15Proc. Arthropod. Embryol. Soc. Jpn. 50, 15 (2016)Ⓒ 2016 Arthropodan Embryological Society of Japan
ISSN 1341–1527

Comparative Embryology of Plecoptera (Insecta)*
Shodo MTOW and Ryuichiro MACHIDA
Sugadaira Montane Research Center, University of Tsukuba, Sugadaira Kogen, Ueda, Nagano 386–2204, Japan
E-mail: s610@sugadaira.tsukuba.ac.jp (SM)

Stoneflies, of which nymphs are aquatic, live aroundmountain streams, and represent a polyneopteran order,
Plecoptera. It is divided into suborders Antarctoperlaria (fourfamilies) and Arctoperlaria (12 families) (Zwick, 2000). Nine
families of Arctoperlaria inhabit Japan.
The basal position within Polyneoptera has been often
bestowed to Plecoptera, but its affinity with other polyneopteranorders has been variously argued (e.g., Beutel et al., 2014). For
phylogenetic discussion like the reconstruction of groundplan
and phylogeny, the comparative embryological approach isone of the most useful methods. However, our embryologicalknowledge on Plecoptera remains fragmentary, being
restricted to the relatively detailed studies on two
arctoperlarian families (e.g., Miller, 1939, 1940; Kishimoto andAndo, 1985) and some brief reports on few other families ofthe same suborder. In such a background, to reconstruct thegroundplan and phylogenetic affinity of Plecoptera, we havestarted a comparative embryological study of Plecoptera, as
the first step, using nine all arctoperlarian families from Japan.
In the present talk, we provide the outlines of the embryonicdevelopment of these plecopterans.
Based on the comparison of the embryogenesis of nine
arctoperlarian families referring to the previous studies, theembryonic development of Plecoptera is characterized by: 1)
the formation of the embryo at the posterior pole of the egg, 2)elongation of the embryo along the egg surface, 3) immersionof the embryo into the yolk with its cephalic and caudal ends
left on the egg surface, and 4) blastokinesis involving thereversion of embryoʼs axis (except for Scopuridae). Thesefeatures may be considered to be the groundplan ofArctoperlaria. In Peltoperlidae (Yoraperla uenoi), which haveflattened eggs, the embryo shows the reversion accompaniedwith rotation of embryo during blastokinesis, as known in
Pteronarcyidae (Pteronarcys proteus), of which eggs are
likewise flattened in shape (Miller, 1939, 1940). However, theembryos in Scopuridae (Scopura montana) were revealed tosuffer from neither reversion nor rotation during
blastokinesis. Although this may be a potential apomorphy ofthe family, the phylogenetic revaluation of it is a future subject.
References
Beutel, R. G., B. Wipfler, M. Gottardo and R. Dallai (2014).
Polyneoptera or “lower Neoptera” - New light on old and difficult
phylogenetic problems. Atti Accademia Nazionale Italiana diEntomologia, 61, 133–142.
Kishimoto, T. and H. Ando (1985) External features of the developing
embryo of the stonefly Kamimuria tibialis (Pictet) (Plecoptera,Perlidae). Journal of Morphology, 183, 311–326.
Miller, A. (1939) The egg and early development of the stonefly,
Pteronarcys proteus Newman (Plecoptera). Journal of Morphology,
64, 555–609.
Miller,A.

(1940)

Embryonic

membranes,

yolkcells,

andmorphogenesis of the stonefly Pteronarcys proteus Newman(Plecoptera: Pteronarcyidae). Annals of the Entomological Societyof America, 33, 437–477.
Zwick, P. (2000) Phylogenetic system and zoogeography of thePlecoptera. Annual Review of Entomology, 45, 709–746.

* Abstract of paper read at the 51st Annual Meeting of the Arthropodan Embryological Society of Japan, June 12–13, 2015 (Urabandai, Fukushima).