Chironomid midge (Maoridiamesa)

Taxonomic group

Chironomidae: Maoridiamesa

Diagnostic features

Maoridiamesa is the most common member of the Diamesinae, a subfamily of the Chironomidae. Like other chironomids the general body form is worm-like, but with a distinct head, and with paired prolegs under the head and at the end of the abdomen. Maoridiamesa larvae have a green or pale body, brown head with prominent hairs, and a distinct black collar. The eye can be a circular black mass or two joined spots.

[Maoridiamesa]. Image: Stephen Moore Image — Maoridiamesa. Image: Stephen Moore

[Maoridiamesa]. Black collar behind brown head. Image: Stephen Moore Image — Maoridiamesa. Black collar behind brown head. Image: Stephen Moore

Typical habitats

Maoridiamesa larvae are found in a wide range of streams, particularly at sites with abundant streambed algae.

Feeding

They are presumably collector-gatherers; feeding on algae and other fine organic matter.

Indicator value

Hard bottom: 3
Soft bottom: 4.9

The tolerance values (ranging from 0 to 10) give an indication of which are the sensitive taxa (values of 8 or more) and which are the tolerant taxa (values of 3 or less). For more information see: Indicator species

Maoridiamesa can be common in good quality streams, but also in nutrient enriched streams with prolific streambed algae. They have tolerance values of 3 (hard bottom sites) and 4.9 (soft bottom sites).