Eos, t. LXIII, págs. 101-105 (1987).

Observations on Cerceris (: Sphecidae) preying on Scarabaeidae (Coleóptera) in South Afruca

BY

E. McC. CALLAN

The use of of the family Scarabaeidae as prey by of the ge- nus Cerceris is unusual and is reported for four species in South Africa. Their nesting behaviour is described.

INTRODUCTION.

The solitary genus Cerceris LATREILLE is worldwide in distribution and the largest in the family Sphecidae with over 850 species. The wasps are ground- nesting and usually exploit bare, flat and hard-packed soil, but some nest in fria- ble sand and a few in sand banks. Nests are stored with adult Coleoptera and Hy- menoptera as food for the larvae, and the burrow is left open during provisioning. The most striking feature of the behaviour of Cerceris is the diversity of the taken as prey and the prey specificity of the different species. GESS (1980) presented prey records for 20 Afrotropical Cerceris and suggested that the genus is Old World and its original prey Hymenoptera. The adoption of Coleoptera as prey by Cerceris made available an extremely numerous order, exploited by few other wasps, and has undoubtedly contributed to the success of the genus. A few Cerceris store their nests with Hymenoptera, mainly Apoidea, and hy- menopterous prey other than has been reported from South Africa (GEss, 1980) and elsewhere. Most Cerceris, including all New World species, provision with Coleoptera and records exist of at least 13 families of beetles used as prey: Anthicidae, Anthribidae, Bruchidae, Buprestidae, Cerambycidae, Chrysomelidae, Coccinellidae, Curculionidae, Eucnemidae, Nitidulidae, Phalacridae, Scarabaei- dae, and Tenebrionidae. Beetles most used are Curculionidae and several families are only rarely taken. It is unusual for Scarabaeidae to be used as prey, but this is now reported for four species of Cerceris in South Africa.

Cerceris nasidens obscura SCHLETTERER, 1887. This subspecies occurs in the coastal region of the Eastern Cape Province, reaching as far as the Natal coast. The nominate subspecies inhabits inland arid regions of the Karoo. EMPEY (1969) synonymized C. africana CAMERON, descri- bed from Port Elizabeth, with C. n. obscura, according it subspecific rank becau- se it differs from the nominate subspecies in the shape of the female clypeus,_ in coloration, and ecologically. It is a black and ferruginous wasp, the female 14-15 mm., the male 13-14 mm. long. In providing prey records, GESS (1980) did not associate C. n. obscura with its

102 E. McC. CALLAN prey himself, but merely reported my finding it provisioning with "small melo- lonthid beetles". A more detailed account of my observations follows. I first encountered this species on 6 April 1952 at Grahamstown, Eastern Cape Province nesting in my garden in company with the sphecine wasp Podalo- nia canescens (DAHLsom, 1843). The nest site, was the flat, hard-packed soil of a disused flower bed overgrown with weeds. A female carrying a small brown - tle was seen in flight approaching a nest. The prey-laden female descended slowly and the dived precipitously into the open entrance to the burrow. The wasp was captured on exiting and an attempt made to excavate the nest. At the end of the more or less vertical burrow at a depth of about 18 cm. a cache of 14 beetles was found. The prey comprised two species and was evidently stored temporarily in the bottom of the burrow before cells were prepared in which to place them. This procedure is well known in Cerceris. I found this species again on 22 March 1958 nesting in my garden in the flat, compacted soil of another disused garden bed. Wasps were not observed carrying prey, but several females were captured when digging their burrows. Soil was pushed out of the burrow by the pygidium of the female and a mound allowed to accumulate around the entrance. Males were not seen in the vicinity of the nests when females were nesting, but were taken on vegetation nearby at other times. A nest was excavated, and a cache of eight beetles comprising three species was found at a depth of about 15 cm. in the burrow. The pooled 22 prey of C. n. obscura were all Scarabaeidae, Melolonthinae, Sericini - identified as Ablabera splendida (FABRiclus) (15), Ablaberoides aeneus BLANCHARD (3), and Trochalus aeruginosus BURMEISTER (4). It is noteworthy that the first two species of beetles were among those provisioned in both 1952 and 1958, suggesting consistency in predatory behaviour or availability of prey. Wasps are deposited in the collecction of H. N. EMPEY and prey in the British Museum (Natural History), London.

Cerceris armaticeps caffrariae EMPEY, 1974.

This subspecies was described by EMPEY (1974) from Port Elizabeth. It is res- tricted to the Eastern Cape Province, and differs from the nominate subspecies C. a. armaticeps CAMERON, 1910 which occurs in the Transvaal and Lesotho, in the shape of the petiole and in coloration. It is a black and ferruginous wasp, the female 13-15 mm., the male 11-12 mm. long. I discovered this wasp on 16 April 1979 on the coastal dunes at Saltvlei, Port Alfred, Eastern Cape Province. It was nesting in a vertical sand bank of white, fine-grained sand. Which faced inland, being thereby sheltered from the ocean winds, and received daily several hours of direct sun. A female was seen to plun- April another ge rapidly into an open burrow and was taken on exiting. On 17 in a nearby part of the same female was again seen diving into an open burrow sand bank and captured. Although the nest site was visited on several occasions during the next few days, the wasp not observed again until 30 April. At 11,30 an open nest hours a female carrying a small brown beetle was seen diving into entrance about 1.5 m. from the ground in the sand bank where previous indivi- duals were captured. The wasp .emained in the nest until 11,40 hours, and then exited rapidly and flew away. Three minutes later the female returned to te nest carrying a beetle held closely beneath the body and was captured with the prey As the wasp returned to the nest so soon, the sour- when diving into the burrow. forward be- the prey must have been quite near. The prey was carried well ce of be seen. low the body, but the precise method of prey carriage could not OBSERVATIONS ON «CERCERIS» (HYM.) PREYING ON SCARABAEIDEAE... 103 The nest was excavated and the burrow found to be at first horizontal for about 5 cm. and then descended steeply at an angle of 45° for about 20 cm., at which depth a cache of 8 beetles was discovered. The prey was evidently stored temporarily in the burrow before transference to a ce!!. Although an attempt was made to find cells containing prey with the egg of the wasp, this was not success- ful. The beetles removed from the nest, and the one taken from the wasp, were all Scarabaeidae, Melolonthinae, Sericini - identified as Ablabera sp. It was not possible to identify the prey further, as it was unrepresented in the named collec- tion in the British Museum (Natural History), where the beetles are deposited. Wasps are deposited in the Albany Museum, Grahamstown.

Cerceris natalensis SAUSSURE, 1867. This subspecies was described from the Natal coast. It is a large and quite dis- tinctive species, the female 18 mm. long. black and reddish in colour, and is ap- parently known only from Natal. Dr. R. M. MILLER, of the University of Natal, Pietermaritzburg informed me (1980, pers. comm.) that he had observed a Cerceris provisioning its nest on sand dunes with Scarabaeidae, and kindly sent me a specimen of the wasp with its bee- tle prey. Three wasps were captured by Dr. Miller on 27 January 1980 on coastal dunes at Umlalazi Nature Reserve, 5 Km. E Mtunzini, Natal. This species would clearly repay further study. Its nesting biology is unusual in that it nests in sand and preys on Scarabaeidae. I took the female I received, mounted with its prey, to the British Museum (Natural History), where the wasp was determined as C. natalensis and the beetle prey as Hybocamenta sp, (Scarabaeidae, Melolonthinae, Sericini). The prey could not be identified further from a single female, as no representatives of this genus are named specifically in the Museum collection. The wasp with its beetle prey are deposited in the colecction of H. N. EMPEY, who confirmed the identify of the wasp.

Cerceris latifrons latifrons BINGHAM, 1902. The nominate subspecies was described from the Natal border of the Trans- vaal and is widespread. C. I. sedula ARNOLD, 1940 was described from Zimbabwe (formerly Southern Rhodesia) (as C. sedula), where ARNOLD (1940) recorded it with "an unidentified species of beetle (Hopliinae)". The female is 14-15 mm. long. C. I. laufrons seems to have a predilection for sandy areas. I have found it nesting in fine-grained, friable sand on inland dunes at Sand Flats, near Paterson, Eastern Cape Province, but have not taken it with prey. GESS (1980) reported C. I. latiforns nesting in a sandpit and in a gently sloping sand bank at Hilton, near Grahamstown, where it was the commonest Cerceris encountered and dug very deep nests, reported to be over 50 cm. in depth. This sand-nesting wasp apparently nests only in relatively deep sand. Females were ta- ken by GESS with beetle prey from November to January 1973 to 1978. In all 11 prey were taken, comprising two species, probably Dicranocnemus spp. (Scara- baeidae, Melolonthinae, Hophini). The tribe Hopliini is well represented in South Africa, where these small chafers have been called frog beetles because of their inordinately long hind legs. They are commonly found, often in large numbers, burrowing in the flowers of Compositae, where they are no doubt hunted by the wasp. Wasps and prey are in the Albany Museum, Grahamstown (GEss, 1980). 104 E. N1cC. CALLAN

DISCUSSION.

The genus Cerceris has been relatively well studied in Europe and North America, and a fuller understanding of its behaviour is most likely to come from observations in the southern hemisphere. Apart from South Africa, the use of Scarabaeidae as prey has hitherto been reported only in Australia and Malaysia, as follows: - C. ferox F. SMITH, 1856 - prey Microserica sp. (Sericini) in Malaysia (PAGDEN, 1934); C. venusta venusta F. SMITH, 1873 - prey Automohus maechi- dioides (MAcLEAY) (as Deuterocaulobius) (Automohini) in Australia (KRomBEIN, 1969); and C. australis SAUSSURE, 1854 - prey Liparetrus ferruguineus BLAN- CHARD and other Liparetrus spp. (Liparetriini) in Australia (EvANs and MATT- HEWS, 1970). In all the South African and in the aboye extralimital Cerceris the prey com- prised Scarabaeidae of the subfamily Melolonthinae. The most favoured tribe wit- hin the Melolonthinae was the Sericini (four records), with one record each for the Hopliini, Automollini and Liparetriini. These tribes comprise diurnal chafer beetles commonly found in flowers. Here the wasps undoubtedly hunt for their prey. The four South African Cerceris known to provision with Scarabaeidae are all large species, the females 14-18 mm. long. The prey is of much smaller size, 4- 6 mm. long. When transporting prey some Cerceris are known to grasp either one of the beetle's fore-legs or antennae with the mandibles. In the South African species seen carrying prey it was not observed exactly the role the mandibles played. As the antennae are short of peculiar form in Scarabaeidae, one of the front legs of the beetle is probably grasped with the mandibles. In flight the prey is carried well forward beneath the body, held by the mandibles and supported by the fore —and mid— legs of the wasp. As the burrow entrance is left open during provi- sioning, the prey-laden female can plunge in inmediately on returning to the nest. Caches of beetles were found stored in the burrow of those nests excavated. Temporary burrow storage of the prey prior to its transfer to a definitive cell is known for many Cerceris. The stored beetles appeared to be completely or dee- ply paralyzed and were incapable of movement. Most Cerceris dig their burrows in level, hard-packed soil, others nest in fria- ble sand and in sand banks. One of the South African Cerceris nested in hard soil and three nested in sand. The exploitation of vertical sand banks as nest sites is most unusual, and has been reported in rather few species, e.g. C. dilatata SPINO- LA, 1841 and C. callani KROMBEIN, 1972 in Trinidad, West Indies (CALLAN, 1976). In South Africa C. a. caffrariae nested in a vertical sand bank, and it would be interesting to learn if this is normal or exceptional behaviour and whet- her the subspecies "armaticeps" nests similarly. However, it can probably be pre- dicted with a fair degree of certainty that the nominata subspecies will be found to provision its nests with Scarabaeidae.

ACKNOWLEDGEMENTS.-I am grateful to Mr. C. R. VARDY, Mr. H. N. EMPEY and Dr. F. W. GESS for the identification of Cerceris, and to Mr. R. D. POPE for naming the beetle prey. I also thank Dr. R. M. MILLER for sending me the speci- men of C. natalensis with prey.

Resumen.

La utilización de Coleópteros de la familia Scarabaeidae como presa de avis- pas del género Cerceris es excepcional, habiendose encontrado este hábito en OBSERVATIONS ON «CERCERIS» (HYM.) PREYING ON SCARABAEIDEAE... 105 cuatro especies en la República de Sud-Africa. También se describe el comporta- miento de nidificación.

Bibliography.

ARNOLD, G., 1940.—New specis of African Hymenoptera. N." 4. Ann. Trans. Mus. 20: 101-143.

CALLAN, E. McC., 1976.—Observations on the nesting behavior and prey of gorytine wasps in Trini- dad (Hymenoptera, Sphecidae). Psyche, Camb. 83: 324-335.

EMPEY, H. N., 1969.—Revision of the ethiopian species of Cerceris Latreille, 1802 (Hymenoptera, Sp- hecidae). 1. A synonymical checklist of the described species. J. ent. Soc. sth. Afrf. 32: 297-331.

EMPEY, H. N., 1974.—The status, sex and synonymy of Cameron's types of Cerceris Latreille from the ethiopian region. Ann. Trans. Mus. 29: 99-134.

EVANS, H. E. & R. W. MATTHEWS. 1970.—Notes on the nests and prey of Australian wasps of the genus Cerceris (Hymenoptera, Sphecidae). J. Aust. ent. Soc. 9: 153-156.

GESS, F. W., 1980.—Prey and nesting sites of some sympatric species of Cerceris (Hymenoptera, Sphe- cidae) with a review and discussion of the prey diversity of the genus. Ann. Cape Prov. Mus. (nat. Hist.) 13: 85-93.

KROMBEIN, K. V., 1969.—A revision of the Melanesian wasps of the genus Cerceris Latreille (Hyme- noptera, Sphecidae). Smiths. Contrib. Zool. 22: 1-36.

PAGDEN, H. T., 1934.—Biological notes on some Malayan aculeate (Hymenoptera. I. (Sphecidae) and Vespoidea). J. Fed. Malay States Mus. 17: 458-466.

Recibido el 15-VII-85 Dirección del autor: E. MCC. CALLAN 13 Gellibrand Street Campbell, Camberra A.C.T. 2601 - Australia