Our recent paper on a very cool spider that masquerades as bird-droppings has made the cover of Current Zoology.
In this study Yu Long, then a PhD student at Hubei University in China, combined field observations, field experiments and visual modelling to test whether Phyrnarachne ceylonica spiders aggressively mimics bird droppings in order to deceive potential prey. I was lucky to visit Xishuangbanna Tropical Botanic Garden in beautiful Yunnan in 2015 while I was a postdoc at the National University of Singapore working on jumping spiders. This is where I met Yu Long and was able to give him a hand searching for bird-dropping spiders in the undergrowth of the forest for his experiments.
During his field observations, Yu Long found that the spiders attracted as many fly and hymenopteran prey as nearby fresh bird droppings, and much more prey than a bare leaf. In the next stage of his project Yu Long either experimentally whitened or blackened the spiders to look at how this affected prey attraction rates. As predicted, prey was attracted to experimentally blackened or whitened spiders significantly less frequently than to unmanipulated spiders. Finally, by measuring the colour of the spiders and bird droppings, we were able to show that both of these objects can be seen by visiting fly and hymenopteran prey when contrasting against background leaves. However, the spiders and bird droppings were visually indistinguishable from each other when looking through the eyes of a fly or bee.
Together these findings suggest that insects attracted to spiders may misidentify the spiders as bird droppings, meaning that the spiders not only receive benefits of looking like bird poo to avoid being picked off by predators, but also use aggressive mimicry to lure unsuspecting prey looking for a pooey feed.
Just some of the fascinating invertebrates found in the Xishuangbanna Tropical Botanical Garden