Effects of low-temperature summer nights on adults of Monochamus alternatus (Coleoptera: Cerambycidae)

ABSTRACT

To clarify the factors determining the northern distribution limit of Monochamus alternatus Hope, which vectors the pinewood nematode, we examined our hypothesis that “low-temperature summer nights in cool regions affect the survival, maturation feeding, and ovary development of M. alternatus, and determine its distribution limit.” We measured summer air temperatures in three pine forest stands in northern Japan. Based on the results, we examined the effects of low nighttime temperatures on survival, maturation feeding, and ovary development in the laboratory. Low nighttime temperatures had little effect on the survival and the total amount of maturation feeding of M. alternatus adults. A daytime temperature of 25°C and nighttime temperature of 15°C did not affect ovary development. In contrast, 25°C in the daytime and 10°C in the nighttime delayed ovary development and reduced the number of mature eggs, but some ovary eggs were able to mature under this condition. We concluded that the effect of low-temperature summer nights on ovary development alone could not explain the northern distribution limit of M. alternatus.

KEYWORDS:

• Japanese pine sawyer
• ovary development
• northern distribution limit
• maturation feeding
• survival

Acknowledgments

We would like to thank the anonymous reviewers for their helpful and constructive comments that greatly contributed to improving this manuscript. We would also like to thank the Editor for his generous comments and support during the review process. We sincerely thank Dr T. Aikawa, the Forestry and Forest Product Research Institute, and Dr Y. Ozawa, the Iwate Prefectural Forestry Technology Center, for providing M. alternatus adults. Thanks are also due to the Forestry and Forest Products Research Institute of Aomori Prefectural Industrial Technology Research Center, the Seihoku Regional Branch Office of Aomori Prefecture, and the Akita Regional Branch Office of Akita Prefecture for their permission for the setting of temperature measurement devices in the forests. We are indebted to Ms. S. Matsuzawa and Ms. N. Kawamura for their assistance in rearing beetles.

Disclosure statement

No potential conflict of interest was reported by the authors.

Additional information

Funding

This work was supported by the Japan Society for the Promotion of Science KAKENHI Grant Number [24658143].