Orchestes betuleti

Orchestes betuleti is a very small (about 2.5mm) weevil associated with Elm. It may vary from orange-red to darker red.  The unmarked elytra, head, legs and rostrum are all red. The larvae mine the mature leaves of Elm (see ‘Life History’ section below).

Orchestes alni is a similar weevil and is also associated with Elm, but Orchestes alni is usually larger than Orchestes betuleti and the elytra are usually marked with black.  O. alni also typically has black head and rostrum and at least part of the legs is also usually black.

Adult leaf mine

All records must be supported by good photographs and a note of the host species (was it found on Elm?). Whilst this species remains rare in Leicestershire and Rutland it may be advisable to retain a specimen in case it is required.  Provide backlit photograph of leaf mine and note the host.

Strongly associated with Elm and likely to occur in areas where Elm is present.

The larvae are usually present in the leafmines from July to August, with adults emerging in August.

Around June the egg is laid on an Elm leaf, on the underside of a strong vein.  The leafmine then develops as a narrow corridor that runs from the vein towards the edge of the leaf where it widens into a large blotch.  The frass is concentrated in the centre of the mine forming a dark spot.  The larva pupates in a cocoon inside the mine.

Orchestes betuleti was recorded in Britain for the first time in Bedfordshire in May 2023, but subsequent searches of specimen collections have found examples dating back to 2018. All British adults up to 2024 were from Bedfordshire.

Rare in Leicestershire and Rutland.  The record from Willoughby Waterleys dated 26th August 2024 was the first for VC55.  It is believed to be the first time that this species has been recorded in Britain as a leafmine.

http://www.leafmines.co.uk/html/Coleoptera/o.betuleti.htm

https://bladmineerders.nl/parasites/animalia/arthropoda/insecta/coleoptera/polyphaga/cucujiformia/curculionoidea/curculionidae/curculioninae/rhamphinini/orchestes/orchestes-betuleti/