Do ladybird spiders really mimic ladybird beetles?

Adult male ladybird spiders (Eresus spp. Araneae: Eresidae) possess conspicuous red and black coloration. As these spiders are palatable to many predators, they are likely to be Batesian mimics of some other, defended species. We therefore aimed to identify potential models of two ladybird spider species, the spring-breeding Eresus moravicus and the autumn-breeding Eresus kollari, by assessing the co-occurence and similarity of the spiders and their putative models. The abundance of potential models of Eresus spp. was monitored at nine sites where the spiders are found. Phenotypic similarity between the spiders and their potential models was assessed by comparing their colour, coloration pattern, and body size and shape. The ladybirds Coccinella septempunctata and Hippodamia variegata co-occurred with Eresus spp. at most sites during the whole season and were among the most abundant species found; the leafhopper Cercopis sanguinolenta was common only in spring and the stink bug Graphosoma lineatum only in late summer and early autumn. Analyses of similarity showed that coccinellids, including Coccinella septempunctata, were relatively similar to Eresus spp. We conclude that the seven-spot ladybird beetle Coccinella septempunctata is probably the key model of the ladybird spiders. Other taxa may serve as secondary models, further enhancing the spiders' defence against predators. [ABSTRACT FROM AUTHOR]