There are several species of macro-moth which cannot be identified to species level just by looking at external characteristics, accurate identification can only be made by looking at the genitalia. We have many records in the database and receive many records each year of species such as Common Rustic or Grey Dagger without any indication whether the genitalia have been examined.
Our records are now passed to the National Moth Recording Scheme and it is important that these data are as accurate as possible. All records of critical species that require dissection will be flagged as "Undetermined" in the database if there is no evidence of such. We have already flagged records of these critical species in the database where no evidence exists. If you are using MapMate there are options such as "Common Rustic agg" which will enable you to record them.
Suggested further reading: British and Irish moths: an illustrated guide to selected difficult species . This lists 72 critical British species that require special consideration. Please familiarise yourselves with these species.
Here is a list of some of the more common aggregate species in Dorset:
Red Twin-spot Carpet/Dark-barred Twin-spot Carpet – Typical forms of Red Twin-spot Carpet may be safe to record, but only if you are confident. Records of Dark-barred Twin-spot Carpet may be queried. The "notch" method referred to in many guides is proven unreliable. See species account for Dark-barred Twin-spot Carpet for further details.
November Moth/Pale November Moth/Autumnal Moth – record as November Moth agg if using MapMate and not Epirrita sp - genitalia examination is essential for confirmation.
Dark Dagger/Grey Dagger – record as Dark Dagger/Grey Dagger - genitalia examination is essential for confirmation.
Marbled Minor/Tawny Marbled Minor/Rufous Minor – record as Marbled Minor agg. - genitalia examination is essential for confirmation.
Copper Underwing/Svensson’s Copper Underwing – The underside of the hindwing is considered the most, but not totally reliable distinguishing feature, therefore dissection will be required for 100% certainty. All other external features are currently used are considered subjective and unreliable - record as Copper Underwing agg. if the underside hindwing has not been referred to.
Common Rustic/Lesser Common Rustic – record as Common Rustic agg. - genitalia examination is essential for confirmation.
Large Ear/Ear Moth/Crinan Ear/Saltern Ear – record as Ear Moth agg. on MapMate rather than Amphipoea sp. Some authors state there may be subtle differences between typical specimens of Ear Moth and Saltern Ear; however, these are not consistent diagnostic features and variation within these species is considerable. Therefore to be 100% safe and certain of verification, and the accurate distribution in Dorset, dissection is required. There is a confirmed record of a migrant/wanderer Large Ear, and less likely but possible Crinan Ear may also turn up in Dorset.
Uncertain/Rustic - some counties now only accept records of dissected species including Dorset as it is suspected most records are dubious; these species are very difficult to distinguish unless fresh and viewed side-by-side. Dissection is recommended for 100% certainty. Record as an aggregate but make a note in the comment of the record what you believe the species to be.
Every year we receive many records of ‘Pug species’, ‘Plume Moth Species’ or ‘Cnephasia species’. These are all deleted from the database so it is best not to record these. You do not have to try and put a name to everything you catch!
Several of the microlepidoptera should not be recorded to species level unless the genitalia have been examined. The option again exists on MapMate to record as the aggregate species. These are:
Last updated 12 December 2013