A new name for the western spruce budworm (Lepidoptera: Tortricidae)?

There currently is considerable confusion regarding the correct application of the name Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae). This name has historically been applied to the western spruce budworm, a serious forest pest in western North America. However, in 2008 Razowski transferred the African species Archips occidentalis (Walsingham) to Choristoneura Lederer and proposed C. freemani Razowski as a replacement name for the western spruce budworm. The validity of these nomenclatural changes and alternative solutions to resolve the confusion they have caused are discussed. Illustrations of wing patterns and genitalia for the two species are provided.

Identification and ecological characterisation of Choristoneura occidentalis (Lepidoptera: Tortricidae) populations in southwestern Alberta, Canada

The western spruce budworm, Choristoneura occidentalis Freeman (Lepidoptera: Tortricidae), is an important pest of western North American coniferous forests, where its principal larval host is Rocky Mountain Douglas-fir, Pseudotsuga menziesii subspecies glauca (Beissner) Murray (Pinaceae). In southwestern Alberta, Canada, populations were recently discovered feeding on an unconventional host, an Engelmann spruce, Picea engelmannii Parry ex. Engelmann × white spruce, Picea glauca (Moench) Voss hybrid (Pinaceae), in a transition zone between the two major forest types characterised by these conifer species. We use molecular evidence to verify the species identity of outbreaking Choristoneura populations collected from Douglas-fir and hybrid spruces in southwestern Alberta in 2009, and characterise the larval and male moth phenology. Both mitochondrial and microsatellite markers confirmed these populations as C. occidentalis, but admixture with Choristoneura fumiferana (Clemens) (Lepidoptera: Tortricidae) was detected in some individuals. Few differences associated with separate host trees were evident in the phenology of larvae and the flight period of male moths.

Effect of artificial diet components on conspecific repellency of larval oral secretions from western spruce budworm (Lepidoptera: Tortricidae)

A choice feeding bioassay was used to investigate the effects of artificial diet components on the repellency of larval oral secretions from western spruce budworm, Choristoneura occidentalis Freeman, to conspecific larvae. Oral secretions from insects fed on agar supplemented with linseed oil were as repellent as secretions from insects fed on complete artificial diet. Secretions from insects fed on agar alone, agar and casein, or agar and wheat germ were not significantly more repellent than distilled water; neither was linseed oil alone. Linseed oil consists of glycerides of several fatty acids, which are likely metabolized quickly in the insect gut; repellency of oral secretions could be due to any of the related fatty acids or metabolites.