Thursday 24 July 2014

The Meadow Brown, Maniola jurtina.

This is almost certainly the commonest butterfly in the UK, found wherever there is grass that is not regularly cut or heavily grazed. Generally brownish, the females are however much more brightly coloured and distinctly patterned than the males.


Description 

This is a lovely view of the underside of the wings of a Meadow Brown, probably a male from the relatively even colour of the hind wing, taken in Dene Park in 2011. This individual has got three dots on its hind wing.



This photo is of a fairly typical female, much more brightly coloured than the male, with a brighter forewing eyespot, but fewer dots on the hindwing:


This is another quite bright female, but this time with two black spots clearly visible on the hind wing!


This individual has a double eyespot, and so could be confused on first glance with a Gatekeeper. However, its other features confirm that it is a Meadow Brown, possibly a female, but with two "hind wing specks":



Distribution

Meadow Browns can be found almost all over the countryside in Hadlow, but are commonest wherever there is long grass in reasonable amount. They will be present wherever you look in pasture fields and meadows allowed to grow long, so that at least some of the grass is in flower. In suitable meadows you will find them regularly year after year, at densities of over 1 every 10 square metres. You will find at least some along almost every grassy road verge and field margin, and along most woodland paths and rides.

In Britain and Ireland they are found everywhere except the Highlands of Scotland, never in the Northern Isles, and rarely at high altitudes on the mainland. In Europe it extends throughout Europe and Asia as far east as Iran.

Meadow Browns are quite sedentary, but some will move, particularly perhaps the males, to find new habitat.


Life cycle

The first adults generally appear around the beginning of June, and numbers usually peak in around the second half of July. In some of the best sites however adults may still be found as late as September.

The males are the most active, and search assiduously for the newly emerged females. When found, the males cover the females in an odd, musky scent causing the female to settle quietly, ready to mate, which they generally do only once. Here the male is to the left, the female to the right.



Individual life span is generally around half a dozen to a dozen days, and the females are able to ripen their eggs and start laying in as little as 3 or 4 days, flapping jerkily above and among suitable grassy food-plants, fine or medium grasses. The eggs are laid on grass, or rather more carelessly, nearby. The grass chosen may be infected with fungi that the caterpillars can ingest and perhaps use themselves as bactericides. The small caterpillars feed by day, hibernating, until the spring, when, as they grow and become more obvious, they switch to feeding at night, sometimes at densities up to 10 per square metre. At this stage they are green and relatively hairy, with a tiny white projection on their tails. By June most caterpillars have pupated.


Oddities

The numbers and patterns of dots varies with gender and location, and the variation has led to considerable speculation on the evolutionary value of the traits associated with the spotting. The butterflies use their colours and patterns for both concealment and eliciting surprise, in ways that do not appear to have been fully elucidated to date, although huge amounts of data have been collected and about which a great deal of papers have been written. This very common butterfly still has a lot to teach us!

This particular female has rather exceptionally well-pronounced rear wing specks!

Haysden Country Park, Tonbridge, 05-07-2013

Predators and parasites

Birds are known to try and catch them - and often manage to get a nip in!



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