Naturwissenschaften

, Volume 100, Issue 6, pp 581–594

Divergent mating patterns and a unique mode of external sperm transfer in Zoraptera: an enigmatic group of pterygote insects

  • R. Dallai
  • M. Gottardo
  • D. Mercati
  • R. Machida
  • Y. Mashimo
  • Y. Matsumura
  • R. G. Beutel
Original Paper

DOI: 10.1007/s00114-013-1055-0

Cite this article as:
Dallai, R., Gottardo, M., Mercati, D. et al. Naturwissenschaften (2013) 100: 581. doi:10.1007/s00114-013-1055-0

Abstract

A remarkable external sperm transfer is described for the first time in a species of a group of winged insects (Pterygota), the enigmatic Zoraptera. Mating and sperm transfer of two species of the order were examined in detail, documented, and compared with each other and with patterns described for other species belonging to the order. The behavior differs strikingly in Zorotypus impolitus and Zorotypus magnicaudelli. A copula is performed by males and females of the latter, as it is also the case in other zorapteran species and generally in pterygote insects. In striking contrast to this, males of Z. impolitus do not copulate but deposit small (100 μm in diameter) spermatophores externally on the abdomen of the female. Each spermatophore contains only one giant spermatozoon (3 mm long and 3 μm wide), a unique feature in the entire Hexapoda. External sperm transfer in Pterygota is a highly unusual case of evolutionary reversal. The very small relict group Zoraptera displays a uniform general morphology but exhibits very different reproductive structures and patterns of mating behavior. This may be an extreme form of a more general situation in insects, with a specific form of selection resulting in an accelerated rate of evolution in the reproductive system.

Keywords

ZorapteraMating behaviorSpermatophoreInsect reproduction

Supplementary material

114_2013_1055_MOESM1_ESM.doc (24 kb)
ESM 1Schematic sequences of Zorotypus impolitus mating behavior (DOC 24 kb)
114_2013_1055_MOESM2_ESM.doc (24 kb)
ESM 2Schematic sequences of Zorotypus magnicaudelli mating behavior (DOC 24 kb)
114_2013_1055_MOESM3_ESM.mpg (8.3 mb)
ESM 3Video showing the mating behavior of Zorotypus impolitus (MPG 8460 kb)
114_2013_1055_MOESM4_ESM.mpg (3.6 mb)
ESM 3Video showing the mating behavior of Zorotypus magnicaudelli (MPG 3706 kb)

Copyright information

© Springer-Verlag Berlin Heidelberg 2013

Authors and Affiliations

  • R. Dallai
    • 1
  • M. Gottardo
    • 1
  • D. Mercati
    • 1
  • R. Machida
    • 2
  • Y. Mashimo
    • 2
  • Y. Matsumura
    • 3
  • R. G. Beutel
    • 3
  1. 1.Department of Life SciencesSienaItaly
  2. 2.Sugadaira Montane Research CenterUniversity of TsukubaUedaJapan
  3. 3.Institut für Spezielle Zoologie und Evolutionsbiologie mit Phyletischem MuseumFriedrich-Schiller-Universität JenaJenaGermany