VERTICAL DISPLACEMENT OF IPS LATIDENS AND IPS PINI (COLEOPTERA: SCOLYTIDAE) BY SEMIOCHEMICAL INTERRUPTION

The effect of semiochemical interruptants was examined for Ips latidens (LeConte) and Ips pini (Say) using artificial trees (tall-traps) consisting of an array of seven Lindgren multiple-funnel traps suspended vertically on a rope ladder. S-(+)-Ipsdienol reduced the numbers of I. latidens captured in (±)-ipsenol-baited funnel traps relative to funnel traps immediately above them and to control tall-traps. The combination of (±)-exo-brevicomin and cis- and trans-verbenol reduced the numbers of I. pini captured in (±)-ipsdienol-baited funnel traps relative to funnel traps immediately above them and to control tall-traps. These results provide support for semiochemical-based pest-management tactics that utilize a point source of interruptant at the base of a tree while noting limitations in behavioural effects and efficacy.

DOSE-DEPENDENT AND SPECIES-SPECIFIC RESPONSES OF PINE BARK BEETLES (COLEOPTERA: SCOLYTIDAE) TO MONOTERPENES IN ASSOCIATION WITH PHEROMONES

Monoterpenes affected the attraction of three sympatric species of bark beetles (Coleoptera: Scolytidae) to pheromone-baited multiple-funnel traps in stands of lodgepole pine. Catches of Ips pini (Say) in traps baited with its pheromone, ipsdienol, were directly related to the release rates of 3-carene, β-phellandrene, and β-pinene. Catches of Dendroctonus ponderosae Hopkins in traps baited with exo-brevicomin and cis- and trans-verbenol were directly related to the release rates of 3-carene, myrcene, and β-phellandrene. Ips latidens (LeConte) exhibited preferences for traps baited with ipsenol and β-phellandrene or β-pinene but not in a dose-dependent fashion. Catches of I. latidens in traps baited with its pheromone, ipsenol, were inversely proportional to the release rates of 3-carene, myrcene, and terpinolene. Similarly, catches of I. pini in traps baited with its pheromone, ipsdienol, were inversely proportional to the release rates of myrcene and terpinolene. These results demonstrate a degree of species specificity among three phloeophagous species with respect to preferred host odours. The bark beetle predators–associates Lasconotus complex LeConte (Coleoptera: Colydiidae) and Corticeus Piller and Mitterpacher sp. (Coleoptera: Tenebrionidae) demonstrated some measure of specificity to monoterpenes in their responses to ipsdienol-baited funnel traps. γ-Terpinene increased attraction of L. complex but had no effect on Corticeus sp., whereas α- and β-pinene increased attraction of Corticeus sp. but had no effect on L. complex.

THE USE OF MONOTERPENES AS KAIROMONES BY IPS LATIDENS (LECONTE) (COLEOPTERA: SCOLYTIDAE)

The responses of Ips latidens (LeConte) to multiple-funnel traps baited with various monoterpenes were determined in stands of lodgepole pine in British Columbia. β-Phellandrene was attractive to I. latidens in the absence of the pheromone ipsenol. β-Phellandrene increased the attraction of I. latidens to ipsenol-baited traps while α-pinene, 3-carene, terpinolene, and myrcene reduced trap catches. Differential responses by males and females to sources of ipsenol with or without β-phellandrene suggest that the information conveyed to males differs from that conveyed to females. Species-specific responses to monoterpenes by I. latidens and three sympatric species of scolytids suggest that unique combinations of kairomones could be important in facilitating matings with conspecifics. Pheromones need not be the sole constituent of species-specific chemical messages.

Taxonomy and chemistry of a new fungus from bark beetle infested Pinus contorta var. latifolia. Part 1. Arthrographis pinicola sp.nov.

Arthrographis pinicola sp.nov. (Hyphomycetes) is described; it was isolated from galleries and adult beetles of Ips latidens and from galleries of Dendroctonus ponderosae in Pinus contorta var. latifolia in western Canada. In I. latidens infested lodgepole pine, this species extensively colonizes nuptial chambers and egg galleries, characteristically forming floccose conidiomata composed of repeatedly branched hyphae which divide to form arthroconidia having schizolytic dehiscence. The fungus is antagonistic to some blue stain fungi in vitro. Arthrographis pinicola is compared with other species of Arthrographis, and with Arthropsis microsperma and the discomycete Pezizella chapmanii. Key words: Arthrographis pinicola, Hyphomycetes, bark beetle fungi, antifungal compound, arthrographol.

PRIMARY ATTRACTION OF IPS LATIDENS (LECONTE) AND HYLASTES GRACILIS LECONTE (COLEOPTERA: SCOLYTIDAE) TO HIGH-GIRDLED LODGEPOLE PINE, PINUS CONTORTA VAR. LATIFOLIA ENGELMANN

In the absence of secondary attraction, 2 species of Scolytidae, Ips latidens (LeConte) and Hylastes gracilis LeConte, showed significant preference while in flight for high-girdled over non-girdled lodgepole pines, Pinus contorta var. latifolia Engelmann. In contrast, beetles in 2 genera of Elateridae, Ampedus and Ctenicera, showed significant preference for non-girdled over high-girdled lodgepole pines. Beetles in 12 other families, as well as other scolytids and elaterids, did not show any significant preference or aversion to high-girdled trees. This is the first clear demonstration of primary attraction for a North American Ips species and the second for an Hylastes species.

LIFE HISTORY AND BIOLOGY OF IPS LATIDENS (LECONTE) (COLEOPTERA: SCOLYTIDAE)

The life history and biology of Ips latidens (LeConte) were investigated using bark-sandwich and whole-log rearing methods. In contrast with other Ips spp., some females initiated galleries under conditions of female-biased sex ratios, and sometimes 2 or more males were present in a gallery. In general, however, I. latidens exhibited typical ipine characteristics. A single male usually admitted 1–3 females into a gallery. Females oviposited at a rate of 2.25 eggs/day and achieved a mean fecundity of 64.4 eggs. The larval stage comprised 80% of the generation time (egg to teneral adult) and analysis of head-capsule widths disclosed 3 larval instars. The mean survivorship within broods was 56.0% after 70 days; the reproductive success of monogamous pairs of beetles was 36.1 teneral adults. Single females constructed 3–4 egg tunnels/gallery system; hence, harem size cannot always be inferred from the number of egg tunnels in each gallery. The mean generation time in the laboratory was 2.07 × greater than for I. pini. By comparing laboratory data on I. latidens with laboratory and field data on I. pini, the generation time of I. latidens is estimated at 64–124 days in the field. In south-central British Columbia, I. latidens probably has 1 generation, and possibly 2 broods, per year.