Lucilia species
These are the familiar ‘greenbottles’ so called because of the brilliant metallic green coloration of the adults. The colour appears to vary with age, newly emerged flies being a deep blue/green, which fades to green, and then finally to a dull coppery green (Smith 1986).The adults are somewhat smaller than Calliphora (4.5-10mm), but share similar habits and biology. North American authors (see Shewell 1987) split Lucilia, as it is understood here, into several genera. As a result the sheep-strike fly Lucilia sericata appears in the literature as both Lucilia sericata and Phaenicia sericata, depending on the author’s country of origin. An overall phylogenetic analysis of the subfamily Luciliinae on the basis of a broad range of characters is required to reach a consistent classification for the group. Adults of Lucilia, especially females, and larvae, are not easy to identify to species and should be submitted to a specialist.
Biology
All species in the genus are oviparous, and females need a protein meal to mature an egg batch. Larvae are primarily saprophagous in decaying animal matter, some species have become facultative parasites, and a couple are obligate parasites of amphibians (e.g. Lucilia bufonivora). There have been occasional reports of myiasis on tortoise and other reptiles caused by Lucilia species (Frank, 1981).
Adults visit flowers, faeces and dead animals. Unlike Calliphora, adults seldom come indoors and in the main are found in sunlit conditions, although some species are woodland. Many species are involved in animal myiasis and readily infest wounds. The genus is of great medical, hygiene, and forensic importance.
Two species in particular are well known as primary producers of myiasis, the so called "blowfly strike" of sheep. The primary agent in South Africa and Australia is Lucilia cuprina, and in temperate areas of Europe, North America and New Zealand, it is Lucilia sericata. The life history of the two species is very similar. Females lay their eggs on the wool of sheep, in particular if it is soiled with urine, faeces or blood. Under the temperature conditions found at the skin surface (31 °C for healthy skin, and up to 39 °C on an already infested lesion) (Zumpt 1965) eggs will hatch in 8-10 hours and larval development is completed in just 2 days, and the larvae will leave the wound to pupate in the soil. Unlike the screwworms, Lucilia larvae feed only on the surface of the skin and exudates from the lesion, and do not burrow deep into the host tissues. However they can penetrate where existing wounds are present.
In addition to sheep, other animals attacked include horses, cattle and humans (Zumpt, 1965; Smith 1986).
Lucilia sericata larvae are also sometimes referred to as ‘surgical maggots’ and are used in maggot therapy to treat intractable wounds on human patients. Specially reared sterile larvae are deliberately introduced into the wound where they ingest necrotic tissues, stimulate the wound healing process, and have been shown to clear wounds of bacterial infection (Sherman et al 2000). At the same time, however, naturally occurring infestations with Lucilia larvae are a medical problem for bed-ridden patients unable to clean or otherwise care for themselves.
Distribution
The genus contains numerous species, and occurs in all faunal regions, but is best represented in the Holarctic.
Sources
- Frank, W. 1981. Ectoparasites. Chapter 10, pp. 357-383 in, Diseases of the Reptilia, Volume 1, Cooper, J.E. & Jackson, O.F. (Eds.), xi + 383 + xxxii pp.
- Rognes, K. (1991). Blowflies (Diptera, Calliphoridae) of Fennoscandia and Denmark. Fauna Entomologica Scandinavica. Vol. 24, pub. E.J. Brill/Scandinavian Science Press Ltd.
- Sherman, R.A., Hall, M.J.R. & Thomas, S. (2000) Medicinal maggots: an ancient remedy for some contemporary afflictions. Annual Review of Entomology 45: 55-81.
- Shewell,G.E. (1987). 106 Calliphoridae. Pp 1133-1145 in: McAlpine, J.F., Peterson, B.V., Shewell, G.E., Teskey, H.J., Vockeroth, J.R. & Wood, D.M. (eds.), Manual of Neararctic Diptera, 2. Res. Branch Agric. Canada Monograph 28: vi + 675-1332. Ottawa.
- Smith, K.G.V. 1986. A manual of forensic entomology. London, British Museum (Natural History). 205 pp.
- Zumpt F. (1965). Myiasis in Man and Animals in the Old World. Butterworths, London,UK, 267 pp.
