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Insects and other arthropods

Western conifer seed bug

Leptoglossus occidentalis

Tabs group


This large reddish-brown leaf-footed bug is 15 to 20 mm long. It has broad tibiae on its hind legs and its slightly thickened forewings have a fairly distinct white zigzag marking.

Life cycle

In spring, the adults that survived the winter in a shelter start seeking conifers on which to feed. The females lay their eggs on the conifer needles and the eggs hatch in about ten days. The nymphs that emerge moult five times before reaching adulthood, in late

When temperatures start dropping in fall, these bugs start seeking suitable spots to overwinter. At that time, they can often be seen near or even inside people’s homes.

Geographic distribution

This species is native to the west coast of the United States. It has expanded across the continent since 1950, reaching the east in the early 1980s. In Canada, it is now found as far east as New Brunswick. It is now the most common Coreidae species in northeastern North America, having followed its host plants as their distribution area changed.

In Europe, it appeared in Italy in 1999 and in France in 2005. It travels mainly aboard ships with cargos of timber, and is now found in a number of European countries.


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