Ips grandicollis

Wood & Bright, 1992

eastern five-spined engraver, eastern five-spined ips, southern pine engraver, fivespined engraver

Ips grandicollis is a bark beetle in the Curculionidae, commonly known as the eastern five-spined engraver or southern pine engraver. The is native to North America and has been introduced to Australia. It primarily colonizes Pinus species, attacking weakened, stressed, or recently felled trees rather than healthy standing timber. Males initiate gallery construction and produce to attract multiple females. The species has reached economic importance in some regions, including Jamaican pine plantations, where it can kill trees when aggregate on living .

Ips grandicollis by Simon Hinkley & Ken Walker, Museum Victoria. Used under a CC BY 3.0 au license.

Ips grandicollis larva by Erich G. Vallery, USDA Forest Service, Bugwood.org. Used under a CC BY 3.0 license.

Ips grandicollis larva crop by Erich G. Vallery, USDA Forest Service, Bugwood.org. Used under a CC BY 3.0 license.

Pronunciation

How to pronounce Ips grandicollis: /ˈɪps ˈɡrændɪˌkɒlɪs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from other Ips by five spines arranged in two rows on the declivity ( slope) of the . Ips avulsus has four spines; Ips calligraphus has six spines. The species is small, with typically 3-5 mm in length. The elytral declivity is concave with the spine rows flanking a central depression. Identification requires examination of the posterior elytra; similar species in the Dendroctonus lack the spine rows characteristic of Ips.

Images

Habitat

Pine forests and plantations. Colonizes freshly cut logs, slash, and weakened or stressed standing trees. In Jamaica, thrives mainly on freshly cut logs and weakened trees, with recent expansion to economic pest status in plantations. Successful attack on live trees is enhanced by mass of dispersing .

Distribution

Native to North America: Canada (Manitoba, Ontario, Quebec), United States (widespread in eastern and central states from Maine to Florida, west to Minnesota, Nebraska, and Texas), Mexico, Central America and Caribbean (Bahamas, Cuba, Dominican Republic, Guatemala, Honduras, Jamaica, Nicaragua). Introduced to Australia (New South Wales, Queensland, South Australia, Victoria, Western Australia).

Diet

Phloem of Pinus . Feeds on inner bark tissues of trees.

Host Associations

Pinus caribaea - attacked in Jamaica
Pinus elliottii - attacked in North America
Pinus radiata - attacked in Australia and New Zealand plantings
Pinus spp. - five Pinus attacked in Jamaica, four newly recorded for these scolytids on the island

Life Cycle

disperse to locate suitable material. Males initiate galleries and release . Females construct galleries branching from the central chamber. Eggs hatch into legless larvae that tunnel through phloem, creating characteristic engraver patterns. Some adults may re-emerge after oviposition to disperse to new food sources. muscles degenerate during oviposition and regenerate to allow subsequent flights. Mean eggs per gallery: 19.29 ± 3.04. Sex ratio at : approximately 50% female.

Behavior

Males are the primary finders and initiators of . Upon locating suitable host material, males bore into bark and produce ipsenol and other to aggregate conspecifics, including multiple females. Beetles respond to host volatiles including α-pinene. During host selection, beetles may reject trees with active resin exudation; continued boring and pheromone production occurs only in hosts where resin defenses are overcome or absent. Mass enhances attack success on living trees. losses are substantial: minimum 44% of lost during dispersal, with male losses (77.3%) higher than female losses (35.4%).

Ecological Role

Secondary colonizer of stressed, damaged, or recently killed pines. Contributes to nutrient cycling by accelerating decomposition of woody material. In natural forests, thins weakened trees. Can shift to primary pest status when aggregate on living trees, particularly in plantations or during drought stress. Associated with blue-staining fungi including Ophiostoma ips, which are vectored to trees. Serves as host for phoretic mites and parasitic .

Human Relevance

Economic pest in pine plantations, particularly in the southeastern United States, Jamaica, and Australia. Damage occurs when beetles colonize stressed or damaged trees, and subsequent mass attacks can kill apparently healthy trees. Can infest cut Christmas trees and stored logs. Management includes rapid utilization or treatment of felled timber, maintaining tree vigor, and monitoring for conditions. -based monitoring and mass trapping are used for management.

Similar Taxa

Ips avulsusFour spines on elytral declivity versus five in I. grandicollis; smaller size; different blend
Ips calligraphusSix spines on elytral declivity versus five in I. grandicollis; larger size; different gallery patterns
Ips piniFive spines but different arrangement and body proportions; different chemistry (ipsdienol primary)
Dendroctonus frontalisLacks spine rows on declivity entirely; different with distinct gallery architecture and

More Details

Pheromone chemistry

Produces ipsenol as primary ; also produces and responds to cis-verbenol and ipsdienol. Detects monoterpene α-pinene and interspecific compounds including frontalin and verbenone from Dendroctonus .

Associated organisms

Phoretic mites including Dendrolaelaps quadrisetus and Histiogaster arborsignis attach to dispersing and detach within trees. Mites feed on fungal including Ophiostoma ips. Parasitic Contortylenchus grandicolli coordinates its with the .

Flight muscle plasticity

Exhibits reversible muscle degeneration during reproductive phase, with enabling subsequent . This physiological allows resource tracking across ephemeral patches.