Thursday 20 June 2013

A new species of Stick Insect from southern Spain.

Stick Insects, Phasmida, are large insects noted for their camouflage abilities, frequently resembling sticks or leaves. They are related to Mantises, Cockroaches and Termites, and like them undergo hemimetabolous development; the larval forms resemble the adults, and never pupate or undergo a radical metamorphosis during their development. In many species of Stick Insect (and other Insects) the males do not have a sex chromosome (such as the Y chromosome in humans), instead having an odd number of chromosomes (i.e. they have one unpaired X chromosome). Some such species breed sexually, with the males contributing one or zero X chromosomes to the young and the females (which have two X chromosomes); offspring either inherit one or two chromosomes, which determines their sex. In other species all the offspring produced by sexual reproduction are female, the males are produced pathogenically (without sex). In other species a Y chromosome is present, and reproduction follows a similar pattern to that seen in mammals.

In a paper published in the journal Contributions to Zoology in 2012, Valerio Scali, Liliana Milani and Marco Passamonti of the Department of Biologia Evoluzionistica Sperimentale at the University of Bologna, describe a new species of Stick Insect from southern Spain, discovered during a review of Iberian members of the genus Leptynia.

The new species is named Leptynia annaepaulae in honour of Anna Paola Bianchi, of Rome University La Sapienza, a student of Stick Insects who first pointed out that there appeared to be a unique species of Leptynia in southern Spain, but who did not formally describe it. Member of the genus Leptynia are notoriously hard to tell apart, and are usually distinguished by karyotype (number and shape of chromosomes), and the males of Leptynia annaepaulae are essentially similar to other species found in Iberia, brownish Stick Insects reahing 4-6 cm in length. However the females have a distinctive pink colour which immediately makes them stand out. 

The male (top) and female (bottom) of Leptynia annaepaulae. Scali et al. (2012).

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