Pollen digestion by flower-feeding Scarabaeidae: protea beetles (Cetoniini) and monkey beetles (Hopliini)

The Pollination of Mid Mesozoic Seed Plants and the Early History of Long-proboscid Insects1,2,3

“…Studies of the pollination biology within the Nymphaeaceae (Capperino & Schneider, 1985;Williamson & Schneider, 1994;Hirthe & Porembski, 2003;Seymour & Matthews, 2006), Calycanthaceae (Crepet et al, 2005), Magnoliaceae (Azuma et al, 1999;Dieringer et al, 1999), and Annonaceae (Gottsberger, 1989) all implicate these taxa and others with similar floral features in the attraction of larger-sized beetle pollinators-the cantharophily syndrome (Proctor et al, 1996). Specializations for this type of pollen feeding include maxillary pollen brushes (Fuchs, 1974) and modified mandibular teeth (Grinfel'd, 1975), which should be retrievable from fossils, or perhaps digestive enzymes (Johnson & Nicholson, 2001). …”

Pollen grains adhere to the moist mouthparts in the flower visiting beetle Cetonia aurata (Scarabaeidae, Coleoptera)

“…Representatives of protea beetle (Cetoniini) and monkey beetles (Hopliini) are reputed to be the pollinators for several South African plants (Johnson and Nicolson 2000). Their mouthparts are similar to C. aurata, i.e., equipped with numerous rows of bristles and the dense galeal brushes.…”

“…Furthermore, these beetles are able to take up liquids by licking motions of the galeal brushes. The liquid is then presumably squeezed out when the labrum and labium are pressed together (Johnson and Nicolson 2000). C. aurata is also recorded to ingest nectar, plant saps and liquids from rotten fruits (Bürgis 1989).…”

“…Pollen grains are encased by a hard and highly resistant outer hull, the exine (Johnson and Nicolson 2000) and single grains range from 10 to 200 lm in diameter (Stanley and Linskens 1974). The challenges confronting pollen feeders are the removal of the often dry pollen and gaining access to the encapsulated nutrition.…”

“…The challenges confronting pollen feeders are the removal of the often dry pollen and gaining access to the encapsulated nutrition. Pollen is potentially a valuable food source for flower visiting insects since it contains a wide variety of lipids, carbohydrates and different protein concentrations (Johnson and Nicolson 2000).…”