Abstract
The eggs of six East Palaearctic species in the subgenera Ephemera Linnaeus s.s. and Sinephemera Kluge from the Russian Far East are investigated by scanning electron microscopy. Eggs of the subgenus Ephemera have a thick adhesive layer ranging from 1.3 to 3.0 µm. In species of the subgenus Sinephemera, the adhesive layer is thin, amorphous, and 0.5 µm in E. (S.) shengmi Hsu, while in the other two species it is presented in the form of a thin film. All studied species have micropyles of the “tagenoform type,” with the exception of E. (S.) shengmi, in which the micropyle can be classified as linear. The shape of the sperm guide is species-specific and is clearly visible only on the adhesive layer. The structure of the chorion varies markedly among the species studied. So in E. (S.) japonica McLachlan, it is practically smooth; in E. (E.) transbajkalica Tshernova, it is reticulate; in E. (E.) orientalis McLachlan and E. (S.) strigata Eaton, it is finely wrinkled; and in E. (E.) sachalinensis Matsumura and E. (S.) shengmi, it is intermittently sinuous. The use of micropyle structure, size of eggs, along with chorion sculpturing, resulted useful in egg and species identification.
References
- Bae, Y.J. (1995) Ephemera separigata, a new species of Ephemeridae (Insecta: Ephemeroptera) from Korea. Korean Journal of Systematic Zoology, 11 (2), 159–166.
- Balasubramanian, C., Venkataraman, K. & Sivaramakrishnan, K.G. (1991) Life stages of a South Indian burrowing mayfly, Ephemera (Aethephemera) nadinae McCafferty and Edmunds 1973 (Ephemeroptera: Ephemeridae). Aquatic Insects, 13, 223–228. https://doi.org/10.1080/01650429109361449
- Bauernfeind, E. & Soldan, T. (2012) The mayflies of Europe (Ephemeroptera). Apollo Books, Ollerup, 781 pp. https://doi.org/10.1163/9789004260887
- Degrange, C. (1960) Recherches sur la Reproduction des Éphémeroptères. Travaux du Laboratoire d’Hydrobiologie et de Pisciculture de l’Université de Grenoble, 51, 71–93.
- Hsu, Y.-C. (1937) The mayflies of China. Peking Natural History Bulletin, 11 (3), 287–296.
- Hwang, J.M. & Bae, Y.J. (2008) Review of the tropical Southeast Asian Ephemera (Ephemeroptera: Ephemeridae). Aquatic Insects, 30 (2), 105–126. https://doi.org/10.1080/01650420701883333
- Hwang, J.M., Bae, Y.J. & McCafferty, W.P. (2008) A checklist of the burrowing mayfly family Ephemeridae. In: Hauer, F.R. & Stanford, J.A. & Newell, R.L. (Eds.), International advances in the ecology, zoogeography and systematics of mayflies and stoneflies. University of California Publications in Entomology 128. Preceding of the 11 International. Conference on Ephemeroptera, Montana, USA, 22–29 August 2004, pp. 159–172. https://doi.org/10.1525/california/9780520098688.003.0012
- Eaton, A.E. (1892) On two new and some other Japanese species of Ephemeridae. Entomologist’s Monthly Magazine, Series 2, 3 (28), 302–303.
- Kang, S.C. & Yang, C.T. (1994) Ephemeroidea of Taiwan (Ephemeroptera). Chinese Journal of Entomology, 14, 391–399.
- Kluge, N.J. (2004) The phylogenetic system of Ephemeroptera. Kluwer Academic Publishers, 456 pp. https://doi.org/10.1007/978-94-007-0872-3
- Kluge, N.J. (2023) Ephemeroptera of the world. Available from: http://insecta.bio.spbu.ru/z/Eph-spp/index.htm (accessed 14 February 2023)
- Koss, R.W. (1968) Morphology and taxonomic use of Ephemeroptera eggs. Annals of the Entomological Society of America, 61, 696–721. https://doi.org/10.1093/aesa/61.3.696
- Koss, R.W. & Edmunds, G.F. Jr. (1974) Ephemeroptera eggs and their contribution to phylogenetic studies of the order. Zoological Journal of the Linnean Society, 55, 267–349. https://doi.org/10.1111/j.1096-3642.1974.tb01648.x
- Matsumura, S. (1931) 6000 illustrated Insects of Japan-Empire. Ephemerida, 1465–1480. Tokoshoin, Tokyo, 1497 pp.
- McCafferty, W.P. & Edmunds, G.F. Jr. (1973) Subgeneric classification of Ephemera (Ephemeroptera: Ephemeridae). Pan-Pacific Entomologist, 49 (4), 300–307.
- McLachlan, R. (1875) A sketch of our present knowledge of the neuropterous fauna of Japan (excluding Odonata and Trichoptera). Transactions of the Entomological Society, London, 167–190. https://doi.org/10.1111/j.1365-2311.1875.tb01906.x
- Okazaki, H. (1981) On the eggs of Japanese mayflies (1). Biology of Inland Waters, 2, 8–10.
- Okazaki, H. (1984) Observation of the eggs of Japanese mayflies by scanning electron microscope. Biology of Inland Waters, 3, 19–27.
- Su, C.-R. & Zhu, C.-D. (1997) Observation on the chorion structure of four species of mayfly by scanning electron microscope. Journal of Nanjing Normal University (Nature Science), 20 (4), 121–123.
- Tojo, K. & Machida, R. (1998) Egg Structures of Japanes Ephemeridae species (Ephemeroptera). Entomological Science, 1 (4), 573–579.
- Tshernova, O.A. (1973) Palearctic mayfly species of the genus Ephemera (Ephemeroptera, Ephemeridae). Revue d’Entomologie de l’URSS, 52 (2), 324–339.
- Ubero-Pascal, N.A. & Puig, M.A. (2007) Egg morphology update based on new chorionic data of Potamanthus luteus (Linnaeus), Ephemera danica Müller and Oligoneuriella rhenana (Imhoff) (Insecta, Ephemeroptera) obtained by scanning electron microscopy. Zootaxa, 1465 (1), 15–29. https://doi.org/10.11646/zootaxa.1465.1.2
- Ulmer, G. (1912) H. Sauter’s Formosa-Ausbeute. Ephemeriden. Entomologische Mitteilungen, 1, 369–375. https://doi.org/10.5962/bhl.part.25902
- Ulmer, G. (1920) Neue Ephemeropteren. Archiv für Naturgeschichte, Series A, 85 (11), 1–80.
- Zhang, J., Gui, H. & You, D.S. (1995) Studies on the Ephemeridae (Insecta: Ephemeroptera) of China. Journal of Nanjing Normal University (Nature Science), 18 (3), 68–76. [in Chinese]
- Zhou, C.F. (2013) A species list of Chinese mayflies (Insecta: Ephemeroptera). Biology of Inland waters, 6 (2), 167–225.