Climate change induces an alteration in the life cycle of many poikilothermic organisms, resulting in changes in the structure and function of communities. Changes in voltinism in the pine moth Dendrolimus spectabilis (Butler), which is known to be univoltine in South Korea, were studied to elucidate the effects of climate change on their voltinism. The developmental stages of the pine moth were evaluated through field surveys, and the developmental rate was estimated at five different temperatures: 17, 20, 25, 28, and 32°C. Field surveys showed that the moths completed two generations per year, indicating that the phenology of the pine moth in this area had changed from univoltinism to bivoltinism. Laboratory experiments showed that increasing the temperature could induce a change in voltinism in the pine moth population. Generations of the bivoltine population displayed phenotypic plasticity: the fitness of the first generation was greater than that of the second generation with regard to size and fecundity. The difference in fitness between the first and second generations could be due to the influence of factors such as low food quality and heat stress on the second generation. Therefore, changes in thermal conditions due to climate change have offered this species the chance to develop a bivoltine population, but they have also exerted ecological costs, especially for the second generation of the pine moth.

Three of chalcidoid wasps are newly reported as pupal parasitoids of the fallwebworm to Korea: Tetrastichus septentrionalis Yang and Chouioia cunea Yang (Hymenoptera: Chalcidoidea: Eulophidae); Dirhinus sp. (near D. anthracia) (Hymenoptera: Chalcidoidea: Chalcididae). Two eulophids were first described as pupal parasitoids of the fallwebworm from China and have been used as biological control agents against the moth for many years. Both species display distinctive sexual dimorphism in male. Apart from the color of legs and antennae, Dirhinus sp. agrees well with the description of D. anthracia. It remains as Dirhinus sp. at present as it requires further comparative study on morphology between our parasitoid and D. anthracia.