Posted by: lensweb | October 18, 2017

Moths for the Sake of Ivy

National Moth Night is normally confined to the warmest months but takes place on different date periods every year. National Moth Night 2017 was held in autumn and focused on ivy,

Some of you may know that we hold regular working parties at Forbes Hole, one of our Local Nature Reserves in Long Eaton. We battle against ‘scrub’ that is a combination of unwanted saplings, bramble and nettles which choke the growth of the woodland flowers such as speedwell, ground ivy, red campion, sweet violets and primroses. One of our great battles is against horizontal ivy. In the dark and dry conditions underneath crowded trees, ivy has taken hold and the tangle of seeking tendrils with their dark green palmate leaves can cover the ground 25cm deep. Every tendril develops rhizomes which can make a new plant. Newts and toads love to shelter beneath it but you can have too much of a good thing. The ivy branches are quite satisfying to snap off but the prodigious growth means it is an everlasting battle.

On the other hand, vertical ivy is a most attractive plant. While it is probably best to remove it from specimen trees which can be smothered in a green leather coat, on standing dead wood it provides shelter for bats and birds such as wrens nest under the green armoury.

Chartreuse pompoms of tiny flowers appear in autumn which provide nectar and pollen, an essential food source for insects and birds during autumn and winter when food is scarce. Honey bees, drone flies, hoverflies and many other insects can be seen frenziedly feeding in the autumn sunshine. The last month of the butterfly transect season saw our recorders lurking in ivy clad areas counting an abundance of butterflies. Brimstone, Comma, Red admiral and Speckled Wood could be seen unfurling their long proboscis and feasting. In winter they may then hibernate beneath the green mantle of ivy.

 

The caterpillar of the Holly Blue butterfly actually feeds on the flowers, together with moth larvae such as the Small Dusty Wave, Angleshades and Swallow-tailed Moth. The ivy bee Colletes hederae is completely dependent on ivy flowers, timing its entire life cycle around ivy flowering. In winter the fat black berries of ivy are a nutritious food resource for birds such as thrushes, blackcaps, woodpigeons and blackbirds.

 

Unfortunately the ivy at Forbes Hole had almost finished flowering by 13-15 October, the named date for National Moth Night and our torchlight survey was not very productive. The ivy in the previous few weeks had been entertaining the entomologists very well. Honey bees and drone flies of many types buzzed happily around the bounteous ivy blossom; a handsome hornet hoverfly and a wasp like conopid were regular visitors.   As a warm night was forecast we set up our moth traps and waited to see what would fly in.

 

List of moths and foodplants  13 October 2017  Forbes Hole LNR, Long Eaton
Acleris sparsana Ashy Button Sycamore
Chloroclysta miata Autumn Green Carpet Rowan and Sallow
Tiliacea aurago Barred Sallow Field maple and beech
Aporophyla nigra Black Rustic Heather and dock
Dryobotodes eremita Brindled Green Oak
Dysstroma truncata Common Marbled Carpet Low growing plants
Colostygia pectinataria Green Carpet Bedstraw
Thera obeliscata Grey Pine Carpet Pine and spruce
Noctua pronuba Large Yellow Underwing Herbaceous plants
Epiphyas postvittana Light Brown Apple Moth Polyphagous
Epirrita dilutata November Moth Trees and shrubs
Chloroclysta siterata Red-green Carpet Oak and rowan
Rivula sericealis Straw Dot Various grasses
Orgyia antiqua Vapourer Trees and shrubs

The 125W mercury vapour lamp moth traps were run from 7pm to midnight. The moth trap which was placed in the tree lined ride attracted a greater variety of moths than the trap which was placed on the shore of the pond, probably because this is where the moths were nectaring on the topmost ivy flowers. The moth of greatest interest to moth recorders was possibly the Autumn Green Carpet which is locally distributed throughout Britain.  It flies in September and October, and again, though less commonly, in March and April.The temperature stayed a balmy 18C, and although there were plenty of caddis flies we did not get bitten by mosquitoes as so often happens on warm summer evenings. We considered ourselves fortunate to have an opportunity to record the autumn flying species of moth which are so often missed off the list.

Marion Bryce 13 October 2017

Thanks to Atropos and Butterfly Conservation for organising National Moth Night and UK Moths for information


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