Fenusa dohrnii

Alternative names
European Alder Leafminer
Description

The larvae of the sawfly Fenusa dohrnii mine the leaves of various species of Alder (Alnus sp.). The mine takes the form of a large brownish blotch, without an initial corridor. Usually the mine starts near a vein axil, and expands towards the leaf margin. The mine mostly remains enclosed by two thick lateral veins. The adult sawfly is largely black in colour but it is the larval mines that are more regularly recorded.

The fully grown larva is pale in colour, with fairly long and slender feet- but the young larvae may have black markings on the thorax, underneath

Similar Species

Heterathrus vagans leaf mines on Alder can be very similar, and to be sure of ID the larva should be examined. 

Identification difficulty

Adult Leafmine (when host plant is identified)

ID guidance
Recording advice

Leaf mine photographs should be backlit so that the frass patterns and larva can be seen.  The host plant must be identified in the comments

Habitat

Wherever Alder occurs.

When to see it

When Alder is in leaf.

UK Status

Widespread in Britain but infrequently recorded.

VC55 Status

Probably quite frequent but under-recorded in Leicestershire and Rutland.

Leicestershire & Rutland Map

MAP KEY:

Yellow squares = NBN records (all known data)
Coloured circles = NatureSpot records: 2020+ | 2015-2019 | pre-2015

UK Map

Species profile

Species group:
Sawflies
Kingdom:
Animalia
Order:
Hymenoptera
Family:
Tenthredinidae
Records on NatureSpot:
36
First record:
10/10/2016 (Smith, Peter)
Last record:
15/09/2023 (Calow, Graham)

Total records by month

% of records within its species group

10km squares with records

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