A new species of beetle with remarkably long genitalia that hint at a curious evolutionary “sexual arms race” has been described from Malaysian Borneo.
The new insect was named after actress and biologist Isabella Rossellini in honour of her stage shows and Webby Award-winning series of films about animal reproduction, featured on SundanceTV.
The species is described by scientists Menno Schilthuizen and Iva Njunjic of Naturalis Biodiversity Center and Universiti Malaysia Sabah, and Michel Perreau, Sorbonne Université, Paris. Their paper is published in the open access journal ZooKeys.
The new species, Ptomaphaginus isabellarossellini, finds a place among the 30 known species of round fungus beetles (subfamily Cholevinae) recorded by the authors from the island of Borneo. Of these, there are a total of 14 which had remained unknown to science until now.
The reason why the scientists named this particular species after the famous actress is its genitalia. The beetle’s penis carries a long, whip-like thread, called flagellum, whereas the female has a similarly long tube leading up to a sperm storage organ.
Lead author Menno Schilthuizen, who himself has previously released a simultaneously educative and entertaining book about the evolution of genitals, says that such exaggerated male and female genitalia often betray an “evolutionary sexual arms race”.
On the male side, natural selection favours longer genitalia because of the ability to directly reach the female’s sperm storage organ. However, female beetles would rather retain their right to favour the DNA of a certain mate over the rest. The upshot is that, over long periods of evolution, penises get longer and vaginas get deeper. Similar evolutionary genital exaggeration is also known in rove beetles and ducks.
“This is better than winning the Oscar,” says honoured Isabella Rossellini.
The Italian-born actress, filmmaker, author, philanthropist, and model has even featured the new beetle in her new Link Link Circus stage shows. Dealing with animal behaviour, the series will be touring theaters in Europe this fall.
Schilthuizen M, Perreau M, Njunjic I (2018) A review of the Cholevinae from the island of Borneo (Coleoptera, Leiodidae). ZooKeys 777: 57-108. https:/