Pine wilt disease (PWD), caused by the pinewood nematode (PWN), Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle 1970, is a serious threat to susceptible pine forests of the world. The PWN is primarily vectored by Monochamus species (Coleoptera: Cerambycidae). The first occurrence of PWD was reported from Japan in the early 1900s. Following this report, Japanese scientists documented the community of barkand phloem-inhabiting insects associated with the nematodes in dying trees to determine possible vectors of the nematode. Monochamus alternatus was reported to be the most effective vector in Japan. The primary vector in North America is Monochamus carolinensis, and in Europe, it is Monochamus galloprovincialis. Further studies have been expanded through the nematode-invaded countries of Korea, Taiwan, China and Portugal. There is an interspecific association between the PWN and its insect vectors, and it is an obligatory component of the disease cycle. It is crucial to understand this relationship as well as the population ecology of the beetle to aid in monitoring and control of this worldwide threat to pine forests. Studies to date indicate a remarkable similarity among beetle species around the globe for a variety of lifehistory traits, including lifespan, adult emergence numbers, flight capability, nematode transmission rates and attraction to pine volatiles. Wherever pines are found, there is a beetle species capable of transmitting the nematode. Although flight performance and range is generally poor for this group of beetle vectors, the cryptic nature of the species and the lack of interest in the beetles by countries in the absence of the nematode have led to the disease establishing a foothold in a variety of countries such as Portugal. In this paper, studies conducted in different countries on Monochamus vector species of the PWN are compared and discussed.

The study of the life history dynamics of the pine sawyer beetle Monochamus galloprovincialis (Olivier) is important because the beetles vector the pinewood nematode. The objectives of this study were to investigate diVerences in beetle life history parameters between the two common host tree species in Turkey, Pinus sylvestris and Pinus nigra. Relationships between the number of oviposition sites, holding time (time between log cut and oviposition), log moisture content, log volume and area, and adult survivorship were evaluated. No signiWcant diVerences were found between the two tree species except adult density per m 2 . The holding time did not inXuence the number of oviposition sites, larval entry holes or adults for P. sylvestris. There was a negative correlation between the holding time and the number of oviposition sites for P. nigra. The number of adults emerged per log was correlated with the number of larval entry holes only for P. sylvestris. Only 12 and 15% of the initial cohort completed development and emerged as adults for P. sylvestris and P. nigra, respectively. Both tree species are equally suitable hosts for M. galloprovincialis development. We conclude that the high within-log mortality of beetles is a combination of resource quality and quantity factors and intraspeciWc competition and cannibalism during larval development.

The study of life history dynamics of the pine sawyer beetle Monochamus carolinensis (Olivier) is of interest because the beetles are vectors for the pinewood nematode, Bursaphelenchus xylophilus (Steiner and Buhrer) Nickle, the causal agent of pine wilt in susceptible pine trees. Previous observation of a laboratory colony of M. carolinensis suggested numbers of adult beetles reared from logs varied little in relation to oviposition densities among individual logs. Logs in laboratory colonies are routinely subjected to artificially high oviposition rates. The objectives of this study were to examine the relationship between initial oviposition rate, holding time (time between log cut and oviposition), log volume and area and adult survivorship in laboratory colony. This study examined the number of eggs, larvae, adults and generation survivorship in logs over a 2‐year period. The number of adults emerged per log was not related to the number of eggs laid. Late larval and adult numbers were significantly correlated with log size. Only 12% of the initial cohort completed development and emerged as adults. We attribute the high within‐log mortality of beetles to intraspecific competition and cannibalism.

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