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Nursery Web Spiders

Arachnid Anomaly

6-1-17 wolf spider 124

Wolf spiders and nursery web spiders look a lot alike. One way to tell one from the other is to look at the arrangement of the spider’s eyes. Nursery web spiders (family Pisauridae) have two rows of four eyes each, all roughly the same size. Wolf spiders (family Lycosidae) have a row of four small eyes, above which there are two large eyes, with two very small eyes a short distance behind them. From looking at the eyes of the pictured spider, one would assume it was a wolf spider (smallest, topmost eyes are not visible).

However, a second way to distinguish these two families of spiders is to notice how the females carry their egg sacs (the females of both species carry their egg sacs with them wherever they go). Wolf spiders attach their egg sacs to the spinnerets located at the tip of their abdomen, whereas nursery web spiders carry them in their pedipalps (two appendages that look like, but aren’t, legs ) and mouthparts, as seen in this photo.

Thus, this particular spider has wolf spider eye arrangement, and practices a nursery web spider egg sac-carrying technique. My assumption is that this is a mixed up wolf spider or one with tired spinnerets.

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Predator Eating Predator

fishing spider and dragonfly 385The Six-spotted Fishing Spider, Dolomedes triton, is an arachnid in the nursery web spider family Pisauridae. As its name implies, the Six-spotted Fishing Spider does occasionally eat small fish, but also consumes other invertebrates and tadpoles. The hunting techniques of fishing spiders are varied. Often they sit patiently during the day, waiting hours with their legs stretched out for an unsuspecting insect (such as the pictured Dot-tailed Whiteface dragonfly) to land on the same lily pad or leaf that the spider is sitting on. They can and do walk on water as well as dive up to seven inches deep in order to catch aquatic prey. The Six-spotted Fishing Spider in this photograph has removed the head of its prey and is drinking its liquefied innards.

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Jumping Spider Guards Egg Sac

6-5-14 jumping spider2  077Spiders protect their eggs by wrapping them up in a sac they make out of silk. Some species (such as garden, or black-and-yellow argiope, spiders) then die, leaving their egg sac to withstand the elements, as well as potential parasites and predators, on their own. As you would guess, these sacs are usually fairly impenetrable. In other species, female spiders survive long enough to guard their eggs until they hatch, or even until the young spiderlings disperse, and these sacs are usually far less tough. In the species where the female protects her eggs, some females carry their egg sacs with them at all times (wolf spiders, nursery web spiders) while others (jumping spiders) simply remain with the sac. Their excellent eyesight and impressive ability to leap many times their body length gives jumping spiders an advantage over any potential predators. (Photo – jumping spider with egg sac)

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