🏠 Caddisflies

Grannom Caddisfly

Brachycentrus subnubilus

About Grannom Caddisfly

A small dark caddisfly that produces massive spring hatches on European rivers. Larvae build distinctive square-sectioned cases from silk and plant fibers.

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Did You Know?

Grannom hatches are so dense on some rivers that local people historically swept up mounds of dead adults to use as fertilizer.

How to Identify Grannom Caddisfly

Grannom Caddisfly (Brachycentrus subnubilus) belongs to the order Trichoptera, family Brachycentridae. Adults typically measure 8-12 mm.

Grannom Caddisfly Habitat

Grannom Caddisfly 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.

Grannom Caddisfly Diet and Feeding

Grannom Caddisfly is a detritivore that feeds on decaying organic matter and dead plant material. By breaking down dead matter, detritivores play a crucial role in nutrient recycling and soil formation.

Where Is Grannom Caddisfly Found?

Grannom Caddisfly 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 Grannom Caddisfly can be found

Is Grannom Caddisfly Dangerous?

Grannom Caddisfly 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.

Grannom Caddisfly Role in Nature

Grannom Caddisfly plays a vital role in decomposition and nutrient recycling. By breaking down dead organic matter, it helps return nutrients to the soil, supporting plant growth and maintaining ecosystem health.

Seasonal Activity

Jan
Feb
Mar
Apr
May
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Aug
Sep
Oct
Nov
Dec
Peak activity Moderate Low / dormant

Frequently Asked Questions About Grannom Caddisfly

What does Grannom Caddisfly look like?

The Grannom Caddisfly typically measures 8-12 mm.

Where is Grannom Caddisfly found?

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

What does Grannom Caddisfly eat?

The Grannom Caddisfly feeds on decaying organic matter and dead plant material.

Is Grannom Caddisfly dangerous to humans?

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

What is an interesting fact about Grannom Caddisfly?

Grannom hatches are so dense on some rivers that local people historically swept up mounds of dead adults to use as fertilizer.

Cite This Page

APA:
InsectDiscover. (2026). Grannom Caddisfly (Brachycentrus subnubilus). Retrieved from https://insectdiscover.com/insect/grannom-caddisfly

MLA:
"Grannom Caddisfly." InsectDiscover, https://insectdiscover.com/insect/grannom-caddisfly.