Exapion ulicis

(Forster, 1771)

Gorse Seed Weevil

Exapion ulicis is a small seed-feeding weevil specialized on gorse (Ulex europaeus). are light gray with a prominent snout roughly half the body length. The is native to western Europe and has been introduced to New Zealand, California, Hawaii, and other regions as a agent targeting gorse . Larval feeding destroys seeds within pods, reducing plant spread, while adult feeding on stems and spines causes minor damage.

Exapion ulicis by (c) Landcare Research New Zealand Ltd., some rights reserved (CC BY). Used under a CC-BY license.Exapion ulicis by (c) Landcare Research New Zealand Ltd., some rights reserved (CC BY). Used under a CC-BY license.Exapion ulicis (Gorse Seed Weevil) - Flickr - S. Rae by S. Rae from Scotland, UK. Used under a CC BY 2.0 license.

Pronunciation

How to pronounce Exapion ulicis: /ɛɡˈzeɪpiɒn ˈjuːlɪsɪs/

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

Identification

Light gray coloration with a long, straight snout approximately half as long as the body. Total length 2–3 mm. create characteristic round holes in gorse stems and spines when feeding. Distinguished from the Exapion lemovicinum by seasonal activity (spring versus autumn) and primary association; molecular data confirm -level separation.

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Habitat

Associated with stands of Ulex europaeus (common gorse). In native range, occurs in western European gorse . In introduced range, established in gorse-invaded pastures, forest gaps, and natural areas.

Distribution

Native to western Europe. Introduced to New Zealand (1931), California and Oregon (1950s), Hawaii, and Chile (Araucanía and Los Ríos regions). Established in western United States. GBIF records confirm presence in Belgium and absence in Sweden.

Seasonality

Active in spring; reproductive period coincides with gorse pod availability in spring. Contrast with E. lemovicinum, which is active in autumn.

Diet

Larvae feed exclusively on seeds within Ulex europaeus pods. feed on soft tissue of gorse stems and spines, creating round holes.

Host Associations

  • Ulex europaeus - primary Native and introduced range; seeds consumed by larvae, stems/spines fed upon by
  • Ulex gallii - occasional Used in spring in some years in some when pods available; not primary
  • Ulex minor - occasional Used in spring in some years in some when pods available; not primary

Life Cycle

laid inside gorse seed pods. Larva emerges within pod and feeds on seeds for 6–8 weeks. lasts approximately 2 months. Development occurs entirely within gorse pods.

Behavior

Females make oviposition decisions based on external and internal pod cues, including pod size and seed content. Oviposition targets more fecund pods. Feeding preferences differ from oviposition preferences.

Ecological Role

Seed that reduces seed production and spread of Ulex europaeus. Does not eliminate established gorse stands due to limited damage. Subject to by three , though parasitization rates are low (0–1.6%) and do not limit weevil abundance.

Human Relevance

Used as agent against common gorse (Ulex europaeus), classified as a noxious weed in multiple countries. Seed destruction reduces gorse spread but does not control existing .

Similar Taxa

  • Exapion lemovicinumCongeneric seed weevil on gorses; distinguished by autumn reproductive period versus spring activity in E. ulicis, and primary association with U. gallii and U. minor rather than U. europaeus. Molecular data confirm separation.

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Sources and further reading