Pinus koraiensis twigs affect Monochamus saltuarius (Coleoptera: Cerambycidae) longevity and reproduction

This study was conducted to investigate the longevity, reproduction and ovarian development of M. saltuarius adults feeding on Pinus koraiensis twigs of three different age classes (current-year, 1-year and 2-year). Longevity and fecundity of female adults decreased with increasing twig age class (58.4, 41.9 and 35.9 days, respectively, for longevity and 43.0, 13.2 and 6.6 eggs, respectively, for fecundity). In ovarian development, the average follicle size after 1 week of feeding on current-year twigs was 3.1–3.5 times greater than those of beetles fed 1- and 2-year-old twigs. After 2 weeks of feeding, follicle size was 2.3–2.4 times greater than those of beetles fed 1- and 2-year-old twigs. These results showed that current-year twigs of P. koraiensis increase longevity and reproduction of M. saltuarius. By analyzing sugars using high performance liquid chromatography (HPLC), the quantity of fructose was found to be highest in current-year twigs and lowest in 2-year-old twigs. A sugar feeding bioassay indicated that fructose was preferred by M. saltuarius. Therefore, fructose is important to adult feeding and ovariole development in M. saltuarius.