Endocrine relations between certain larval Diptera and their mermithid parasites

Laboratory studies in Newfoundland showed that the endocrinology of last-instar larvae of Prosimulium mixtum Syme & Davies and P. fuscum Syme & Davies infected with the mermithid parasite Neomesomermis flumenalis was unaffected by the parasitism and that slight disturbances in the endocrinology of larvae of Simulium venustum Say infected with the same nematode were probably due to stressful symptoms of parasitaemia rather than to the developing nematode. Further tests showed that administering the insect growth regulator methoprene (Altosid 5E) to larvae of Aedes aegypti (L.) infected with Romanomermis culicivorax (Reesimermis nielseni auct.) had no affect on the infectivity of the pre-parasites or on parasitic or post-parasitic development of the mermithid. The data indicated that integrated mosquito control programmes employing both mermithids and insect growth regulators would prove more effective than use of either type of control agent alone..