The saproxylic beetleBolitophagus reticulatus: its frequency in managed forests, attraction to volatiles and flight period

Abstract

T. 2003. The saproxylic beetle Bolitophagus reticulatus: its frequency in managed forests, attraction to volatiles and flight period. -Ecography 26: 421-428.Reduction in amount of dead trees in Scandinavian forests due to intensive forest management has aroused interest in the requirements of saproxylic (wood-living) species. Much attention has been focused on Bolitophagus reticulatus, a tenebrionid beetle that lives on polypore fruiting bodies of Fomes fomentarius. Although earlier studies have suggested that the species has limited dispersal abilities, the beetle is abundant and widely distributed in Swedish forests. To resolve this paradox we conducted a series of field experiments. Firstly, the frequency of the species was found to be similar in six forest stands with a low density of fruiting bodies and six stands with a high density. Secondly, flying individuals were caught in window traps placed in all of eight randomly chosen, well-managed pine stands. Thirdly, we tested volatiles that flying beetles may use to find hosts by baiting window traps. We found strong attractions to ethanol and to a combination of ethanol and fruiting body. The dispersal period was almost entirely restricted to one week during the summer. Our results suggest that B. reticulatus is distributed wherever the host occurs. Long distance dispersal of B. reticulatus is difficult to observe, but appears to be effective when it does occur. Previously observed patchy distribution patterns of the species are probably due to short-distance movements being more frequent than long-distance movements. A general conclusion is that interpretations based on mark-recapture data and indirect measures of substrate and beetle occurrences that claims limited dispersal should be treated with caution. M. Jonsell

Species coexistence patterns in a mycophagous insect community inhabiting the wood-decaying bracket fungus Cryptoporus volvatus (Polyporaceae: Basidiomycota)

“…That the movement of adults of Bolitophagus cornutus (Panzer) across super-patches (logs) is restricted was confirmed by a mark-and-recapture study (Heatwole & Heatwole, 1968). The frequent shortdistance movements and infrequent long-distance dispersal of adults of B. reticulatus (L.) occur in only a few weeks in summer (Jonsell et al, 2003).…”

“…Toda et al, 1999;Wertheim et al, 2000). Empirical studies have demonstrated that restricted movements occur at much larger scales than a patch, but at a smaller scale than limitation by dispersal (Heatwole & Heatwole, 1968;Rukke & Midtgaard, 1998;Jonsell et al, 2003). Although the combined effect of patch-and super-patch-level aggregation did not increase stability, certain super-patches attracted more individuals and consequently more species of insects.…”

“…At the opposite end of the continuum there are the "persistent, bracket fungi", the studies of which have focused on trophic patterns (Komonen, 2001;Komonen et al, 2003) or the colonization abilities of mycophagous beetles (Jonsell et al, 2003;Jonsson, 2003), rather than on interspecific competition. Nonetheless, niche partitioning occurs in ciid (Ciidae) beetle communities.…”

Measuring the dispersal of saproxylic insects: a key characteristic for their conservation

“…This is because for O. eremita, the occupancy per tree was systematically lower in smaller stands (and thus, the species was absent in many of the smallest stands), which not would be the case if the beetles readily moved between trees belonging to different stands. For B. reticulatus this was not analysed by Rukke and Midtgaard (1999), however, in a study by Jonsell et al (2003) found only a very small genetic differentiation at a larger geographical scale, between their two study areas. They found significant genetic differentiation between trees, probably due to a founder effect .…”

Dispersal of individuals of the flightless grassland ground beetle, Carabus hungaricus (Coleoptera: Carabidae), in three populations and what they tell us about mobility estimates based on mark-recapture

“…Compared to other methods, such as population genetic analyses, telemetry, and dispersal simulators (i.e. flight-mills), the MRRbased results tend to give lowest dispersal estimates due to underestimation of long-distance movements (Koenig et al, 1996;Jonsell et al, 2003;Drag et al, 2011;Chiari et al, 2013;David et al, 2013;Oleksa et al, 2013), and vary due to local conditions and/or sampling designs (e.g. Stevens et al, 2010;Hassal & Thompson, 2012).…”