A new case of trophobiosis between ants and Heteroptera.

Despite the large specific diversity of equatorial rainforests, Caternaultiella rugosa (Heteroptera; Plataspidae) was only noted on two euphorbiaceous trees (Bridelia micrantha and B. grandis) and was attended by two ant species, Camponotus brutus (Formicinae) and Myrmicaria opaciventris (Myrmicinae). We recorded semiochemical (attending workers palpated the dorsal abdominal glands of the nymphs) and semantic signals (nymphs ready to excrete honeydew raised their bodies; they alternated the extrusion and withdrawal of the first honeydew droplet when the workers did not immediately absorb the honeydew). Cat. rugosa was recorded in carton pavilions built by the ants at the base of the tree trunks. During proliferations of the population, clusters of nymphs and adults developed outside pavilions. In the latter case, M. opaciventris workers did not modify their rhythm of activity in order to attend these clusters, while Camp. brutus workers, normally nocturnal, attended them day and night.