Thursday, 31 October 2013

A Sunny, Noisy Summer

White Letter Hairstreak on Hemp Agrimoney

What a fantastic summer this year has had, with some really hot spells from June through to October, interspersed with some rain. This has been beneficial to the insects that thrive within our meadows, hedges and woodlands, especially the butterflies, with large numbers of Gatekeepers, Meadow Browns, Small Coppers and Common Blues in July and August with an influx of Red Admirals, Commas, Small Tortoiseshell and Peacocks noticeable in August and October.

The White Letter Hairstreak with its conspicuous W-shaped line on the underside of the hind wing was recorded in a few places in Merseyside this year. Usually seen predominately flying among the tree tops particularly the elm tree it will also feed on nectar from low growing shrubs and is very fond of bramble blossom. This year it was seen and kindly photographed by John Jakeman, the Ranger from Tam O' Shanter, on the Hemp Agrimony within the Walled Garden at Royden Park in August.

Field Grasshopper

Other insects such as Grasshoppers have been very active within our meadows. Here the two most common species, the Meadow and Common Field Grasshoppers are present, their ‘song’ or stridulation giving their location away. Very active in the hot sunshine, males stridulate by rubbing their hind legs against their forewings. The pitch varies with the number of pegs and also with the rate at which the legs are moved. Each species has its own characteristic song.

Common Field Grasshopper are abundant within the meadows at Royden Park and show an array of colours, usually brown with purple but also often green, black and a combination of these. The Meadow Grasshopper, also very abundant in our meadows, tends to be greener but also varies showing browns, purples and blacks. So to identify the species the ‘song’ is the most important aspect to pin down the species, along with the line markings on their thorax.

The Common Field Grasshopper song is usually 6 - 10 short chips, like time-signal pips at a lower pitch and repeated irregularly. The female of this species will also sing before mating.

Meadow Grasshopper

The Meadow Grasshopper in contrast has a song like a sewing machine in burst of up to 3 seconds, getting louder and repeated every 5 - 15 seconds. This grasshopper has no hind wings and is therefore flightless.

Another common grasshopper located on lusher grasslands and recorded at Upton Meadows is the Common Green Grasshopper. Despite its name it too can vary in colour from grey to green and brown. The fore wing is often dark towards its tip. Its song is a fluctuating hiss lasting 10 -20 seconds and gets louder, rather like an approaching moped, before ending abruptly. Full volume is reached about half-way through the song.

Within dry habitats and heathland is another common species the Mottled Grasshopper, again with a varied coloration of browns, greens and blacks. So again the song is the main identification feature and this one has a series of 10 - 30 short chips, increasing in volume over 10 - 15 seconds and rather like the sound of winding a clock repeated at irregular intervals.

So next year why not get closer to the ground and spot, or should I say hear, the different Grasshoppers that abound within our meadows, heathlands and woodland edges.

Paul Greenslade

Ranger, Royden Park and Heathlands, Wirral.

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