Worcestershire Record No. 5 Nov 1998 p. 6

LONGHORN BEETLES IN WORCESTERSHIRE, 1998 (Coleoptera, Cerambycidae)

By Kevin McGee

Until recently, I have concentrated most of my fieldwork into recording ornithology, lepidoptera and odonata. All of these groups involve conspicuous species. By and large, it is a fairly straightforward matter to be reasonably accurate in identifying a particular species with the multitude of quality field-guides now available to the naturalist. However, this is not always the case when it comes to safely identifying less 'popular' groups, which is very frustrating if you find a particularly handsome 'bug' or beetle or whatever.

Following a couple of chance encounters with two of the more unusual 'Longhorn' Beetles during 1997; which I was able to safely identify from my photographs, I became very interested in finding out further information on this family. In one respect the study of the Cerambycidae is not unlike the study of British Butterflies. There are approximately, (according to most sources), 70 species on the British Butterfly list, and the same number on the British Cerambycidae list. Of the Butterflies, 60 species can be seen in any one year if you are lucky and prepared to travel considerable distances at key times. This includes the commoner migrants! As most of you are aware, to see 30 of these species locally in a single year, you will have done extremely well! From my initial research, the pattern for the Cerambycidae is somewhat similar. About 20 out of the 70 on the British list are either believed extinct or are extremely rare Red Data Book (RDB) species. Only about 20 out of the remaining 50 are described as either common or 'local'. So, roughly equal to the Butterflies, one could expect to see 20-30 cerambycidae species in a single year.

The similarity with Butterfly recording ends here! Most of the Cerambycidae are only associated with ancient woodland remnants, unlike the many and diverse habitat requirements of Butterflies. The need for dead or decaying timber is essential for most of the Cerambycidae as the larval stage is spent gnawing galleries through the interior of dead wood for between 1-2 years. The species of trees involved differs between each species of Longhorn, although both oak and pine are very important. Some of the Cerambycidae do specialise in using larval host-plants other than tree-species, e.g. Agapanthia villosoviridescens utilises various herbaceous plants including thistles and hogweeds.

Also unlike Butterflies, the optimum 'season' for seeing adults of the Cerambycidae is relatively short, the peak period being between the end of April to the end of June, with hot, sunny weather proving to be most beneficial. Many species will feed on pollen as adults, so a good ground flora in woodland rides and at wood margins is very attractive to them, particularly umbelliferous plants such as hogweeds in my experience. Like Butterflies, I consider all of our Cerambycidae to be spectacular, and once located, most can usually be approached quite readily for photography or observation. But some species can be infuriatingly illusive and difficult to approach. These are those that do not normally feed at pollen sources and should best be searched for at log-piles or amongst decaying branches of standing timber.

There are a few books available as guides to the Cerambycidae, but none that I know of illustrate in detail all of just the British species. The two books that I refer to most are 'A field-guide in colour to Beetles' by K.W. Harde, published by Octopus in 1984, and 'Longhorn Beetles (Coleoptera Cerambycidae) of Fennoscandia and Denmark' by S. Bily; Fauna Entomologica Scandinavica, Volume 22.

In Worcestershire we are fortunate to have a lot of high quality habitat suitable for the Cerambycidae. It was with this in mind that I set out to see what I could find at my favourite 'patches' during 1998. I recorded and photographed 22 species, so bringing my 'personal list' for Worcestershire to 23 species, following my 1997 record of a single Leptura rubra at Tiddesley Wood, which I did not see in 1998. The following lists the species I have so far recorded, and photographed:-

Aromia moschata. normal size range 13-34 mm.
Anaglyptus mysticus normal size range 6-14 mms.
Tetrops praeusta mormal size range 3-6 mms. 

1. Asemum striatum

Nationally : LOCAL 
25.5 Pair in-cop plus a single male photographed at Tiddesley Wood.
30.5 4 pairs copulating plus 5 singles distributed throughout Tiddesley. Most were found towards the bases of mature Scots-Pines with a few at the bases of oaks. (with Scots Pine nearby).

2. Rhagium mordax

Nationally : COMMON 
16.5 One photographed on a log pile at the Knapp & Papermill. Reserve managers, Stuart and Tina, told me of about "half a dozen at the same site yesterday".
1.6 Two at Monkwood. Both at the log pile.

3. Stenocorous meridianus

Nationally : LOCAL
This large species appears to be quite widespread in Worcestershire, I have found it fairly easily at most sites visited. Some books refer to it as the 'Variable Longhorn', most I have found locally are of a constant golden-brown colour, however, there is a population of very dark, almost black specimens, in Grafton Wood
5.7 Recorded in one's and two's at Tiddesley, Drakes Broughton Orchards, Malvern Hills, Monkwood, Knapp & Papermill, Bredon Hill and Grafton Wood. Look for them on blossoms of bramble, dog-rose, meadowsweet and hogweed.

4. Grammoptera ruficornis

Nationally : COMMON
This small, dark species is easily found at the blossoms of hawthorn, dog-rose and bramble pretty well everywhere, even in lightly-wooded localities. Approximately 20 were counted at Tiddesley Wood on 4.7.

5. Alosterna tabacicolor

Nationally : LOCAL
Quite commonly found in the County, but less so than the previous species which is often seen alongside it, especially in major woodlands such as Monkwood. I have found the species to be very fond of Field-Maple blossom, e.g. Tiddesley Wood on 25.5.

6. Leptura livida

Nationally : LOCAL
This species is unusual in that the biology of the life-history is not fully understood. A report by Svácha and Danilevsky (1986) states that the larva lives freely in the soil with mycelium of the fungus Marasmius oreodes, which apparently is the food component; (Fauna Entomologica Scandinavica, Volume 22).

As yet, I have only found small numbers of this species at hogweed flowers along the track to Tiddesley Wood from the new car-park, and alongside the nearby Bow Brook to the west of the woodk on four dates between 14.6 to 7.7.

7. Leptura rubra

Nationally : UNCERTAIN
This was once a RDB species but has spread from the east of the country in recent years.

My only record so far is of a single male I photographed on the blossom of Rosebay Willowherb in Tiddesley Wood on 19.7.97. I doubt that it was actually feeding at the plant as it just seemed to 'crash-land' on it, an observation I have made with other Longhorn species.

8. Judolia cerambyciformis

Nationally : LOCAL 
1.6 two at Monkwood
12.6 one at the Knapp & Papermill
20.6 one at Monkwood
All of the above were found taking pollen at hogweed blossoms.

9. Strangalia maculata

Nationally : COMMON
This rather large and striking beetle may be very familiar to many of you as the 'Spotted Longhorn'. It is very common in the county and readily encountered in numbers of 20 or more at the flowers of hogweeds, angelicas, brambles, dog-roses and meadowsweets. A later species, with the bulk of my records during July and August, e.g. 30+ at Grafton Wood on 5.7.

10. Strangalia melanura

Nationally : LOCAL
A rather similar species to the commoner Alosterna tabacicolor, but once known it is rather more robust and of a deeper, stronger orange-brown colour. I have found it only at Tiddesley Wood and Monkwood in small numbers. Look for it at hogweed blossom and the flowers of both dog-rose and guelder-rose (Tiddesley 30.5.).

11. Strangalia quadrifasciata

Nationally : LOCAL
An unmistakeable species that I have so far only found at Monkwood:
A single at angelica blossom on 27.7.97
A single at angelica blossom on 5.8.98
This is also quite a 'late' species.

12. Molorchus minor
Nationally : NATURALISED ALIEN HOST PLANT

25.5, 4 at Tiddesley Wood on cut logs of Douglas Fir.
30.5, 7 at Tiddesley Wood on cut logs of Douglas Fir.

13. Molorchus umbellatarum

Nationally : Notable A
21.6 one at Drakes Broughton Orchard on flowers of hogweed.
26.6 four at Tiddesley Wood on flowers of hogweed.
4.7 one at Tiddesley Wood on flowers of hogweed.
A nationally rare species whose host-plants include Crab-apple and Pear, so should be present at sites with old orchards in the vicinity, i.e. the vale of Evesham!

14. Aromia moschata

Nationally : Notable B
This truly magnificent Longhorn is commonly known as the 'Musk Beetle'. I was lucky enough to encounter a large specimen at the Tiddesley Wood 'log-pile' along the main ride during the early evening of 4.7.

Look for it in the vicinity of ancient pollarded willows, e.g. the Bow Brook.

15. Clytus arietis

Nationally : COMMON
A common insect which many of you will know as the 'Wasp Beetle'. It is easily found in a variety of situations, whether at log-piles or amongst ground flora. Present at all the sites I visited with peak numbers of 20+ at Tiddesley Wood on 30.5. and 20+ at Monkwood on 1.6.

16. Anaglyptus mysticus

Nationally : Notable B
I first encountered this attractive beetle amongst stems of hogweed in a hedgerow near Eckington Bridge on 27.5.97. I have since found it at two more localities.
24.5 six at Monkwood 'log-pile'.
30.5 one female at Tiddesley Wood ovipositing in a cut birch log.
1.6 four at Monkwood 'log-pile'.

17. Pogonecherus hispidulus

Nationally : LOCAL
This is a rather small but robust species with incredible camouflage! I was lucky enough to catch a glimpse of movement amongst a log-pile at the Knapp & Papermill which made me take a closer look. The date was 7.6., a closer search revealed another specimen. I suspect traditional 'beating with a tray' would prove to be far more successful when searching for this species.

18. Leiopus nebulosus

Nationally : LOCAL
Another beautifully camouflaged species, and not normally associated with flowering plants. However, I found one taking pollen at hogweed just before darkness set in at the Knapp & Papermill on 12.6. Two more records were made:
14.6 one on a poplar at Tiddesley Wood.
20.6. one at the Monkwood 'log-pile'.

19. Agapanthia villosoviridescens

Nationally : LOCAL
One of the few species of the Cerambycidae that is not strictly associated with ancient woodland remnants. I found seven of these large, handsome beetles on stems of hogweed at the margins of Moors Pool, Upton Warren, on 21.6. It is known to utilise hogweed as a larval host-plant as well as robust species of thistle. Look for it in similar lush meadow environments near wetlands.

20. Saperda populnea

Nationally : LOCAL 
23.5 one at Tiddesley Wood on Aspen
30.5 one at Tiddesley Wood on Aspen
1.6 one at Monkwood on Aspen
Almost wholly reliant on the Aspen tree, I found these sitting around on the leaves of lower branches. It is also present in Trench Wood, where I photographed one in 1996.

21. Stenostola dubia

Nationally : Notable B 
29.5 one at Swinyard Hill, Malverns, on branches of a very old, decaying hawthorn.
1.6 one at the Monkwood 'log-pile'. Unlike the typical 'blue' version at the Malverns, this specimen was of an iron grey colouration, so proving to be rather unusual.

22. Phytoecia cylindrica

Nationally: Notable B
10.5 two found at Monkwood, on emergent hogweeds.
28.5. two at Bredon Hill amongst stems of Rough Chervil.
Another species that does not require dead wood as a host plant, it is associated with plants of the Apiaceae. Quite an early beetle in my experience.

23. Tetrops praeusta

Nationally: LOCAL
Only found at Drakes Broughton orchard so far, and there it is limited to only two old crab-apples as host trees. A small species and easily overlooked, it should be present in many similar localities in the County. Up to 10 at Drakes Broughton between 17.5. and 1.6.

 

I would be very interested to hear from anyone who has any records of Longhorn Beetles in Worcestershire that they would like to share with me. Or perhaps, you may like to join Geoff Trevis and myself in expanding our local 'Invertebrate Recording Group', we are attempting to gain more recruits who are interested in the less popular and under-recorded Insects and Invertebrates within Worcestershire.

I would like to take this opportunity to thank Mr Paul Whitehead for kindly confirming the identities of some of the more difficult species from my slides, particularly the following:-
Strangalia melanura, Tiddesley Wood, 30.5.
Molorchus umbellatarum, Tiddesley Wood, 28.6.
Pogonecherus hispidulus, Knapp & Papermill, 7.6.
Stenostola dubia, Monkwood, 1.6.

References:

BILY, S 1989 Longhorn Beetles (Coleoptera Cerambycidae) of Fennoscandia and Denmark Fauna Entomologica Scandinavica, Volume 22. (like all of the series this is written in English)
HARDE, KW 1984 A field guide in colour to beetles. Octopus Books
Editor's note:
The following bilingual (English & German) book is also useful:
BENSE, U 1995 Longhorn beetles. Illustrated key to Cerambycidae and Vesperidae of Europe. Ulrich Bense: Margraf

There is also Norman Hickin's little Shire Publications Book on Longhorns which is quite useful in illustrating many British Longhorns but at the moment I can't find my copy to give you a full reference.

 
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