Giant Aphids Found at Attenborough!

A colony of Giant Willow Aphids - © Rothamsted Research

Two weeks ago during a volunteer works party in Beeston Marsh one of our volunteers discovered a strange black mass covering the stump of a coppiced willow tree. On closer inspection this mass turned out to be a colony of insects similar in appearance to aphids yet bigger, in fact much bigger. They were grey with black spots and had a large distinct thorn on their back, a bit like a sharks fin. When disturbed the insects waved their long hind legs around in the air as an act of self-defence. A few photos were taken on mobile phones as a record, and hopefully to identify them from, and the conservation work continued.

On return to the Nature Centre the insects were confirmed to be Giant Willow Aphids - Tuberolachnus salignus. It would be the first time that this species has been recorded on the Nature Reserve and it is assumed to be the first time that they have been recorded in Nottinghamshire too (awaiting confirmation). According to the National Biodiversity Network's Gateway, which contains distribution maps of most wildlife species within the UK, the Giant Willow Aphid has only ever been recorded on two other sites in the country! However, it is likely that this species’ range has spread and that under-recording may be responsible for the lack of information regarding its distribution.  

Aphids are probably better known as greenfly and blackfly and the Giant Willow is one of around 600 species in the UK. Keen gardeners may be all too familiar with aphids as they will probably spend many hours trying to stop them from destroying their prized roses and vegetables. Whilst it is true that some species can cause damage to plants by piercing the soft fresh stems to reach the sap in which they feed upon, many cause little or no damage at all. That said, at around 6mm in length (which is big for an aphid) the Giant Willow Aphid looks altogether rather menacing and is thought to be one of the largest aphid species in the world (certainly the largest willow feeding species). Although it is not exactly a garden pest, a great deal of research is being carried out to see what impact this species could have on commercial willow plantations.

The lifecycle of the Giant Willow Aphid is truly amazing. No males have ever been found and it is thought that this is because males no longer exist in this species! The females are able to reproduce asexually without the need for males. Instead they give birth to live young that are exact copies of themselves - or clones. So similar are these clones that studies have shown very little genetic variation between individuals – even between individuals found on different continents!

Unlike almost every other species of aphid in the UK adult Giant Willow Aphids and their young can also survive in some of the harshest of winter conditions often remaining active through periods of snow and ice. Yet despite extensive studies having been carried out on the Giant Willow Aphid, there is still one big mystery that remains to be unsolved - where they disappear to in February. Aphids have been recorded between the months of August and March, then for almost five months of the year they completely disappear without trace.

Nottinghamshire is well known for its many different willow species and The Delta Sanctuary on the Attenborough Nature Reserve (adjacent to where the Giant Willow Aphid was first discovered) contains one of the largest continuous expanses of willow woodland in the region - around 25ha. You would therefore think that the Nature Reserve would provide the perfect habitat for the Giant Willow Aphid, and that they would be found almost everywhere. However, on returning to get some more photographs of the aphids they too had vanished and after many hours of searching, could not be relocated - and have not been seen since.

Maybe next time you visit the Attenborough Nature Reserve you could look on the branches and trunk of willow trees on the Reserve and see if you can find a colony of Giant Willow Aphids for yourself. You may help to answer the question of where the aphids disappear to for part of the year.

Contact the Nature Centre on 0115 972 1777 or enquiries@attenboroughnaturecentre.co.uk to report your wildlife sightings.

All change for Attenborough's Wildlife!

October started with southwesterly winds bringing relatively mild air and rain at times and it was still warm enough to view migrant hawker dragonflies being caught by a hobby flying over the lakes on the 1^st. The southwesterly winds continued for the next two weeks, and combined with sunny days, sightings of hoverflies, butterflies and dragonflies were reported.

From mid-month, the temperature was generally cooler and the number of insects spotted by volunteers lowered considerably, with far less butterflies and hoverflies observed compared to earlier in the month. Autumn sunshine can still be strong at times however, and the 17^th was very sunny and saw the last sighting of Peacock and Red Admiral butterflies before they went into hibernation.

Around the 21^st to the 25^th, a warm front moved north over the region bringing a lot of grey low cloud, mist and fog, and intermittent drizzle. These conditions can cause some migrating birds to seek shelter in the Nature Reserve until the conditions have improved and they can carry on their journey. Sometimes the birds cannot see physical markers, such as the River Trent, which they rely on for orientation, or it may just be the unsettled weather is not fit to fly in.

An easterly wind dominated most of the remainder of the month and the sprinkling of snow during the early hours of the 27^th signalled the arrival of our winter migrants, those birds that breed in Scandinavia and Eastern Europe but spend the winter in our milder climate, such as goosander, wigeon and goldeneye. These easterly winds have also brought large numbers of Scandinavian thrushes, such as fieldfares, to our shores, and many are now being seen at the Nature Reserve feeding on berry-laden trees such as hawthorn.

Overall, October has been cooler than average, and if this winter is cold and the wind direction is just right, we might be in for an avian treat over the upcoming months.

Nottinghamshire Wildlife Trust manages many wetland nature reserves important for overwintering wildfowl, such as Idle Valley. Please visit: www.nottinghamshirewildlife.org/nature-reserves/idle-valley to find out more.

Arachnids on the run!

Dicranopalpus ramosus - A Recent arrival from the Mediterranean

Love them or hate them, each year as autumn approaches spider numbers seem to increase dramatically. You certainly see more at this time of year than any other as adult males are coming out of hiding to seek a mate and as the temperature drops, both adults and this year’s young start to look for somewhere to escape the cold of winter.

Over 40 different species have been recorded on the Reserve and you don’t need to go far to find them. A whole host of species can be found by simply looking on the outside of the Nature Centre building, where the un-treated oak frame provides them with a perfect winter hideaway. Whilst most of these species only come out at night to hunt for their prey, many can be seen resting by day if you look closely within the space between the wooden panels.

Some of the more commonly encountered species at this time of year on the Nature Centre building are in fact not spiders at all, but they are closely related and belong to the same order - arachnidae. These are the harvestmen (sometimes called ‘daddy-long-legs’) and they belong to the family of opiliones – from the latin for ‘shepherd’ (which is thought to refer to the way that shepherds used to stand on stilts to get a better view of their flocks). With eight long legs harvestmen look superficially like spiders, however they do not have true fangs (their ‘fangs’ are more like clasping claws) and they do not produce silk webs - using only hooks on the ends of their legs to catch their prey. They differ structurally to spiders in that they appear to only have a single body section rather than head, thorax and abdomen. Harvestmen also have only two eyes whereas true spiders have up to eight.

Leiobunum rotundum - another regular at Attenborough

Only three species of harvestmen have ever been recorded on the Reserve (of the 30+ species recorded in the UK) and one, Dicranopalpus ramosus, can be readily found on the Nature Centre building during late October. Despite its relative abundance here at Attenborough this species is quite rare elsewhere in the UK (although its range is now spreading). Originally from Morrocco and the Mediterranean, Dicranopalpus ramosus was first discovered in the south of England in the 1950’s and has slowly spread north. Unlike other species of harvestmen it can be easily identified from its characteristic resting position with its legs spread flat out to the side (see photograph).

As with all arachnids in the UK, harvestmen are often misunderstood and there is an urban myth that they are the most venomous and deadly of them all. However, with the absence of true fangs and venom – not to mention small mouthparts that would be unable to penetrate human skin – this is totally untrue. Like their spider cousins, harvestmen do a wonderful job of keeping insect numbers low (including pests such as mosquitoes) and should therefore be loved and not feared.

Colour'fall'

Many bright colours can be seen on the Reserve at this time of year

The wet summer was not all bad; a bumper crop of leaves on the trees at Attenborough Nature Reserve was the first hint of a glorious autumn. If it was hot and dry, the stress would have caused the trees to shed their bounty long before it could turn golden. It was all down to September now, would the month that herald’s autumn also herald in a season of awe and colour?

The warm start to September was like an extra growing season for the trees and this last spurt of growth ensured there were lots of sugars in the leaves before a seasonal change occurred.

As hours of daylight gradually reduced during September, this triggered a layer of cells, called an abscission layer, to grow at the base of the leaf, effectively cutting it off from the rest of the tree. The countdown to leaf fall had begun, but what colour had not been decided yet?

One consequence of the abscission layer forming is that chlorophyll, the green pigment that gives leaves their characteristic colour, is not produced anymore and gradually disappears from the leaf, allowing other pigments such as xanthophylls (yellow) and carotenoids (orange) to be seen. Lots of sunshine and cool nights hasten the destruction of chlorophyll, thus revealing these other pigments which are less susceptible to low temperatures. During the first half of September high atmospheric pressure brought clear skies both day and night; the solar panels regularly reached generation levels akin to summer and 12 nights recorded temperatures below the average minimum for September of 10.9^oC.

If your idea of a perfect autumn includes shades of red and purple, then another pigment, called anthocyanin, is needed. This pigment results from the breakdown of sugars that are left in the leaves after the abscission layer has formed, and put simply, the brighter the light the more anthocyanin is produced during autumn! September had slightly above average sunshine levels, but there are a few flies in the ointment that could dispel any arboreal treat this autumn.

Minima below freezing will stop the leaf from manufacturing anthocyanin, so an early frost is bad news for a colourful display. September was frost free as usual but another factor to consider is wind. Stormy weather can cause the leaves to fall from the trees before they take on their colourful hues. A deep depression did bring 76% of the month’s rain on the 24^th but we escaped the worse of the winds and no mass leaf fall was recorded at the Nature Reserve. 

If the rest of autumn is sunny and calm, with some cool but not frosty nights, we might witness one of nature’s spectacles, and one you can see on your doorstep.

If you want to enjoy the colours of autumn, Nottinghamshire Wildlife Trust manages some excellent woodland reserves. Please visit www.nottinghamshirewildlife.org/nature-reserves to find out more.

Nature in the Dark

Our Homemade Moth Trap

A break in the wet weather along with a recent news article reporting on the re-discovery of the once locally extinct Small Ranunculus moth, has inspired us to set up a moth trap at the Attenborough Nature Centre. With well over 1000 species of plant and animal having been recorded on the Reserve since the 1960’s (including some 220 macro moths), we thought it would be a great opportunity to learn a little more about some of our less seen nocturnal inhabitants – and hopefully see the Small Ranunculus moth for ourselves.

As the trap was to be left overnight, we chose to use a low voltage UV blacklight bulb to attract the moths, set upon a waterproof plastic container that would withstand any unexpected rain showers. The UV bulb would not attract as many moths as the typically used 125w mercury vapour bulbs, however they use far less energy than MV bulbs and are somewhat less obtrusive. Cardboard egg boxes in the bottom of the container provide shelter for the moths in the trap where they settle overnight before being identified and released the following morning.

Our first trapping session on the 22^nd July produced very few individuals; a single Large Yellow Underwing, a Common Rustic and two Dark Arches. However, it was not the moth trap that provided the excitement the following morning! Whilst releasing the few moths that had been previously trapped, an unusual moth was spotted resting on some Purple Loosetrife in the margins of the Nature Centre garden pond. After a number of photos were taken (in-situ), the moth was collected for identification. The species turned out to be the Wormwood Moth (Cucullia absinthii), a first for the Reserve and one of only five sites in Nottinghamshire where this species has been recorded – the last being in 2009 at Misson Carr.

The Nationally Scarce, Wormwood Moth

The Wormwood Moth is a Nationally Notable species in the UK and a Grade 1 species for Nottinghamshire (Nationally Notable Group B species recorded from five or fewer 10Km squares in Nottinghamshire since 1990). As both the common and the Latin name suggest, the larvae of this species feed on the flowers and seeds of Wormwood (although can also be found on Mugwort). This species report has been described as the best moth find at Attenborough Nature Reserve to date – narrowly beating the Red-Tipped Clearwing (a Red Data Book species). We released the moth later that day.

Following a couple of adaptations to the moth trap (involving a plastic drinks cup funnel), the number of species being caught began to increase. Some common yet very attractive individuals such as the migrant Silver Y and Burnished Brass were found during a trapping session on the 3^rd August, along with a number of previously un-recorded micro moths including the Grey Knot-Horn (Acrobasis advenella) and the Bulrush Veneer (Calamotropha paludella) – a scarce species at the very north of its range, to name just a couple.

As the last egg box was turned over a small yet intricately marked moth was spotted. The moth’s greeninsh grey forewing with a scattering and border of orange spots could only mean one thing – Small Ranunculus! Another first for the Reserve! Having spoken to other local naturalists, who have also noted this species at their trapping sites, it would seem that the fortunes of the Small Ranunculus Moth are beginning to change and that it will once again become a common species in Nottinghamshire.   

We are currently experiencing a general northward shift in distribution of native species and this, along with constant effort monitoring will mean that the number of moths recorded on the Reserve will continue to rise - in particular the micro moths - a group of species that have historically been under-recorded at Attenborough.

With the help of visitors to the Reserve reporting their sightings, our knowledge of local wildlife can increase further. If you would like help in identifying a species you have found on the Reserve, or would like to report your sightings, please send the details along with a photograph (if you are able to take one) to: enquiries@attenboroughnaturecentre.co.uk

When possible species caught during moth trapping sessions on the Reserve will be displayed in the Nature Centre (as they mostly remain inactive during the day). Details will appear in the ‘News & Events’ section of our website: www.attenboroughnaturecentre.co.uk

Butterflies Suffer Through Wet Summer

Brown Argus - A Scarce Species at Attenborough - © Sean Browne

If the soggy summer is getting you down, spare a thought for your local wildlife – in particular the butterflies. Prolonged wet weather during the spring and summer months can literally spell disaster for these usually abundant insects. A recent walk around the Reserve produced only a handful of individuals including ringlets, meadow browns and a single red admiral thus giving an indication of the true impact the weather might be having.

Whilst wet summers are not uncommon in the UK, this year we have seen unprecedented levels of rainfall along with localised flooding and below average temperatures. It is this combination of events that has started to have an impact on many species of British butterflies – drowning and washing away eggs, reducing food availability and grounding adults so that they are unable to seek a mate.

Around 20 species of butterfly are typically recorded on the Nature Reserve each year along with a few local rarities such as the purple hairstreak and brown argus. Some of these, including the purple hairstreak, have flight periods of just a few weeks – giving them a very short window of opportunity to find a mate and lay eggs and putting them more at risk from inclement weather. Most other species are more fortunate and have two generations within a single year (usually one in the spring and one in late summer) or a longer flight period. Many would have taken advantage of the warm and dry start to spring to successfully lay their eggs, however those butterflies emerging during the warm spell towards the end of May would have been confronted with downpours throughout June.

As adult butterflies will not emerge from their cocoons until the conditions are just right there are further concerns that if the cold and wet summer continues it could result in delayed emergence of second generation adults. The length of time that they will have to find a mate and lay eggs will be subsequently reduced and this will in turn lead to further population crashes next spring.

Butterflies in the UK are already suffering huge declines through habitat loss with almost three quarters of species having reduced in number over the last ten years. The recent wet weather can only add to this situation. Whilst we have had wet summers in the past (one of the wettest Junes locally being in 1982) wildlife habitats were once better connected, via green corridors, and gave butterfly populations the opportunity to recover more quickly.

How can you help?

The ‘Big Butterfly Count’ organised by Butterfly Conservation runs between Saturday 14th July and Sunday 5th August 2012 and is a survey that members of the public can get involved in to help build up a picture of butterfly populations across the UK. These results will give the first indications of the impact that the recent weather has had on butterflies on a national scale. It only takes 15 minutes to complete and a full list of information can be found at www.butterfly-conservation.org

Wildlife Webcam Update

Our First Glance at the Newly Hatched Reed Warbler Chick

This summer the Nottinghamshire Wildlife Trust have set up a series of special webcams to capture some of the action from the amazing wildlife here at Attenborough Nature Reserve. All of which we will be broadcasting live on our website.

Earlier, we reported on the success of a Blue Tit family occupying one of the recently installed camera nest boxes. At the time of writing, nine chicks, which had been eagerly watched from the moment the eggs were laid, were preparing to leave the nest. The following day all but two of the chicks, which sadly didn’t go on to survive, had left the box.

Within days of turning the camera off in the Blue Tit box, we started to notice increased activity around a Reed Warbler’s nest that we had been closely monitoring for some weeks prior. We hoped to use a small mobile camera, similar to that used in the Blue Tit box, to deliver live images of the rarely-seen nesting behaviour of this species both online and on our big screen in the Nature Centre.

The Reed Warbler is an incredible little bird (smaller than a Sparrow) which makes its way to the UK each spring from its over-wintering grounds in sub-Saharan Africa - some 4000 miles away! As their name suggests, Reed Warblers inhabit the marginal vegetation surrounding wetlands where they choose to nest deep within patches of Common Reed – typically in areas of lowland central, Southern England and Wales. Due to the Reed Warbler’s breeding habits they often go un-noticed, nests are rarely seen, and the bird’s location is only given away by the male’s song.

Fortunately the nest we had selected for the camera was located in a thin strip of reeds adjacent to the Nature Centre. This meant that we could position the equipment on a nearby bank and still get clear footage – without being too intrusive. Even still, the mobile camera (not much bigger than a bulrush head on a stem and camouflaged to match) had to be moved into position by experienced staff at the Nature Centre over a period of a few weeks - so as not to cause disturbance to the prospecting birds (all wild birds nests are protected by law).

When we switched the camera on we noticed that four eggs had been laid – the average clutch size for this species. In just 12 days (on June, 6^th) the eggs had started to hatch. At least three chicks have been spotted in the nest so far and both the adult male and female have been busy bringing food to their young. In only 12 or 13 days after hatching the chicks will be ready to leave the nest. They will remain in and around the reedbed and will feed up through the summer before they make their first long migration to Africa.

You can follow the Reed Warbler chick’s progress and view this and our other webcams online at: www.attenboroughnaturecentre.co.uk/sightings