Sexual sorting in hummingbird flower mites (Mesostigmata : ascidae)

Hummingbird flower mites (Rhinoseius Baker & Yunker and Tropicoseius Baker & Yunker, and certain Proctolaelaps Berlese species; Acari: Mesostigmata: A scidae) feed on nectar and pollen, mate, and oviposit in the inflorescences of hummingbird pollinated plants and are phoretic in the nasal cavities of hummingbirds. Unlike many phoretic mites, males as well as females of most of these species disperse-on the phoretic host (hummingbirds). Theory sugg ests that male dispersal may increase mating success ia species in which br eeding groups are small and males can seek groups with a more favorable (mo re female-biased) sex ratio by dispersing, a process we call sexual sorting . Laboratory experiments in which mites were confined to a lattice of inter connected capillary tubes, some with nectar present to simulate flowers, sh owed that both Proctolaelaps kirmsei Fain Hyland, & Aitken and Proctolaelap s so. nov. #1 from La Selva, Costa Rica, demonstrate significant sexual sor ting. Field census data from the same site for P. kirmsei showed that, cons istent with theory and the laboratory results, sexual sorting also occurs i n nature among incipient mite breeding groups on inflorescences, when these groups are small.