General Comments:
Widespread, usually numerous where found.
Listed in older text books as Sesia bembeciformis - a European species with which it was erroneously confused.

Formerly regarded as extremely rare, but this was an artificial situation reflecting the survey methods used. Traditional collectors, seeking cabinet specimens in pristine condition,would dig up roots of the foodplant and rear the adults. Effective, but time-consuming and rarely repeated at any other site. During the 1980s, however, surveys of brownfield sites in the East Thames Corridor area of South Essex showed that adult moths were regularly caught in sweep-nets whilst looking for other insect groups. They were mostly battered and quite unsuitable for a collection, but from a pure recording aspect this technique was perfect. Since then, the creation and widescale availability of artificial pheromone lures for clearwing species has shown clearly that the moth is widespread and numerically common.

Hertfordshire Notes: Foster (1937) lists only a single report, from 'Drayton Beauchamp, one on canal bank in 1893' but questions whether or not this site is in Hertfordshire. The village is certainly not - the vice county boundary runs some 500 metres east of it. canal crosses the border, but as the village is named it seems likely that this record was made in Buckinghamshire not Hertfordshire; I have not included it in the map. There are no other records until 1995, though for the reasons already mentioned above it is difficult to believe that the moth is a recent colonist. Writing in Larger Moths of the London Area (1993), I observed that all records of this species were at that time confined to areas of chalk geology. Since then, many of us have found this insect to be abundant in association with Lotus corniculatus and other Lotus species on post-industrial sites to the east of London along the River Thames where the substrate is dominated by pulverised fuel ash (PFA). This by-product of industry is strongly alkaline and supports a calcareous flora and fauna. Most current Herts records do still affect calcareous ground, notably on the chalk itself in the north-west but also on the Chalky Boulder Clay that covers most of the county. However, this is not exclusive and the moth is likely to be found in almost all areas where the foodplant has been allowed to grow for a couple of years or more.

Middlesex Notes: The western half of the county, as well as along the River Thames in the south and River Lea in the east appear to support populations, but there is an obvious gap in eastern Middlesex - coinciding with the densest urban zone. Undisturbed ground supporting the foodplant is likely to be generally absent here, so the pattern of the distribution map might reflect reality? Recent endeavours to recreate suitable habitat are applauded, but newly created sites must be managed as permanent features.

Recorded in 27 (66%) of 41 10k Squares.
First Recorded in 1995.
Last Recorded in 2023.