We are one month into our North America-wide citizen science project and I am thoroughly enjoying reading every entry that is submitted even though I can't respond to every one individually (there have been hundreds). Some participants have sent great photos, including the one below, by Rick Parent:
Two participants were fortunate enough to catch acts of predation on adult lily beetles. The party line is that lily beetles don't have any predators here in North America, leading to the population explosions in gardens and natural areas with lilies. Of course nothing is ever absolute in nature. Here are two great photos to show that occasionally, adult lily beetles do make a meal for native predators. The first is by Joelle Koller, who photographed this robber fly snacking on an adult lily beetle:
And here is a ground crab spider with its meal, photo credit to Linda LaBonte:
Notice how nicely the spider matches its background...great camouflage! In contrast, the lily beetle is bright scarlet. Bright colours typically mean that a prey item is toxic or distasteful to predators (warning or "aposematic" colouration), or that it is just pretending to be toxic (mimicry). Lily beetles may very well be chemically defended by sequestering the toxins present in lilies for their own defense. While lilies are not among the most toxic plants, they do contain defensive chemicals, as do all plants to some extent. To my knowledge, lily beetle defensive chemistry has not yet been studied. Too many potential projects; too little time!
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