Pselactus

Broun, 1886

Species Guides

1

Pselactus is a of weevils (Curculionidae: Cossoninae) distributed across Europe, Northwestern Africa, Northern America, and the Cape Verde Islands. At least one , Pselactus spadix, is a wood-borer of marine and coastal timbers, capable of completing its entire within wood without . The genus belongs to the tribe Onycholipini and includes species such as P. affinis, P. apionoides, P. obesulus, P. spadix, and P. strakai.

Pselactus spadix by (c) Landcare Research New Zealand Ltd, some rights reserved (CC BY). Used under a CC-BY license.Pselactus spadix by (c) Landcare Research New Zealand Ltd, some rights reserved (CC BY). Used under a CC-BY license.Pselactus spadix lateral by Landcare Research New Zealand Ltd. Used under a CC BY 4.0 license.

Pronunciation

How to pronounce Pselactus: //ˈsɛl.æk.təs//

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Identification

identification requires examination of ; P. obesulus and P. strakai have been diagnosed and illustrated in recent taxonomic treatments. Larval morphology has been described for some species and may aid identification of stages.

Images

Habitat

Marine and coastal timber environments; at least one (P. spadix) has been investigated in Scots pine heartwood under laboratory conditions. The occurs in the Cape Verde Islands (São Vicente, São Nicolau).

Distribution

Europe, Northwestern Africa, Northern America, and Cape Verde Islands (São Vicente, São Nicolau). Distribution records from GBIF include Denmark, Norway, and Sweden.

Diet

Wood; P. spadix has been reared on Scots pine (Pinus sylvestris) heartwood.

Host Associations

  • Pinus sylvestris - larval food sourceScots pine heartwood used in laboratory rearing of P. spadix

Life Cycle

Five larval instars identified by capsule width measurements. Development from 2nd instar to : 70.5±6.9 weeks. Pupal duration: 14.6±5.8 days. Development from 2nd instar to reproductive adult: 17–20 months. Total approximates 24 months at 22±2°C and 99±1% relative humidity. Oviposition occurs inside adult tunnels.

Behavior

mate within galleries at 2–3 months of age. The can complete without adults emerging from wood. Larval tunnels originate from adult tunnels and increase in diameter distally, terminating in -free pupal chambers.

Ecological Role

Wood decomposer and borer of coastal and marine timbers.

Human Relevance

P. spadix damages marine and coastal timbers, producing circular holes approximately 1.48 mm in diameter.

Similar Taxa

  • Other Cossoninae generaPselactus is distinguished by its placement in the tribe Onycholipini; larval and diagnostic characters separate it from related .

More Details

Life cycle duration

Laboratory studies on P. spadix indicate a approximately 2-year under controlled conditions (22±2°C, 99±1% r.h.), though field timing may vary.

Sexual dimorphism in longevity

Post-mating longevity differs significantly between sexes in P. spadix: males live 11.7±2.9 months versus females 6.3±1.1 months.

Systematic position

The systematic position of Pselactus within Onycholipini and its placement in Cossoninae have been reviewed in recent taxonomic treatments.

Sources and further reading