Pole with 10 sticky traps for monitoring Ips typographus in Denmark
Byers, J.A., Anderbrant, O., & Lfqvist, J. 1989a. Effective attraction radius: A method for comparing species attractants and determining densities of flying insects. Journal of Chemical Ecology 15:749-765.

Abstract-- The catches of bark beetles (Coleoptera: Scolytidae) were compared between attractive traps releasing semiochemicals and passive traps (cylindrical sticky screens long at 10 heights of 0.7-11.5 m, on poles). A central attractive-trap pole was surrounded by three passive-trap poles spaced 50 or 100 m away at the apices of an equilateral triangle. The catches of Tomicus piniperda and other scolytid species on the attractive-trap pole baited with host monoterpenes, or the catches of Ips typographus attracted to synthetic pheromone, were compared to passive trap catches in a Scots pine forest or in a Norway spruc clear-cut, respectively. Information about flight height distributions of the above scolytid species, and Hylurgops palliatus, Cryphalus abietis, Pityogenes chalcographus, P. quadridens, P. bidentatus, and Trypodendron domesticum were obtained on the passive and attractive trap poles. A new method is presented for determining the densities of flying insects based on the passive trap's dimensions and catch, duration of test, and speed of insect. Also, a novel concept, the effective attraction radius (EAR), is presented for comparing attractants speices, which is independent of insect density, locality, or duaration of test. The EAR is obtained by the ratio of attractive and passive trap catches and the dimensions of the passive trap, and thus should correlate positively with the strength of the attractant and the distance of attraction. EARs are determined from catch data of T. piniperda and I. typographus as well as from the data of previous investigations on the same or other bark beetles.
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Chemical Ecology