RESUMO
Cerambycid species of the Spondylidinae subfamily are distributed worldwide and are known for being prolific invaders that infest conifers. In New Zealand, Arhopalus ferus (Mulsant), the burnt pine longhorn beetle, is well-established and requires monitoring at high-risk sites such as ports, airports, and sawmills as part of the requirements to meet pine log export standards set by the New Zealand Ministry of Primary Industries (MPI). Currently, its surveillance relies on traps baited with host volatiles (i.e., ethanol and α-pinene). We used volatile collections from adult beetles, electroantennograms, and field trapping bioassays to identify the pheromones emitted by the burnt pine longhorn beetle A. ferus and their effects on its behaviour. We show that A. ferus males emit mainly (E)-fuscumol and geranylacetone, as well as the minor components, α-terpinene and p-mentha-1,3,8-triene, and that all four compounds elicit a dose-dependent response in antennae of both sexes. Traps baited with the binary combination of geranylacetone plus fuscumol captured significantly more female A. ferus than did unbaited traps in two of three field experiments. α-Terpinene did not affect A. ferus trap catches and effects of p-mentha-1,3,8-triene on trap catch were not determined. Our findings provide further evidence of the use of fuscumol and geranylacetone as aggregation-sex pheromones by longhorn beetles in the Spondylidinae subfamily, and suggest that their deployment in survey traps may improve the efficacy of A. ferus monitoring in New Zealand and elsewhere.
RESUMO
Quickly, accurately, and easily assessing the efficacy of treatments to control sessile arthropods (e.g., scale insects) and stationary immature life stages (e.g., eggs and pupae) is problematic because it is difficult to tell whether treated organisms are alive or dead. Current approaches usually involve either maintaining organisms in the laboratory to observe them for development, gauging their response to physical stimulation, or assessing morphological characters such as turgidity and color. These can be slow, technically difficult, or subjective, and the validity of methods other than laboratory rearing has seldom been tested. Here, we describe development and validation of a quick easily used biochemical colorimetric assay for measuring the viability of arthropods that is sufficiently sensitive to test even very small organisms such as white fly eggs. The assay was adapted from a technique for staining the enzyme hexokinase to signal the presence of adenosine triphosphate in viable specimens by reducing a tetrazolium salt to formazan. Basic laboratory facilities and skills are required for production of the stain, but no specialist equipment, expertise, or facilities are needed for its use.
