Alternatus Larvae Research Articles

Density of Woodpeckers and the Predation upon Monochamus alternatus larvae in pine Trunks in Shimane Prefecture

Density of Woodpeckers and the Predation upon Monochamus alternatus larvae in pine Trunks in Shimane Prefecture

Biology of a Tylenchid Nematode Parasitic On the Japanese Pine Sawyer, Monochamus Alternatus

A nematode which parasitizes the reproductive organs of the Japanese pine sawyer, Monochamus alternatus, has both a parasitic cycle and a mycetophagous free-living cycle. Entomoparasitic adult females lay eggs and hatched juveniles develop to 4th stage juveniles within the ovary and testis of M. alternatus adults. The 4th stage juveniles leave M. alternatus adults during defecation and during egg deposition. They moult to free-living adult males or infective adult females in the presence of M. alternatus larvae. The juveniles also moult to mycetophagous free-living adult males or females and propagate on the mycelia of an as yet unidentified fungus. The life history of the nematode is similar to that of Deladenus spp. but the morphology of the entomoparasitic female adult is similar to that of Contortylenchus spp.

Larval Diapause Termination of Monochamus alternatus HOPE(Coleoptera:Cerambycidae)under Natural Conditions

To determine the time of diapause termination of Monochamus alternatus larvae under natural conditions, debarked bolts of Pinus thunbergii and P. densiflora inhabited by diapausing larvae within the xylem were transferred from outdoors to constant conditions of 25°C, 90-100% R.H. and 16L-8D between December 15, 1989 and April 18, 1990. The females required longer incubation time than the males to emerge as adults. The mean incubation time for both sexes to adult emergence decreased as the start of incubation was delayed from mid-December through mid-February, and became constant when the incubation was started between mid-February and mid-March. Larval diapause was thus terminated by mid-February. In pine bolts transferred earlier, a small number of yellow larvae survived in pupal chambers even after a 113-144 day incubation. The proportion of such larvae decreased from 12 % to 0% as the start of incubation was delayed.