Med J Malaya, 1950;4:260-271.

Abstract

This paper records some interesting findings of anophelines resting by day in vegetation In' Malaya. Anophëles maculatus was the commonest species and the majority of specimens were found to have had a recent blood meal, In general few Malayan anophelines are endophilic, so the author instituted systematic searches of vegetation in the vicinity of labourers' lines and cattle sheds on a rubber estate, where breeding sites of A. maculatus in the form of small streams and ravines abounded. Searching was carried out by trained assistants using hand catching with cyanide tubes, and catches on different occasions yielded results varying from 1 to 13 anophelines per man-hour. It was found that the densely shaded banks of streams had a relatively small population of anophelines. Rather they favoured the more open type of vegetation under trees, represented mostly by the common Malayan bracken fern. A. maculatus was by far the commonest anopheline found under these conditions, usually within a few inches of the ground where the bracken was 1-2 feet high and sheltered but reasonably free of access. Of the other 8 species of anophelines found, A. hyrcanus and A. barbirostris were usually found at a greater height from the ground, A. aconitus in more secluded spots and A. philippinensis in vegetation where ferns were replaced by sedges and small bushes. Analysis of the specimens captured showed that there were more than six times as many females as males of A. maculatus. Of these females approximately two-thirds contained fresh blood while the remainder were gravid or unfed indicating that adults in all stages of development make use of the same daytime harbourages. Dissections showed that maturation of the ovaries was complete 48 hours after a single blood meal and this same period appeared to hold good for several other of the species concerned. A. vagus, however, probably completes the whole cycle in 24 hours. Precipitin tests showed that 20 per cent. of A. maculatus had fed on man and nearly all of the remaining 80 per cent. on cattle. Of the other species only 7 per cent. of A. hyrcanus and a single specimen of A. karwari had fed at all on man.