sabine.nouvet's picture

Grub found in our leather tanning pit

Observed: 30th March 2011 By: sabine.nouvet
tannin grub scale
tannin grub front view
Description:

it moves like a catterpillar, has a retractable, slimy tail, and a pair of very small antenae.
there were loads of them in the tanning solution for the last month (different stages), and they are eating the leather. what are they?

Identifications
Species interactions

No interactions present.

Comments

DavidNotton's picture

Eristalini

Rat-talied maggots are found in the tribe Eristalini which includes a number of well known genera such as Helophilus and Myathropa. The rat-tailed maggots of Myathropa florea for example live in putrid wet habitats, I have found them in huge numbers in waterlogged compost.

The 'antennae' on the specimen above are most likely the anterior spiracles which are extruded at the time of pupation.

Major Bombylius's picture

They are said to feed on

They are said to feed on "decaying organic matter" eg in slurry lagoons and cess-pits. Not sure if they could "eat" leather unless you have definite evidence of this. Doesn't seem to be much info about their diet on the internet...

DavidNotton's picture

maggot food

Generally speaking I think a lot of fly maggots feed on liquid or fine suspensions, or finely comminuted material, which often include a high proportion of microorganisms such as bacteria, yeast etc. They have mouth hooks with which they can rasp the substrate to release fine particles, possibly this is how your maggots are damaging the leather?

If you want more information, I would recommend starting with Ken Smith's book on the immature stages of Diptera in the Royal Ent. Soc. Hanbooks series.

Cheers

David