Sperm structure of Mecoptera and Siphonaptera (Insecta) and the phylogenetic position of Boreus hyemalis


Sperm ultrastructure has been studied in three species of the taxa Mecoptera and Siphonaptera. The spermatozoon of the scorpion fly Panorpa germanica shows an apical bilayered acrosome, a helicoidal nucleus, a centriolar region and a 9+2 flagellar axoneme helicoidally arranged around a long mitochondrial derivative. A second mitochondrial derivative is very short and present only in the centriolar region. A single accessory body is present and it is clearly formed as a prolongation of the centriole adjunct material. Two lateral lamellae run parallel to the nucleus. The snow fly Boreus hyemalis has a conventional sperm structure and shows a bilayered acrosome, a long nucleus, a centriolar region, two mitochondrial derivatives and two accessory bodies. The axoneme is of the 9+2 type and is flattened at the tail tip. Both P. germanica and B. hyemalis have two longitudinal extra-axonemal rods and have a glycocalyx consisting of longitudinal parallel ridges or filaments. The spermatozoon of the flea Ctenocephalides canis has a long apical bilayered acrosome, a nucleus, a centriolar region, a 9+2 axoneme wound around two unequally sized mitochondrial derivatives, and two triangular accessory bodies. In the posterior tail end the flagellar axoneme disorganises and a few microtubular doublets run helicoidally around the remnant mitochondrial derivative. The glycocalyx consists of fine transverse striations. In all three species, the posterior tail tip is characterised by a dense matrix embedding the disorganised axoneme. From this comparative analysis of the sperm structure it is concluded that Mecoptera, as traditionally defined, is monophyletic and that B. hyemalis is a member of Mecoptera rather than of Siphonaptera.

This is a preview of subscription content, log in to check access.

Fig. 1A–G.
Fig. 2A–K.
Fig. 3A–H.
Fig. 4A–H.
Fig. 5A–D.
Fig. 6.


  1. Baccetti B (1968) Lo spermatozoo degli artropodi. V. Aphaniptera. Redia 51:153–158

    Google Scholar 

  2. Baccetti B (1987) Spermatozoa and phylogeny in orthopteroid insects. In: Baccetti B (ed) Evolutionary biology of orthopteroid insects. Horwood, Chichester, pp 12–112

  3. Baccetti B, Dallai R, Rosati F (1969) The spermatozoon of Arthropoda. III. The lowest holometabolic insects. J Microscopie Paris 8:233–248

    Google Scholar 

  4. Baccetti B, Bigliardi E, Rosati F (1971) The spermatozoon of Arthropoda. XIII. The cell surface. J Ultrastruct Res 35:582–605

    CAS  PubMed  Google Scholar 

  5. Bilinski S, Büning J, Simiczyjew B (1998) The ovaries of Mecoptera: basic similarities and one exception to the rule. Folia Histochem Cytobiol 36:189–195

    CAS  PubMed  Google Scholar 

  6. Breland OP, Gassner G, Riess RW, Biesele JJ (1966) Certain aspects of the centriole adjunct, spermiogenesis, and the mature sperm of insects. Can J Gen Cytol 8:759–773

    Google Scholar 

  7. Dallai R (1979) An overview of atypical spermatozoa in insects. In: Fawcett DW, Bedford JM (eds) The spermatozoon. Urban and Schwarzenberg, Baltimore, pp 253–265

  8. Dallai R, Afzelius BA (1990) Microtubular diversity in insect spermatozoa: results obtained with a new fixative. J Struct Biol 103:164–179

    Google Scholar 

  9. Dallai R, Afzelius BA, Mamaev BM (1996) Flagellar axonemes with 10 microtubular doublets in spermatozoa from gall-midges (Diptera, Cecidomyiidae). Acta Zool 77:153–160

    Google Scholar 

  10. Dallai R, Beani L, Kathirithamby J, Lupetti P, Afzelius BA (2003) New findings on sperm structure of Xenos vesparum (Rossi) (Strepsiptera, Insecta). Tissue Cell 35:19–27

    Article  CAS  PubMed  Google Scholar 

  11. Gassner G, Breland OP, Biesele JJ (1972) The spermatozoa of the scorpion fly Panorpa nuptialis: a transmission electron microscope study. Ann Entomol Soc Am 65:1302–1309

    Google Scholar 

  12. Hennig W (1969) Die Stammesgeschichte der Insekten. Kramer, Frankfurt am Main

  13. Jamieson BGM, Dallai R, Afzelius BA (1999) Insects. Their spermatozoa and phylogeny. IBH Publishing, Oxford

  14. Kristensen NP (1981) Phylogeny of insect orders. Annu Rev Entomol 26:135–157

    Article  Google Scholar 

  15. Kristensen NP (1991) Phylogeny of extant hexapods. In: Naumann ID, Carne PB, Lawrence JF, Nielsen EF, Spradberry JP, Taylor RW, Whitten MJ, Littlejohn (eds) The insects of Australia, 2nd edn. CSIRO, Melbourne University Press, Melbourne, pp 125–140

  16. Phillips DM (1969) Exceptions to the prevailing pattern of tubules (9+9+2) in the sperm flagella of certain insect species. J Cell Biol 40:28–43

    CAS  PubMed  Google Scholar 

  17. Phillips DM (1970) Insect sperm: their structure and morphogenesis. J Cell Biol 44:243–277

    CAS  PubMed  Google Scholar 

  18. Ross HH (1965) A textbook of entomology, 3rd edn. Wiley, New York

  19. Smith DS (1968) Insect cells. Their structure and function. Oliver and Boyd, Edinburgh

  20. Whiting MF (2002) Mecoptera is paraphyletic: multiple genes and phylogeny of Mecoptera and Siphonaptera. Zool Scr 31:93–104

    Article  Google Scholar 

  21. Whiting MF, Carpenter JC, Wheeler QD, Wheeler WC (1997) The Strepsiptera problem: phylogeny of the holometabolous insect orders inferred from 18S and 28S ribosomal DNA sequences and morphology. Syst Biol 46:1–68

    CAS  PubMed  Google Scholar 

Download references


We thank Prof. S. Bilinski, University of Krakow (Poland), who kindly provided fixed material of Boreus hyemalis. This research was supported by a grant to R.D. from MIUR COFIN.

Author information



Corresponding author

Correspondence to Romano Dallai.

Rights and permissions

Reprints and Permissions

About this article

Cite this article

Dallai, R., Lupetti, P., Afzelius, B.A. et al. Sperm structure of Mecoptera and Siphonaptera (Insecta) and the phylogenetic position of Boreus hyemalis . Zoomorphology 122, 211–220 (2003). https://doi.org/10.1007/s00435-003-0087-y

Download citation


  • Insect spermatozoa
  • Insect ultrastructure
  • Insect phylogeny