Prioninae

Hardwood stump borer Mallodon dasytomus, copyright Ben Sale.

Belongs within: Cerambycidae.
Contains: Macrodontia, Prionini.

The Prioninae are a group of longicorn beetles characterised by the presence of elevated lateral margins on the pronotum. Members of the tribe Solenopterini have finely faceted eyes whereas they are coarsely faceted in other tribes (Turnbow & Thomas 2002).

There’s something on your back
Published 7 September 2009
The Palo Verde borer, Derobrachus hovorei, a member of the Prioninae from North America. Photo by Alex Wild.

The Prioninae are a subgroup of the Cerambycidae, the longicorn beetles. The common name refers to the elongate, back-swept antennae that are a feature of most members of this family. Cerambycidae are a simply huge family—over 20,000 species have been described, of which about 700 belong to the Prioninae (Bílý & Mehl 1989). The most familiar longicorns are large beetles but longicorns come in all sizes from the very large to the very small. Larvae of most longicorns live in and feed on dead wood (females may oviposit in live wood; the process of oviposition kills off the oviposition site and rot spreads through the tree allowing the larva to feed, making some of these species serious horticultural pests), and can take as long as two years to develop. Adults, in contrast, are relatively short-lived.

The most obvious feature distinguishing Prioninae from other longicorns is the presence of a sharp lateral keel on either side of the pronotum (the anterior shield of the thorax). Prioninae are large longicorns, dark in colour and crepuscular or nocturnal in habits. Adult Prioninae probably don’t feed (Willemstein 1987), but they nevertheless possess impressive jaws with which the males engage in vicious battles to win females. The larvae are generally polyphagous (that is, they’re not particularly picky over exactly what type of wood they’re eating), though some exceptions occur, and oviposition by the females is usually little more complicated than pushing the eggs into already rotting wood (Bílý & Mehl 1989).

Witchety grubs, dressed for the table. Photo by David Hancock.

Among the better-known members of the Prioninae are the witchety grubs of the genus Cnemoplites which were eaten by Australian Aborigines (Lawrence & Britton 1991)—still are, in fact, by those who have the nous to know where to find them. I’ve tried them on one occasion, cooked in wood ash. To be honest, I thought they tasted a bit like snot, but the woman who had brought them assured us that they were wonderful when spread across bread in lieu of butter. The most notorious of all Prioninae, however, is probably the rather self-explanatorily named Titanus giganteus, the Titan beetle of northern Amazonia. At twenty centimetres in length, Titanus is one of the largest of all insects. Technically, the Goliath beetles of the scarabaeid genus Goliathus are larger, but for some reason—probably their more compact build and less prominent mandibles—Goliath beetles don’t seem quite so bowel-openingly intimidating as Titanus. Titan beetles are a rare sight even within their native range (outside Amazonia, they have only ever been recorded as specialised parasites on time-travelling comediennes) which may just be all for the best; I suspect that even an avid entomophile like myself would be hard-pressed not to go into a blind panic and start screaming like a little girl if one of those suckers started crawling up my arm.

Titanus giganteus, the largest of the Prioninae. Photo by Bruno Ramos.

David Attenborough, who is seemingly a braver man than I, did handle a specimen of Titanus giganteus on an episode of Life in the Undergrowth. In that episode, Attenborough commented on the point that the larval stage of Titanus has not yet been conclusively identified. It might seem unusual that something as doubtlessly impressive as a Titanus grub would be should go unnoticed, but when you consider the concealed habitat of the larvae, the short lives of the adults, and the extreme difficulty of identifying a holometabolous larva with its corresponding adult, this situation becomes much less surprising. The words of Francis Pascoe, commenting in 1866 on a collection of longicorns from Penang in Malaysia, are just as appropriate today as they were 140 years ago:

If we consider that the Longicorns in their perfect [i.e. adult] state are generally short-lived, and that a great majority of the species frequent particular plants or families of plants, so that only where these plants occur can we expect to find the insects, it will be readily understood how this limited range and brief existence make it almost impossible for any collector to obtain more than a portion of those that inhabit even a moderately extensive district. And thus it is that sometimes perhaps half the species of a large collection are represented each by one or two individuals only. The number of species, therefore, and the many superb novelties which Mr. Lamb has had the good fortune to capture, whilst it excites our imagination, shows us how much more might be expected if all those rich tropical lands were as thoroughly worked by entomologists as Europe has been.

Systematics of Prioninae

Characters (from Turnbow & Thomas 2002): Labrum fused with epistoma; inner lobe of maxillae obsolete; antennae surpassing base of pronotum; pronotum with elevated lateral margin; procoxae strongly transverse; mesonotum without striated stridulatory area; wings with a spur on the radio-medial crossvein, closed cell in anal sector, vein 2A1 absent; tarsi pseudotetramerous, padded beneath, third tarsomere dilated, concealing true fourth tarsomere.

<==Prioninae [Macrotominae, Prionides]
    |--+--PrioniniLL20
    |  `--+--Psephactus remigerLL20
    |     `--MegopisLL20
    |          |--*M. muticaP66
    |          |--M. costipennisP66
    |          |--M. procera Pascoe 1866P66
    |          `--M. sinicaLL20
    `--MacrotominiTT02
         |--Nothopleurus Lacordaire 1869TT02
         |--Archodontes Lameere 1903 [incl. Paramallus Casey 1912]TT02
         |    `--A. melanopus (Linnaeus 1767)TT02
         |--Neomallodon Linsley 1957TT02
         |    `--N. arizonicus (Casey 1912)TT02
         |--Strongylaspis Thomson 1860TT02
         |    `--S. corticarius (Erichson in Schomburg 1848)TT02
         |--Stenodontes Audinet-Serville 1832TT02
         |    |--S. chevrolati Gahan 1890TT02
         |    `--S. exsertus Ol. 1795 [incl. S. capra, S. cinnamomeus, S. mandibularis]FS90
         |--MacrotomaM87
         |    |--M. cnemoplitoides Thoms. 1877M87
         |    |--M. herosRD77
         |    |--M. papyria Pascoe 1864M87
         |    `--M. servilis Pascoe 1863M87
         `--Mallodon Lepeletier & Audinet-Serville 1830LL20, TT02
              |--M. australis d’Urville in Boisduval 1835B35
              |--M. dasytomus (Say 1823)TT02
              |--M. maxillosus Drury 1773 [incl. M. spinibarbis Sturm 1826]FS90
              `--M. stigmosus Newm. 1840M87
Prioninae incertae sedis:
  Prionoplus reticularis White 1846M59, H82
  XixuthrusM87
    |--X. microcerusZS10
    `--X. nycticorax Thoms. 1877M87
  Brephilydia jejuna (Pascoe 1871) [=Mallodon jejuna]M87
  MacrodontiaB14
  CtenoscelisB14
  Paroplites australisLB91
  EurynassaLB91
    |--E. australis Boisd. 1835M87
    |--E. figurata (Pascoe 1859) [=Mallodon figuratus]M87
    |--E. odewahni (Pascoe 1864) [=Mallodon odewahni]M87
    `--E. servilleiM87
  CnemoplitesLB91
    |--C. australis Erichs. 1842M87
    |--C. cephalotes (Pascoe 1864) [=Mallodon cephalotes]M87
    |--C. edulis Newm. 1842M87
    |--C. impar Newm. 1844M87
    |--C. insularis Hope 1841M87
    `--C. spinicollis Macleay 1827M87
  Rhipidocerus australasiaeLB91
  PhaolusLB91
    |--P. macleayi Pascoe 1863M87
    `--P. metallicusLB91
  SceleocanthaM87
    |--S. glabricollis Newm. 1840M87
    `--S. pilosicollis Hope 1834M87
  Miocydus prionoides Pascoe 1875M87
  Catypnes macleayiM87
  Remphan hopeiP66
  AgrianomeC96
    |--A. gemella Pascoe 1859M87
    `--A. spinicollisC96
  Teispes dorsalis Thoms. 1864M87
  Aspectrogaster flavipilis Thoms. 1877M87
  Dioclides prionoides Thoms. 1864M87
  Analophus parallelus Waterh. 1877M87
  Nothophysis lucanoides Serv. 1832M87
  Dorx pentamera Newm. 1840M87
  Pithanotes falsa Newm. 1840M87
  ToxeutesM87
    |--T. arcuatus [incl. T. curvus Gmel. 1817]M87
    `--T. punctatissimusM87
  ElaptusM87
    |--E. brevicornis Pascoe 1875M87
    `--E. simulator Pascoe 1867M87
  Enneaphyllus aeneipennis Thoms. 1877M87
  Iotherium metallicum Newm. 1838M87
  Ergates Audinet-Serville 1832 [incl. Callergates Lameere 1904, Trichocnemis LeConte 1851; Callipogonini]TT02
  SolenopteriniTT02
    |--Sphenostethus Haldeman 1845 [incl. Hoplopteryx Westwood 1845]TT02
    |    `--S. taslei (Buquet 1841)TT02
    `--Elateropsis Chevrolat 1862TT02
         |--E. lineatusFS90
         |--E. quadrilineatusFS90
         |--E. scabrosus Gahan 1890TT02
         |--E. sulcicollis Thoms. 1860 [incl. E. zebra]FS90
         `--E. thomaeFS90
  Tragosoma Audinet-Serville 1832 [Meroscelisini]TT02

*Type species of generic name indicated

References

Bílý, S., & O. Mehl. 1989. Longhorn beetles (Coleoptera, Cerambycidae) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica 22. E. J. Brill.

[B35] Boisduval, J. B. 1835. Voyage de Découvertes de l’Astrolabe. Exécuté par ordre du Roi, pendant les années 1826–1827–1828–1829, sous le commandement de M. J. Dumont d’Urville. Faune entomologique de l’océan Pacifique, avec l’illustration des insectes nouveaux recueillis pendant le voyage vol. 2. Coléoptères et autres ordres. J. Tastu: Paris.

[B14] Bouchard, P. (ed.) 2014. The Book of Beetles: A lifesize guide to six hundred of nature’s gems. Ivy Press: Lewes (United Kingdom).

[C96] Calder, A. A. 1996. Click beetles: genera of the Australian Elateridae (Coleoptera). CSIRO Australia: Collingwood.

[FS90] Fleutiaux, E., & A. Sallé. 1890. Liste des coléoptères de la Guadeloupe et descriptions d’espèces nouvelles. Annales de la Société Entomologique de France, 6e série 9: 351–484.

[H82] Helmore, D. W. 1982. Drawings of New Zealand insects. Bulletin of the Entomological Society of New Zealand 8: 1–52.

[LB91] Lawrence, J. F., & E. B. Britton. 1991. Coleoptera (beetles). In: CSIRO. The Insects of Australia: A textbook for students and research workers 2nd ed. vol. 2 pp. 543–683. Melbourne University Press: Carlton (Victoria).

[LL20] Lee, S., & S. Lee. 2020. Multigene phylogeny uncovers oviposition-related evolutionary history of Cerambycinae (Coleoptera: Cerambycidae). Molecular Phylogenetics and Evolution 145: 106707.

[M87] Masters, G. 1887. Catalogue of the described Coleoptera of Australia. Part VI. Proceedings of the Linnean Society of New South Wales, series 2, 1 (4): 979–1036.

[M59] Morgan, F. D. 1959. The ecology and external morphology of Stolotermes ruficeps Brauer (Isoptera: Hodotermitidae). Transactions of the Royal Society of New Zealand 86 (1): 155–195.

Pascoe, F. P. 1866a. Catalogue of longicorn Coleoptera collected in the island of Penang by James Lamb, Esq. Part I. Proceedings of the Zoological Society of London 1866: 222–267.

[P66b] Pascoe, F. P. 1866b. Catalogue of longicorn Coleoptera collected in the island of Penang by James Lamb, Esq. Part II. Proceedings of the Zoological Society of London 1866: 504–536.

[RD77] Richards, O. W., & R. G. Davies. 1977. Imms’ General Textbook of Entomology 10th ed. vol. 2. Classification and Biology. Chapman and Hall: London.

[TT02] Turnbow, R. H., Jr & M. C. Thomas. 2002. Cerambycidae Leach 1815. In: Arnett, R. H., Jr, M. C. Thomas, P. E. Skelley & J. H. Frank (eds) American Beetles vol. 2. Polyphaga: Scarabaeoidea through Curculionoidea pp. 568–601. CRC Press.

Willemstein, S. C. 1987. An Ecological Basis for Pollination Ecology. E. J. Brill.

[ZS10] Zborowski, P., & R. Storey. 2010. A Field Guide to Insects in Australia 3rd ed. Reed New Holland: Sydney.

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