Mites and leaf domatia: no evidence of mutualism in Coffea arabica plants

we conducted experiments by blocking off pit-like domatia from old and new leaves of coffea arabica l., using tiny resin drops, to investigate the role of domatia on i) mite abundance at the community level and on ii) leaf damages. more than 77% of the mites collected were predators, whereas 19 and 3.3% were omnivores and phytophages, respectively. domatia blockage treatment had no influence either on mite abundances or leaf damages. however, predatory and omnivorous mites were more abundant on new than on the old leaves; phytophagous mites occurred at very low density and occupied only plants having open domatia. the absence of mutualism between mites and c. arabica probably occurred because the entrances of domatia were too small and did not enable the entry of fitoseid predators in these structures.