Shelter Plant Preference of an Atypical White Grub Species, Lepidiota mansueta Burmeister (Coleoptera: Scarabaeidae) in Relation to Plant Morphological Characters

Abstract

Efforts were undertaken to identify the most preferred shelter plant of a white grub beetle, Lepidiota mansueta on the basis of different morphological characters of the plants with the objective of improving beetle management strategies. During the study period, seven most preferred shelter plants viz., Tamarix (Tamarix dioica), Bush morning glory (Ipomea carnea), Wild sugarcane (Saccharum spontaneum), Ber (Ziziphus jujuba), Tropical soda apple (Solanum viarum), Chinese chaste tree (Vitex negundo) and Lantana (Lantana camera) were recorded. These plants were naturally grown in the sand bars of Majuli river island, Assam and found preferred by the beetles as shelter plants where they exhibited both normal and multiple mating behaviour. Field and laboratory studies revealed the most preferred plant among the seven shelter plants by the beetles as Tamarix dioica (14.40±1.17 numbers/ plant) which registered a mean plant height of 187.50±14.77 cm, total leaf area of 2.18±0.15 cm2, leaf length and breadth of 6.91±0.78 and 0.26±0.07 cm, respectively. Shelter plants with alternate type of leaf phyllotaxy and horizontal spreading canopy were further recorded to be highly preferred by the beetles over the plants with whorled or opposite type of leaf phyllotaxy. The findings of the present study will practically enhance beetle trapping efficiency under endemic field conditions leading to their effective management.