22/05/18 - Invertebrate bonanza

Recently on Skipwith Common NNR, we have been treated to great views of Green Tigers Beetles, a species which inhabits the open heaths on the Common, usually appearing in April/May. They are a shiny little beetle, with iridescent green colouring and yellow spots making them fairly distinctive, however on closer inspection their large eyes and mandibles reveal a fearsome predator. Rather cunningly they make burrows which act as pitfall traps, where they lie in wait as other insects such as spiders and ants drop in. Look out for them on warm, sunny sites often with bare ground and little vegetation, the old walls around the bomb bay loop and the bare peat of the sheep tracks weaving through the heather can be good sites to spot them. 

Along with the Green Tiger Beetles, Skipwith Common has also been a good site for spotting other invertebrates lately. Last week the first Hawthorn Shield Bug of the year was seen, and rather unusually in flight, as it buzzed passed us on our way round the bomb bay loop, before crash landing onto the path. This species is one of the larger shield bugs, and could be confused by the similar Birch Shield Bug, however the latter being much smaller. After over-wintering, the adults emerge and mate in spring, with the larvae later appearing between May – October. As their name may suggest, the larvae feed primarily on hawthorn berries, however they can also be found on oak, hazel and birch trees. Always a pleasure to spot one. 

The first of our larger dragonflies has been on the wing over recent weeks – the Four-spotted Chaser, with a number of individuals reported from Skipwith Common NNR and around the pool at Wheldrake Ings. They are rather ‘bulky’ and medium sized with four dark spots on the wings - giving the species its name. They are often found on most still waters, preferring well vegetated margins where males will perch on vegetation spikes overlooking the water. They can be found throughout the valley, with individuals even seen on our small reserve base pond where they rest on the Yellow Flag Iris. They can also be very numerous on more acidic lakes and waterbodies and can be found around most of the ponds on Skipwith Common NNR, usually between late April to mid-September.  Now is a great time to start getting out and looking for them as they will soon be at their most numerous (June/July), and particularly fresh having just emerged from larvae that has been developing under the water’s surface.

As well as dragonflies last week we noticed a large emergence of butterflies in the fine weather, with a number of species recorded including several firsts for the year - a single Holly Blue, and several Large Whites and Speckled Woods, like the one pictured below, photographed recently on Skipwith Common NNR. This species has expanded its range in the local area dramatically over the last 20 years, having previously been quite a scarce and rather local butterfly in the area. Trends like these are picked up by the Butterfly Monitoring Scheme, of which we undertake a weekly transect around the reserve base and riverside path between Bank Island and Wheldrake. Our team started with the first visits at the beginning of the month and recorded 24 butterflies of six species. 

Lastly, whilst putting up the remainder of the breeding bird signs, we came across the first Red-and-black Froghoppers of the year, brightening up a nettle patch in Ellerton, shortly followed by one in the NNR base garden – pictured below, with their vibrant colours they really are unmistakeable. They can be seen between April and August and are found in a range of habitats including grasslands, meadows, gardens and woodland. The adults (which can fly and also have the ability to jump up to 70cm with powerful back legs – hence the name ‘froghopper’) largely feed by sucking juices from grasses. As always when visiting the NNR please let us know of any wildlife you come across by using the log books provided, thank you.