Invertebrates of Dromore Wood
with particular reference to dragon and damselflies, butterflies and moths and some curious mini beasts
Ringlet ButterflyRinglet butterfly
Considered a major site for dragonflies and damselflies Dromore Wood also boasts a large proportion of the various Irish butterfly species. Both purple and brown hairstreaks have been recorded in Dromore recently along with many spring and summer varieties. Brimstones abound from as early as February and in July and August sunny open areas are lit up by the beautiful, large, ginger-coloured silver-washed fritillary.
Dragonflies and Damselflies (Odonata)
With lakes, river, streams and extensive reed and rush beds Dromore Wood is a superb habitat for dragonflies and damselflies. Some of the species known to inhabit the wetland areas include; Blue tailed damselfly, common blue damselfly, variable damselfly, azure damselfly, Irish damselfly, banded demoiselle and the relatively rare scarce-emerald damselfly. The dragonflies known here include; hairy dragonfly, black tailed skimmer, common darter and brown hawker.
Ruddy darter DragonflyCommon darter dragonfly
The brown hawkers patrol large open areas defying anything to enter their territory, looking like azure winged helicopters on seriously aggressive missions.
In contrast the beautiful but fragile-looking banded demoiselles flutter gently around the area of the stream at the bridge to Rabbit Island resting tantalisingly on a reed stem almost long enough to enable a closer look!
Dragonflies have been inhabiting the earth for almost 300 million years but in those days they measured as much as a metre wide. They are predators, in fact their family name Odonota means toothed jaws!
What is the difference between dragonflies and damselflies? Put simply adult damselflies are very slender and delicate with widely spaced eyes and a slow flight. When resting their wings lie along their body unlike the dragonfly whose wings are always outstretched.
The species listed are taken from sightings by visiting enthusiasts and also those specimens discovered during a Bio-Blitz that coincided with torrential rain, the worst possible conditions. There can be little doubt that a thorough study would considerably lengthen the species list.
Butterfly species of Dromore Wood
With a wide variety of habitat including dense woodland, understorey growth, extensive meadows, lightly forested woodland margins, open sunny rides and a multitude of wild flowers from early spring through autumn, Dromore Wood is a superb area for a variety of butterfly species and some of those you may see are mentioned here.
Brimstone (Gonepteryx rhamni /Buíóg Ruibheach)
The earliest butterfly to appear in Dromore Wood is the brimstone which is often seen in February having just awoken from a winter’s dormancy. The male is lemon yellow and the females slightly paler but both have a distinctive orange spot on each of their four wings.
The brimstone is an important pollinator of another early riser, the primrose and during the summer is noticeably attracted to purple blooms such as thistle and knapweed. The eggs are laid on the Buckthorn which is the food plant for the caterpillars.
Brown hairstreak (Thecla betulae /Stiallach Donn)
The brown hairstreak is quite rare but is sometimes found in Dromore Wood by enthusiastic entomologists. The upper wings are brown with a small wing tail. The female has an orange band on the fore-wings. The mature females feed on bramble flower nectar but lay their eggs singly on the stems of the blackthorn tree. The eggs remain dormant until the following spring when they hatch, the caterpillars feeding on the blackthorn leaves.
Lepidoptera expert and author Jesmond Harding offers the following tip for successful spotting of these rare insects:
“When looking for Brown Hairstreaks check young, vigorous slim-stemmed south facing Blackthorn plants that are less than two metres high growing out a little, perhaps a metre from the wood edge. The butterfly will not normally lay on isolated plants or on stunted and thick-stemmed plants. A sunny spot with flowering bramble is a likely site for feeding adults.”
The name is given due to the two white streaks on the light brown under-wings. An autumn species, the brown hairstreak is on the wing between August and October but has a lifespan of three weeks.
Orange tip (Anthocharis cardamines /Barr Buí)
The orange tip is another springtime butterfly and is seen on the wing in April and May in woodland glades and open meadow. The male has the distinguishing orange tip on the white fore-wings, whilst the female has dark grey wing tips.
A lively flier, the orange tip lays its eggs on plants of the cabbage family of which there are many, including ladies smock. Life is short for the orange tip butterfly lasting just eighteen days.
Peacock (Inachis io /Péacóg)
Another butterfly that lays eggs on the nettle plant, the colourful peacock is named because of the peacock feather-like ‘eyes’ on fore and hind-wings. These ‘eyes’ are an important adornment as they help repel attackers such as birds. The peacock butterfly is common during sunny summer days in open rides in Dromore Wood as it flies from blossom to blossom, feeding on the nectar.
The eggs are laid on nettles in June and the caterpillars are large, black and hairy and when they become chrysalis they hang from a nettle stalk or tree trunk. The butterflies emerge from the pupae in July and will live until the following May.
Ringlet (Aphantopus hyperantus /Fáinneog)
Ringlets are small brown butterflies with small ring-like markings on their under-wings. They love the shade and dappled light of the forest edge, the damp areas around the wet meadow ‘callows’ in Dromore Wood and particularly brambles in bloom. Ringlets are unusual in that they fly in dull conditions and even when it is raining.
The caterpillars exist in that form for around eleven months including over winter and feed on grasses. The mature insects have a much shorter life span at just 2 weeks.
Silver Washed Fritillary (Argynnis paphia /Fritileán Geal)
During July and August you may notice a large, ginger coloured butterfly in the open sunny areas of Dromore Wood. This is the unmistakeable silver washed fritillary. On dull days the silver washed fritillary remains roosting in the tree tops but emerges when the sun breaks through.
This is a unique butterfly in that it lays eggs individually on the trunks of trees. The caterpillar hatches and then hibernates amongst the tree bark only to emerge in spring and crawl down the tree to seek out the food plant, species of violets. The butterfly gets its name through the light coloured ‘wash’ on the under wings.
Small tortoiseshell (Aglais urticae /Ruán Beag)
A very common butterfly that may try to hibernate behind your curtains or in a wardrobe, the small tortoiseshell appears from a winter’s sleep in March. Though the mature insect is particularly fond of feeding on the nectar of thistle flowers the food plant of the caterpillars is nettles and they can strip large areas of nettles clean of foliage.
The eggs are laid on the nettle plants in May. The male small tortoiseshell is territorial and when it has chosen a particular site it will drive away any interlopers who enter their sunlit area. The small tortoiseshell is an array of red, orange, yellow and dark brown.
Speckled Wood (Pararge aegeria /Breacfhéileacán Coille)
The speckled pattern and dark brown and buff colours of this butterfly give superb camouflage in the areas of mottled sunlight in their preferred areas of the woodland margin. In the 18th century the speckled wood was also known as the ‘wood argos’ after the Greek mythological character.
There may be two or more broods in a year with those caterpillars born early in the year growing quickly. Caterpillars from a later brood will over-winter, feeding when conditions are mild. The food plant is grasses. They may remain in the chrysalis state for as little as one month.
Wood white (Leptidea sinapis /Bánóg Choille)
The smallest of the white butterflies, the male wood white has grey fore-wing tips though this may be absent on the female. The wood white is a lover of shade and dappled light areas and that is where it can be found in Dromore Wood.
Mature insects will feed on a variety of flower blossoms but the main food plant of the caterpillars is bird’s foot trefoil and the vetch species. The eggs are laid singly in May and the month of June is the optimum period to look for this species which is slow and weak in flight.
Other species include small copper, meadow brown, common blue, dark green fritillary, pearl bordered fritillary, red admiral, painted lady, holly blue and even a purple hairstreak has been reported.
Moth species of Dromore Wood
Various moth species have been recorded in Dromore Wood. To download a list of those species please click the following link:
Knopper Gall Wasp
There are numerous gall wasp species, flying insects that use a variety of trees and plants on which they lay their eggs and on which their larva hatch and feed. Some common examples include the Robin’s pincushion where the stem of the Dog Rose is used as host by the Bedeguar Gall Wasp creating a green growth that turns red in autumn and is regularly seen in hedgerows. Other well-known galls are the oak gall, a ball like growth on the oak twig as is the oak apple and also spangle galls, round blobs that appear on the underside of oak leaves.
Oak trees figure largely as host to different species of galls but surely none are as curious as the Knopper Gall and the wasp Andricus quercuscalicis.
The Knopper Gall wasp lays its eggs in the developing acorns of the Pedunculate Oak tree. The larva hatch and feed inside the acorn causing the fruit to form into a very weird and un-acorn-like shape. There is a Pedunculate Oak immediately outside the visitor centre in Dromore Wood and in autumn over the last few years these Knopper galls litter the ground where one would expect healthy acorns to be found. These sticky galls will be seen to have an exit hole at the top from where the developed wasps – females only - will depart. Whilst this all seems normal and acceptable what happens next is interesting.
The following spring our female wasp, having departed the disfigured acorn, lays her eggs in the developing flower catkins of the Turkey Oak Quercus cerris. Small galls develop and from these galls, both male and female wasps appear. Mating takes place and the females lay their eggs on the forming acorn of the Pedunculate Oak and the cycle continues again. That Knopper Gall wasps develop on at least one of the Pedunculate Oak trees in Dromore Wood as part of their life cycle suggests that somewhere, surely not too far away, stands a Turkey Oak tree.
It is thought that the first report of the Knopper Gall wasp in Ireland occurred as recently as 1991 in Dublin while in the UK they were discovered around 1960.
The oak trees most common in our woodland and parks are the Pedunculate that has its acorns on a stem, the Sessile on which the acorns grow directly on the twig and the Turkey Oak which has frilly acorn ‘cups’ and more deeply indented leaves.
The life of the Knopper Gall Wasp is an odd story but what about the relationship of two other residents of Dromore Wood, Uroceras gigas and Rhyssa persuasoria?
Occasionally, anywhere in the wood, but especially when a larch tree has fallen across a path requiring the chainsaw for its safe removal, a large buzzing, yellow and black striped creature might appear from nowhere, attracted to the scent of the larch sap.
This extra-large wasp is the Horntail or Giant Wood Wasp (Uroceras gigas) and is a true monster compared to the average wasp. If the size of the wasp isn’t enough to give you the willies check out the great long spike sticking out of the rear end of the female. Don’t panic though, the Horntail is completely harmless and the long ‘spike’ is actually the ovipositor and is used to lay eggs up to 10 mm into the trunk of dead or decaying trees. This is where this story gets interesting.
The egg inside the trunk hatches and the larva feeds on the decaying wood, perhaps spending two or three years in the trunk before it prepares to leave as a mature insect. To enable easier egress as a mature insect the larva will have settled close to the outer layer of the tree trunk.
All well and good for the Horntail unless the remarkable Sabre Wasp (Rhyssa persuasoria) a species of Ichneumon has other ideas. This parasitic wasp, black with white spots and red legs is between 20 and 35 mm long. However the female’s ovipositor can be up to 50 mm long and she puts it and her antennae, to great use.
Using her antennae the Sabre Wasp can detect the presence of the Horntail larva deep in the wood. She then drills her ovipositor into the tree trunk – it may take an hour or more - and lays her egg on the grub of the Horntail! The hatching larva feed on the grub of the Horntail but leave the vital life retaining organs until the very last.
While the larva of the Sabre Wasp and the other Ichneumon species feed mainly as parasites on grubs and caterpillars the adult insects feed on nectar from flowers or the honeydew emitted from aphids.