Sunday 15 November 2015

Wandering male lace weavers

In the last week I have found two different males Amaurobius similis wandering, one in the porch and the other in the house. Note the different abdominal pattern in the photos below, especially the dark blotches surrounding the cardiac mark (the midline elongated area over the abdomen). In this species, mature males are most likely to be found between September and November, and they abandon their webs in search of the female retreats. I released them both after taking their photo paying especial attention to the palp (above), which is diagnostic and separates this species from the similar one A. fenestralis. Males A. similis have an inward pointing, curved sharp projection on its palp, which in A. fenestralis is thicker and blunt.
Male 10/11/15.
Male 15/11/15.

Tuesday 3 November 2015

Spiders in glasshouses

Today at work, I had the chance of inspecting some glasshouses in the Thwaite Botanical Gardens of the University of Hull. They are heated glasshouses holding cacti, succulents, ferns and other plants from around the world. I was pleasingly surprised by the diversity of spiders in them. I found a single Woodlouse Spider, Dysdera crocata, under a bin (above). Quite fitting as we were collecting woodlouse for a practical on woodlouse diversity. The students were quite impressed!
 The first surprise was to find several Walnut Orb Weavers, Nuctenea umbratica. We dislodged an individual from a tree growing in a pot and it proceeded to play dead, legs drawn in, as they do when disturbed. They are usually nocturnal, spending the day in a crack in bark, but this large female I found later was sitting in the middle of her web, I wonder if the reason is it was a very dark, overcast day. There were many more smaller sized individuals, also sitting out in their webs, and it is quite likely this spider matures on her second year of age.
Mature female Nuctenea umbratica.
A student pointed this female Tegenaria to me, she found under a tarpaulin.
A mature, gravid Araneus diadematus sitting on her web.
This was the second nice surprise. One of the glasshouses held a healthy population of Garden Centre spiders, Uloborus plumipes.
By the toilets, a number of Pholcus phalangioides.
Where there are windows, there are window-frame spiders, Zygiella x-notata
I found a single Ero sp. egg sac. These spiders abandon their characteristic egg sacs, and they are not the easiest to find.
On a window ledged, a female Araneus diadematus looking like it has seen better days. Its abdomen shrivelled. Her days are counted after she lays her eggs and weaves her egg sac.