Components of the Catch Curve of Culex annulus in Singapore

Abstract

REGULAR cycles of flight and/or feeding activity are known to occur in a variety of insects, particularly mosquitoes, and theories have been advanced to account for the form and regularity of the observed rhythms; references to most recent work on mosquito-biting cycles have been given by Haddow¹. In discussing the biting cycle of Anopheles leucosphyrus in Borneo², I have myself suggested that the catch curve is the resultant of two separate factors: a cycle of arrival at the bait, and a cycle of activation to produce feeding activity; also that arrival at the bait is conditioned by initial spatial distribution, a cycle of activation to flight activity, and factors orientating such flight. With regard bo the latter, it was suggested that the mosquitoes arrive at the bait by a process of random wandering, or at least one not orientated by the bait itself. Recently, my attention has been directed to a paper by Webster and DeCoursey³, demonstrating that the daily catches in a variety of arthropods are in fact determined by a process of random arrival at the trap, in accordance with a theoretically derived equation of the form: where K is the initial population, C the cumulative catch, t time, and a and b are constants.