Research Article |
Corresponding author: Dominic Wanke ( dominic.wanke@smns-bw.de ) Academic editor: David C. Lees
© 2018 Dominic Wanke, Hossein Rajaei.
This is an open access article distributed under the terms of the Creative Commons Attribution License (CC BY 4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Citation:
Wanke D, Rajaei H (2018) An effective method for the close up photography of insect genitalia during dissection: a case study on the Lepidoptera. Nota Lepidopterologica 41(2): 219-223. https://doi.org/10.3897/nl.41.27831
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Characters of male and female genitalia in insects in general, especially in Lepidoptera, are essential for species identification as they display extensive morphological variation. In embedded genitalia, due to the positioning of the genitalia and the pressure of the cover glass, the appearance of some diagnostic characters might be confusing. This potentially leads to taxonomic misinterpretation. Additionally, the photography of genitalia structures in ethanol is difficult, due to drift or hardening of genitalia. A method is presented here to fix the position of the genitalia in ethanol, which allows comparative close up photography. The advantage of the method is demonstrated by illustrating the sacculus projection of three Triphosa species.
Reproductive organs of insects are extremely diverse in form and function and they are a valuable source of information for taxonomic purposes. The complex genitalia, especially the sclerotized male genitalia in the Lepidoptera, have been extensively used in taxonomic revisions (
Unfortunately, during the embedding process of the genitalia, some important diagnostic characters may become hardly visible, due to the pressure of the cover glass on the genitalia. As a result, the arrangement of some diagnostic characters might be confusing. Additionally, studying the three-dimensional structures in an embedded position may lead to taxonomic misinterpretation. In most, if not all, cases a comparison and photography of these structures in fluid (e.g. ethanol or glycerol) and three-dimensional arrangement is necessary to obtain reliable results. However, drift and movement of the genitalia is a major problem during the stacking photography.
In the genus Triphosa, the sacculus projection of the valva (Figs
Triphosa dubitata (Linnaeus, 1758)
1 ♂, Georgia: Borjomi Kharaguali NP, Borjomi District, vic. Likani, trail 1 near ranger shelter, 1850 m, 22.VII.2006, 41°51’01,6”N, 43°15’39,1”E, at light, leg. C. Häuser, D. Bartsch, g. prep. 0016/2018 D. Wanke. 1 ♂, Iran, Elburs, vic. Kendevan, 2500 m-3000 m, 7.-9.VIII.1977, leg. W. Thomas, coll. W. Schäfer, Stuttgart, g. prep. 0015/2018 D. Wanke.
Triphosa sabaudiata (Duponchel, 1830)
1 ♂, Gempenhöhle, 23.11.47, g. prep. 0024/2018 D. Wanke. 1 ♂, Gempen, Jan. 59, S. Blattner, g. prep. 0052/2018 D. Wanke.
Triphosa tauteli Leraut, 2008
1 ♂, Hispania, Lerida, Boixols Umgeb., 1300 m, 2.7.1976, leg. Aistleitner, coll W. Schäfer, Stuttgart, g. prep. 0053/2018 D. Wanke.
All examined material is deposited in SMNS (State Museum of Natural History, Stuttgart).
Required material: Petri dish, plastic pipette, razor blade, super glue (transparent, highly fluid glue, based on Ethyl cyanoacrylate (ECA); Trade name: “UHU Sekundenkleber blitzschnell”).
Preparation procedure of the mounting system:
1. Cut the tip of plastic pipette (about 2–3mm, diameter of the tip must be chosen according to the size of the genitalia capsule, Fig.
2. Split the tiny piece of pipette into two halves (Fig.
3. Attach one of the halves on the bottom of the petri dish using super glue (fig. 1C), to generate a half tunnel-shaped holder.
4. Dissect the genitalia following standard methods (
5. Place the genitalia capsule in the half tunnel shaped holder (see Figs
6. Cover the half tunnel and genitalia with 70% ethanol.
7. Photograph the sample (here we used a Keyence microphotography system (Model: VHX-5000) and a Visionary Digital System (Model: LK Imaging System)).
The sacculus projection of Triphosa species is heavily sclerotized and distally forked. Size and shape of sacculus projection contains valuable diagnostic information (
Here we compared the embedded genitalia of three species: Triphosa sabaudiata, T. dubitata and T. tauteli (Fig.
Using the new method suggested in this paper, we fixed the genitalia capsule (with valvae unspread) in the tunnel-shaped holder. As is visible in the figures 3A–C, the shape of sacculus projection is distinctly different in all three listed species. The fork-shaped tip of the sacculus projection in T. sabaudiata consists of two identical processes ‘thorns’ (Fig.
Unmounted genitalia capsule with closed valvae in ventral view in the tunnel-shaped holder. A. Overview of a T. sabaudiata genitalia placed in the tunnel; B–D: Close up photography of the sacculus projection, B. T. sabaudiata; C. T. dubitata and D. T. tauteli. Abbreviations: u.t. upper ‘thorn’ of sacculus projection; l.t. lower ‘thorn’ of sacculus projection. The sacculus projections appear diagnostic in this angle.
Using the method explained above, or a modification of it, photography of the genitalia structures of the male and female in different angles and views could easily be obtained before mounting them on permanent slides.
Special thanks go to Pasi Sihvonen (Finland), who encouraged us to publish this method. We thank David Lees (UK) and Joseph Millhouse Taylor (Australia) for linguistic proof reading. This paper is a part of the Master thesis of the first author.