Some New Aspects in Forest Entomology

The Role of Mites in Bark and Ambrosia Beetle-Fungal Interactions

“…Ambrosia beetles are "xylomacetophagous" (feed on fungi grown in the xylem), and their activity is easily recognized by the distinct staining of wood by the inoculation of ectosymbiotic fungi, used as the sole nutrient source by both adults and larvae [10,11,47,48]. Like bark beetles, ambrosia beetles transport these fungi via specialized mycangia [49], the location of which differs between beetle species [50]. Typically (as seen in European ambrosia beetles), females tend to have more well-developed mycangia [49], i.e., large and lined with glandular dermal cells containing a waxy substance [51] than males, and are responsible for depositing the fungi along the tunnel walls [10,50].…”

“…Like bark beetles, ambrosia beetles transport these fungi via specialized mycangia [49], the location of which differs between beetle species [50]. Typically (as seen in European ambrosia beetles), females tend to have more well-developed mycangia [49], i.e., large and lined with glandular dermal cells containing a waxy substance [51] than males, and are responsible for depositing the fungi along the tunnel walls [10,50]. The waxy secretions of the female mycangium contribute to the growth of ambrosia cells [52].…”

“…Coevolution theory suggests that the ambrosia beetle-fungal association is adaptable to a given host environment. However, problems arise when atypical beetle-host relationships form, i.e., exotic ambrosia beetles attack foreign hosts [50,51,54]. A recent concern in North America is an increase in exotic species of ambrosia beetles attacking living trees with.…”

Dutch elm disease and elm bark beetles: a century of association

“…Concerning insects, the structure and ultra-structure of the mycangia or mycetangia on the bark beetle tegument was deeply investigated in the past (Francke-Grosmann 1956a, 1956b, 1963a, 1963b, 1967, Batra 1963, Beaver 1989, Berryman 1989, Lévieux et al 1991, but not specifically in the Scolytus species except for a few preliminary observations (Faccoli 1995). The host-pathogen interactions leading to DED symptoms were recently analyzed in vitro by histo-and cyto-chemical tests.…”

Two Ophiostoma species associated with bark beetles in wave-regenerated Abies veitchii forests in Japan

“…Kendr. ) are commonly associated with bark beetles (Coleoptera: Scolytidae) that particularly infest conifers (Francke-Grosmann 1963;Paine et al 1997 (Lagerberg et al 1927;Gibbs 1993) or tree mortality (Harrington 1988;Brasier 1991).…”