Ips avulsus

(Eichhoff, 1868)

Small Southern Pine Engraver

Ips avulsus, the small southern pine engraver, is a bark beetle in the Curculionidae. It colonizes pine , primarily attacking the lower bole of stressed or damaged trees. The uses a blend of ipsdienol and lanierone for , with responses to influenced by context and spatial arrangement. It cohabits trees with other Ips species and Dendroctonus frontalis, showing differential attack height partitioning.

Ips avulsus larvae and pupae in host phloem tissue. (33284857492) by ChattOconeeNF. Used under a CC BY 2.0 license.

Ips avulsus adult by W.H. Bennett, USDA Forest Service, Bugwood.org. Used under a CC BY 3.0 license.

Ips avulsus damage on pinus taeda by Erich G. Vallery, USDA Forest Service, Bugwood.org. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Ips avulsus: /ɪps əˈvʊlsəs/

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Identification

Distinguished from sympatric Ips by attack height preferences (lower bole, 0.3-2.0 m), blend composition (ipsdienol and lanierone), and differential response to enantiomeric ratios of ipsdienol. Ips calligraphus uses ipsdienol with cis-verbenol and trans-verbenol; Ips grandicollis uses ipsenol. Attack failure rate is notably higher than cohabiting species (45.5%).

Images

Appearance

Small bark beetle with typical scolytine . possess paired spines on the declivity, characteristic of the Ips. Specific spine count and arrangement distinguish it from .

Habitat

Bark and phloem of pine trees, specifically the lower bole region (0.3-2.0 m height). Found in loblolly pine plantations and pine forests where trees experience stress or damage.

Distribution

North America and Caribbean. Documented from southern United States pine forests, including North Carolina, South Carolina, and Florida.

Diet

Phloem tissue of pine trees. and larvae feed on inner bark.

Host Associations

Pinus taeda - primary Loblolly pine; most abundant in studied
Pinus - Pine generally

Behavior

Males initiate attacks on trees and excavate chambers. Females enter male-initiated galleries for mating; polygamous system with multiple females joining single male galleries. Shows context-dependent responses to components, with attraction to ipsdienol modified by presence of ipsenol, lanierone, and spatial separation of sources. Host monoterpene α-pinene increases attraction when released 4 m from pheromone source but reduces catches when collocated.

Ecological Role

Primary colonizer of stressed and damaged pine trees. Contributes to tree mortality in association with other bark beetles. Attacks trees with lowest oleoresin flow and highest crown damage ratings among cohabiting . Induces resin response in trees; attacked trees exude approximately three times more resin than control trees.

Human Relevance

Forest pest contributing to pine tree mortality, particularly during drought or stress conditions. Subject of chemical research for -based monitoring and management. Cedar oil products have been tested for preventing .

Similar Taxa

Ips calligraphusSympatric with overlapping range; distinguished by blend (includes cis-verbenol and trans-verbenol), attack height (upper bole), and preference for less stressed trees
Ips grandicollisSympatric ; distinguished by composition (ipsenol rather than ipsdienol/lanierone) and different attack patterns
Dendroctonus frontalisCohabiting bark beetle with mid-bole attack height; distinguished by different chemistry and reproductive

More Details

Chemical ecology

blend of ipsdienol and lanierone; enantiospecific response to ipsdienol depends on context including co-baits ipsenol and lanierone. Responses shaped by interspecific interactions and absence of conspecifics or related .

Attack dynamics

Highest proportion of unsuccessful attacks (45.5%) and lowest gallery among cohabiting Dendroctonus frontalis, Ips avulsus, and I. calligraphus. Preferentially attacks most suppressed and damaged trees with lowest oleoresin flow.