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.