Reticulitermes hesperus (Banks, 1920)

Western subterranean termite

The West Coast's version of the subterranean termite, same underground habits, different coastline.

Order: Blattodea
Family: Heterotermitidae
Group: Termites
Ontario status: Not established in Ontario, western North America species; included as reference for identification and exam contrast

Why it matters

The primary structural termite pest of the Pacific coast; a useful reference for Ontarians because misidentifications in shipped lumber and the identical biology make it exam-relevant contrast material.

Origin

Native to western North America, from British Columbia down the Pacific coast to California.

Behavior

Underground foraging year-round; winged swarmers emerge in spring on warm humid days. Workers avoid light and dry air.

Living conditions

Same requirements as its eastern cousin: soil contact, constant moisture, wood to eat. Builds mud shelter tubes from soil to lumber in coastal homes.

Signs of presence

Mud shelter tubes on foundations
Shed wings near windows in spring
Hollow-sounding wood with mud-packed galleries

Weaknesses

Desiccates rapidly outside humid shelter tubes or soil
Colony collapses without its reproductives
Cold-intolerant compared with the eastern species, limited by climate

Myths and facts

Myth All subterranean termites in Canada are the same species.
Reality Eastern and western Canada have different Reticulitermes species, geography, not appearance, usually separates them.

Research notes

Morphology

Workers ~6 mm, pale, blind. Soldiers with rectangular heads and mandibles; morphometric differences from R. flavipes are measurable but not field-reliable. Alates dark, ~10 mm body, two pairs of equal membranous wings.

Diagnostics

Geography is the practical diagnostic: west of the Rockies = hesperus. Laboratory separation uses soldier head measurements and cuticular hydrocarbon profiles.

Easily confused with

Eastern subterranean termite, Reticulitermes flavipes Geographic range; morphology overlaps, molecular or morphometric analysis required for certain separation.

Life cycle

Adult: Sterile workers/soldiers; winged alates disperse seasonally
Egg: ~1 mm, laid by queen in royal chamber
Egg to adult: Several months for workers under favorable conditions
Generations per year: Perennial colonies persisting many years
Nymph or larva: Nymphs develop along worker, soldier, or reproductive pathways under pheromonal regulation

Development

Hemimetabolous with caste polyphenism; no pupal stage.

Reproduction

Single mature queen produces thousands of eggs daily at peak; colonies mature over several years.

Distribution

Global: Native range plus limited human-assisted movement
Native range: Pacific coastal North America, British Columbia to California
Ontario: Not established; reference species only

Ecology

Gut flagellate symbionts digest cellulose; foraging via shelter tubes; moisture-obligate.

Resistance

Unknown, no significant documented resistance; limited study compared with eastern species.

IPM implications

Same colony-target logic as R. flavipes: monitor with in-ground stations, manage moisture and wood-soil contact, target the colony rather than foragers.

Chemical ecology

Trail and caste-regulating pheromones as in other Reticulitermes; soldier defensive secretions.

Genetics and DNA

No reference genome published as of 2026.

Taxonomy

Order Blattodea, family Heterotermitidae (revised from Rhinotermitidae, Hellemans et al. 2024). Eusocial with worker/soldier/reproductive castes; caste polyphenism as in R. flavipes.

Open questions

Northern range limits in BC under climate change; hybridization potential where ranges meet other Reticulitermes.

References

Bignell, D.E., Roisin, Y. & Lo, N. (eds.) (2011). Biology of Termites: A Modern Synthesis. Springer.