The Pompilidae (spider hunting wasps) show a marked diversity in their hunting and reproductive ecology, but difficulties in phylogenetic taxonomy have hindered the elucidation of their evolutionary processes. We present here a review of the hunting and reproductive ecology of the pepsine tribe Ageniellini (including the first prey record for Macromerella), and phylogenetic analyses of this group to reconstruct the evolution of nest-constructing behaviour. The maximum parsimony and Bayesian inference analyses are based on 45 adult morphological characters, coded for 41 exemplar species, including five out-group species, representing almost all the genera and subgenera in this tribe. Results supported the following eight clades uniting more than one genus: (1) Cyphononyx + Cryptocheilus + Ageniellini; (2) Ageniellini; (3) Auplopodina, containing Dimorphagenia, Auplopus, Machaerothrix, Phanagenia, Dichragenia, Paragenia, Macromerella, and Macromeris; (4) Phanagenia + Dichragenia + Auplopus artemis + Paragenia + Macromerella + Macromeris; (5) Auplopus artemis + Paragenia + Macromerella + Macromeris; (6) Paragenia + Macromerella + Macromeris; (7) Macromerella + Macromeris; and (8) Ageniella (Lissagenia) + Phanochilus. The monophyly of the genera Auplopus and Ageniella s.l. was not confirmed. The evolution of nesting behaviour was inferred, as burrowing in the soil without using water was ancestral in Ageniellini, and constructing nests by plastering mud obtained by softening soil with water was derived only once at the ancestor of the Auplopodina. The origin of cleptoparasitism was unclear. The origin of communal nesting is also discussed in relation to the evolution of nest-constructing behaviour. The following new combinations are proposed: Ageniella (Alasagenia) sartoriana (Cresson) comb. nov., Cyemagenia certator (Nurse) comb. nov., and Auplopus artemis (Bingham) comb. nov.
© 2010 The Linnean Society of London, Zoological Journal of the Linnean Society, 2010, 160, 88–117.