If you’ve never seen a crab spider, you’re missing out. These are small spiders that hide on flowers and ambush insects as they stop for a drink of nectar (similar to the ambush bug I wrote about earlier). I often notice these little predators hunting on flowers, but back in June I witnessed a hunt with more layers of drama than I had ever seen. It all started when I stopped to photograph a crab spider sucking the juices out of a hoverfly (Syrphidae sp.) that it had caught on a spiderwort flower (Tradescantia sp.).
It seemed quite lucky to me that the spider had caught any prey, given her failure to camouflage. Crab spiders can change their color to yellow or white, and they usually pick a matching flower to hunt on, but this spider seemed to be doing just fine without camouflage. To my great surprise, a second hoverfly was brave, hungry, or stupid enough to land on the same flower flower. Maybe it thought the spider would be content with the fly in her fangs. It was wrong.
The spider quickly honed in on the intrepid visitor, even though her fangs were already more than full. What she planned to do with the second hoverfly, I don’t really know, but watch what happened when the clueless hoverfly strayed a little too close:
Apparently, this hoverfly liked adrenaline, because it continued to gorge itself on delicious spiderwort nectar for a few more moments and eventually flew off to safety. Thinking the spectacle had ended, I started to pack up my camera gear. But before I could, another fly landed on the flower!
As you can see from the photo sequence above, the spider was once again too slow to catch the visitor. I watched her for a little longer, but eventually left to photograph a bird singing nearby. I came back a few minutes later to check on the spider and found yet another surprise.
In the five minutes I was away, the crab spider had finished eating the first hoverfly and caught another one. I don’t know if spiderworts are irresistible to flies, or if hoverflies are terrible at spotting white crab spiders on purple flowers, but this spider sure was lucky that morning!
Another hour watching a flower well spent.