Mother knows best: Emerald ash borer oviposition host preference corresponds with larval performance

The optimum oviposition theory states that female insects will oviposit on hosts on which their progeny will best perform with regards to growth, survival, and reproduction. It is believed that success of wood-borer larvae is particularly tied to female oviposition choice because larvae are unable to switch hosts. The invasive emerald ash borer (EAB) is one example. Past work suggests that EAB adults prefer to feed on ash species that are good larval hosts over species that are more resistance to larval feeding. We examined the relationship between EAB oviposition preference and larval performance on three susceptible North American ash species and a resistant Asian species at two field sites, one at Novi, MI near the site of the initial infestation, and another in Dayton, OH at the leading edge of the invasion front. Adult oviposition began in late May in Dayton, OH and approximately one week later in Novi, MI, peaked in roughly mid-June, and then declined in early July. Host species was a highly significant predictor of oviposition preference with the North American natives being much more preferred as oviposition sites than the highly-resistant Asian species. Interestingly, these results match adult feeding preferences and inversely match host resistance to the insect, supporting the strong coupling between oviposition choice and larval success predicted for wood-borers by the optimum oviposition theory.