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

Abstract

AbstractIn 1988/89 the nature and degree of hyperparasitism in two newly introduced parasitoids of exotic mealybug plant pests were examined in Togo. Associated with Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae) (cassava mealybug) five indigenous hymenopterous hyperparasitoids were found adapted to the primary parasitoid Epidinocarsis lopezi (De Santis): Chartocerus sp. A (Signiphoridae), Prochiloneurus insolitus (Alam), P. aegyptiacus (Mercet) (Encyrtidae), Tetrastichus sp. (Eulophidae), and Marietta leopardina Motschulsky (Aphelinidae). The rate of hyperparasitism varied considerably (20–90%). At one sampling site Chartocerus sp. A was most frequent (52%), at the other site P. insolitus was found to dominate (55%). The same hyperparasitoids were associated with Rastrococcus invadens Williams (Hemiptera: Pseudococcidae), but with an additional Chartocerus (sp. B). Hyperparasitism ranged from 56 to 86%, with Chartocerus sp. 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.