Diptera.info

Posted by Ingrid Altmann on 31-12-2019 10:57

Hello,
on 18.5.15 I found unter bark this Diptera pupae (near Furth im Wald, Bavarian Forest, Bavaria, Germany). I took some of it home to breed them. These little red flies hatched on the 30.5.15. Length: 1,8 mm
Do they belong to the Cecidomyiidae?

Best regards
Ingrid

Edited by Ingrid Altmann on 01-01-2020 18:36

Posted by John Carr on 31-12-2019 14:23

It's probably one of the basal lineages of fungus-feeding Cecidomyiidae but I'll need to pull out some books. The eyes are unusually small. Can you tell how many tarsomeres they have?

Posted by John Carr on 31-12-2019 15:39

Four tarsomeres (first longest), palps present, and not "buff-coloured" with "head and dorsum of thorax pale brown" should make them Miastor metraloas.

Quoting Wyatt (1967): "Larvae are readily found under the bark of rotting birch, where they often occur in large numbers and form dense star-shaped clusters. The decaying wood of many other trees may also be colonised to a lesser extent. The white larvae feed on the mycelium of wood-rotting fungi and reproduce by paedogenesis throughout the year."

Edited by John Carr on 31-12-2019 15:40

Posted by John Carr on 31-12-2019 15:49

The structural difference between the two species of Miastor given by Wyatt is "first flagellar segment [of M. castaneae] twice as long as broad and twice as long as third segment (in M. metraloas this ratio is 1½)". The behavioral difference is "larvae were found in small numbers in the rotting bark of chestnut posts, not aggregated as are those of M. metraloas."

Edited by John Carr on 31-12-2019 15:49

Posted by Ingrid Altmann on 01-01-2020 18:06

#10

Dear John,
great! I would not have thought that a determination up to the species would be possible.
If I remember correctly, I indeed found the pupae under birch bark.
Thank you very much for your help and for the detailed description!

All the best!
Ingrid