Pseudohylesinus grandis

Swaine, J.M., 1917

Pseudohylesinus grandis is a bark beetle (Curculionidae, formerly ) associated with western hemlock forests of coastal North America. It completes one annually with two and four larval instars, as a . The exhibits distinct breeding preferences, utilizing fresh slash in thinned stands rather than stumps. Adult females engage in pre-oviposition feeding on the inner bark of standing live trees before constructing galleries in slash material.

1956. Pseudohylesinus grandis egg galleries and larval mines on the inner bark surface of Abies amabilis. (34720905961) by R6, State & Private Forestry, Forest Health Protection. Used under a Public domain license.1955. Pseudohylesinus grandis egg galleries and larvae on inner bark of silver fir. Baker River District, Mt. Baker National Forest. Washington. (34466337570) by R6, State & Private Forestry, Forest Health Protection. Used under a Public domain license.1955. Pseudohylesinus grandis egg galleries on Pacific silver fir. Upper part - galleries on wood; lower part - galleries on bark, removed from upper part. Baker River District, Mt. Baker National Forest. Washington. (34042520163) by R6, State & Private Forestry, Forest Health Protection. Used under a Public domain license.

Pronunciation

How to pronounce Pseudohylesinus grandis: /suː.doʊ.hɪˈliːsɪnəs ˈɡrændɪs/

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Habitat

Young coastal stands of western hemlock; specifically thinned stands containing fresh slash used as breeding material. Distinguished from the P. tsugae, which prefers fresh stumps in the same type.

Distribution

Coastal western North America; specifically documented from young coastal stands of western hemlock.

Seasonality

with two per year; occurs as , with activity resuming in appropriate seasonal conditions.

Host Associations

  • western hemlock - primary females feed in inner-bark region of standing live trees; breeding occurs in fresh slash

Life Cycle

One per year with two ; four larval instars; overwinters as .

Behavior

females feed in the inner-bark region of standing, live trees before initiating galleries in slash. Shows strong preference for fresh slash over stumps for breeding material in thinned stands.

Ecological Role

Bark beetle contributing to decomposition of slash material in thinned western hemlock stands; participates in nutrient cycling through wood-boring activity in dead and dying material.

Similar Taxa

  • Pseudohylesinus tsugaeSympatric with similar and association; distinguished by breeding substrate preference (P. tsugae uses fresh stumps, P. grandis uses fresh slash) and stage (P. tsugae as fourth instar larva, P. grandis as )

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