Crambus

Belongs within: Crambini.

Crambus, the sod webworms, is a diverse genus of pale-coloured moths whose larvae feed primarily on grasses.

‘Ware the Crambus

There are some names that just immediately suggest problems. So if an animal gets labelled with the moniker of ‘sod webworm’, you just know its going to be trouble.

The animals designated in this way are larvae of Crambus, a diverse genus of snout moths. Over 150 species have been recognised in this genus to date though, like most snout moths, they are small and dull-coloured, not easy to distinguish. Significant features of the genus include the presence of two signa (hardened, sclerotised structures) on the inner wall of the bursa copulatrix in the female genital system, together with lost of the eighth abdominal sternite and fusion of the corresponding eighth tergite to the ostium bursae (Gaskin 1975). The signa are thought to function in the female’s control of fertilisation, by breaking up undesired spermatophores. Crambus is most diverse in the Holarctic and Afrotropical realms; it is absent in Australia and somewhat restricted in the Neotropics.

The majority of Crambus species whose natural history is known feed as larvae on grasses, though a smaller number attack broadleaf plants. The eggs are dry and non-adhesive, being scattered on the soil close to suitable host plants (Miller 1940). Newly hatched larvae feed on the epidermis of host leaves, eventually chewing grooves between leaf veins as they grow. Feeding is done at night; during the day caterpillars conceal themselves in silken tubes dug into the soil at the base of the plant.

Sod webworms are best known as pests of lawns and other turfs, though in tropical regions they have also been known to attack crops such as rice and sugar cane (Bohart 1947). They most often become an issue when turf is stressed by other factors such as drought or close mowing. Control is often achieved by encouraging predators of the caterpillars, or application of pesticides such as pyrethrins. Because the caterpillars do not attack the crowns of the grass, affected plants may often recover readily if given the opportunity. So if you care for your charges, you may be spared the Crambus.

Systematics of Crambus

Characters (Latreille 1802): Wings elongate, narrow, molded to the body. Four forward-directed palps, furnished with scales, forming an almost conical beak; terminal segment short.

Crambus Fabricius 1798LLN19
    |--C. argyreusG20
    |--C. carneusL02
    |--C. cuneiferellus [incl. C. microphaeellus]M86
    |--C. dicrenellusP27
    |--C. fascelinellusP01
    |--C. flexuosellusL27
    |--C. grammiculellus Guénée 1849E12
    |--C. lathoniellusLLN19
    |--C. luteellusP01
    |--C. malacellusP27
    |--C. minuellusH01
    |--C. pascuumL02
    |--C. perlellus [incl. C. warringtonellus]C90
    |--C. pinetiR26
    |--C. pratellusLLN19
    |--C. pratorumR26
    |--C. ramosellusL27
    |--C. tuhualisL27
    `--C. uliginosellusLLN19

*Type species of generic name indicated

References

Bohart, R. M. 1947. Sod webworms and other lawn pests in California. Hilgardia 17 (8): 267–308.

[C90] Chrétien, P. 1890. Observations suivantes. Annales de la Société Entomologique de France, 6^e série 9: cxxix–cxxx.

[E12] Evenhuis, N. L. 2012. Publication and dating of the Exploration Scientifique de l’Algérie: Histoire Naturelle des Animaux Articulés (1846–1849) by Pierre Hippolyte Lucas. Zootaxa 3448: 1–61.

Gaskin, D. E. 1975. Revision of the New Zealand Crambini (Lepidoptera: Pyralidae: Crambinae). New Zealand Journal of Zoology 2 (3): 265–363.

[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.

[H01] Hampson, G. F. 1901. The Lepidoptera-Phalaenae of the Bahamas. Annals and Magazine of Natural History, series 7, 7: 246–261.

[L02] Latreille, P. A. 1802. Histoire Naturelle, générale et particulière des crustacés et des insectes vol. 3. Familles naturelles des genres. F. Dufart: Paris.

[LLN19] Léger, T., B. Landry & M. Nuss. 2019. Phylogeny, character evolution and tribal classification in Crambinae and Scopariinae (Lepidoptera, Crambidae). Systematic Entomology 44: 757–776.

[L27] Lindsay, S. 1927. A list of the Lepidoptera of Deans Bush, Riccarton, Canterbury. Transactions and Proceedings of the New Zealand Institute 57: 693–696.

[M86] Meyrick, E. 1886. Notes on synonymy of Australian micro-Lepidoptera. Proceedings of the Linnean Society of New South Wales, series 2, 1 (3): 803–806.

Miller, H. D. O. 1940. Observations on sod webworms (Crambus spp. Lepidoptera) in Kansas. Transactions of the Kansas Academy of Science 43 (267–281).

[P01] Pável, J. 1901. Lepkék [Lepidopteren]. In: Horváth, G. (ed.) Zichy Jenő Gróf Harmadik Ázsiai Utazása [Dritte Asiatische Forschungsreise des Grafen Eugen Zichy] vol. 2. Zichy Jenő Gróf Harmadik Ázsiai Utazásának Állattani Eredményei [Zoologische Ergebnisse der Dritten Asiatischen Forschungsreise des Grafen Eugen Zichy] pp. 171–177. Victor Hornyánszky: Budapest, and Karl W. Hierseman: Leipzig.

[P27] Philpott, A. 1927. The maxillae in the Lepidoptera. Transactions and Proceedings of the New Zealand Institute 57: 721–746.

[R26] Risso, A. 1826. Histoire naturelle des principales productions de l’Europe méridionale et particulièrement de celles des environs de Nice et des Alpes maritimes vol. 5. F.-G. Levrault: Paris.