The arrival of male moths of the cotton leaf-worm Spodoptera littoralis (Boisd.)(Lepidoptera, Noctuidae) at a new continuously recording pheromone trap

Abstract

AbstractA pheromone trap is described which records the exact time individual male moths enter a trap. This apparatus was operated for approximately three months at two sites in Cyprus. Continuous recordings were made of wind speed, wind direction, temperature and relative humidity near the trap site. Males of Spodoptera littoralis (Boisd.) were generally attracted to a trap baited with S. littoralis virgin females for the first two to three hours after dark. Males of S. exigua (Hb.) arrived most frequently at a trap baited with S. exigua females between 03.00 and 04.00 h. A relationship between wind speed and numbers of males of S. littoralis recorded was found at one site; for winds at a height of 1–37 m varying between 0·8 and 5·2 m s-1, increased wind speed resulted in an increase in the numbers of males recorded. Increase in relative humidity at one site was associated with a decrease in the number of males recorded. No apparent relationship was established between temperature and the number of males recorded, other than the fact that below 13°C many fewer males arrived at the trap. The implications of these findings in relation to movement of adult male S. littoralis are discussed.