Does the appearance of orbweaving spiders attract prey?

Recent studies proposed that the colouration of diurnal orbweaving spiders can attract hymenopteran prey. The main assumption behind the prey-attraction hypothesis is that orbweavers might lure pollinators by mimicking floral images. However, the visual appearance of spiders hunting in webs seems to mimic foliage, soil or a dead leaf. Here, we performed a field experiment with artificial webs to test the hypothesis that the appearance of diurnal orbweavers serves to attract pollinating insects. We predicted that if the presence of diurnal spiders attracts prey, the nets containing diurnal Argiope bruennichi should intercept more prey than both empty nets and the nets with nocturnal Larinioides cornutus. Alternatively, if diurnal spiders are cryptic to diurnal prey, Argiope nets should collect more prey than Larinioides nets, but Argiope's capture success should be similar to that of empty nets. We found that Argiope webs collected more insects than Larinioides webs, yet their capture success was comparable to that of the nets containing no spider. Also, Argiope showed less saturated colouration than Larinioides. Our work supports the hypothesis that the physical appearance of diurnal orbweavers might have evolved to camouflage them in their hunting habitat.