Over the last year or so I have had comments from a few people based on the idea that the Broad-bordered Bee Hawk-moth is a scarce moth in Suffolk. If the status of the moth were based on sightings of the adult it may appear to be a quite scarce species but my impression from looking for the larvae in the past and other larval records received is that the moth is probably not that scarce. The moth flies during the day and can be seen most commonly as an adult nectaring at flowers in May and June in normal years. I would typically expect to see the adult nectaring at bugle or honeysuckle in some of the woods in south Suffolk, although others may have a different experience of it.
As it has been some time since I intentionally looked for the larva and given the concerns of others about its scarcity it seems a good idea to have a targetted search for the larva this year and if others can help search it would be of great assistance. At the end of the year we should have a clearer idea of its status in the county based on up to date information.
The larvae are relatively easy to find when they are small in late June and July as they make characteristic feeding signs on leaves of honeysuckle. The larva sits on the underside of the leaf along the mid-rib and eats a parallel series of holes either side of the mid-rib as shown in the photos below.
The following photo is one of the best examples I have seen of the feeding sign, with finer pairs of holes/windows in the leaves on the left near the tip of the shoot. As the larva has grown in size it has moved down to the leaves shown on the right and started eating larger and more irregular holes. I actually found the larva on a leaf in the pair next one down from the right-hand leaves.
These holey leaves can be spotted quite easily with a little searching on honeysuckle bushes. As the larva gets bigger it tends to feed in a more irregular pattern and the holes may not be so neat and may also tend to spend the day deep in the clump of honeysuckle. If you do find a green larva on a honeysuckle it can be identified as the right species by its characteristic hawk-moth ‘horn’ on its tail end.
Don’t just restrict yourself to searching for this species in woodland and clearings, as I have tended to find this moth more commonly on heathland or grassland habitats where clumps of low-growing honeysuckle can be found in full sunshine.
If you’re unsure of the identity, hawk-moth larvae are not the only cause of holes in honeysuckle leaves, then you can collect or photograph the holey leaves and send them to myself with details of your name, location and date. If you send me details of any sightings they can be added to the blog here.
The small larvae have been seen already this year and I found the one above yesterday so you can start searching for them now.