Beetles feeding on bugs (Coleoptera, Hemiptera): repeated shifts from mycophagous ancestors

A review of the literature shows that predation on Hemiptera (mainly Sterno rrhyncha) by Coleoptera is widespread in the order, but little understood, even from a biocontrol perspective. Phylogenetic information indicates that feeding on hemipterans evolved predominantly in lineages containing fungus feeders (Derodontidae, Silvanidae, Laemophloeidae, Nitidulidae, Endomychid ae, Anthribidae) and whose ancestors were fungus feeders (Coccinellidae) or were sap feeders (cetoniine Scarabaeidae). Other predators on Hemiptera wh ose ancestry could not be determined unequivocally (predatory/phytophagy or phytophagy/mycophagy) are included in families that contain a large number of species that are mycophagous (Trogossitidae, Mycetophagidae, and Salpin gidae). Because changes in diet to feeding on hemipterans have repeatedly o ccurred in mycophagous taxa, and this shift is not present in other largely predatory groups of beetles, it is presumed that certain preconditions, wh ich have promoted this specialised behaviour, only exist in these lineages. Ancestral associations with sooty moulds that grow on honeydew may have me diated shifts from mycophagy to predation, rather than having ancestors tha t were predatory and attracted to a novel prey type. Natural history data s how that species that prey on Hemiptera also feed on honeydew and sooty mou lds and a model is presented for the host shift from mycophagy to feeding o n Hemiptera. An annotated list of Hemiptera prey for beetles (exclusive of Coccinellidae) includes records for species in the families Adelgidae, Aley rodidae, Aphididae, Coccidae, Diaspididae, Kermesidae, Kerriidae, Margarodi dae, Membracidae, Phoenicococcidae, and Pseudococcidae.