Invertebrates, bugs, creepy-crawleys – call them what you will! The smaller inhabitants of the National Park are everywhere! Forget the larger wildlife in the Park – the bugs are truly fascinating, and well worth a Bug Safari. You need no equipment, but a catching net, a small jar to examine the bugs in, and an identification book. Search all the different habitats – sunny banks, walls, woods, hedgerows, bogs, rivers, lakes. You will be amazed at the diversity that you can find! (But do remember to never harm the bugs, and always put them back where you got them.)
The invertebrates are much more diverse than the birds and the mammals of the Park. There are thousands of different species and the one only thing they all have in common is the lack of a spine. That’s why scientists call these small creatures invertebrates because they have no back bones (vertebrae). With the exception of the dragonflies, damselflies and butterflies, there has not yet been a comprehensive survey of all the invertebrates that occur in the Park, but at least 500 species have been recorded.
There are thousands of species of beetle in Ireland, and while most of them share the same basic shape (six legs and a rounded shiny body with hard wing cases), they have different mouthparts and cover a range of different life styles. Ground beetles, rove beetles, soldier beetles, longhorn beetles, click beetles, water beetles, tiger beetles, ladybirds, weevils, chafers, and many more, are all found in the Park. A few of the interesting beetles that may be encountered in the Park are described here.
Dor Beetle (Geotrupes stercorosus)
This large beetle can be easily recognised by its shiny metallic blue undersides. It is often encountered in Glendalough in the summer months as it lumbers along the paths. Often two are met together – one slightly larger than the other. These are a pair looking for a nice juicy animal dropping – Dor beetles are also known as Dung beetles. In summer a pair roll a ball of animal dung to a suitable site where they bury it. They then lay their eggs upon it, and when the eggs hatch, the little beetle larvae feast on the dung, safe underground. It may sound a bit disgusting, but without dung beetles (and other decomposers), this world would be a far less pleasant place. The adult beetles have a more refined palate – they eat rotting fungi.
Violet Ground Beetle (Carabus violaceus)
There are many different species of Ground beetle. All are similar, with black shiny bodies. The Violet Ground beetle is one of the larger ones and has a shiny purple edge to its black body. All the Ground beetles live under stones and similar places. They are fierce predators – hence their long fast legs and big jaws. These jaws can easily be seen if you look closely. They like to eat other bugs – a nice juicy slug would go down well!
Soldier Beetle (Cantharis rustica)
This colourful beetle is very common in summer, feeding on pollen and nectar in flowers and grasses. They are called Soldier beetles because their colourful appearance is reminiscent of the old colourful soldiers’ uniforms of bygone
days. The beetles like to fly – if you put one on your hand it will invariably run up to the highest point and then spread its wings and take off.
Wasp Beetle (Clytus arietis)
This pretty beetle can be found occasionally between May and July. It mimics wasps, in the hope that other creatures will leave it alone, but in fact it is quite harmless. The beetle feeds on flowers, but it lays its eggs in dead wood. The larvae feed on the decaying wood, thereby helping to break it down. One advantage of National Parks and other protected areas is that dead wood is not ‘tidied up’. Many decomposer bugs feed on rotting wood, and if we are too tidy many bug species can find themselves without a food source.
Wasps and Bees
Wasps and bees have particularly fascinating life styles; many are social and form large colonies. In woodland areas, enormous, scary-looking – but harmless – Giant Wood Wasps may be found. Below are profiles of the Giant Wood Wasp, the Bumblebee and Gall Wasps which are all found in the Park.
Giant Wood Wasp (Urocerus gigas)
The sight of a large female Giant Wood Wasp in summer is enough to send any visitor running back to the car. In fact, she is completely harmless – the long ‘stinger’ is in fact an ovipositor and is used to lay eggs deep into the wood of trees. The larvae feed on the wood. They like spruce trees best, so coniferous forests are the place to look for these beauties. The males are slightly smaller, have a brown abdomen instead of a yellow and black one, and do not have an ovipositor. In fact, you could be forgiven for thinking that they are a totally different species.
Bumblebee (Bombus spp.)
There are many different species of bumblebee. All are furry social insects with distinctive markings. Only the fertilised queen survives the winter. In the spring she finds a suitable nest-site, usually low down in a hedge. There she lays eggs and within three weeks, the first workers are on the wing. The queen now stays at home and lays the eggs whilst the workers busy themselves collecting pollen to feed the colony. In late summer, new queens and males hatch and mate. As autumn arrives, the colony dies, leaving only the new queens to find somewhere safe to hibernate. Bumblebees do have a sting, but they are remarkably gentle and are unlikely to use the sting unless severely provoked.
You may see some strange growths on the oak trees in the Park. These are caused by the larvae of Gall Wasps as they parasitise the trees. There are two common species – the Spangle Gall Wasp (Neuroterus quercus-baccarum) and the Cherry Gall Wasp (Cynips quercusfolii). The Spangle galls are the small flat ones that lie flat on the back of an oak leaf, and look a little like party glitter. The Cherry galls are large round balls about the size of a marble, and usually found singly.
The adult gall wasps are tiny ant-like creatures. In spring, female wasps lay their eggs singly into the leaves, and inject a fluid which makes the gall grow. The maggoty little grub is protected in his gall until he emerges as an adult in late summer.
Butterflies and Moths
Butterflies and moths are common in the Park. Most require special habitats and food-plants. Most moths are dull coloured and fly by night. Most butterflies are brightly coloured and fly by day. Of Ireland’s 36 species of butterfly, 26 have been recorded in the Park. This includes the rare Purple Hairstreak (Quercusia quercus) that is found in the canopy layer of oakwoods, and is very difficult to see. Below are profiles of some of the other butterflies and moths you may see in the Park followed by a list of the 26 species recorded to date.
Emperor Moth (Saturnia pavonia)
This is very much a species of heathland and bogs. The large green caterpillar can be found feeding on heather in spring. It then spins a very noticeable cocoon, before the moth takes to the wing in May and June. Often empty cocoons may be found attached to the heather.
Orange Tip (Anthocharis cardamines)
This is one of our earlier butterflies and may be seen on the wing from April to June. The male is easily recognised with his orange wing tips. The female, being white, is trickier to identify, but the mottled hind wings are diagnostic. The caterpillar feeds on Lady’s Smock and other crucifers. The species over-winters as a pupa.
Silver-washed Fritillary (Argynnis paphia)
This spectacular large butterfly is frequently seen in Glendalough in July and August. It is primarily a species of woodland clearings. On the higher heathlands you are more likely to see the Dark Green Fritillary (Argynnis paphia). Fritillary caterpillars feed on violets and over-winter as a small caterpillar.
There are many other species of butterfly and moth to be seen in the National Park. The Information Office at the Upper Lake in Glendalough sells an excellent poster with pictures of all our Irish butterflies and good details of their lifecycles.
Names of butterflies
Dragonflies and damselflies are large flying insects, many of which are brightly coloured. Dragonflies and damselflies are closely related and look very similar but there are differences. Dragonflies at rest hold their wings out horizontal like an aeroplane. Damselflies hold their wings over their back when they rest. Typically damselflies are also smaller and daintier than dragonflies. Adult dragonflies and damselflies are fierce predators that hunt other flying creatures. Their larvae live in water, and hence the adults are found near water – lakes, ponds, rivers and bogs are all good places to search for dragonflies. A survey of dragonflies and damselflies in the Park found eleven different species. Below are profiles of four of these species.
Common Blue Damselfly (Enallagma cyathigerum)
As its name suggests, this is one of the commoner species of damselfly, and can easily be seen at the Upper Lake in Glendalough in the summer. Often large numbers can be found together in the long grass and vegetation at favoured sites. The underwater larvae can take up to 4 years to develop, although if conditions are good they can grow to adulthood in one year.
Beautiful Demoiselle (Calopteryx virgo)
This damselfly likes clean fast-flowing streams in acid areas and is intolerant of pollution. A colony of them can be found by the stream between the two lakes in Glendalough. Only the males have the unusual dark patches on the wings, but the females have a metallic green body that is also distinctive.
Common Hawker (Aeshna juncea)
Hawkers set up territories that they patrol continually as they look for flying bugs to prey upon. They are impressive creatures as they fly back and forth over their patch and well worth watching for a while as you sit in the sun.
Four-spotted Chaser (Libellula quadrimaculata)
This is a dragonfly of the bogs. The larvae live in bog pools and ditches, and take two years to mature. The adults can often be found flying over the bog, but also, curiously, in woods and heaths quite far away from their pools.