Turk J Zool 33 (2009) 387-392 © TÜBİTAK Research Article doi:10.3906/zoo-0807-12

External morphology of eggs of Macronemurus bilineatus and Megistopus flavicornis (, Myrmeleontidae): a scanning electron microscopy study

Zekiye SULUDERE1,*, Savaş CANBULAT2, Selami CANDAN1 1Gazi University, Arts and Science Faculty, Department of Biology, 06500 Ankara - TURKEY 2Sakarya University, Arts and Science Faculty, Department of Biology, 54140 Sakarya - TURKEY

Received: 09.07.2008

Abstract: The eggs ofMegistopus flavicornis (Rossi, 1790) and Macronemurus bilineatus Brauer, 1868 were studied by light and scanning electron microscope and are described in detail in this paper. Both species have roughly elongate and cylindrical eggs with rounded ends and have 2 flattened disc-like micropylar processes at the opposite poles. The chorionic surface is tuberculated and differs between the 2 species. The eggs of M. flavicornis additionally have some rows containing polygonal pattern of exochorion near the micropyles. Moreover, a number of morphological differences between the 2 species are noted.

Key words: Scanning electron microscope, chorion, eggshell, micropyle

Macronemurus bilineatus ve Megistopus flavicornis (Neuroptera, Myrmeleontidae) Yumurtalarının dış morfolojisi: taramalı elektron mikroskopi çalışması

Özet: Megistopus flavicornis (Rossi, 1790) ve Macronemurus bilineatus Brauer, 1868 yumurtaları ışık ve taramalı elektron mikroskobu ile incelendi ve detaylı olarak açıklandı. Her iki türün yumurtası da kabaca uzun, iki ucu yuvarlak silindirik şekildedir. M. bilineatus ve M. flavicornis karşılıklı kutuplarda iki yassılaşmış disk şeklinde mikropile sahiptir. Yumurta koryon yüzeyi her iki türde de tüberküllüdür ve az çok birbirinden farklıdır. M. flavicornis yumurtası mikropillerin yakınlarında birkaç sıralı poligonal yapıya sahiptir. İki tür arasındaki bir seri morfolojik fark da gösterilmiştir.

Anahtar sözcükler: Taramalı elektron mikroskobu, koryon, yumurta kabuğu, mikropil

Introduction 1987; Sahlen, 1996; Suludere et al., 1999; Wolf and The surface structure of eggshells with Reid, 2004). Scanning electron microscopy is an ideal various chorionic modifications has morphological, tool for detailed description of surface morphology physiological, and taxonomic significance (Salkeld, and ultrastructure of the eggs (Hinton, 1981; 1983, 1984; Downey and Allyn, 1984; Gaino et al., Margaritis, 1985; Suludere et al., 2000a, 2000b;

* E-mail: [email protected]

387 External morphology of eggs of Macronemurus bilineatus and Megistopus flavicornis (Neuroptera, Myrmeleontidae): a scanning electron microscopy study

Candan and Suludere, 2006). Several authors have both species are roughly elongate and cylindrical with illustrated morphological details of eggs of rounded ends (Figures 1A, 2A); an average of 1.11 × Neuropterid species. However, accurate knowledge of 0.75 ± 0.1 mm and 1.21 × 0.75 mm, respectively. the egg ultrastructure is still lacking for many taxa The eggs of both species have 2 flattened disc-like (Mazzini, 1976; Hinton, 1981; Monserrat, 1985, 1996; micropylar apparatus per pole (Figures 1A-D, 2A-D). Gepp, 1990; Cutler, 1993; Monserrat and Martinez, In M. bilineatus, the micropylar apparatus in the 1995; Shields and Pupedis, 1997; Popov, 2002; Candan anterior and posterior pole are morphologically et al., 2005; Satar et al., 2006, 2007). Suludere et al. similar and measure on average 58-85 μm in diameter. (2006) studied the egg of another Neuropterid, M. flavicornis also has similar micropyles and their Dielocroce baudii (Griffini), using scanning electron diameters range from 56 to 79 μm. The basal microscopy (SEM). Recently, Kubrakiewicz et al. periphery of the micropylar knob is divided into 10- (2005) examined and compared the eggs of 5 12 lobes in M. bilineatus and 11-12 lobes in M. Neuropterid species, including 1 of the flavicornis, distributed around the margin of the Myrmeleontidae species Euroleon nostras (Fourcroy). micropylar process with roughly circular orifices of In the present study the eggs of 2 more Myrmeleontid various diameters, in the center of each lobe (Figures species, Megistopus flavicornis (Rossi, 1790) and 1C-D, 2C-D). Macronemurus bilineatus Brauer, 1868, were examined using SEM for the first time. The chorionic With both light microscopy and SEM at low structures are described below. magnifications, the egg surface of both examined species appears smooth (Figures 1A, 2A), except for the micropylar regions. However, at high Materials and methods magnifications, the SEM revealed that the entire Females of both species were collected in Turkey, surfaces of both species are covered with raised, Macronemurus bilineatus from Bolu (Kıbrıscık, irregular small tubercles (Figures 1E-F, 2E-F). In M. Karaköy), (40°26´25˝N/31°50´13˝E, 1234 m, on bilineatus, most of the tubercles are distributed singly; 25.07.2006) and Megistopus flavicornis from Karabük the diameters of these projections range from 1.1 to (Bolkuş village), (41°09´35˝N/32°33´29˝E, 237 m, on 1.9 μm (Figure 1F). On M. flavicornis eggs, the 23.06.2006). Gravid females were individually chorionic surface contains various shaped tubercles, separated and placed separately into plastic jars in some of which are connected to each other (Figure order to obtain fresh eggs under laboratory 2F). The diameters of these projections range from conditions. Initial observations and examinations of 0.8-9.1 μm to 0.8-1.0 μm. The eggs of M. flavicornis the eggs were made with an Olympus SZX7 have some rows containing polygonal shapes only stereomicroscope and photographed with the near the micropylar area at each pole. The borders of Olympus digital camera (5.1 MP) mounted on it. The the polygons lack tubercles (Figures 2E-F). The eggs were immersed in 70% ethanol for subsequent interior of the polygons is similar to that of the SEM. Brush cleaned and air dried eggs were mounted remaining parts of the egg. In both species, the inter- with double sided tape on SEM stubs and coated with tubercle area is irregular (Figures 1F, 2F). gold in a Polaron SC502 Sputter Coater. Several eggs were examined and 10 of them were measured with a Discussion and conclusion JEOL JSM 6060 scanning electron microscope at 10 kV in Gazi University (Faculty of Arts and Science, The eggs of species of Neuroptera vary in shape, Electron Microscopy Unit, Turkey). i.e. ovoid, elongate, cylindrical etc., and size. For instance, eggs can vary from almost spherical to ovoid (Ascalaphidae, , Myrmeleontidae, Results Psychopsidae) as well as being elongated The egg shape and chorionic structures of (Coniopterygidae, Dilaridae, Osmylidae, and Macronemurus bilineatus and Megistopus flavicornis sometimes in Myrmeleontidae) or cylindrical are presented in Figure 1 and Figure 2. The eggs of (Berothidae, Chrysopidae, and Mantispidae)

388 Z. SULUDERE, S. CANBULAT, S. CANDAN

X75 200 µm A X250 100 µm B

C D

E F

Figure 1. The eggs of Macronemurus bilineatus, SEM micrographs. A. General view of egg with 2 micropyles (arrows), B. Micropyle at 1 pole, C. Top view of micropyle in detail, D. Side view of micropyle and micropylar orifices in detail, E. Chorionic surface, F. Tubercles and chorionic surface in detail.

389 External morphology of eggs of Macronemurus bilineatus and Megistopus flavicornis (Neuroptera, Myrmeleontidae): a scanning electron microscopy study

A X250 100µm B

C D

E F

Figure 2. The eggs of Megistopus flavicornis, light and SEM micrographs. A. General view of egg with 2 micropyles (arrows) (LM), B. Polygonal pattern () of chorionic surface and micropyle at 1 pole (SEM), C. Top view of micropyle in detail, D. Side view of micropyle and micropylar orifices in detail, E. Polygonal pattern of chorionic surface near micropylar area, F. Tubercles and chorionic surface in detail.

390 Z. SULUDERE, S. CANBULAT, S. CANDAN

(Mazzini, 1976; Monserrat, 1985, 1996; Gepp, 1990; is divided into lobes with a micropylar orifice. The Minter, 1990; Shields and Pupedis, 1997; Candan et numbers of lobes or indentations vary within the al., 2005; Suludere et al., 2006; Satar et al., 2006, 2007). Neuroptera; some species have 8-10 lobes as in The eggs in some families, such as Berothidae, Mantispa sayi, 30 as in Chrysoperla carnea, or 6-8 as in Chrysopidae, Mantispidae, and Nymphidae, are D. baudii (Mazzini, 1976; Shields and Pupedis, 1997; deposited on stalks (Mazzini, 1976; Gepp, 1990; Suludere et al., 2006). The eggs of M. bilineatus and Minter, 1990; Rùžička, 1997). The eggs of M. M. flavicornis have 10-12 and 11-12 lobes, bilineatus and M. flavicornis are roughly elongate and respectively. cylindrical with rounded ends similar to those of The egg surface of Neuroptera shows very different other Myrmeleontidae. sculpturing, such as smooth surface in Croce schmidti In neuropterans, the number, shape, and size of the (Satar et al., 2007), with chorionic reticulation in micropylar apparatus differ depending on the species. Mantispa sayi (Shields and Pupedis, 1997), with In some families of Neuroptera, such as Mantispidae, sponge-like elevations in Hemerobius marginatus Chrysopidae, and some Berothidae, eggs have a (Gepp, 1990), with granular structures in Pterocroce micropylar process at one end and a short, thin, capillaris (Monserrat, 1985), with tubercles or papilla- flexible stalk at the other, which fastens the eggs to the like projections connected by narrow bridges in some substrate (Mazzini, 1976; Gepp, 1990). In addition, in Chrysopidae species (Mazzini, 1976; Gepp, 1990), and some families of Neuroptera, such as Nemopteridae, with polygonal patterns in Coniopteryx (C.) Hemerobiidae, Psychopsidae, Dilaridae, and tineiformis and Conwentzia psociformis (Gepp, 1990), Coniopterygidae, only one micropyle exists and there Euroleon nastras (Kubrakiewicz et al., 2005), and is no egg stalk (Gepp, 1990; Minter, 1992; Candan et sinuata (Candan et al., 2005). In Dielocroce al., 2005; Suludere et al., 2006; Satar et al., 2007). This baudii, the egg surface has 2 types of small raised is in contrast to 2 other families, the Myrmeleontidae projections, which lack connections between them and Ascalaphidae, which have 2 micropyles, symmetrically positioned on the opposite poles of the (Suludere et al., 2006). The chorionic surface of M. egg (Withycombe, 1925; Henry, 1972; Hinton, 1981; bilineatus and M. flavicornis is covered with small, Minter, 1990; Michel, 2001; Kubrakiewicz et al., 2005). raised, irregular tubercles. The structure and The eggs of M. bilineatus and M. flavicornis have 2 distributions of projections or tubercles differ micropylar processes at opposite poles like other between these species. M. flavicornis has some rows Myrmeleontidae species. containing polygonal shapes near the micropylar area at both poles as opposed to that of some species In Neuropteran species, the micropylar apparatus previously mentioned above in which the entire egg may be button-like (as in Nemoptera sinuata, has a polygonal chorionic pattern. Nemopteridae), knob-like (as in Dielocroce baudii, Nemopteridae), dome-shaped (as in Mantispa sayi, General classifications of Neuroptera are mainly Mantispidae), have a flattened disc (as in Podallea sp., based on adult characters (Monserrat, 1996) and egg Berothidae), or be reminiscent of a mushroom stage is often overlooked as a taxonomic tool. (Nallachius krooni, Dilaridae) (Minter, 1990, 1992; However, chorionic sculpturing can provide Shields and Pupedis, 1997; Candan et al., 2005; distinctive characters as noted above. Consequently, Suludere et al., 2006). In M. bilineatus and M. it will be necessary to investigate the surface designs flavicornis, the micropyles resemble a flattened disc of additional species of Neuroptera utilizing the SEM in which the basal periphery of the micropylar knob to fully explore their use as taxonomic markers.

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