Wild Profile: Meet the goldenrod spider

Do you know the goldenrod spider? Probably not. (They’re not nearly as famous as dock spiders. But they should be!) As the name suggests, these arachnids like to spend their time on goldenrod flowers—though you can spot them on a wide range of species. The goldenrod spider is a crab spider. It has a set of long front legs that it holds out to the sides, like a crab. The spider uses them to grab and hang on to prey (mostly insects). Goldenrods don’t spin webs and trap bugs. They hunt, using the sit-and-wait technique—which is exactly what it sounds like. When an unsuspecting fly or grasshopper wanders by, the spider snatches it up, and injects it with venom by biting it with a set of fangs. This paralyzes the bug, and the spider can suck the fluid from the prey’s body. Mmm, liquid lunch.

Goldenrod spiders use a sneaky trick to hide from both prey and predators: they can change colour. They have a white “morph” (pictured) and a yellow “morph”. While those two colours don’t help the spider camouflage if it decides to hang out on a purple or red flower, it allows them to blend in with white or yellow flowers. When a white goldenrod spies a yellow flower, the visual stimulation triggers its body to secrete a liquid pigment that floods the layers of the spider’s external “cuticle” or exoskeleton.

This costume change isn’t quick, mind you. It takes a goldenrod spider five to six days to change from yellow to white, and 10 to 25 days to change from white to yellow. The two colour changes involve slightly different physiological processes; scientists aren’t exactly certain why yellow-to-white takes less time. (Scientists also aren’t certain why goldenrods will sit on flowers that are neither yellow nor white. There’s some evidence that the colour contrast—say, white spider on red flower—is attractive to certain prey species, such as bees. So, in those cases, not blending in could work to the spider’s advantage.)

While the goldenrod spider doesn’t spin a web, females do produce silk, and use it to protect their eggs once they’ve been laid. A mother goldenrod places her soon-to-be spiderlings in a pouch made out of a folded leaf, then wraps the leaf in silk. She doesn’t stick around; once the eggs are safe and secure, she’ll stop eating. She usually dies within three weeks, and the baby goldenrods are on their own.

If you see a goldenrod spider, that’s a good thing. They’re sensitive to habitat disruption, which makes them an “indicator species.” They also eat a lot of pest insects. Oh, and that venom they produce? It’s too mild to hurt a person (plus, they almost never bite). To encourage these arachnids to visit your cottage property, plant native white and yellow flowers such as trillium and fleabane.

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