Studies in the effect of weather conditions on the activity and abundance of insect populations

Abstract

This paper is a statistical analysis of captures of insects every night for over 4 years in traps in a locality in the Scottish Highlands. It should be considered in relation to a similar account of work in south-east England (Williams 1951 a ). From the trap catches (on a logarithmic scale), and meteorological records taken alongside the traps, statistical analyses, chiefly by multiple regressions, were made to show (1) the relation between day to day changes in log catch and corresponding changes in temperature and wind, and (2) the relation between changes in mean log catch in the same month in different years and changes in rainfall and temperature in the three previous months. The former is an activity effect, and the latter a population effect. Details are given for total Diptera, for the bloodsucking flies of the family Simuliidae, and for total Lepidoptera in a light trap, and for total Diptera in a suction trap, this latter for activity only. The results show quantitatively the very high dependance, more so in some groups and at certain seasons, of the activity of insects on the current weather conditions, and of the population level on the previous weather. A fuller summary is included in the paper, pp. 367 to 369.