Oxygen consumption in mosquito larvae parasitized by Romanomermis culicivorax (nematoda)

1. 1.The effect of parasitism by Romanomermis culicivorax on the oxygen consumption of three species of mosquito larvae was studied by manometric methods. 2. 2.The Q o2 , of Culex pipiens, both parasitized and unparasitized, decreased as the host larvae developed from the second to fourth instar. 3. 3.In the early stages there was no significant difference in go, in parasitized and unparasitized hosts but the Q o2 increased significantly in parasitized fourth instar larvae. 4. 4.The Q o2 of parasitized and unparasitized fourth instars of Aedes taeniorhynchus. Anopheles quadrimaculatus and C. pipiens were compared. 5. 5.The go, of all parasitized hosts was significantly increased and the go, of the two culicine species displayed a dramatic increase in oxygen consumption. 6. 6.The oxygen consumption of the parasitic mermithid larvae was estimated from that obtained earlier for the post-parasitic larvae but did not account for more than 9–36% of the increased Q o2 of the parasitized hosts. 7. 7.On this basis it seems probable that the increased metabolic rate as reflected by oxygen consumption of the parasitized mosquito larve was principally a manifestation of the physiological and nutritional stress induced by the mermithid nematodes.