Phloeosinus

Chapuis, 1869

cedar bark beetles, cypress bark beetles

Species Guides

12

Phloeosinus is a of bark beetles (Curculionidae: Scolytinae) comprising at least 20 described . Species in this genus are specialized on conifers in the Cupressaceae, including genera such as Cupressus, Thuja, Juniperus, and Chamaecyparis. Several species have become significant pests, causing economic damage to ornamental trees and forest . The genus exhibits specialized chemical , with species using plant volatiles and for mate and host location.

Phloeosinus by (c) Trevor Van Loon, some rights reserved (CC BY), uploaded by Trevor Van Loon. Used under a CC-BY license.Phloeosinus cupressi by (c) Landcare Research New Zealand Ltd, some rights reserved (CC BY). Used under a CC-BY license.Phloeosinus cupressi by (c) Desmond W. Helmore , some rights reserved (CC BY). Used under a CC-BY license.

Pronunciation

How to pronounce Phloeosinus: /flɪoʊˈsaɪnəs/

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

Identification

identification within Phloeosinus relies on detailed examination of elytral declivity patterns, with males typically bearing small, individual, sparse, sharply pointed tubercles on odd interstriae, and females showing smaller, blunt, nippled tubercles. Phloeosinus metasequoiae is distinguished by deeply , coarse frontal and prothoracic surfaces with reticulate texture, and deeply V-shaped basal margin of the .

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Habitat

Associated with Cupressaceae conifers including cypresses, junipers, arborvitae, and related ornamental and forest trees. occupy bark and phloem tissues of trees, with some preferring stressed, dying, or dead wood while others attack living trees.

Distribution

Native range includes North America, Mediterranean region, and Asia. Multiple have established : P. aubei across temperate Europe; P. cupressi in Australia, New Zealand, and Panama; P. serratus in Jamaica. Climate modeling indicates potential for further range expansion under warming scenarios.

Seasonality

P. aubei shows bimodal activity: females search for declining trees to establish breeding galleries in April–May, while adults of both sexes visit healthy trees to bore tunnels from August to October.

Diet

Phloem tissues of trees. feed on phloem and bore into bark and small twigs.

Host Associations

  • Cupressus - primary
  • Thuja occidentalis - including cultivar 'Smaragd'
  • Juniperus communis - older, damaged trees with stems >3 cm diameter
  • Juniperus flaccida - confirmed primary for P. deleoni
  • Juniperus deppeana - confirmed primary for P. deleoni, with direct feeding observed
  • Chamaecyparis lawsoniana -
  • Platycladus orientalis -
  • Metasequoia glyptostroboides - for P. metasequoiae
  • Pinus nigra subsp. laricio - for P. laricionis, the only Palaearctic known from pine

Life Cycle

Females initiate gallery construction in bark, creating chambers and breeding galleries. Larvae develop within phloem tissue. P. aubei overwinters as in small tunnels bored into healthy trees. Some show preference for dead or dying host material for .

Behavior

use volatile organic compounds for location, with distinct responses to volatiles from healthy versus stressed trees. P. aubei detects α-thujone from healthy trees, and α-pinene, α-thujene, β-pinene, myrcene, limonene, and p-cymene from infested or stressed trees. P. cupressi bore into small twigs creating downward-extending tunnels while preserving thin outer bark, causing twig breakage that attracts conspecifics. P. aubei males produce cis-verbenol and verbenone as components upon mating, which interact with female-produced components and host to mediate .

Ecological Role

As primary bark borers on Cupressaceae, contribute to tree mortality and nutrient cycling in native . In invaded ranges, several species function as destructive pests causing significant economic losses and aesthetic damage to ornamental plantings and urban forests. P. dentatus serves as alternate for hymenopterous that primarily attack southern pine beetle and Ips species.

Human Relevance

Multiple are significant economic pests of ornamental trees in nurseries and urban green spaces. P. aubei and P. cupressi are particularly damaging in Europe, Australia, and New Zealand. P. aubei is monitored using blends containing myrtenol, α-pinene, and cis-verbenol. Climate change is projected to expand suitable for invasive species, necessitating and monitoring programs.

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