Pollination by monkey beetles (Scarabaeidae: Hopliini): do color and dark centers of flowers influence alighting behavior?

Monkey beetles (Scarabaeidae: Rutelinae: Hopliini) visit mostly unscented ßowers with conspicuous dark center patterns that have been suggested to mimic resting beetles. Field observations in South Africa showed that monkey beetles are the primary pollen vectors of the dark-centered ßowers of Ixia dubia Vent. (Iridaceae) and Spiloxene capensis (L.) Garside (Hypoxi- daceae), and the dark-centered ßowerheads of Gazania pectinata (Thunb.) Spreng. (Asteraceae). Monkey beetles used the ßowers of these species as mating rendezvous sites and consequently showed a signiÞcant clumped distribution in ßowers. We used model ßowers approximating the study species to determine which traits are important for eliciting alighting behavior in monkey beetles. Contrary to expectations, beetles did not signiÞcantly prefer dark-centered to plain models in 7 of 8 independent experiments, nor did beetles discriminate signiÞcantly between plain models and models with male or female beetles glued to their surface. However, beetles did show a strong preference for orange over red, yellow, and blue models. The results of this study indicate that alighting behavior of monkey beetles is inßuenced primarily by ßower color rather than ßower patterning or presence of other beetles.