Päiväkirja-arkisto kohteelle syyskuu 2021

21. syyskuuta 2021

The Erigoninae

21 September 2021

The Erigoninae or Dwarf Spiders are, as their common name suggests, tiny (on iNaturalist, they are referred to as Money Spiders). For iNaturalist observations, it is a rare day when such specimens can be identified to species from mere photographs of the animal in its natural setting. They are just too small and there are just too many similar species. Most require microscopic examination or even dissection to identify to species, and even then there is no guarantee.

If you find one, you hope it is a male. The Spiders of North America manual for identifying spiders to the genus level only has an identification key for males. There is no such thing for the females. If you have a female, you'll have to search several scientific papers for illustrations or point your internet browser to repositories of photographs of female reproductive parts. And yet...this group of spiders is probably the one that I get most excited about finding. Our knowledge of the distribution of these diminutive spiders is limited and I have found several dwarves that represented new records for Minnesota and a significant expansion of their known range.

There are several species of dwarf spiders that mature in fall and it is an active ballooning period for them. I was reminded of that again a couple of weeks ago when I was sitting at a picnic table with my wife and a male Erigoninae landed on the table in front of me. Unfortunately, he was there only momentarily and blew away again before I could get a jar to put him in. The state's first record of Islandiana flaveola arrived in similar fashion, landing on one of my sharp-eyed students who noticed it crawling on her as she walked to class. She knew that I might find it valuable and guarded it until she got to the lab and we could capture it in a jar.

As you enjoy the cooler weather of the fall, keep an eye out for our smallest spiders and snap a few pictures if you get a chance.

Lähetetty 21. syyskuuta 2021 20:35 käyttäjältä cheins1 cheins1 | 0 kommenttia | Jätä kommentti