Hawkmoths are largest and most spectacular insects in Borders

A Poplar Hawkmoth at rest.
A Poplar Hawkmoth at rest.

Hawkmoths are amongst the largest insects in the Scottish Borders though because most are nocturnal they are rarely seen.

The one most often seen is the day-flying Humming-bird Hawkmoth which is a regular visitor between May and September to Berwickshire, especially along the coast. It is very aptly named as it is often seen in gardens on sunny days hovering like a Hummingbird in front of flowers and drinking nectar through its long tongue.

There are only doubtful records of it hibernating in Britain over winter, and most adults are immigrants from southern Europe, although the food plant of its caterpillars (Bedstraw) is common, so with increasing temperatures perhaps it could become fully resident in the future.

Less-often seen, but probably the most abundant Hawkmoth in the Borders is the Poplar Hawkmoth which is night-flying. It is attracted to light and is on the wing in May, June and July. It is quite dull in colour with grey and brown wings and a thick body. Its sitting posture is unusual in that its hind wings project forwards beyond the forewings.

The large caterpillars are more colourful - green, yellow and red - and can be found by careful searching on leaves of aspen, poplar and willow trees, where the adults lay their shiny green eggs.

The Elephant Hawkmoth is now quite common though at one time it was a rarity in the Borders. Its main foodplant is the Rose-bay Willow-herb or Fireweed which reputedly increased in Britain after colonising bomb-sites in London during World War II. The plant is now conspicuous along roadsides in the Borders, flowering in late summer.

The moth’s name comes from the large caterpillars which have a colour and texture rather like an elephant’s trunk. By day these hide low down in the vegetation and at night climb up to feed on the young willow-herb leaves. The adults have beautiful olive green and pink stripes on their forewings and body.

The Small Elephant Hawkmoth is quite similar in colour but smaller than its cousin and feeds on plants in the Bedstraw genus. In Berwickshire it has been recorded mostly along the coast.

A few other Hawkmoths have very rarely been seen locally, and all are migrants arriving in summer from southern Europe. Perhaps the most famous is the Death’s Head Hawkmoth with a yellow skull-shaped pattern on its black head. This has given rise in the past to superstitious associations, enhanced by its ability to make a loud squeaking noise when disturbed. This species is also known to raid beehives to steal honey.