Published online by Cambridge University Press: 10 July 2009
An investigation using modified Manitoba traps on a forest track in Scotland showed that carbon dioxide, coloured spheres, movement, heat, Haematopota pluvialis (L.) and a swarm of other adults of Hydrotaea irritans (Fall.) were attractive. Traps with coloured spheres attracted more flies than traps without spheres. Matt black, shiny black and shiny red spheres attracted more males and females than did shiny green, white or yellow spheres. Significant increases in the number of flies caught did not occur when carbon dioxide was released from a trap at rates above 2 litres/min. Carbon dioxide seems to act as a long-range attractant, with vision becoming important near the host. Manitoba traps were also used with three repellents for H. irritans in order to evaluate the trap's potential for testing repellents.