Eusthenia spectabilis
Eusthenia spectabilis is a very large species of stonefly in the family of giant stoneflies, Eustheniidae. At 4 cm (1.6 in) Eusthenia spectabilis is the largest member of the genus and emerges later than other similar species.
| Eusthenia spectabilis | |
|---|---|
 | |
| Adult | |
Scientific classification  | |
| Domain: | Eukaryota |
| Kingdom: | Animalia |
| Phylum: | Arthropoda |
| Class: | Insecta |
| Order: | Plecoptera |
| Family: | Eustheniidae |
| Genus: | Eusthenia |
| Species: | E. spectabilis |
| Binomial name | |
| Eusthenia spectabilis | |
 | |
| distribution for Eusthenia spectabilis, restricted to Tasmania | |
Appearance
Extremely similar to other members of the genus Eusthenia, mature adults have an elongate, flattened and soft body with long, filamentous cerci however, those of E. spectabili are shorter and thicker in relation to body size than other species. The head, thorax, legs and abdomen is mostly dark grey to black however can have orange to red fringes, the occipital ridge is often red in pristine individuals. The wings of this species are also dark with a purple base, pale veins and horizontal band two-thirds of the way down, the hindwing is mostly red with the distal end being dark.
Sexual dimorphism is found in all life stages with females being larger in both adult and nymph forms the species is perhaps best identified from it external genitalia, males having short and untoothed epicrot whilst females having a simple genital plate which are distinctive compared to other members of Eusthenia.[2]: 115
Life history and behaviour
As with most stonefly E. spectabilis is a completely aquatic carnivore at juvenile stages, developing into a less voracious winged, ephemeral adult.
Laying and egg shape of many stoneflies including E. spectabilis was largely researched by Hugh Bernard Noel Hynes,[3] where eggs enter the stream by deposition via the females ovipositor.
Nymphs, often referred to as a naiad can vary in colour with younger individuals starting off green and darkening to brown or black, despite this individuals may retain the colour of lower instar.[2]: 119 Naiads will emerge roughly after year then, climbing into the riparian zone to moult into adults.
Distribution
It is endemic to Tasmania, where its range is mainly found in alpine and subalpine streams and rivers of Western Tasmania.
Research
E. spectabilis has had little attention from science as many Australian invertebrates, many stoneflies have been used to indicate water quality however.[4] Studies on E. spectabilis have shown to survive when water is polluted with heavy metals. E. spectabilis was the first freshwater invertebrate recorded to produce metallothionein this was in response to high cadmium concentrations[5]
References
- Westwood, J. 0. (1832). The Animal Kingdom of Cuvier. Griffith. pp. 15, 348, 374.
- Hynes, H.B.N. (1976). "Tasmanian Antarctoperlaria (Plecoptera)". Australian Journal of Zoology. 24 (1): 115. doi:10.1071/ZO9760115.
- Yoshimura, M. (2004). "Seasonal and daily flight timing of oviposition in several stonefly species (Plecoptera) in the field". Zoological Science. 21 (2): 189–195. doi:10.2108/zsj.21.189. PMID 14993831. S2CID 36122335.
- Saltveit, S.J.; Brittain, J.E.; Lillehammer, A. (1987). "Stoneflies and river regulation-a review". In Craig, J.F.; Kemper, J.B. (eds.). Regulated Streams: Advances in Ecology. Boston, MA: Springer. pp. 117–129. doi:10.1007/978-1-4684-5392-8_8.
- Everard, L.B.; Swain, R. (1983). "Isolation, characterization and induction of metallothionein in the stonefly Eusthenia spectabilis following exposure to cadmium". Comparative Biochemistry and Physiology Part C: Comparative Pharmacology. 75 (2): 275–280. doi:10.1016/0742-8413(83)90192-5.
External links
- Eusthenia spectabilis. Atlas of Living Australia.