Two Rare Scarabaeid Beetles rediscovered in the Suffolk Breckland

TRANSACTIONS TWO RARE SCARABAEID BEETLES REDISCOVERED IN THE SUFFOLK BRECKLAND by (THE

NATURE

DR. M .

G.

MORRIS

CONSERVANCY—MONKS

WOOD

EXPERIMENTAL

STATION)

THE Coleopterous family Scarabaeidae contains some relatively large and noticeable species, including the chafers and dorbeetles, as well as some small and insignificant forms. The two species recorded here can be fairly said to represent one of each type.

Odontaeus armiger Scop. (subfamily Geotrupinae) is only of medium size (about six to eight mm. long) but the male is distinguished by having a long vertical horn and two shorter lateral horns on the head. The vertical horn can be moved by the beetle in life, giving rise to the earlier trivial name, mobilicornis F. The female beetle has none of the horns of the male and might be mistaken for a very small dor-beetle (Geotrupes sp.). O. armiger has always been regarded as a rarity in this country ; this fact and the exotic appearance of the male explain the great attraction that the species has for collectors. Previous records of O. armiger have been recently summarised by W. J. Eeles (1961), although he omits several of the records listed in a footnote to Wilkinson (1953). Both Eeles and Morley (1899) give the only Suffolk record as Stephens' in 1864. The beetle was taken Aying, but other details and the locality were not recorded. Since then, apparently, the beetle has not been found in the county.

In a study of the invertebrate fauna of Breckland " grass heaths " two pairs of pitfall traps (1 lb. jam jars sunk into the soil) were put down in the Deadman's Grave area, near Icklingham, in the summer of 1962. This area is a calcareous grass heath with an open type of Vegetation. Trapping in the area ceased on 1 Ith September but before this three examples of O. armiger had been recorded from the traps. A female was taken in one jar between

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25th July and 14th August, and a male and female together in another jar between 14th and 28th August. No specimens were found from 28th August to 1 Ith September. In the ecological Classification of habitats of Elton and Miller (1954) these beetles would be referred to the non-acid ground zone of the terrestrial system ( T /2). Little appears to be known about the biology of O. armiger. Abroad it is said to be associated with truffles, but it seems more likely that the larva feeds in dung, as in other Geotrupinae. It is usually found from June to September, and has been taken at light, including Lepidopterists' mercury vapour light traps (Ansorge, 1958, 1962 ; Wakely, 1957 ; Wilkinson, 1953).

Diastictus vulneratus Sturm, (subfamily Aphodiinae) is a very small and insignificant species, about three mm. long, but it is among the rarest of British beetles. A single specimen was discovered near Mayday farm, three miles south of Brandon in 1902 (Morley, 1902) and a description of the beetle was published (Newbery, 1902). In 1906 and 1907 three further examples were found in the same locality by Morley and Chitty (Morley, 1909).

In 1912 two specimens of D. vulneratus were taken by P. Harwood near Brandon and later recorded by Morley (1939), who stated that they had been taken during 1913 in the same vicinity (i.e., as his own). Dr. M. W. R. de V. Graham has kindly informed me that the specimens in Harwood's collection, now at the Hope Department, Oxford, bear the data " nr. Brandon, 27.V.12., Norfolk. P.H. " . The " Norfolk " label may mean that Harwood's examples were taken some distance away from Morley's original locality. In 1939 Morley rediscovered D. vulneratus at a new locality when he took ^single male at Knettishall Heath on 20th April (Morley, 1939). This specimen, the seventh, was apparently the last to be recorded in Britain until 1962.

I found a single exampi, of D. vulneratus, half buried in sandy soil, at Icklingham, about half a mile south of the locality where O. armiger was trapped, on 12th September, 1962. T h e beetle was lying near plants of flixweed, Descurainia sophia L. In Elton and Miller's (1954) Classification this habitat would be described as topsoil in a ground zone dominated, non-acid area of the terrestrial system ( T / 2 / l ) . T h e specimen was not identified until November, so that no further search has yet been made for it.

D. vulneratus was associated with rabbits' dung by Morley (1939) who also stated that its biology was probably similar to that of Onthophilus sulcatus F. (Histeridae). What the effects of myxomatosis on D. vulneratus were can only be guessed at, but the beetle has apparently survived them.

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The localities in which I took O. armiger and D. vulneratus are part of the Elveden estates. It is a pleasure to thank Lord Iveagh and his Agent, Mr. V. Harrison, for permission to work on the areas.

References

Ansorge, Sir. E. (1958). Odontaeus armiger Scop. in (Coleoptera Scarabaeidae). Ent. Gaz. 9 101.

Buckinghamshire

Ansorge, Sir E. (1962). Odontaeus armiger Scop. in (Coleoptera Scarabaeidae) ibid 13 177.

Buckinghamshire

Eeles, W . J. (1961). Odontaeus armiger Scop. in S o u t h Oxon. tera Scarabaeidae) ibid 97 236.

(Coleop-

Elton, C . S. and Miller, R . S. (1954). T h e ecological survey of animal c o m m u n i t i e s : with a practical system of classifying habitats b y s t r u c tural characters. J. Ecol. 42 460.

Morley, C. (1899).

The Coleoptera of Suffolk.

J. H . Keys, P l y m o u t h .

Morley, C. (1902). S u p p l e m e n t a r y n o t e on Diastictus vulneratus, S t u r m .

Ent. mon. Mag. 38 254.

Morley, C . (1909). F u r t h e r British examples of S t u r m . , ibid 45 235.

Morley, C. (1939).

4 122.

Rediscovery of Diastictus.

Diastictus

vulneratus

Trans. Suff. Nat.

Soc.

N e w b e r y , E . A. (1902). Diastictus vulneratus S t u r m . , an addition to t h e British List. Ent. mon. Mag. 38 253.

Wakely, S. (1957).

Proc. S. London Ent. Nat. Hist. Soc. 1956 10.

Wilkinson, W . (1953). Box Hill, Surrey, a c o n f i r m e d locality f o r Odontaeus armiger, Scop., (Coleoptera Scarabaeidae). Ent. mon. Mag. 83 166.