Parasitization of three species of mango leafhoppers by Halictophagus sp. (Strepsiptera: Halistophagidae) in the Philippines

The presence of mango leafhoppers stylopized by Halietophagus sp. on two cultivars was investigated. The density of Idioscopus clypealis was the highest among the three leafhopper species on mango. Aside from the reported I. clypealis, Halietophagus sp. also parasitized I. niveosparsus and Bakera nigrobilineata. The mean weekly parasitization rates reached 16.6% on I. clypealis, 16.6% on I. hivesparsus and 2.85% on B. nigrobilineata, based on extrusions. The lowest year-long parasitization rate was observed on B. nigrobilineata. The parasitization rate was not influenced by density of I. clypealis but positively influenced by temperature. The density of the hosts and environmental factors did not influence the parasitization rate on both I. niveosparsus and B. nigrobilineata. The stylopized hosts' sex ratio was 1 female:1.35 male in I. clypealis and 1 female:0.85 male in I. niveosparsus. The sex ratio of Halictophagus sp. was 1 female:1.09 male on I. clypealis. Hundreds of globular eggs hatched by batch inside an ovisac into C-shape or shrimp-like triungulins. The free-living elongated sub-oval or tubular triungulins emerged singly from the female cephalothorax and infected leafhopper nymph hosts, then molted into apodouslarval instars inside the new hosts. Super-parasitization occurred with maximum three parasitoids per host. Dark, hard C-shaped and soft white larvae were found inside the parasitized hoppers. The anterior region of the male pupa and of the adult female extruded through the intersegmental membrane of the abdomen of the host. The adult free-living adult male and neotenic female showed extremely sexual dimorphism. Male extrusions affected the length of the whole body, abdomen, forewing, hindwring and the width of the hindwring of the adult male I. clypealis. The parasitization of Haliotophagus sp. also reduced the size of the seminal vesicles in male I. clypealis.