Infection of Tomicus piniperda (Col., Scolytidae) with Canningia tomici sp. n. (Microsporidia, Unikaryonidae)

Abstract

Canningia tomici sp. n. (Microsporidia, Unikaryonidae) infects the midgut epithelium, the gut muscules, Malpighian tubules, connective tissues, adipose tissues and the gonads of the pine shoot beetle, Tomicus piniperda (L.) (Coleoptera, Scolytidae). The infection is present in populations of Tomicus piniperda in Europe and in the United States. Uninucleate oval single spores occur in two sizes: 2.8 ± 0.4 · 1.4 ± 0.4 lm and 3.8 ± 0.3 · 2.0 ± 0.2 lm. The polar filament of this microsporidium is fixed subapically in a flat anchoring disc. The thick posterior lamellae of the binary polaroplast are asymmetric due to the lateral fixation of the polar filament.

Infection, course of disease and action of Canningia tomici in Tomicus piniperda and Tomicus minor (Coleoptera: Curculionidae)

“…This separation in space and time of the two beetle species limits the opportunity for horizontal transmission of C. tomici. Although we were unable to provide evidence of pathogen transfer from parental beetles to offspring, results of an earlier study suggest that C. tomici is transmitted vertically in T. piniperda (20).…”

“…Our results further indicate that the potential for horizontal transmission before maturation feeding period is low; we were never able to infect 100% of the test beetles and successful infection of filial beetles increased with a maturation feeding period. Though the infection of gonads and the vertical transmission of C. tomici has been reported for T. piniperda (20), we were not able to provide any further evidence for the vertical transmission of C. tomici in both tested beetle species. Our results show that the successful infection of T. piniperda and T. minor offspring did not depend on the rearing temperature or sex of the beetles but was influenced by the duration of maturation feeding.…”

“…Sampling was conducted over the entire 3-year period (2002)(2003)(2004) at sampling sites with known populations of healthy, uninfected parental and filial beetles, and sites where C. tomici-infected beetles were known to occur and fresh spores could be obtained for experiments (20). T. piniperda and T. minor were collected from several locations in Austria (Lower Austria, Burgenland and Styria), Finland (Hyytiälä), Poland (Sękocin), the Czech Republic (Stará Boleslav), and Croatia (Korenica).…”

“…Biological control has never been seriously attempted with bark beetles (18,19) and should be reconsidered in light of the results of a study conducted by Kohlmayr et al (20), which reports the presence of the microsporidium Canningia tomici in cells of the midgut epithelium, adipose tissue, and ovariols of T. piniperda. Little has been reported about the pathogen-host interaction, effects of infection in T. piniperda, or the epidemiological consequences in populations.…”

Pathogens and parasites of adults of the great spruce bark beetle, Dendroctonus micans (Kugelann) (Coleoptera: Curculionidae, Scolytinae) from Turkey

“…Another interesting result was that no microsporidian and eugregarine infection could be observed in D. micans populations during the study, although several such infections have been reported to occur in other bark beetle species (Weiser 1970;Wegensteiner et al 1996;Weiser et al 1998Weiser et al , 2000Weiser et al , 2002Händel et al 2003;Haidler et al 2003, Kohlmayr et al 2003Weiser et al 2006;Yaman 2007). For example, Weiser (1970) found Nosema dendroctoni, Ophryocystis dendroctoni and Chytridiopsis typographi in the douglas fir beetle (Dendroctonus pseudotsugae), and Knell and Allen (1978) identified Unikaryon minutum from the southern pine beetle, Dendroctonus frontalis.…”