A RARE beetle newly discovered in Britain may have “hitched a lift” on a boat across the Channel.

The shiny brown striped summer chafer, which emerges after sunset for a few minutes before hiding away again, had never been seen in the UK outside the Channel Islands.

But it has now been found in its thousands at Castle Hill Local Nature Reserve in Newhaven – and an expert believes it may have boarded a boat to get there.

Steven Teale, the specialist who identified the rhizotrogus aestivus, said the bulky bug’s “poor navigational skills” and limited period of post-sunset activity meant it was unlikely to have made the journey under its own steam.

“It is rare for such a large, conspicuous and charismatic beetle to have been overlooked until now,” he said.

“It is probable that it hitched a lift, possibly on more than one occasion, on a boat across the English Channel rather than making the journey on its own.”

This method of introduction is surprisingly common. Newly colonising species are often first recorded around ports like Newhaven and other rare arrivals including moths and beetles have been found at Castle Hill over the years.

The striped summer chafer is smaller and less hairy than more familiar beetles including the cockchafer and summer chafer. Like other species, it feeds on the roots of plants as a larva.

The adults rise shortly after sunset and are active for just 25 minutes before settling down again. In this brief window of opportunity, the males search for females, which perch on grass stems and appear to produce pheromones to attract the males.

Steven said: “Although this chafer is much less clumsy than cockchafers and summer chafers, it is still quite clumsy and can take some time to home in on a female.

“Clusters of several amorous males can be found clambering over a female and, where more than one female is in the same patch of ground, up to several dozen males have been found in a scrum around them.”

The discovery was made after Steven identified a beetle photographed last year by Sue Cross, a member of the Friends of Castle Hill Local Nature Reserve.

The group has now found thousands of the insects forming a large grassland colony along the coast between Cliff Road in Peacehaven and Poverty Bottom near Denton. The spread suggests the beetles began arriving some years ago and experts are now making further searches – while following Covid-19 distancing measures – to see if the stowaway could be even more widespread than first thought.