Evolution of money spiders
Erigoninae, known as dwarf spiders in the United States and money spiders in England, are unsurprisingly tiny spiders (0.8 – 4.0 mm in body length) that are superbly adapted to cool temperatures. Barely visible, they are the most species-rich subfamily of spiders in the temperate zone. In Switzerland, about 25% of spider species belong to this subfamily. But there is little knowledge about their tribal history.
A group of very closely related genera stands out in particular. Some of their males have developed bizarre head structures that carry their eyes. In addition, these often elevated head structures are equipped with hair and glandular fields. They include genera with the catchy names Diplocephalus, Savignia, Erigonella, Araeoncus or Dicymbium.
The evolution of the different head structures is particularly exciting alongside the evolution of the complex copulatory organs and shows the importance of sexual selection in the speciation of top predators. Holger Frick is investigating the relationships of these closely related genera and species together with researchers from the University of Bergen (Norway).
