UPDATE:
To identify this species, experts at the Environmental Records Centre for Cornwall and the Isles of Scilly followed their usual verification procedures and also consulted a local entomologist, who agreed that the record appeared genuine. The sighting was considered plausible given recent developments in the species' distribution. Adult European praying mantises (Mantis religiosa) were photographed at four separate Cornish locations last year. The species has become established in the Channel Islands and on the Isle of Wight, and further sightings have been reported elsewhere in the UK this year.
Following media coverage of this story, we have received a number of questions and comments, and we are grateful to everyone who has taken the time to get in touch. We have since been contacted by specialists in this field who have advised that the available evidence is not sufficient to confirm the species.
We now understand that it is not possible to make a definitive species identification for this particular species at this stage. The photographs clearly show mantis nymphs (order Mantodea), but the insects are still at an early stage of development and have not yet developed the distinguishing features needed for reliable species identification.
We have asked the recorders at Truro School to continue monitoring the nymphs, as identification should become easier as they develop.
We will provide an update if further observations allow the species to be confirmed.