This is probably the best photo I’m ever going to get of this, so I have to share. This is what spider sex looks like.
The female is the larger one, which is very typical of spiders. The little ‘legs’ seen here extending out to the front are pedipalps, and one of the ways you can easily (well, more or less) tell the gender of a spider, because the male’s are always larger – very often club-shaped rather than slender like the female’s. His are visible too, the dark blobs extending towards the underside of the female’s abdomen. Arachnosex consists of the male stretching his pedipalps underneath his own abdomen and depositing semen therein, then crawling or reaching underneath the female and delivering the semen, uh, manually. It all seems odd from our perspective, until you think about our perspective anyway.
This is the scale shot – all of it took place in the female’s lair on the underside of a holly leaf (one of my current go-to’s for arthropod pics, at least until more plants come into full leaf.) The female might be all of 3mm in body length – the blurry blobs in the top image are not ghosts or spirits, but pine pollen.
The best I can say is that these belong to the family Theridiidae, otherwise called the cobweb spiders, which includes probably half of the species you might find within your home. That identification only came about because I recognized the body shape and eye positions (visible in other images not shown here) to be very similar to black widows; eye position is actually a very good way to determine families of arachnids.
I had spotted the two spiders within her protective cluster of web strands and knew something was imminent – spiders do not tolerate close proximity unless either mating or newly hatched. I returned with the camera just in time to catch the money shot action. No way to use a tripod and nothing to brace against, so these are handheld while partially crouched and aiming slightly upwards, tripping the shutter as I swayed into sharp focus range. Sounds like I’m drunk, but when sharp focus is obtained within a 2mm bracket (for the lens used in the closeup image anyway,) only the rock-steadiest of people will not be leaning in and out of range constantly.
Artistically, however, I like this pic better, a neighbor only 15cm away on the same tree. That would be within earshot, except spiders don’t have ears, so the horrified look is just how jumping spiders appear normally. I love the cartoon eyelashes.
