Horseshoe Ladybird Clitostethus arcuatus
This is an elusive species that took me a long time to find but I now see almost annually.
The majority of my records have been found by beating Ivy, with one in Euonymus.
Identification Length 1.2-1.5mm
This is a variable species, some are mostly brown and cream, whilst others are mostly black.
The distinctive and diagnostic feature is a pale horseshoe mark on the wing cases.
This is often broken or slimmer in the middle and bulges towards the ends.
This mark also resembles an archer's bow or in a modern context a pair of headphones.
There is often a hint of a second paler arc at the rear of the wing cases, similar to a double rainbow.
This is a very tiny species, equal in size to Dot ladybird, which makes it difficult to find.
The brown and cream individuals are likely to be males.
The wing cases are typically a dark brown with a paler brown pronotum and cream face and cream cheeks (pronotum sides).
The legs are pale and the horseshoe mark is also a pale cream.
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Presumed male with cream face Fishers Green, Lee Valley, North Essex
The darkest individuals are likely to be female.
The wing cases are blackish and with the naked eye look very like Dot Ladybirds.
Checking photos or using an eye lens will show the horseshoe markings as well as variable pale cheeks (edges of the pronotum).
Some dark individuals have a reddish tint to the legs and also have a reddish tip to the abdomen.
Presumed female with dark face Whitewebbs, Middlesex
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Fishers Green, Lee Valley, North Essex
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Fishers Green, Lee Valley, North Essex
Photo by Mark Hows
Fishers Green, Lee Valley, North Essex
Upshire, North Essex
Upshire, North Essex
Upshire, North Essex
Very pale but with dark centres to horseshoe mark Upshire, North Essex
Upshire, North Essex
Whitewebbs, Middlesex
Reddish tip to abdomen Whitewebbs, Middlesex
The pale coloured legs and pale front contrast with the dark abdomen when viewed from underneath. There is usually a faint pale tip to the rear abdomen.
On the lightest individuals these pale markings are cream coloured but on the darkest individuals they have a reddish tint.
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Fishers Green, Lee Valley, North Essex
Upshire, North Essex
Upshire, North Essex
With two Dot Ladybirds
With Epaulet Ladybird
With Epaulet Ladybird
With Epaulet Ladybird
With Harlequin Ladybird
With Green Shieldbug
Cornmill Meadows, North Essex
Extremely small and easy to overlook Whitewebbs, Middlesex
Fishers Green, Lee Valley, North Essex
Cornmill, Lee Valley, North Essex
Almost tucked out of sight in umbrella, easy to overlook.
With Epaulet Ladybird.
Habitat
This has traditionally been considered a very scarce species, but records are currently increasing. This is probably due to a better understanding of the habitat requirements of this species.
An important factor is knowing that the Horseshoe Ladybird feeds on Whitefly Aleyrodidae and so habitats need to contain this prey species.
Whitefly on Ash
Royal Tunbridge Wells, Kent
All the sites I have visited looking for this species were in shaded woodland with a lot of understory, especially Holly and Ivy, were it can be found overwintering.
The one I found at Fishers Green, Essex was beaten from Ivy growing on a tree trunk in a small but dark shaded patch of woodland.
I have not managed to find any more Horseshoe Ladybirds in this patch, despite continued searching.
Ivy covered tree trunk Fishers Green, Lee Valley, North Essex
Ivy covered tree trunk Fishers Green, Lee Valley, North Essex
I found my second in an Ivy-covered hedge in a private garden in Upshire, Essex.
I have recorded many Epaulet and Ivy Ladybirds from this hedge over the years but despite regular coverage, it took me two further years, until I found another one in this location.
Ivy covered hedge Upshire, North Essex
My third was a surprise find on an ivy covered fence in woodland at Whitewebbs Park, Middlesex.
The surrounding woodland contained areas of Ivy, a Holly and Yew understorey, with several patches of Honeysuckle.
Ivy covered fence
Flash Lane Aqueduct, Whitewebbs, Middlesex
Ash tree with Whitefly Royal Tunbridge Wells, Kent
No Horse-shoe Ladybirds were seen on this visit, although they had been reported shortly before.
In January 2022 I found a second location at Fishers Green, Essex. This time on an Ivy covered tree trunk on the edge of a narrow lane. In February I found another in Ivy at the nearby location of Cornmill Tree Park, with another at Fishers Green a few days later.
Ivy covered tree trunk Fishers Green, Lee Valley, North Essex
Ivy covered tree trunk Cornmill, Lee Valley, North Essex
Ivy covered tree trunk Fishers Green, Lee Valley, North Essex
Whilst this species is often reported wintering in Holly and Ivy, in autumn it has been reported feeding on Whitefly on Honeysuckle in the same areas.
They can also be found in gardens, although I have not managed this yet. Again the associasion with Whitefly is important and it has been reported with this species on Greater Celendine Chelidonium majus as well as the evergreen shrub Viburnum tinus.
In 2023 I found a Horseshoe Ladybird in a Euonymus shrub. I have not heard of others finding them in this habitat but I find this shrub very productive for a range of inconspicuous ladybird species.
Potted Euonymus shrub Upshire, North Essex
Looking at the distribution of this species on the NBN Atlas shows a few distinct clusters. This is probably observer bias and shows the areas where a recorder has discovered the skill set to locate this species.
The other possibility is that this is not a very mobile species and it does have a patchy distribution. Hopefully as more people search for this species we will discover its true distribution.
Look-alike Species
When seen well Horseshoe Ladybird is unlikely to be confused with other inconspicuous ladybirds, except Dot Ladybird which shares the same tiny size.
However when searching for this species in typical habitat with a beating tray it is common to find numerous small early instar true bugs. Whilst these are a very different shape, many of them are the same size and cream and brown colour as paler Horseshoe Ladybirds.
Care needs to be taken not to overlook Horseshoe Ladybirds amongst these.
Early instar bug with similar colouring to Horseshoe Ladybird
Additional Images
In September 2022, I tapped a regular Ivy-covered hedge in Upshire, Essex and found lots of inconspicuous ladybirds. I spent several minutes photographing and counting Dot and Ivy Ladybirds. I looked carefully for Horseshoe Ladybird as I had seen one previously in this spot and was targeting this species but failed to find any.
Later at home I was editing the photos and was stunned to see a slightly out of focus Horseshoe Ladybird in the back of shot with a Dot Ladybird.
This shows how easy it is to overlook this tiny and subtle species.
An overlooked Horseshoe Ladybird with Dot Ladybird
I was able to return two days later and I retapped the bit of hedge where I had returned the mixed group of ladybirds and remarkably found another, or probably the same Horsehoe Ladybird and was able to get a good series of photographs.
Upshire, North Essex
Upshire, North Essex
Upshire, North Essex
In September 2022 I found a very dark individual at Fishers Green, North Essex.
I was photographing an Epaulet Ladybird in my umbrella having just beaten some Ivy growing on a tree trunk.
Whilst doing this I became aware of a tiny beetle nearby.
I thought it looked like a Dot Ladybird, but it seemed rather elongate. It was walking like a ladybird, but I was still not sure what it was. I took its photo and saw on my camara monitor an all-dark Horseshoe Ladybird, with a clear and distinctive horseshoe mark.
Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
In January 2023 I found another dark individual, probably female, at Fishers Green, Essex.
Beaten from Ivy, I also mistook this for a Dot Ladybird, until checking the photos on my camera.
Fishers Green, Lee Valley, North Essex
Pale orange legs Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
In January 2023 I tapped a pale, presumed male, from a potted Euonymus shrub in an Upshire garden, North Essex.
Upshire, North Essex
Upshire, North Essex
In February 2023 I found another two in Ivy, one at Cornmill Tree Park and another at Fishers Green, North Essex.
Cornmill Tree Park, Lee Valley, North Essex
Cornmill Tree Park, Lee Valley, North Essex
Cornmill Tree Park, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
Fishers Green, Lee Valley, North Essex
In August 2023 I tapped another one from Ivy in an Upshire garden, North Essex
