19Proc. Arthropod. Embryol. Soc. Jpn. 50, 19 (2016)Ⓒ 2016 Arthropodan Embryological Society of Japan
ISSN 1341–1527

Egg Structures and Egg Teeth in Some Orthopterans (Insecta:Polyneoptera)*
Atsuhiro HARADA and Makiko FUKUIGraduate School of Science and Engineering, Ehime University, Bunkyo-cho, Matsuyama, Ehime 790–8577, Japan
E-mail: fukui.makiko.me@ehime-u.ac.jp (MF)The egg tooth is a cuticular hatching device on the frontal
region of insect hatchlings. Egg teeth are found exclusively in
Dicondylia and can be regarded as an autapomorphy of thegroup. Recently, Mashimo et al. (2014) compared the egg
structures and egg teeth in Zoraptera, Embioptera andPhasmatodea on the basis that these three orders aremonophyletic, and suggested that the forms with the egg
operculum for hatching more elaborate have less developed
egg teeth and vice versa, i.e., the forms with the operculum
less developed or lacking have well developed egg teeth.
Orthoptera are the most speciose order in Polyneoptera.
Orthopterans show a wide-ranging variety of egg teeth inshape and size, from the well-developed to totally lacking(Brookes, 1951; Wada, 1966; Ingrisch, 1984; Pétavy, 1985;
Houston, 2007). In the present study, we examined the egg
teeth of three species belonging to different superfamilies ofEnsifera, namely, Gryllus bimaculatus of Grylloidea,
Nippancistroger testaceus of Gryllacridoidea and Gampsocleis
buergeri of Tettigonioidea, and compared them referring tothe egg structures of each species.

totally lacking. Hatching occurs, with the anterior pole of theegg or the “operculum” detached and with the egg body tornalong the hatching line.
The present study revealed that the hatching devices on theegg such as the “operculum” or “hatching line” are lessdeveloped in the ensiferan orthopterans with well-developed
egg teeth, contrary that the hatching devices on the egg are
well developed in those with egg teeth less or not developed,
as generalized in Zoraptera and Eukinolebia (Embioptera +Phasmatodea) by Mashimo et al. (2014).
References
Brookes, H. M. (1952) The morphological development of the embryoof

GrylluscommodusWalker(Orthoptera:Gryllidae).

Transactions of the Royal Society of South Australia, 75, 150–159.
Houston, T. F. (2007) Observations of the biology and immature stagesof the sandgroper Cylindraustralia kochii (Saussure), with notes
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Ingrisch, S. (1984) Embryonic development of Decticus verrucivorus(Orthoptera: Tettigoniidae). Entomologia Generalis, 10, 1–9.

In Gampsocleis buergeri, the egg tooth is well developed,
occupying the frons length, and shows a regional
differentiation, i.e., the anterior and posterior blades andmedian spine. The egg of the species lacks any hatching
devices such as the operculum or hatching line. Hatchingoccurs, simply with the chorion torn by the egg tooth. InNippancistroger testaceus, the prelarva has a small-sized egg
tooth at the center of the frons, resembling the median spine
in G. buergeri. The egg has a circular hatching line around theanterior pole of the egg. Hatching occurs, with the anteriorpole “operculum” detached from the egg body, as well as withthe anterior half of the egg body longitudinally torn by the egg
tooth. In Gryllus bimaculatus, the egg has a circular hatchingline around the anterior pole of the egg as in N. testaceus andlikely a longitudinal hatching line on the body. The egg tooth isMashimo, Y., R. G. Beutel, R. Dallai, C. -Y. Lee and R. Machida (2014)
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Pétavy, G. (1985) Origin and development of the vitellophags during
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Wada, S. (1966) Analyse der Kopf-Hals-Region von Tachycines(Saltatoria) in morphogenetische Einheiten. II. Mitteilung:Experimentell-teratologische Befunde am Kopfskelett mit
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* Abstract of paper read at the 51th Annual Meeting of the Arthropodan Embryological Society of Japan, June 12–13, 2015 (Urabandai, Fukushima).