To celebrate National Insect Week, Rare Invertebrates in the Cairngorms Project Officer Genevieve Tompkins shares a bit about some of the other special invertebrates the team comes across.
Even more Rare Invertebrates in the Cairngorms
The Rare Invertebrates in the Cairngorms partnership project is a quest, led by volunteers, to find six of the rarest invertebrates across the Cairngorms. These insects really are rare, it’s been seven years since an adult pine hoverfly was last seen in the wild here, so motivation to keep looking is key. Luckily for us, these invertebrates live in a unique and beautiful landscape and, while exploring these special places to look for them, other scarce treasures are revealed.
Caledonian pine forests are home to the pine hoverfly, one of our target species, with rotting holes in dead trees a vital resource for this extremely rare fly. Despite deadwood invertebrates making up 20% of the entire British fauna, deadwood has only in recent decades begun to receive the attention it deserves as an invertebrate super-habitat. Warm June days find us searching the forests for the adult hoverflies, enveloped in the delicious smell of hot pine. These places teem with insect life. Across our path runs the nationally scarce longhorn beetle, Judolia sexmaculata, while on a log sits the ribbed pine borer beetle, Rhagium inquisitor, both of who’s young develop under the bark of fallen and standing dead pine trees. A cursory glance over the pile of logs further rewards us with the colourful appearance of an ant beetle, Thanasimus formicarius, on patrol for its deadwood beetle prey. Then a velvet blue flash alerts us to the presence of a blue rove beetle, Ocypus ophthalmicus, who raises its abdomen in fierce defence, like a scorpion, as we look at it. This Nationally Scarce beetle is making use of the sandy soil and low vegetation found on forest edges and in recently felled plantations.
Judolia sexmaculata, Credit: Genevieve Tompkins.
Combing the forest for flowering rowan, a favourite food plant for the pine hoverfly, leads to further discoveries. There is excitement with the unexpected arrival of an aspen hoverfly, an endangered species and another deadwood specialist, this time relying on decaying aspen trees. And, after a few more minutes searching, we are suddenly dazzled by an emerald jewel, the northern rose chafer, Protaetia metallica, placidly feeding on a rowan spray. This is a real rarity outside the Spey valley and yet another species which relies on decaying wood, the young beetles feeding on it within wood ants nests.
Northern rose chafer, Credit: Genevieve Tompkins.
Wood ants host another of our target species, the shining guest ant. Patience is required to survey for this miniscule insect, with many hours spent staring at the nests. However, time spent on this has paid off for species champions Ross and ‘Antboy’ Xander Johnston, who in the process have also discovered new locations for the endangered narrow-headed ant and exciting potential evidence for the very rare silky gallows spider.
The ‘slow-and-staring’ method also comes into play when looking for the camouflaged eggs of Kentish glory moths on young birch. This activity would be bordering on tedious were it not for the way it opens the door to a whole new world of invertebrate life. Paying close attention to birch trees reveals their secrets, with the lichen-like spots of the scalloped oak caterpillar making it almost impossible to differentiate from neighbouring twigs. This survey method can also throw surprises into your path, with a young raft spider spotted quietly resting on a birch leaf. This nationally scarce arachnid is usually found sitting on the surface of boggy waters, but the youngsters often hide in nearby tree canopies. Meanwhile, birds-foot trefoil and other flowers, abundant in the sunny forest rides, attract the beautifully dusky small blue butterfly.
Young raft spider, Credit: Genevieve Tompkins.
The male northern silver stiletto fly, another target species, is to be found either sunbathing on sunny shingle banks or hovering in small groups, called leks, attempting to attract females with their shimmering dance. River shingle is an incredibly important and fragile habitat, supporting unique and diverse invertebrate communities. It is also another place where the ‘slow-and-staring’ survey method pays dividends. Volunteers searching for the stiletto fly have inadvertently found several sites for the rare five-spot ladybird, another river shingle specialist.
River Feshie shingle, Credit: Genevieve Tompkins.
Sometimes it is the individual plants themselves which draw in the fascinating distractions. A meadow of devil’s-bit scabious is a wonder to behold; a waving ocean of lavender-blue lapping at the foot of the mountains. This plant provides food for developing small scabious mining bees, another of our project invertebrates, as well as for the young of the orange-horned scabious sawfly, Abia sericea, which was spotted at a scabious bee site in Aviemore. The late flowering season of this plant also makes it a vital food source for many end-of-summer hoverflies, with a visit to such a meadow in late August to early September a sensation of colour and sound.
Orange-horned scabious sawfly Abia sericea, Credit: Genevieve Tompkins.
The Rare Invertebrates in the Cairngorms (RIC) partnership project, between RSPB, Buglife, Cairngorms National Park Authority, Butterfly Conservation and Scottish Natural Heritage, is working to improve the conservation fortunes of six of Britain’s rarest insects.
Find out more about the project by heading to the RIC-Cast podcast, available on soundcloud: https://soundcloud.com/gabrielle-flinn. To follow the project, you can find us on Facebook or Twitter.
In 2020, the project is financed by the Cairngorms National Park Authority and RSPB. Between 2017-2019, the project was part-financed by the Scottish Government and the European Community LEADER 2014-2020 programme.
Header Image: Scalloped oak caterpillar, Credit: Genevieve Tompkins
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