How to identify a Christmas Beetle
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Is the specimen a Christmas Beetle?
The Christmas Beetles belong to the family Scarabaeidae, subfamily Rutelinae, genus Anoplognathus. To identify the genus Anoplognathus work through the following four steps:
Step 1. Is the specimen a beetle, Order Coleoptera?
To determine if the specimen is a beetle confirm the specimen:
- has 3 body parts
- a head,
- thorax
- abdomen
- 3 pairs of legs
- 2 pairs of wings
- The forewings should be hardened into sheath like protective coverings
- These are called elytra that protect their delicate hindwings
- A tough exoskeleton
If it is a beetle, check whether it belongs to the family Scarabaeidae.
Step 2. Identification of the family Scarabaeidae
The family Scarabaeidae is large, consisting of around 2,300 genera and over 27,000 species worldwide (Cassis & Weir 1992).
The Australian Scarabaeidae possess the following characteristics (modified from Lawrence & Britton 1994):
- body not capable of rolling into a ball
Figure 2[i]
- head not covered by pronotum (Figure 2[i])
- labrum or mandibles or both usually hidden below edge of head (Figure 2[i])
- less than 11 antennal segments (Figure 2[i])
- 3-8 segmented antennal club present and distinct (Figure 2[i])
- antennal club segments strongly asymmetric, often lamellate (Figure 2[i])
Figure 2[ii]
- foretibial spur single or absent (Figure 2[ii])
- fore coxae large, occupying most of underside of prothorax
Figure 2[iii]
- tarsi with 5 simple, unlobed, segments (Figure 3[iii])
- abdomen with 6 visible ventrites
Step 3. Identification of subfamily Rutelinae
The subfamily Rutelinae includes about 200 genera and 3800 species worldwide, of which 23 genera and approximately 109 species occur in Australia (Cassis & Weir 1992).
Adult Rutelinae can be distinguished by a combination of the following characteristics (Figure 3[i])
Figure 3[i]
Figure 3[ii]
- unequal tarsal claws on hind leg (Figure 3[ii]).
- claws flattened and flexible (Figure 3[ii]).
Figure 3[iii]
- mesotarsus with 5 distinct tarsal segments (Figure 3[iii]).
- pygidium visible beyond apex of elytra.
- elytral epipleura with a membranous margin.
- at least one pair of abdominal spiracles exposed below elytral margin.
Figure 3[iv]
- head and pronotum without prominences (Figure 3[iv]). (Lawrence & Britton, 1994).
Step 4. Identification of the genus Anoplognathus (Christmas Beetles)
Christmas Beetles belong to the genus Anoplognathus Leach. Anoplognathus is endemic to Australia, except one species shared with New Guinea. There are 36 species, 21 of which occur in New South Wales (Cassis & Weir, 1992). Adult beetles feed on leaves, usually of eucalypts, and larvae feed on roots, usually of grasses. Several species are economically important pests in eucalypt plantations.
Anoplognathus can be separated from other genera of Rutelinae, in New South Wales, by the following characteristics (adapted from Carne, 1957,1958)
- foretibia with 1-2 lateral teeth (Figure 4[i]).
Figure 4[i]
Figure 4[ii]
- metaventrite process projecting anteriorly between the mid coxae (Figure 4[ii]).
Figure 4[iii]
- tarsal claws simple, not toothed, in males (Figure 4[iii]).
- hindtibia not greatly enlarged (Figure 4[iii]).
- frontoclypeal suture distinct (Figure 4[i]).
- labrum not projecting beyond clypeus.
References
- Allsopp, P. G. and Logan, D. P. 1999. Seasonal flight activity of scarab beetles (Coleoptera: Scarabaeidae) associated with sugarcane in southern Queensland. Australian Journal of Entomology 38: 219-226
- Brewster, M. N., Brewster, A. A. and Crouch, N. 1920. Life stories of Australian insects. Dymocks book store, Sydney. xii + 424pp.
- Carne, P.B. 1957. A revision of the ruteline genus Anoplognathus Leach (Coleoptera:Scarabaeidae). Australian Journal of Zoology 5(1): 88-143
- Carne, P.B. 1958. A review of the Australian Rutelinae (Coleoptera:Scarabaeidae). Australian Journal of Zoology 6(2): 162-240
- Carne, P.B. 1981. Three new species of Anoplognathus Leach, and new distribution records for poorly known species (Coleoptera: Scarabaeidae: Rutelinae). Journal of the Australian Entomological Society 20(4): 289-294
- Carne, P. B., Greaves, R. T. G. and McInnes, R. S. 1974. Insect damage to plantation-grown eucalypts in north coastal New South Wales, with particular reference to Christmas Beetles (Coleoptera: Rutelinae). Journal of the Australian Entomological Society 13: 189-206
- Carne, P. B. and Monteith, G. B. 1971. Three little known species of Christmas Beetle. Australian Entomological Society News Bulletin 7(2): 61-3
- Cassis, G. and Weir, T.A. 1992. Rutelinae. pp 359-382. In: Houston, W.W.K. (ed.) Zoological Catalogue of Australia. Coleoptera: Scarabaeoidea. Canberra: AGPS Vol. 9.
- De Baar, M. and Hockey, M. J. 1987. Additional records for Qld Anoplognathus (Coleoptera: Scarabaeidae: Rutelinae). Entomological Society of Queensland News Bulletin 14(10): 153-4
- Edwards, P. B., Wanjura, W. J. and Brown, W. V. 1990. Mosaic resistance in plants. Nature 347: 434
- Edwards, P. B., Wanjura, W. J. and Brown, W. V. 1993. Selective herbivory by Xmas beetles in response to intraspecific variation in Eucalyptus terpenoids. Oecologia 95: 551-7
- Froggatt, W. W. 1907. Australian inescts. William Brooks, Sydney. 449pp.
- Green, A.1983. A far-flying Christmas Beetle: the first record from Tasmania of Anoplognathus velutinus (Coleoptera: Scarabaeidae). Tasmanian Naturalist (July 1983): 2
- Lawrence, J. F. and Britton, E.B. 1994. Australian Beetles. Melbourne University Press, Melbourne. x + 192pp.
- Lawrence, J. F. 1999. The Australian Ommatidae (Coleoptera: Archostemata): new species, larva and discussion of relationships. Invertebrate Taxonomy 13: 369-390
- McKeown, K. C. 1942. Australian insects, an introductory handbook. Royal Zoological Society of New South Wales, Sydney. pp1-304.
- McQuillan, P. B. 1985. The identification of root-feeding cockchafer larvae (Coleoptera: Scarabaeidae) found in pastures in Tasmania. Australian Journal of Zoology 33: 509-546
- Moore, B. P. 1980-1996. A guide to the beetles of south-eastern Australia. Australian Entomological Press, Greenwich. 226pp.
- Ohmart, C. P. and Edwards, P. B. 1991. Insect herbivory on Eucalyptus. Annual Review of Entomology 36: 637-657
- Steinbauer, M. J. and Wanjura, W. J. 2002. Christmas Beetles (Anoplognathus spp., Coleoptera: Scarabaeidae) mistake peppercorn trees for eucalypts. Journal of Natural History 36: 119-125
- Thomson, V. P., Nicotra, A. B. and Steinbauer, M. J. 2001. Influence of previous frost damage on tree growth and insect herbivory of Eucalyptus globulus globulus. Austral Ecology 26: 489-499
- Tillyard, R. J. 1926. The insects of Australia and New Zealand. Angus & Robertson, Sydney. 560pp.
- Torre-Bueno, J.R de la. 1989. The Torre-Bueno Glossary of Entomology. The New York Entomological Society, New York. xvii + 840pp.