Exploring the potential for novel associations of generalist parasitoids for biological control of invasive woodboring beetles.
Cerambycid and buprestid woodborers are important invasive forest pests. Parasitoids play a unique role in reducing woodborer populations because of their specific adaptations regarding host concealment. We reviewed parasitoid guilds of cerambycid and buprestid woodborers to characterize their life-history traits and macroecological patterns of host use. The parasitoid guilds shift from more specialist endoparasitoids to more generalist ectoparasitoids following the hosts' ontogeny and the increased concealment of host feeding niche. Larval ectoparasitoids dominate the guilds, and many of them locate hosts through substrate vibration from living hosts, rendering attacked (paralyzed) hosts undetectable by other parasitoids and consequently leading to a rarity of multiparasitism. These characteristics promote novel associations between exotic woodborers and extant larval parasitoids, leading to coexistence and synergistic regulation of host populations by different parasitoids. We provide case studies to propose a framework of optimal use of co-evolved and novel associations for complementary suppression of invasive woodborer populations. We also discuss potential non-target impacts for the use of generalist parasitoids in biological control of invasive cerambycid and buprestid woodborers.