Spodopotera frugiperda is a worldwide invasive pest that has caused major economic damage. According to classical biological control theory, natural enemies that can control invasive pests come from the area of origin as the pests that have gone through coadaptation processes. However, the new association’s approach suggests that local natural enemies are equally capable to control invasive pests. Due to the lack of data on the association of S. frugiperda and local natural enemies, research was conducted through a rapid survey to study the population density of S. frugiperda in Yogyakarta, Indonesia and to study the diversity of parasitoid associated with S. frugiperda. The results showed the difference in S. frugiperda population and parasitism rate, with 15 parasitoid species associated with S. frugiperda. Four egg parasitoids, eight larval parasitoids, and three pupal parasitoids were found to be associated with S. frugiperda for three years after it was first discovered in Indonesia. A new association was found between S. frugiperda and three parasitoid species, consisting of two egg parasitoids (Platygasteridaesp.01 and Platygasteridaesp.02) and a larval parasitoid (Eupelmidaesp.01). A relatively new association was found between S. frugiperda and two larval parasitoids (Coccygidium sp. and Stenobracon sp.), and an existing association was found between seven species including an egg parasitoid Telenomus remus, three larval parasitoids (Cotesia sp., Microplitis sp., Campoletis sp.), and three pupal parasitoids (Brachymeria lasus, B. femorata, and Charops sp.). Telenomus remus is the most dominant parasitoid, with a higher abundance and parasitism rate. This study also reported the first findings of the association of S. frugiperda with the larval parasitoid Megaselia scalaris in Indonesia. The result suggests another method for biological control using the new association approach since local natural enemies can foster quick adaptation to invasive pests.

Thermal variations affect tri-trophic interactions involving plants, herbivores, and parasitoids, causing a mismatch between their phenological cycles. In the current environmental context of climate change, climatic factors can undergo profound and sudden changes, such as sudden hot or cold snaps. Here we show that episodes of short but sustained low temperatures have increased, mainly in the month of May, in the last two decades. We subjected galls induced by Asian chestnut gall wasp (ACGW) Dryocosmus kuriphilus to cold stress to assess if and how the pest and its parasitoids were affected. Over the course of two years seasonal parasitism, parasitism rates, the relative abundance of each parasitoid species, and mortality of ACGW were calculated. We found that the cold treatment affected both pest and parasitoids, resulting in a reduction in emerging ACGWs and differing ratios of species within the parasitoid community. The striking example was the change in the relative frequency of three species of Eupelmus spp. and of Mesopolobus tibialis, which doubled in thermally-stressed galls in all chestnut fields. The thermal effects on the development of the host and the direct effects of cold temperatures on the surface of galls (i.e., humidity or hardness of the galls) warrant further research in this direction.