natural enemies of this defoliator. For this purpose the four studied plots of each researching area in 2010 were located as follows: two plots in highly infested stands by L. dispar and other two plots in stands low infested by this lepidopteran species. In each plot we installed two trap types: pitfall (8 traps per tree; 10 trees randomly selected per plot), and cross-vane transparent intercept traps (10 traps per plot, hung from the same trees where pitfall traps were installed). The orders Coleoptera, Diptera, Hemiptera and Hymenoptera were represented with altogether 125 families. Among them, 13 families were considered as candidates to contain potential natural enemies of L. dispar, with Carabidae (Coleoptera) being the most represented family among potential predating insects (accounting for 17 candidate morphospecies), whiles three Hymenoptera families (Braconidae, Encyrtidae and Ichneumonidae) accounted for ~ 59% of the identified candidate parasitoid morphospecies. When the whole candidate natural enemy complex was considered, the insect abundance per tree was significantly higher in low infested plots than that of highly infested plots (68.1 ± 3.9 and 49.1 ± 5 specimens, respectively).