The structure and ultrastructure of the egg capsule of Brachyptera risi (Plecoptera, Nemouroidea, Taeniopterygidae) with some remarks concerning choriogenesis

Abstract

The organization of the egg capsule of the euholognathan stonefly, which represents the family Taeniopterygidae (Nemuroidea) was investigated using light and electron microscopy techniques. The presence of a complex, multilayered egg capsule, composed of a vitelline envelope, multilayered chorion, and extrachorion is described. The morphology of the eggshell of Brachyptera risi was compared with that of euholognthan and systellognathan egg coverings and the ground plan of the egg capsule in Plecoptera was discussed.

The structure and ultrastructure of the egg capsules of stoneflies of the genusIsoperla(Insecta, Plecoptera, Perlodidae)

“…Morphology of the egg capsules of Plecoptera (stoneflies) of both groups distinguished in the suborder Arctoperlaria: the Euholognatha and Systellognatha has been investigated and described many times (Isobe, ; Kishimoto, ; Knispel, Rościszewska, Vinçon, & Lubini, ; Michalik, Rościszewska, & Miliša, ; Poprawa, Baran, & Rościszewska, ; Rościszewska, , b, ; Rościszewska & Jankowska, ; Sivec & Stark, ; Stark & Szczytko, ; Tierno de Figueroa & Derka, ; Tierno de Figueroa, Belardinelli, Fausto, Fochetti, & Mazzini, 2001; Ubero‐Pascal, Soler, & Puig ). Numerous differences in eggshell structure and ultrastructure were observed and interpreted as adaptations to the stoneflies mode of life (predatory—Systellognatha vs. herbivorous/detritusivorous—Euholognatha), or the environmental conditions of habitats of egg development (speed of the flow of water, its temperature, etc.).…”

“…The eggshells of the Euholognatha preferring slow flow waters are very thin and display simple regional organization. They are practically not regionally differentiated (except of a micropyle, Michalik et al, ; Poprawa et al, ; Rościszewska, ). In radial organization, however, they are multilayered, and, as it was recently reported for Brachyptera risi Morton 1896 (Taeniopterygidae), they can be quite complicated (Michalik et al, ).…”

“…They are practically not regionally differentiated (except of a micropyle, Michalik et al, ; Poprawa et al, ; Rościszewska, ). In radial organization, however, they are multilayered, and, as it was recently reported for Brachyptera risi Morton 1896 (Taeniopterygidae), they can be quite complicated (Michalik et al, ). In contrast, the Systellognatha, which prefers turbulent streams—lay their eggs in thick, hard, usually regionally, as well as radially, differentiated egg capsules (Fenoglio & Rościszewska, ; Knispel et al, ; Rościszewska, , 1995, 1996b, present study).…”

“…In the context of the aforementioned differences of the egg capsules which function in such different aquatic environments, the question arises of whether a ground‐plan of the egg capsules in Plecoptera does exist. The egg capsules of the two groups: Euholognatha and Systellognatha, distinguished in the Plecoptera–Arctoperlaria differ greatly, though it seems they are similar common in their ground‐plan (compare Michalik et al, ). Namely, they are multilayered and equipped with a micropyle (Michalik et al, ; Poprawa et al ; Rościszewska, , 1995, 1996a).…”

“…The egg capsules of the two groups: Euholognatha and Systellognatha, distinguished in the Plecoptera–Arctoperlaria differ greatly, though it seems they are similar common in their ground‐plan (compare Michalik et al, ). Namely, they are multilayered and equipped with a micropyle (Michalik et al, ; Poprawa et al ; Rościszewska, , 1995, 1996a). Attachment structures and/or adhesive layers are common of both groups; however they can be developed as sophisticated structures (anchors/discs) in Systellognatha or simple adhesive layers in Euholognatha.…”