Hyperparasitism in two newly introduced parasitoids,Epidinocarsis lopeziandGyranusoidea tebygi(Hymenoptera: Encyrtidae) after their establishment in Togo

In 1988/89 the nature and degree of hyperparasitism in two newly introduced parasitoids of exotic mealybug plant pests were examined in Togo. Associated withPhenacoccus manihotiMatile-Ferrero (Hemiptera: Pseudococcidae) (cassava mealybug) five indigenous hymenopterous hyperparasitoids were found adapted to the primary parasitoidEpidinocarsis lopezi(De Santis):Chartocerussp. A (Signiphoridae),Prochiloneurus insolitus(Alam),P. aegyptiacus(Mercet) (Encyrtidae),Tetrastichussp. (Eulophidae), andMarietta leopardinaMotschulsky (Aphelinidae). The rate of hyperparasitism varied considerably (20–90%). At one sampling siteChartocerussp. A was most frequent (52%), at the other siteP. insolituswas found to dominate (55%). The same hyperparasitoids were associated withRastrococcus invadensWilliams (Hemiptera: Pseudococcidae), but with an additionalChartocerus(sp. B). Hyperparasitism ranged from 56 to 86%, withChartocerussp. A being the most important species. Multiple parasitism was observed on several occasions. In spite of generally high hyperparasitism, no detrimental effect on the control efficiency of either primary parasitoid was noticed.