Under laboratory conditions, Dendroctonus frontalis Zimmermann and Ips grandicollis (Eichhoff) adults became self-marked with fluorescent powders upon emergence from treated logs. The technique provided a reliable procedure for marking adult bark beetles without having to handle them. When the powder remained dry, nearly all of the emerged beetles were marked. However, the percentage of marked beetles decreased dramatically following simulated rain events. Once marked, the mark remains intact on beetles stored dry or in ethylene glycol or ethanol (95%). Marking did decrease the adult life span of both D. frontalis and I. grandicollis, but had no significant effect on flight initiation by either species or semiochemical perception by I. grandicollis. No semiochemical tests were conducted with D. frontalis. If beetles are recaptured shortly following emergence and self-marking, the technique should be useful for examining scolytid dispersal in the field.

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