Some of the more colorful and active spiders in our world are Jumping Spiders – members of the family of spiders known as Salticids. The Tan Jumping Spider is an exception, at least at first sight, if you can spot it to begin with. But why is it so shy?
Platycryptus undatus has an appropriately descriptive scientific name, with a flattened body (platy – Greek), that has cryptic coloration (crypto – Greek), with wavy patterns across its body (undalat – Latin). Yes, some taxonomists use appropriate language that makes sense to nature nerds like me.
All these characteristics point to a lifestyle that is all about hiding, rather than being seen. The Tan Jumping Spider is a crevice dweller, where it seeks shelter in tight spaces and where it hunts for other critters that share those spaces. Its coloration is not about being seen by its prey but about not being seen by its predators, like birds and lizards.
This species is most often found associated with loose bark on trees, like the pine tree where I spotted this one. I almost missed it at first, as I was checking under loose bark looking for Pseudoscorpions before it got to cold to find them https://ourmshome.com/quest-que-cest-a-scorpion-with-no-tail/ . The spider spotted me long before I spotted it but gave itself away as it turned to check me out.
As you can see from the photos, it is well-camouflaged! The mottled patterns across its cephalothorax, abdomen, and legs are dramatic, as are the chevron-shaped “v’s” on its abdomen. Its flattened body is also apparent. In an instant, it was able to dart under the nearest loose piece of bark.
Most other Salticids are much less shy in their behavior and sport bright colors and patterns, some with iridescent scales that help them communicate with their own. Male spiders in this group have colorful scales on their swollen pedipalps – the short leg-like structures around their jaws – that they use to wave or “flag” a message to would be mates. “Hey there Sweetie. Aren’t I pretty?”
These structures also house specialized hooks and spines that the male uses to clutch and transfer packets of sperm from his genitalia underneath its abdomen to females during courtship. The dance needs to be a good one or the female may ignore the male, or worst, attack! No pressure, really.
Most of us have watched these small acrobats, as they dance about and jump on their prey (salti – Latin). Two of their eight eyes are large and centrally located on their heads, helping them locate their quarry and judge the right distance to strike.
As for the Tan Jumping Spider, males do have distinctive pedipalps, albeit muted, but they apparently work well enough. This species was first described in 1778! That fella must have had the same reaction as when I first saw it – “What is it?” and “Hey, where did it go?”
What is fascinating to me is that this is one of many crevice dwelling creatures that are out of sight and out of mind unless we take the time to look. The bark of trees is an important habitat for many critters https://ourmshome.com/tree-bark-protector-and-habitat/, a highway for many others, day or night https://ourmshome.com/millipedes-rock-the-night/ , and a place to find food (woodpeckers, other birds, and lizards.
Take the time to look and see what appears on the bark of your trees.
Hope to see you in our great outdoors!