Glasgow & SW Scotland Butterflies

Glasgow & SW Scotland Branch Website

July 21, 2010

Commas confirmed breeding in South West Scotland

Filed under: Butterflies — Tags: , , , , , , — Scott Shanks @ 1:11 am

In recent years we’ve seen a significant increase in the number of Comma sightings in SW Scotland. Until now these records have all been of adult commas, but thanks to Heather Young of the SW Scotland branch we now have proof of Commas breeding in the branch area.

Comma Caterpillar 13-07-2010

Comma Caterpillar 13-07-2010

On the 13th of July, Heather found this nearly full grown caterpillar on an elm near Bridge of Allan, Stirlingshire (NS788988). She suspects it was wych elm, but is having the elm species confirmed by a botanist to be sure. The caterpillar began to pupate a few days later.

There have been only 2 other records of comma caterpillars in Scotland in recent times. On both occasions they were in the Borders. The first was seen in 2006 at Sprouston near Kelso, on elm, and the second at Duns in early July 2010, on nettle.

The Comma caterpillar is quite distinctive, with a large white patch at the rear of the body which gives them the appearance of a bird’s dropping. The mature caterpillar will sit happily on the upper surface of leaves, trusting in their bird-dropping mimicry to keep them safe from predators. In England and Wales comma caterpillars can be found on stinging nettles, elm, wych elm, hops and occasionally currents. The pupa resembles a dried leaf dangling from the food plant and is much harder to find!

If you are out for a walk and pass patches of nettles or a stand of elms in SW Scotland keep an eye out for Comma caterpillars (and adults!) and let us know.

Heather Young & Scott Shanks

Caterpillar photograph (c) Heather Young 2010.

January 20, 2010

So, where do all the butterflies go in winter?

Filed under: Butterflies — Tags: , , , , , , , , , , — Scott Shanks @ 11:54 pm

Good question! I’m sure everyone must have fond childhood memories of warm summer days during the School holidays, playing in the sunshine, Swallows in the sky and warblers singing in the trees and of course, butterflies fluttering by. As summer turns to autumn the swallows and warblers take their leave and head south for warmer lands. BUT, where do all the butterflies go?

Well, although you’re unlikely to see them, most UK species don’t head south with the swallows and warblers. They spend the winter in gardens, parks and the countryside hibernating either as an adult, chrysalis, caterpillar or an egg!

There are a number of survival strategies used by butterflies in the UK to survive the chilly winter conditions. Species listed are those found in South West Scotland.

The Life Stages of Scottish Butterflies during winter

The Life Stages of Scottish Butterflies during winter

 

 

Species such as Painted Ladies, Clouded Yellows and Red Admirals migrate to the UK each year in varying numbers from their breeding grounds in Southern Europe and North Africa. These butterflies generally can’t survive our winter, and until recently it was thought that most died with the first chilly days. However in 2009 scientists with Butterfly Conservation showed that at least a proportion of Painted Ladies make a reverse migration in autumn, heading back across the English Channel and down through Europe. Clouded Yellows and Red Admirals may also use this strategy.

Some species such as Peacocks, Small tortoiseshells and Commas spend the winter hibernating as adults. These butterflies spend the summer and autumn feeding up on lots of nectar and the fermenting juices of windfall apples, plums and brambles, building up enough body fat to last them through the winter. The butterflies seek out log piles, crevices in tree trunks, dense vegetation and piles of leaves and occasionally garden sheds, barns and other out buildings. On warm days the butterflies may emerge to search for any plants still in flower to top up their reserves, but swiftly return to their hibernation site if it clouds over. In England the Brimstone also hibernates as an adult. Butterflies that hibernate as adults are often the first to be seen in the year. This generation takes advantage of early spring flowers and new vegetation on which to lay their eggs that will go on to produce the next generation.

If you find a butterfly hibernating behind your curtains or the wardrobe in the spare room, leave it where it is. However, If the room is heated and the butterfly is quite active it can use up all of its energy very quickly, so it is better to move it to a cooler location such as a shed or outbuilding where it will remain until the good weather comes again in March/April. 

Another common strategy is to spend the winter as a chrysalis. This is the magical intermediate stage between caterpillar and adult. Butterflies that spend the winter as a chrysalis often do so at the base of the food plant or in grass tussocks or just beneath the soil. This helps to protect them from the worst of the frost. These butterflies can react quickly to changes in the spring weather, and complete their transformation and emerge as adults to take advantage of fresh growth of their caterpillar food plants. Butterflies that use this strategy include: The whites (Large White, Small White, Green-veined White and Orange-Tips), the Holly Blue and Speckled Woods*. These butterflies commonly have 2 or more broods per year, even in Scotland. This is likely due to their ability to get the first generation of the year going quickly.

Spending the winter as a caterpillar is the most common strategy used by butterflies and most moths. As summer changes to autumn, caterpillars that have been happily munching on their food plant often move down to snuggle among the leaves and debris at the base of the food plant or grass tussock.  During warmer spells the caterpillar can continue to feed  and so can top up energy reserves. The advantage of passing the winter in a relatively mobile form if flooding occurs in spring, they may be able to move to safety. Butterflies which spend the winter as a caterpillar include the Dingy Skipper, Chequered Skipper, Large Skipper, Small Skipper, Common Blue, Northern Brown Argus, Small Copper, Green Hairstreak, Small Pearl-Bordered Fritillary, Pearl-Bordered Fritillary, Dark Green Fritillary, Marsh Fritillary, Speckled Wood (*this species may also hibernate as a chrysalis*), Wall, Mountain Ringlet, Scotch Argus, Meadow Brown, Ringlet, Small Heath and Large Heath.

The final strategy is used by the Essex Skipper and various Hairstreaks in Britain, including the Purple Hairstreak in Scotland, is to spend the winter as an egg. The female Purple Hairstreak lays her eggs at the ends of oak twigs next to buds. The Purple Hairstreak caterpillar is fully formed inside the egg before the onset of winter. When the caterpillar hatches in spring it begins to feed on the little leaf buds, and perhaps avoids high levels of tannins that build up in oak leaves as they age. The Essex Skipper spends the winter as an egg and emerges in April/May to feed. Interestingly the adult Essex Skipper is on the wing just 1 month later than its close relation the Small Skipper which spends the winter as a caterpillar.

Scott Shanks

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