Host plants and nymph morphology of an endemic treehopper, Pyrgonota bifoliata, in the Mount Makiling Forest Reserve, Luzon, Philippines

Pyrgonota bifoliata (Insecta: Hemiptera: Membracidae) is a distinct endemic Philippine treehopper species complex distinguished by its extremely elevated and bifurcated pronotal structures. An earlier study suggested that P. bifoliata is a host specialist that feeds on Bridelia (Phyllanthaceae) in northern Luzon and Rubus (Rosaceae) in southern Mindanao. However, the host plant range across the geographical distribution of the P. bifoliata species complex is still poorly understood. In this study, field observations and DNA barcoding were performed to determine the host plant range of P. bifoliata in the Mount Makiling Forest Reserve of Laguna Province on the island of Luzon. The morphology of the last-instar nymph of P. bifoliata was described to facilitate the identification of the species and its host plants. Behavioural interactions between P. bifoliata and its associated ants were also recorded. The results revealed that Piper umbellatum (Piperaceae) and Saurauia latibractea (Actinidiaceae) were the major host plants used by both nymphs and adults of P. bifoliata. The findings indicate that P. bifoliata in the Mount Makiling Forest Reserve of central Luzon is a polyphagous host generalist that primarily utilises two distantly related plant species. The adults of P. bifoliata also occur on Alangium longiflorum (Cornaceae) and Ficus ulmifolia (Moraceae). The nymphs of P. bifoliata are gregarious in small groups and visited by three ant species (Crematogaster sp., Pheidole sp. and Technomyrmex sp.); however, the adults of P. bifoliata are solitary and are never observed with ants. Unlike other treehoppers that are subsocial, the females of P. bifoliata exhibited no maternal care behaviours, such as egg or nymph guarding.