Biological anomalies in the sugarcane leafhopper, Pyrilla perpusilla (Walker) due to parasitism by Fulgoraecia melanoleuca (Fletcher) (Lepidoptera: Epipyropidae)

Abstract

Abstract Background Fulgoraecia melanoleuca (Fletcher) (Lepidoptera: Epipyropidae) (= Epipyrops or Epiricania melanoleuca) is an important koinobiont nymphal and adult ectoparasitoid of sugarcane leafhopper, Pyrilla perpusilla (Walker) (Hemiptera: Lophopidae). The study aimed to evaluate whether and to what extent this parasitoid effects the fitness of immature (five nymphal stages) and adult (♂ and ♀) stages of its host P. perpusilla. Results The nymphal mortality was significantly more in the younger nymphs, and it decreased as the host aged. The exposure of the first stage host nymphs to the parasitoid resulted in 100% mortality. However, the nymphal mortality rates in second, third, fourth and fifth nymphal stage were 94.0, 75.0, 38.0 and 41.0%, respectively. Furthermore, the longevity of surviving nymphs was prolonged significantly in the later stages. None of the parasitized first to fourth stage nymphs survived as normal adult. In case of the parasitized fifth nymphal stage, 18.0% adults were normal; however, their longevity was comparatively shorter than their un-parasitized counter parts. When male and female adults of leafhopper were offered to the parasitoid, significant differences were found in mortality of parasitized and un-parasitized adults for both sexes. Further, parasitoid-induced prolongation in the longevity of the surviving parasitized adults was also observed. Conclusions Overall, the parasitoid F. melanoleuca had detrimental effects on host fitness and thus played a significant role as a biological control agent in suppressing the sugarcane leafhopper population. This study will clarify host-parasitoid relationship, developing mass rearing protocol under laboratory conditions and implementing effective strategies for augmentative releases of parasitoids in biological control program against P. perpusilla in sugarcane ecosystem.