Insect Size and Temperature

Abstract

WHEN an insect is reared at graded temperatures, it is commonly found that the size of the resultant offspring decreases with increasing temperature¹. Evidence of the working of this principle in Nature has emerged in a study of the competition amongst the various organisms which scour and keep open the bacteria beds of sewage works¹. Four species of these nematocerous Diptera have been systematically measured for eighteen months, the wing-length of the female being taken as a convenient criterion of size. The flies were trapped on the beds of Leeds and of Huddersfield sewage works, where the monthly mean bed temperatures have a range of about 7°–18° C. They were sorted into monthly groups and the standard sample measured varied from 50 to 200 from each of several trapping sites.