Introduction

The orb weaving spider family Tetragnathidae includes about 1000 described species in 51 genera (Platnick, 2009). The family is most diverse in the tropical regions and many species still remain unknown to science. Many tetragnathids are associated with some of the world's most important and fragile ecosystems, wetlands and river ecosystems, often building their orb webs very close to the water surface. Although many species live in relatively humid conditions, there are also others that thrive in dry climates. A good number of species are known from caves, such as many of the members of the genus Meta. Species in the genus Tetragnatha provide a striking example of dispersion abilities and ecological plasticity. With more than 340 described species and a distribution range that spans from the Arctic to the most remote oceanic islands Tetragnatha is one of the champions of the animal kingdom.