It only took about 300 million years ...

... for the forces of natural selection to produce spiders. Silk-producing arachnids go back even farther (nearly 390 million years), and chelicerates – distant cousins of spiders – were among the first animals to leave the sea and conquer dry land. Of the roughly 40,000 species of spiders in the world about 5,000 belong to the family Salticidae, the jumping spiders.

Jumpers are fun spiders to watch. Unlike the orb weavers which simply hang in the middle of a web waiting for a meal to come to them, jumping spiders actively hunt for their dinner – they almost seem to have character. The sturdy female spider in the next two pictures is a Phidippus whitmani. A photo of a male, which is a striking bright red rather than brown, would have brightened up the color scheme.

The average Phidippus clarus in my area also tends to be a rusty brown but this summer I was lucky and stumbled across several males that were a beautiful red. It's tough to get a dorsal shot of that abdomen, as jumping spiders have a habit of facing toward the camera, aiming those arresting anterior median eyes at whatever they perceive to be a threat. See what I mean about character?

Phidippus clarus is a good sized jumping spider about 10 mm long, my finger to the left in the photo gives a sense of scale.

A male Marpissa formosa basking on the rocks along the river shoreline, also about 10 mm in length but elongated and lean rather than robust.

I was at unable to identify the male spider in the following three images. Despite its length of 6 mm and the shape of the carapace being completely wrong, I nevertheless – tentatively, reluctantly, unhappily – called it a "crab spider" (male crab spiders are tiny, much smaller than 6 mm). This diagnosis was less than satisfactory so I submitted the images to the always helpful people at BugGuide.Net, and it turns out that my "crab spider" is an old friend ...

... Araneus trifolium, the Shamrock Orbweaver. (The little red hitchhiker on the spider's abdomen is a parasitic larval mite, family Erythraeidae.) As is often the case with spiders the male is much smaller than the female, the old girl in the photo below is a good 25 mm in length, and gravid, ready to lay eggs any time. Talk about sexual dimorphism ... looking at these two spiders, who would guess that they were the same species?

This is a white form female, and if the difference between the male and female aren't enough to cause confusion, female Shamrock Orbweavers, a.k.a Pumpkin Spiders, come in an awesome array of colors!

Whilst they don't come in a baffling variety of tints and hues, Flower Crab Spiders such as Misumena vatia can change their color from yellow to white in order to match the color of the flower they are lurking on. Obviously the Flower Scarab (genus Trichiotinus, itself an accomplished bee mimic) is unaware of how perilously close it is to its possible demise ...

Although many species of wasps are parasitoids of spiders, the Thread-waisted Wasp (Ammophila sp.) provisions its larvae with caterpillars and this wasp was simply stopping at these False Solomon's Seal blossoms for drink of nectar, not hunting the spider as a potential source of nourishment for its young.

But Flower Crab Spiders blend into the background so well they are virtually invisible, nature seldom forgives errors in judgement, and unlike the Flower Scarab this wasp wasn't so lucky. The Thread-waisted Wasp won't be passing on its genes to the next generation, the Flower Crab Spider might – if it survives the hazards and vicissitudes of an uncertain life – and who knows ... her descendants may still be around in another 300 million years.

Some Salticid Research Results

It’s been eight months since I stumbled across this impressive female jumping spider at the Vanderwater Conservation Area, an active, robust specimen between 15 to 20 mm in length. I strongly suspected it was genus Phidippus, but despite putting in no small amount of time on the 'net researching images of spiders, I was unable to identify it until now.

This spider encountered on the trail a couple of days ago was very similar in size and build, and this time my efforts at IDing it – about two hours of research on the ‘net – met with success. I think this is Phidippus princeps. The irridescent pale bluish-grey chelicerae can be seen in the following image.

The brownish-red on the abdomen is pale compared to the color of the spider I photographed last August. The photos of Jumping Spiders - Genus Phidippus by Tom Murray at PBase illustrate how dramatically variable these spiders can be.

Large forward-facing eyes endow this predator with excellent vision (among the best in the invertebrate world), and the remainder of its eight eyes are mounted high on raised nubs on the carapace, giving it a wraparound view of its surroundings.

The spider felt uncomfortable with my being so close with the camera. In addition to waving its front legs and showing its chelicerae, it did this ...

Interesting behavior ... a Six-spotted Fishing Spider assuming the same posture, again, it was in response to my presence.

A few more trips down memory lane to catch up on Salticidae images that have been sitting in my "unidentified" files for about a year. In the course of my Phidippus princeps research I found Bev Wigney's excellent Salticid Photo Galley at PBase, and I believe this small jumper (about 5 mm in length) is genus Pelegrina, a Peppered Jumper. And she's gravid and ready to lay eggs any time, by the look of her.

This female Jumping Spider has captured a Robber Fly, a fearsome predator in its own right. Had the fly seen the spider first, the predator/prey outcome here might well have been different! With the help of the aforementioned photos at PBase and at BugGuide.Net I was able to identify this arachnid as Phidippus clarus.

The best match I could find for this male is genus Evarcha. Making a species identification solely on the basis of a photograph is chancy, but this Evarcha falcata at the Encyclopedia of Life looks like a dead ringer to my inexperienced eye. But – a little more research divulged that Evarcha hoyi is the only species extant in my area (eastern North America), so E. hoyi it is.

Females encountered in the same location as the males, E. hoyi seems a reasonable conjecture. Is my guess correct?

When I started photographing and researching odonates I had no field guides to help me sort out males and females – which can often appear radically different – of the same species. One way around this was to hopefully observe a mating pair of dragonflies, and this technique works for spiders as well ... a mating pair of Evarcha hoyi.

Despite some obvious differences in the palps, overall shape and slightly different markings, I initially misidentified this jumping spider as possibly a species of Eris (Spider Snapshots), but having done more reading and research I think it's actually genus Pelegrina.