Insect Portraits – Birch Sawfly

October 1st 2019

This striking insect caught the attention of Charlie Russell on 28th July 2019. It was resting on the deck of his house at Badnaban (NC0721) and photographed on his iPhone.

It is an adult Birch Sawfly Cimbex femoratus and, at some 20mm, one of the largest British sawflies.  Although it looks dangerous, it has no sting, the saw-like appendages of the female being used to insert its eggs into the bark of birch trees.

The pale green larvae hatch in the spring and feed on birch leaves, pupating later inside tough sausage-shaped cocoons anchored to twigs.  The adults emerge in late summer and can be distinguished from other related sawflies by their size, yellow-tipped antennae and the conspicuous white area on the first segment of their abdomens.

Birch Sawflies have been recorded from scattered sites across the British Isles, including the North-West Highlands, and locally from the 10km squares NC02, 12 and 23.

Ian Evans

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Recent Sightings

Corncrake

single bird heard calling, Clachtoll croft (AS) (25/05)

Birch Sawfly (Cimbex femoratus)

single club-horned sawfly on Torbreck croft (Corwin Yates). Photo Gallery - Other Insects. (25/05)

Gannet

single bird at east end of Loch Assynt, circling and looking lost (Helen Morrison). The previous two days there had been south easterly gales, turning then into the west. (24/05)

Sedge Warbler

four birds heard singing of which three were seen, Culkein Stoer (DAH) (21/05)

Turnstone

three birds in breeding plumage, Bay of Culkein (DAH). Photo Gallery - Birds (21/05)

Sanderling

four birds in spring plumage, Bay of Culkein (DAH). Photo Gallery - Birds (21/05)

Dunlin

50+ Bay of Culkein (DAH) (21/05)

Shelduck

single male briefly in Bay of Culkein (DAH) (21/05)

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