🏠 Caddisflies

Western Grannom Caddis

Brachycentrus occidentalis

About Western Grannom Caddis

A widespread European caddisfly forming mass emergences in spring on alkaline rivers. Larvae build four-sided tapering cases and filter-feed in riffles.

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Did You Know?

Spring Grannom hatches on English chalk streams can darken the sky with millions of emerging adults.

How to Identify Western Grannom Caddis

Western Grannom Caddis (Brachycentrus occidentalis) belongs to the order Trichoptera, family Brachycentridae. Adults typically measure 9-12 mm.

Western Grannom Caddis Habitat

Western Grannom Caddis is found in rivers & streams habitats, particularly across Europe. This species has adapted to thrive in its preferred environment, where it can find suitable food sources and shelter.

Western Grannom Caddis Diet and Feeding

Western Grannom Caddis has an omnivorous diet, feeding on both plant and animal matter. This dietary flexibility allows it to exploit a wide range of food sources in its environment.

Where Is Western Grannom Caddis Found?

Western Grannom Caddis can be found in Europe, where it inhabits rivers & streams environments. Its distribution is influenced by climate, food availability, and habitat suitability.

Distribution Map

Where Western Grannom Caddis can be found

Is Western Grannom Caddis Dangerous?

Western Grannom Caddis is generally harmless to humans. It does not bite or sting and poses no significant health risk. Like most insects, it prefers to avoid human contact and will typically flee rather than confront a perceived threat.

Western Grannom Caddis Role in Nature

Western Grannom Caddis plays a role in its ecosystem as part of the food web, serving as both consumer and prey. Insects like Western Grannom Caddis are a vital food source for birds, bats, and other wildlife, and contribute to the overall health and balance of their environment.

Seasonal Activity

Jan
Feb
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Sep
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Nov
Dec
Peak activity Moderate Low / dormant

Frequently Asked Questions About Western Grannom Caddis

What does Western Grannom Caddis look like?

The Western Grannom Caddis typically measures 9-12 mm.

Where is Western Grannom Caddis found?

The Western Grannom Caddis is found in Europe and typically inhabits rivers & streams environments.

What does Western Grannom Caddis eat?

The Western Grannom Caddis has an omnivorous diet, feeding on both plant and animal matter.

Is Western Grannom Caddis dangerous to humans?

The Western Grannom Caddis is generally harmless to humans. It does not bite or sting and poses no significant health risk.

What is an interesting fact about Western Grannom Caddis?

Spring Grannom hatches on English chalk streams can darken the sky with millions of emerging adults.

Cite This Page

APA:
InsectDiscover. (2026). Western Grannom Caddis (Brachycentrus occidentalis). Retrieved from https://insectdiscover.com/insect/western-grannom-caddis

MLA:
"Western Grannom Caddis." InsectDiscover, https://insectdiscover.com/insect/western-grannom-caddis.