News and blog Friday's Farming Thoughts Entry #8 - Sabine McEwan: My recent obsession with Crab Spiders One nice lunchbreak 2 weeks ago, I sat in the garden with my cup of tea enjoying the sunshine and watching a bee buzzing around the lavender. How idyllic, I thought - just as a crab spider climbed up the lavender, grabbed the bee with its long front legs and ended the bee’s life. Crab spiders (Misumena Vatia) are so named after their crab-like legs and apparently they can even walk sideways. They don’t spin webs to trap their prey but sit in waiting on flowers and ambush bees, moths or flies that come to feed on the flowers. Once an insect is caught, the spider uses its fangs to bite and inject its venom to quickly immobilise the prey. Then, the spider squirts digestive enzymes into the prey’s body, dissolving the innards into a tasty soup (delicious!) which the spider can suck out. It is mostly the females who are sat on the flowers, looking pretty and snaring insect after insect. Meanwhile, the males are much smaller and have a much more strenuous and busy life, climbing up and down flowers looking for mates; gender roles I would happily sign up to! I took loads of photos of my crab spider and kept monitoring her. She spent a few hours consuming the bee, then dropped the hollowed-out bee body on the ground and resumed her position: front legs up, waiting for the next prey. The next day she was gone…. I was so excited though when I found a yellow crab spider on a courgette flower the next day- only about 1.5 m away from the lavender. Some quick reading online told me that crab spiders can change colour depending on which flower they sit on. Was that the same spider as before? She was sitting there with the long front legs wide open and nicely posing for my camera. A few hours later, she had been successful and was happily sucking on another insect. Intrigued about colour change, I started experimenting and put her on my favourite field scabious. Whilst the yellow on the light purple looked very photogenic and she caught a hoverfly a few hours later, absolutely nothing happened to her colour. Two days on and still no colour change. I wondered if perhaps purple doesn’t induce a colour change? If I put her back on a white flower, would she change back? So I moved her to white clover on the lawn, the only white flower I had. Sadly, she wasn’t impressed with my flower choice and walked off. Turns out my experimental set-up (or probably more accurately, my patience) was rather poor anyway – a bit of further reading told me that the colour change can take up to three weeks and the most common colours are white and yellow. Crab spiders take visual cues to change colour, a lab study found when spiders whose eyes had been painted lost their ability to change colour. Scientists continue to be puzzled by the crabs spiders’ camouflage and why it has evolved. Spiders who match the colour of their flower didn’t have higher success rates in catching prey, neither were they less at risk of becoming prey themselves. A study in Switzerland found this after watching approximately 2000 occasions when an insect buzzed over flowers with crab spiders on. A similar study discounted the possibility of the spider being hidden in the UV spectrum that bees and other insects can see. I was glad to find that some people in this world had obviously been even more obsessed with those spiders than me! My spider adventures were not over yet. I found her again on the raspberries climbing up to the highest leaf. Mainly to take more pretty pictures, justified by the thought that there is no flower at the top of the raspberry cane, I moved her again, this time to a pretty grape leaved anemone. Don’t they just look so good together? …and another hoverfly a few hours later, so proud of her! Although I enjoyed my crab spider obsession a lot, I decided that it was time to give her some space and turn my attention back to Countryside Stewardship applications instead. I must admit, I wasn’t into spiders much before but this crab spider has totally converted me!