Evidence of sibling species between two host-associated populations of brown planthopper, N. lugens (stål) (Homoptera: Delphacidea) complex based on morphology and host–plant relationship studies

• Main Authors: Latif, Mohammad Abdul, Mohd Yosoh, Omar, Yusop, Mohd Rafii, Malek, Mohammad Abdul, Tan, Soon Guan
• Format: Article
• Language: English
• Published: Elsevier 2013
• Online Access: http://psasir.upm.edu.my/id/eprint/28049/1/28049.pdf; http://psasir.upm.edu.my/id/eprint/28049/; http://www.sciencedirect.com/science/article/pii/S1631069113001030

Morphological and host–plant relationship studies were conducted to differentiate two sympatric populations of brown planthopper (BPH), Nilaparvata lugens, one from rice (Oryza sativa) and the other from Leersia hexandra, a weed grass. In morphometric studies based on esterase activities, an UPGMA dendrogram using 17 quantitative morphological characters, including stridulatory organs (courtship signal-producing organs) between two sympatric populations of N. lugens, one from rice and the other from L. hexandra, a weed grass revealed that both populations were separated from each other. An out-group, N. bakeri, was found to be completely different from the two sympatric populations of N. lugens. Rice plants were best suited for the establishment of the rice-infesting population, and L. hexandra was a favourable host for the Leersia-infesting population. The individuals derived from one host did not thrive on the other host, as shown by a significant reduction in survival and nymphal development, ovipositional preferences, ovipositional response, and egg hatchability. Therefore, morphological and host–plant relationship studies indicate that rice-associated population with high esterase activities and L. heaxandra-associated population with low esterase activities are two closely related sibling species.