Conifer plantation ladybirds

 Three pictures of two ladybirds often associated with conifers, found on a fence post on the edge of a Sitka spruce plantation in the Deerness valley, County Durham. The eyed ladybird is our largest native species, while the larch ladybird, with yellow wing cases, is one of our smallest. 

Ladybirds seem to like climbing to the top of fence posts on sunny days - the lower pictures here, of another eyed ladybird, a 16-spot ladybird Halyzia 16-guttata and a harlequin ladybird, were all taken on fence posts in Teesdale earlier this week.

The unstoppable advance of harlequin ladybirds

 It's now a 14 years since I first saw a harlequin ladybird in Country Durham, and a decade since I first found one in Teesdale. Yesterday, in precisely the same location, there were hundreds, feeding on ivy nectar. This abundant supply of energy in autumn, coupled with their capacity to remain active in cold weather, must surely be important factors in the phenomenal success of this invasive species. 

Harlequin larvae seem to have an affinity with sycamore, perhaps because of the vast supply of sycamore aphids that they find on the leaves. At this location sycamore and ivy grow together, which might account for the population explosion, with dense ivy also providing a sheltered winter hibernation site.

There now seem to be two dominant morphs in this local population, one black with four large, ragged red spots and the other red with multiple black spots, which is more common. 

 This species is known to be a predator of our native ladybirds and can also transmit a parasite that kills other species. It also feeds extensively on eggs of butterflies and moths. Over the last two decades it has spread rapidly, from south east England to the Scottish border. It originated in central Asia but was introduced elsewhere in misconceived biological control programmes aimed at 'environmentally friendly' aphid control in greenhouse crops. Wherever it has been introduced it has escaped and has had a detrimental effect on native insect populations.

No ladybirds for months, then five species all at once.....

Thursday's Guardian Country Diary describes encounters with ladybirds in Weardale and Teesdale.

Back in the spring it seemed as though 2013 might be a good year for ladybirds locally - plenty of 7-spots seemed to have come out of hibernation so I anticipated a thriving population by the time their offspring hatched in summer - but it never seemed to materialise. I found a few isolated individuals of other species - notably 22-spot , 14-spot and an orange ladybird  but then last week .........

........ this huddle, near a pine plantation at Wolsingham in Weardale. It was the largest number of 7-spots I'd seen in one place all year: six that had chosen a split in a fence post as their hibernation site. 7-spot ladybirds aren't usually associated with conifer plantations but his particular row of fence posts, on the sheltered, south facing side of the plantation, as always been a good place to find other species. 

So it was no surprise to find this eyed ladybird - a conifer specialist - sunning itself on the same line of fence posts.

A small, unidentified fly with unusual up-turned antennae had even chosen to hitch a ride on it. The eyed ladybird is our largest species but ...

...... this one, a larch ladybird that shared the same fence post, is one of our smaller species ...

..... here going head-to-head with a staphylinid beetle (which it simply head-butted out of the way!)

Then, a day later at Egglestone in Teesdale I found ivy in full flower that had attracted several orange ladybirds, that were feeding on nectar.

You can see here the translucent pronotum of this species, that used to be considered scarce but seems to have increased in abundance in recent decades, supposedly because it has taken to feeding on fungi that grow on the honeydew secreted by sycamore aphids. On one occasion a few years ago I found a cluster of ten of this species hibernating on the bark of a sycamore in winter - it's certainly a species that can be added to the very small number of insects that are associated with sycamore, which has been present on these islands for around 500 years but has a very small insect fauna.

Close to the orange ladybirds on the ivy I then found a single 7-spot sunning itself on a fence post and ......

.......... scores of this very unwelcome addition to our ladybird fauna - the harlequin. The first time I saw these locally was in Durham city back in 2009, on ivy flowers at almost exactly this time of year. Harlequins are noted for their bewildering range of colour patterns but the indentations at the tail end of the elytra are also a distinctive feature, although they too vary in extent between individuals.

This group of about a dozen individuals had just hatched from their pupae and were still developing their full colours. Harlequins have a breeding season that extends well into autumn.

Some, that also seemed to be the most rotund individuals, were almost entirely black ...

..... but his was a more typical colour pattern in this population.

Finding another population of harlequins was an unwelcome discovery because this disease-resistant species is known to be a predator of our native ladybirds and can also transmit a parasite that kills other species. It also feeds extensively on eggs of butterflies and moths. Over the last decade it has spread rapidly from south east England to the Scottish border. It originated in central Asia but was introduced elsewhere in misconceived biological control programmes aimed at 'environmentally friendly' aphid control in greenhouse crops. Wherever it has been introduced it has escaped and has had a detrimental effect on native insect populations.

The predominantly black individuals seem to have blue eyes.

This was the last unhatched pupa, attached to the fence posts. At the point of attachment you can just see the remains of the larval skin, which is spiny in this species. 

Harlequin larvae also seem to have an affinity with sycamore, perhaps because of the vast supply of sycamore aphids that they find on the leaves - so it may well be that orange ladybirds will also form part of their diet too.

If you find harlequin ladybirds you can report their presence by contributing the record to the Harlequin Ladybird web site.

Harlequin II: the nightmare continues.......

It turns out that the harlequin ladybird (widely tipped to devastate our native ladybird population) that I reported in my last post has accomplices. Nyctalus (from http://standandstare-nyctalus.blogspot.com/) and I found more in the same place today, including this multispotted morph of this highly variable species, and – much more interestingly – a fully developed larva that had anchored itself to an ivy leaf by its tail and was about to pupate. Presumable it will overwinter as a pupa and hatch as an adult next spring, but the fact that the species is breeding so late in the season up here in the North is quite remarkable. I wonder, incidentally, whether this species is attracted to ivy, given this plant’s attraction for other insects in autumn, which would be easy prey for a lurking harlequin ladybird while they are preoccupied with nectar and pollen.....

Harlequin ladybird

Had my first sighting of what I believe was a harlequin ladybird Harmonia axyridis yesterday, when I found it feeding on ivy flowers near the entrance to Durham University Botanic Garden. It matches the published descriptions and photographs, although the legs are usually (but not always) brown, whereas in this specimen they are almost black. It has already been recorded in Durham and further North (see http://www.harlequin-survey.org/images/maps/harlequin_years_20July09.jpg) but this is the first that I’ve encountered. It seemed to be nibbling away harmlessly at the nectar on the surface of an ivy flower, but maybe it was just lurking and waiting to do something unspeakable to a visiting native ladybird species....... current opinion is that it could have a devastating effect on our insect fauna as it becomes more widespread - see http://www.ceh.ac.uk/news/news_archive/2009_news_item_28.html. I'll certainly be keeping a lookout for it next year. The wing colour patterns on the harlequin ladybird are astonishingly varied (see http://www.harlequin-survey.org/recognition_and_distinction.htm#).