Adults are usually about 15–20 mm long.
Fine-art photographic collection
Leptoglossus occidentalis
A conifer-seed specialist that can sense the infrared glow of a warmer pine cone.
About this species
Western Conifer Seed Bug
Leptoglossus occidentalisHeidemann, 1910
Information reviewed15 July 2026
Leptoglossus occidentalis is a leaf-footed bug native to western North America that has spread widely through international trade. Adults and nymphs pierce developing conifer seeds, and adults commonly enter buildings in autumn to overwinter.
Taxonomy
Animalia · Arthropoda · Insecta · Hemiptera · Coreidae · Leptoglossus
Accepted taxon. · checked 2026-07-15
native western North America and introduced across Europe, parts of Asia, North Africa and South AmericaBroad range and selected reference localities — not a complete occurrence map.
native western North America and introduced across Europe, parts of Asia, North Africa and South America
Conifer woodland, plantations, parks and buildings used as winter shelters.
Active on conifers in warm months; adults aggregate in sheltered sites during autumn and winter.
Developing seeds and reproductive tissues of pines and other conifers.
Solitary.
What makes this species remarkable?
Specialised receptors on the abdomen detect infrared radiation, helping the bug orient towards warmer seed-filled cones hidden among cooler foliage.
The adhesive that fixes its egg rows to pine needles contains a sophisticated mixture of resin-like polymers, plasticisers and chemical signals.
From a western North American native range, it crossed the Atlantic and became established across much of Europe in only a few decades.