Sixth-instar larvae of Choristoneura fumiferana were treated with LD50 concn of the juvenile hormone analogues fenoxycarb and methoprene. Fenoxycarb caused an initial decrease, then an increase, in haemolymph concn. Fat-body glycogen was depleted initially, then relatively increased in concn towards...

In vitro growth of R. culicivorax preparasites was monitored in 2 culture media under differing conditions of crowding. Crowding was more important that the character of the medium itself in stimulating in vitro growth. The glycogen, protein, and lipid content of nematodes that had developed after 5...

Analysis of haemolymph samples from field-collected larvae of Simulium venustum Say, S. vittatum Zett. and either Prosimulium mixtum Syme & Davies or P. fuscum Syme & Davies or a mixture of the two showed the haemolymph of all species to be essentially similar with respect to amino-acid pool...

Histological observations were made on larvae of Aedes aegypti (L.) parasitised for 2, 4 or 6 days by Reesimermis nielseni. Little difference was detected between the tissues of uninfected and parasitised larvae 4 days after infection, at which time most hosts were in the early fourth instar and the...

Laboratory methods were developed for culturing the free-living stages of Neomesomermis flumenalis, a mermithid parasite of simuliids, especially Simulium venustum Say and the complex of Prosimulium mixtum Syme & Davies and P. fuscum Syme & Davies, from simuliid larvae collected in the field...

The anatomical relations of the neuroendocrine systems in larvae of Simulium venustum Say and the complex of Prosimulium mixtum Syme & Davies and P. fuscum Syme & Davies are described from histological examination. The neuroendocrine system in the brain showed morphological similarities to c...

In 1973-75, larval blackflies were sampled for mermithid nematodes in 83 streams in Newfoundland, Canada. Prosimulium mixtum/fuscum and Simulium venustum were the predominant hosts of Neomesomermis flumenalis but rates of infection in late-instar larvae were generally low (4.3 plus or minus 0.7% and...

Newly hatched Aedes aegypti larvae were experimentally infected with controlled levels of Reesimermis nielseni and the development of the parasite was recorded. The nematode increased in length by 18-fold and in width by 16-fold during a relatively short 6 to 8-day parasitic phase. Most of the nemat...

Mermithids of three genera and species are known to parasitise North American Simuliids, and a more varied Mermithid fauna probably exists [cf. RAE/B 51, 135]. The host specificity of Mermithid parasites of Simuliids is variable, but the nematodes do not appear to infect other stream fauna. The spor...

A method of collecting postparasitic Neomesomermis flumenalis from larval Prosimulium mixtum/fuscum and Simulium venustum is described. The larval blackflies were collected by sweeping them with paint brushes from rocks into buckets of stream water. The larvae were obtained free of debris by placing...

Histochemical studies in the laboratory in Canada on field-collected larvae of Prosimulium fuscum Syme & Davies (mixtum fuscum) revealed no significant differences in the endocrine activity of larvae infected with mermithid nematodes and healthy larvae (of similar body dimensions). In the case o...

Knowledge of the physiological processes involved in the relationships between insects and their mermithid parasites is reviewed with respect to the effects of mermithids on host physiology, effects of host physiology on mermithids, and the physiology of nematodes themselves. Most physiological rese...

The haemolymph of larvae of Prosimulium mixtum Syme & Davies/P. fuscum Syme & Davies and Simulium venustum Say parasitised by the mermithid nematode Neomesomermis flumenalis was compared with that of unparasitised hosts with respect to protein, amino acid and carbohydrate composition. The me...

A steinernematid nematode was isolated from soil samples collected near St. John's, Newfoundland, Canada. On the basis of its morphometry and RFLPs in ribosomal DNA spacer, it was designated as a new strain, NF, of Steinernema feltiae. Cellulose acetate electrophoresis was used to separate isozymes ...

Laboratory bioassays were conducted to determine the effects of two carbamates, carbofuran (an acetylcholinesterase inhibitor) and fenoxycarb (a juvenile hormone analog), on survival and infectivity of the infective juveniles (IJ) of Steinernema feltiae Umea strain and Steinernema carpocapsae All st...

Trophosomes of the mosquito parasitic mermithid Romanomermis culicivorax and two strains of the simuliid parasitic mermithid Mesomermis flumenalis (Neomesomermis flumenalis) contained in order of prevalence: triacylglycerols, phospholipids, sterols and sterol esters. Triacylglycerols in the trophoso...