The role of field-collected cues in the host recognition of twig girdlers (Oncideres rhodosticta) on honey mesquite (Prosopis glandulosa)

Conspecific gravid females integrate volatile organic compounds (VOCs) to exploit potential oviposition sites; the role of VOCs has not been examined on twig girdlers, Oncideres rhodosticta, and honey mesquite, Prosopis glandulosa. To examine the host selection behavior of female twig girdlers, we examined the preference and searching time between healthy and girdled twigs of honey mesquites in New Mexico, USA. Among 21 different volatile organic compounds, female twig girdlers reacted to six chemical compounds from girdled twigs and four from healthy twigs. While females responded to Heptanal, (E)-2-Heptenal, and Linalool oxide on both healthy and girdled twigs, they also reacted to one healthy specific compound and two girdled specific compounds. Female twig girdlers distinguished healthy twigs over girdled twigs with faster searching time. Our finding demonstrates VOCs in the genus Oncideres for the first time, providing additional empirical information to help decide on the biological control potential of possible agents during the pre-release risk assessment.