Older family, females

2009/10/22 Lakar Iraizoz, Oihane - Elhuyar Zientzia

• Eboluzioa
• Zoologia

Researchers from the Academy of Sciences and Arts of Slovenia and the National Museum of Natural History of the United States have unveiled the phylogeny of the spider family Nephilidae. Along with this, the sexual dimorphism of each species of this family has been made known. It is very common that in these spiders females are much older than males, so they have become an example of study of sexual dimorphism of size.

In the image you can see spiders with two levels of dimorphism: to the left appear two specimens of the species Herennia multipuncta, male and female, and to the right a male and a female of the species Nephila pilipes. Scientists consider the former to have moderate sexual dimorphism and the others extreme dimorphism.

Image courtesy of: Matjaž Kuntner, Jonathan A. Codington