''Spermozoros impolitus'' is a species of insect in the order

Zoraptera The insect order Zoraptera, commonly known as angel insects, contains small and soft bodied insects with two forms: winged with wings sheddable as in termites, dark and with eyes (compound) and ocelli (simple); or wingless, pale and without eyes ...

. This species was formerly a member of the genus ''

Zorotypus ''Zorotypus''Silvestri F (1913) ''Boll. Lab. Zool. gen. agr. Portici'' 7: 196. is a genus of angel insects in the family Zorotypidae. Species The type species is '' Zorotypus guineensis'' from West Africa. Other species are found worldwide ...

''.

Natural history

Individual ''Spermozoros impolitus'' resemble termites in appearance. They are found in decaying tree trunks and eat fungi.

Reproduction

Most Zorapterans copulate during mating, but the male ''Z. impolitus'' has a distinct and primitive form of mating behaviour in which the male ''Z. impolitus'' produces a

spermatophore A spermatophore or sperm ampulla is a capsule or mass containing spermatozoa created by males of various animal species, especially salamanders and arthropods, and transferred in entirety to the female's ovipore during reproduction. Spermatophores ...

, a packaged single sperm, which it attaches to the abdomen of a female ground louse. The female ground louse initiates the intercourse by advancing towards the male and brushing the antenna on the body of the male. If the male ground louse is aroused, it moves behind the female and carries out a mating display which comprises lowering the head, vibrating the antennae and moving back and forth repeatedly. The mating concludes with the male moving under the female and attaching the spermatophore to the abdomen of the female. The female then shifts the spermatophore into the reproductive tract. Such external transfer of sperm is also found in ancient wingless groups like

springtail Springtails (Collembola) form the largest of the three lineages of modern hexapods that are no longer considered insects (the other two are the Protura and Diplura). Although the three orders are sometimes grouped together in a class called Ento ...

s, but in their case, the male deposits its spermatophore on the ground from where the female lifts the sac for transfer to its genital aperture. This mating behaviour is considered to be an intermediate step in the evolution of copulation. This ground louse is also notable because its spermatophore is only long, among the smallest in the arthropod world but the single sperm it contains is wide and long almost as long as the insect itself. This is the only known insect in the world to feature a giant single spermatozoon. The giant spermatozoon is thought to have evolved in this manner so as to act like a

mating plug A mating plug, also known as a copulation plug, sperm plug, vaginal plug, or sphragis (Latin, from Greek σφραγίς ''sphragis'', "a seal"), is gelatinous secretion used in the mating of some species. It is deposited by a male into a female ge ...

References

{{Taxonbar, from=Q16993618 Zoraptera Insects of Malaysia Insects described in 2013