Bioecology of a treehopper, Coccosterphus minutus (F.) (Homoptera: Membracidae)

Bioecology of the membracid, Coccosterphus minutus (F.) was studied during September 1989-August 1990. Field observations revealed it as polyphagous. It was recorded from seven host plants belonging to five different families. Fluggea leucopyrus, Phyllanthus niruri and Rhynchosia minima were new host records. Acalypha indica was its most preferred host plant. The feeding sites for the early nymphal instars were flower stalk, leaf petiole or tender twigs, while the later instars fed on the leaf and nodal regions of mature twigs as also often on the leaf petiole and unopened leaf buds. Such sites provided nymphs and adults a background for protecting them against their natural enemies which, however, varied in each host plant species. The resting posture of the nymphs simulates stipules of its host plant to make them inconspicuous. Though the premating was observed throughout the day, mating was observed only during mornings and evenings. In all the host plants, the adults preferred twigs with 0.1 to 0.4 em diameter of 1to 3 month-old plants for egg laying. It oviposited in 2 to 5 slits with 1to 3 eggs in each slit. The duration of each nymphal instar from first to fifth was respectively 3.8, 3.0, 4.2, 7.3 and 7.3 days. Leaf surface was its most preferred site for moulting where 52.4% of the total exuviae were collected, followed by inflorescence (23.1%) and tender twigs (20.3%). The mean sex-ratio was biased towards female throughout the one-year period. The nymphs bear less resemblance to their adults due to conspicuous colour change during development. The colouration and mimicry were evident in the tree hopper and significantly contributed towards its self defence and survival.