Season of Fine Woody Debris Death Affects Colonization of Saproxylic Coleoptera

A study was conducted to explore the effect of season on colonization of dead twigs by beetles in a Louisiana secondary forest. Previous research showed that twigs cut during spring yielded many specimens and species. The present companion study utilized twigs averaging 14 mm in diameter cut from one tree of Quercus falcata Michaux (southern red oak) during fall (October) 2008, placed in bundles of 10 each, and left in the forest at three sites. Half the bundles were retrieved during winter (January, four months later) and the other half were retrieved during summer (July, nine months later). Coleoptera were collected from bundles using emergence chambers. Only 39 specimens of adult Coleoptera were collected, representing 12 families, 20 genera, and 21 species. Beetle colonization of oak twigs in Louisiana appears to be affected by the interaction of season and twig “quality” (apparently freshness) with the highest colonization taking place in fresh, dead twigs during spring and an order of magnitude lower colonization in 1) fresh twigs during fall or 2) stale twigs during spring and summer.