Sirex areolatus

Distinguished from other horntail wasps by the areolate (net-like) sculpturing pattern. Separated from the similar Sirex noctilio by geographic distribution and host preferences; S. noctilio is a notorious invasive pest of pine plantations while S. areolatus appears restricted to native hardwood associations. The specific epithet 'areolatus' refers to the reticulate surface pattern visible on close examination.

Medium-sized horntail wasp with the characteristic cigar-shaped body form typical of Siricidae, where the abdomen joins broadly to the thorax. Females possess two posterior projections: a longer, needle-like ovipositor and a shorter dorsal cornus. Coloration and specific markings consistent with the areolate (net-like) pattern implied by the species epithet, though detailed descriptions are sparse in available sources.

Associated with dead, dying, or weakened hardwood trees. Develops in wood of deciduous trees where fungal decay has been initiated. Specific host tree associations are not well documented but likely include maple, beech, elm, and other hardwoods typical of the family.

Documented from Canada: British Columbia and Nova Scotia. GBIF records indicate doubtful occurrences in Belgium and France, possibly representing misidentifications or introduced specimens. The species appears to have a disjunct distribution pattern in eastern and western Canada, though this may reflect collection bias rather than true range discontinuity.

Adults likely emerge in late summer and fall, consistent with the phenology of related Tremex and Sirex species. Exact flight period not specifically documented.

• Hardwood trees (deciduous) - larval hostSpecific host genera not documented; likely includes maple, beech, elm based on family patterns
• Wood-rotting fungi - symbioticFemales introduce fungi via mycangia; larvae consume decayed wood and fungal tissue

Females drill into wood with ovipositor, depositing eggs along with symbiotic wood-rotting fungi stored in abdominal mycangia. Larvae are grub-like, feeding on the fungus-decayed wood. Development likely takes more than one year. Pupation occurs within the wood, with adults emerging through exit holes.

Females search for suitable host trees and engage in wood-drilling behavior to oviposit. Males may aggregate at emergence sites seeking mating opportunities. Adults are generally inactive and can be approached closely when at rest.

Contributes to forest nutrient cycling by accelerating decay of dead and dying hardwoods. Serves as host for parasitoid wasps including giant ichneumon wasps (family Ichneumonidae) and ibaliid wasps, which attack larval and pupal stages.

Not considered a significant pest. Unlike the invasive Sirex noctilio, this species appears to exploit only trees already compromised by stress, disease, or other damage. No economic impact documented.

• Sirex noctilioSirex noctilio is a larger, more robust species with different coloration and is a serious pest of pine plantations; S. areolatus is restricted to hardwoods and lacks economic impact
• Tremex columbaTremex columba is larger (females 37-50 mm), has different coloration patterns, and shows geographic variation with western specimens paler than eastern ones; both share the horntail body form and dual posterior projections in females
• Other SiricidaeSeparation requires examination of wing venation, antennal structure, and surface sculpturing patterns best determined by specialist identification

• horntail
• woodwasp
• Siricidae
• wood-boring
• parasitoid host
• native
• hardwood associate

• BugGuide
• GBIF taxonomy match
• iNaturalist taxon
• NCBI Taxonomy
• Bug Eric: Wasp Wednesday: Chlorion aerarium
• Bug Eric: Wasp Wednesday: Pigeon Tremex Horntail
• Bug Eric: Giant ichneumon wasps