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Micro-moths

In the following article, Philip Strickland describes some of the micro-moths found in Ireland. These are our smallest Lepidoptera and were traditionally overlooked but repay attention for the exquisite beauty of many species and their often extraordinarily specialised requirements and life-cycles. Micro-moths are attracting growing interest because of these factors, providing opportunity for further enjoyment and discovery.

Introduction.

Micro-moths (micro-lepidoptera) is an arbitrary grouping of moth families, featuring the ‘smaller’ species of moths, generally with a wingspan of under 20mm.  Conversely moth families that mostly contain the larger species are called macro-moths.  Current taxonomic thinking considers most micro-moth families to be more primitive than macro-moths however there are some exceptions and these are commonly referred to as ‘honorary macros’. Traditionally micro-moths were less known and studied when compared to their larger counterparts mostly because they were harder to identify by external phenotypic markings. Add to this the fact that the majority of species have not been given vernacular names, and that until recently there was no easily accessible literature available, it is understandable that the study of micro-moths was mostly undertaken only by professional entomologists. Thankfully all this has changed in recent times with the advent of many easily accessible resources including field guides, websites and on line identification groups. The advancement in digital camera technology now allows us to take clear, close images of even the smallest micro-moth species which in many instances can now lead to accurate identification to species level.

Irish micro-moths.

There have been approximately 1,440 species of moths recorded in Ireland broken down as about 570 macro species and about 870 micro species. The 870 micro species are grouped into over 40 families however about 80% of these species are represented by just 12 of the families. The families are defined by a range of characteristics and not all of these are obvious at first glance.  When looked at closely many micro moths display intricate patterns and vivid colours and can be positively identified to family and even species level but unfortunately, this is not the case with all individuals and many species need microscopic examination or genitalia dissection to obtain a positive identification.

Micro moths can be found in a broad variety of habitats and ecological niches everywhere in the country and have a wide variety of feeding habits in both larval and adult life stages. Many of the very small species mine leaves during the larval stage and are best identified by the foodplant and patterns that they make in these leaves. Searching for the adult micro-moths by day or in the evening can be quite productive as a surprising number of species tend to be active in sunshine. Most species are slow flying and do not tend to fly far if disturbed. They can be photographed when they settle or alternatively can be netted and transferred to jars where they may be more easily examined using a hand lens.

There follows a very brief mention of some of the families of micro moths and some representative species, many of which are common and easily identifiable. Adults of this primitive family have chewing mouthparts and eat pollen. They are often seen in large numbers sitting on yellow flowers and the species illustrated in Fig 1, Micropterix calthella is common in June and July.

Nepticulidae (Fig 2). There are over 60 species in this family in Ireland and all are tiny and very difficult to identify when adults. The larvae form mines, mostly in leaves and it is possible to identify the species by the patterns they make.

Adelidae (Fig 3). This family is commonly known as ‘Longhorns’ as the antennae are unusually long, up to four times the length of the body. The species illustrated is a mating pair of Adela cuprella, with the male on the right with the longer antennae. It flies in April and May and sometimes the males congregate in numbers, flitting around the tops of willows in afternoon sunshine.

Tineidae (Fig 4). The larvae of this family feed on a variety of material and includes some species that feed on skin, fur and even our clothes. These clothes feeding species are on the decline however as a result of warmer, drier houses and clothes being disposed of sooner. Tinea semifulvella, the species shown is common and feeds mainly in birds’ nests.

Gracillariidae.  Another large family of very small moths, the larvae of which feed as leaf miners. It includes the Horse-chestnut Leaf Miner Cameraria ohridella, which has recently colonised Ireland and is rapidly spreading across the country. Caloptilia betulicola (Fig 5), a birch feeder is shown in typical inclining posture, raised up on extended forelegs and midlegs. Its proboscis is extended as it sucks up moisture.

Yponomeutidae. This family includes the distinctive Small Ermine moths, which are white with black dots. The larvae of some species, including the Spindle Ermine Yponomeuta cagnagella shown (Fig 6), live gregariously and the silk webbing is often noticeable in hedgerows in early summer.

Argyresthiidae. There are about 20 species from this family in Ireland with many well marked and though small, easily identifiable. Argyresthia brockeella (Fig 7) shown feeds on Alder and Birch. It flies in sunshine and is often found by tapping the branches of these trees in summer.

Glyphipterigidea. The Cocksfoot Moth Glyphipterix simpliciella (Fig eight) is tiny and easily overlooked however it can be abundant in much of Ireland. Look for it in grasses or in buttercup flowers where a dozen or more can congregate together.

Coleophoridae. It is fairly easy to identify these moths to family level, with their barrel shaped bodies and forward facing antennae. Identification to species level can often be easier at the larval stage however, as they usually construct a case on the foodplant from which they feed in relative safety. The species shown is Coleophora lixella (Fig 9), which is relatively large and fairly distinctive but quite scarce, being found only in parts of the west and northwest of Ireland.

Elachistidae . This is another large family of very small moths, the larvae of which are leaf miners of grasses and sedges. Elachista argentella (Fig 10), though small is all white is easily to identify. It is widespread and readily encountered by day.

Pterophoridae, Plume Moths. All species in this family stand up on their legs and hold their wings perpendicular to their body resulting in the distinctive ‘T’ Shape. We have over 20 plume species in Ireland, a few of which are common and widespread. Below is the Triangle Plume Platyptilia gonodactyla (Fig 11), which is double brooded and on the wing from May right through to October and can be found in rough grassland and waste ground.

Choreutidae. Whilst this family has only four representative species in Ireland, Anthophila fabriciana or the Nettle-tap Moth as it sometimes is referred to, is perhaps the most commonly found micro moth in Ireland. It occurs almost everywhere and can readily be seen in large numbers during the daytime, around patches of stinging nettle, its larval foodplant.

Tortricidae  With about 240 species of Tortrix moths in Ireland this is by far the biggest family of micro moths. It is a very diverse group, with some relatively recent colonists to Ireland, including the Light Brown Apple Moth Epiphyas postvittana, an Australian native, becoming very common and widespread. Below is the thistle feeder Agapeta hamana (Fig 12), in its typical resting position on a grass stem. Illustrated below right is Eulia ministrana (Fig 13), a common species that flies in May and June. The larvae feed of a range of trees but birch is probably its main foodplant, on which it was photographed at the Crabtree Reserve in Lullybeg in June 2014.

Pyralidae. These are larger micro moths and some species such as the Bee Moth Aphomia sociella are relatively well known. The larvae of the colourful moth, the Meal Moth Pyralis farinalis (Fig 14) feed on stored grain; it is found mainly in barns, warehouses, and other grain stores. The individual shown below was found in Wexford town in August 2015 and is one of very few Irish records.

Crambidae. This is another diverse family of larger micro moths, many of which are familiar and day flying. The group includes the Small Magpie Anania hortulata as well as it close relative Anania funebris (Fig 15),  a day flier found mainly in the Burren. Agriphila tristella (Fig 16), one of our grass moth species, which can be abundant in high summer. Readily disturbed when walking through rough grassland, they usually resettle quickly on a stem of grass in a head down posture. The Brown China-mark Elophila nymphaeata (Fig 17) which is one of a number of closely related ‘china mark’ species. The group are unusual in that their larvae are entirely aquatic, feeding on water plants. They are all relatively common and widespread especially around ponds, lakes and canals throughout Ireland.

Conclusion.

Micro moths can be found just about everywhere in summertime, and are on the wing in sunshine and at dusk. Lots of species also fly at night and are attracted to light and so a moth trap can be employed to record them. In recent times, we are becoming more familiar with the distribution and behaviour of our Irish species and adding new moths to the Irish list as we become more knowledgeable. As is the case with most of our butterflies and macro moths, loss of habitat poses the biggest threat to our micro moths. The reduction or even disappearance of semi-natural grasslands, native hedgerows and other natural habitats has resulted in the direct decline of the vast majority of our species. Thus the importance of habitat management and conservation must not be underestimated and must become a priority in our overall biodiversity plans.

If you would like to learn a little more about our micro moths the following resources may be the best places to begin:

Book: Field Guide to the Micro moths of Great Britain and Ireland, by Phil Sterling and Mark Parsons. British Wildlife Publishing.  May 2012

Websites: http://www.mothsireland.com/ Images and Distribution Maps of Macro and Micro Moths in Ireland.

http://www.ukmoths.org.uk/ An online guide to the moths of Great Britain and Ireland.

Fig 1 Micropterix calthella

Fig 2 Stigmella Sp.

Fig 3 Adela cuprella

Fig 4 Tinea semifulvella

Fig 5 Caloptilia betulicola

Fig 6 Spindle Ermine Yponomeuta cagnagella

Fig 7 Argyresthia brockeella

Fig 8 Cocksfoot Moth Glyphipterix simpliciella

Fig 9 Coleophora lixella

Fig 10 Elachista argentella

Fig 11 Triangle Plume Platyptilia gonodactyla

Fig 12 Agapeta hamana

Fig 13 Eulia ministrana, Lullybeg.

Fig 14 Meal Moth Pyralis farinalis, Wexford Town.

Fig 15 Anania funebris

Fig 16 Agriphila tristella

Fig 17 Brown China-mark Elophila nymphaeata

All photographs copyright Philip Strickland.