I like longhorn beetles – they are large, relatively easy to identify and are found only occasionally so always cause me some excitement! They are not species I specifically go looking for – I normally just bump into them or as happened yesterday they bump into me. Whilst I was a Parke yesterday a large insect flew into me and then landed on an adjacent ash tree. I immediately caught it to see what it was. It turned out to be the black-spotted longhorn beetle Rhagium mordax.
Longhorn beetles have interesting and long lives. The adult female beetle lays eggs into the outer sapwood of rotting stumps (oak predominantly for R. mordax). The larvae then feed on the rotting wood for 2-3 years before emerging as an adult. The adult R. mordax metamorphose in August and stay within the pupal case only emerging in the following April!
This is the closely related species Rhagium bifasciatus – the two-banded longhorn beetle. Again recorded at Parke in 2008. It is a species most often associated with Scots Pine.
This species, found at Parke in 2008 is the golden-haired longhorn beetle Leptura aurulenta. The larvae for this species can spend up to 4 years feeding on the dead wood of various trees – most usually oak.
Golden-haired longhorn beetles are much rarer than the previous two species and are largely restricted to Cornwall, South Devon, Hampshire and West Sussex. It has a rarity rating of Nationally Scarce A – a good find at Parke.
This species is a large one known as the Tanner beetle Prionus coriarius. This individual was trapped at Parke last year during a moth trapping evening on the 25th July when the highlight of the evening was the capture of a Ringed Border moth – a first for Devon! (see here and here for further details). The Tanner beetle larvae live for up to four years on the roots and rotting stumps of old deciduous trees. The adults are out and about between July and September – they are crepuscular which means they fly at dawn and dusk and are often attracted to light. Thank you to Nicola Bacciu for allowing me to use her excellent photograph of the Parke specimen.
The final species I have recorded at Parke is Rutpela maculata – the black and yellow longhorn beetle. I found 4 individuals last July at Parke – see here. The larvae are fond of rotting birch and can live for 2-3 years. The adults are quite conspicuous as they are often found feeding on umbellifer flowers.
Longhorn beetles are good indicators of species rich parklands, woodlands and dead wood habitats – they are species of conservation interest – the more species – the better the habitat. There are records of three other species from Parke – Grammoptera ruficornis the common Grammoptera, Leptura quadrifasciata the four banded longhorn beetle and Pogonocherus hispidulus the greater thorn-lipped longhorn beetle – all are quite common nationally. I am sure there are many more species of longhorn beetle here at Parke and over time they will be recorded. If you have any records of longhorn beetles from Parke or any other National Trust properties I would love to hear from you.
All maps are courtesy of the National Biodiversity Network – see here where you can access (for free) distribution maps of all UK species of wildlife – an amazing resource built largely on the efforts of amateur naturalists who share their records for the greater good.
If you want to know more about longhorn beetles I can recommend the excellent Identification articles in British Wildlife Magazine.
Identification: Longhorn beetles part 1: British Wildlife (2007) vol 18 pp406-414 Andrew Duff & Richard Lewington
Identification: Longhorn beetles part 2: British Wildlife (2007) vol 19 pp35-43 Andrew Duff & Richard Lewington
See here for more details on British Wildlife Magazine – an essential read / subscription!