(2nd Place) Host range of the oothecal parasitoid Aprostocetus hagenowii (Hymenoptera: Eulophidae)

Aprostocetus hagenowii (Ratzeburg) is a generalist parasitoid wasp that parasitizes the oothecae of cockroaches (Blattodea). Most known hosts are peridomestic pest species in the family Blattidae, such as the American cockroach Periplaneta americana (L.) and Oriental cockroach Blatta orientalis L. Typically, investigations of parasitoid host ranges are conducted in relation to species of human importance and heavily bias towards pests. An investigation that includes a diverse selection of pest and non-pest species is better able to explore the wider breadth of relationships between a parasitoid species and its hosts. No-choice experiments were carried out with cockroach species from the Blattidae, Ectobiidae, and Corydiidae with diverse geographic origins and habitats to gain a better understanding of the host range for A. hagenowii. Three new host species were recorded: the Turkestan cockroach Blatta lateralis (Walker), African bullet cockroach Neostylopyga propinqua (Shelford), and fulvous wood cockroach Parcoblatta fulvescens (Saussure and Zehntner). Previously recorded hosts were revisited. Notably, A. hagenowii failed to parasitize or show attraction towards German cockroach Blattella gemanica (L.) oothecae, supporting assertions from previous investigators that the original records are erroneous. The ovipositor length of A. hagenowii was measured and compared to the thickness of the oothecal cuticle for host and non-host species. The mean ovipositor length (0.93 mm ± 0.012 SEM) far exceeded the thickness of all oothecal cuticles measured. Thus, cuticle thickness alone is unlikely to prevent parasitism by A. hagenowii.