Phoroncidia
A few years ago I got an email from Mark Stowe, of bolas spider fame, asking about a spider we had collected in the work we had done on the spiders that live in the epiphytes of the tree canopies in shade coffee plantations. He was very interested in Kaira sp, and asked if we had a specimen. I looked into our data base, and then to the collection, but we had found only one specimen and that one was currently in the arachnid collection of Fernando Alvarez Padilla in the UNAM. After that exchange, I looked up a bit about Kaira and it had a very weird shape, and in this way I sort of memorised the general shape of the body, a technique that birders use to identify birds in flight.
And so, when I did see one after a couple of years, it was the merest glimpse of it, a small stubby jutting out against a macadamia leaf on the tree that grew alongside my balcony that triggered my memory. I looked closely and lo, it was a Kaira! I watched it for a while, it rarely moved, I took some photos and notified Mark, but for one reason or the other it never went beyond that.
After that encounter, I got into the habit of scanning the tree every time I was out on the balcony. A couple more Kairas turned up but disappeared after a while. Then one day a slightly differently shaped spider made its presence felt to my eyes. (I can’t say I saw it, it just appeared in my vision).
I was hard pressed to identify it, by itself not so surprising since I am still getting to know the spider fauna of Mexico. It was just out of reach for a decent photograph.
I quickly ran though my mental spider database and thought it could be an orb web spider of some sort that builds a web at night. But when I checked it out at night it was hanging off a single web strand. Then it clicked. It must be Phoroncidia! A theridiid spider that uses just a single web strand to hunt prey.
I read up about it, and though most people think that insects hit the web by accident, Eberhard suggests that the web contains glue which may have insect attracting compounds. I waited for a long time hoping to catch a predation event in action, but I had no luck. I did find some flies stuck on the web though. I took a series of photos, and even caught it making an eggsac, but not once did I see an insect actually land on the web.
