Abstract:

Objective: The effects of different host tree species, on which Batocera lineolata larvae fed, on adult behavior and the internal mechanism were discussed based on the comparisons of the supplementary nutritional behavior, morphological characteristics and genetic traits of B. lineolata adults. Method: B. lineolata adults emerged from host trees of Populus tomentosa and Fraxinus pennsylvanica were collected respectively. The external morphology and male genital structure of B. lineolata adults from the two host plants were observed and compared. Then, through the feeding preference experiment, the feeding behavior and mating behavior of these two kinds of adults on the shoots of five plant species, i.e. Rosa multiflora, Carya illinoinensis, Viburnum odoratissimum var. awabuki, F. pennsylvanica and P. tomentosa were observed. The interactive mating tests were conducted between B. lineolata adults from the two host plants. Finally, mitochondrial cytochrome c oxidase subunit I(COI) gene sequences of the two populations of B. lineolata were cloned by universal primer, and the sequence differences and phylogenetic relationships were analyzed based on COI gene. Result: 1) There are obvious differences in external morphology between the two B. lineolata beetles whose larvae fed on P. tomentosa and F. pennsylvanica, respectively. The bottom of abdomen of the male adults emerged from F. pennsylvanica is narrow, in obtuse angle, inward-concave and covered with sparse hairs, and the bottom of the female adults is curved-concave, and the central indentation of the bottom is not obvious. However, the bottom of abdomen of the male adult from P. tomentosa is wide, curved, inner-concave and covered with dense hairs. And the bottom of the female adults is flattened and the central indentation of the bottom is obvious. The genital morphological characteristics of the two beetles are similar. 2) B. lineolata adults from F. pennsylvanica only consumed the fresh branches of F. pennsylvanica, and B. lineolata from P. tomentosa fed on three plant species, and preferred order was R. multiflora > C. illinoinensis > V. odoratissimum var. awabuki; 3) Male and female adults from different host plants were able to mate with each other, and the mean mating bouts was equal to that of male and female adults from the same host plant(P > 0.05); 4) Analysis of molecular variation(AMOVA) for COI genes indicated a significant genetic differentiation between the two B. lineolata populations(F_st =0.813 85, P < 0.001), and most of the genetic variance was among populations(81.39%) rather than within populations(18.61%). Conclusion: Larval feeding experience(feeding on different host plants) and habit differentiation can significantly affect feeding behavior of B. lineolata adults and genetic variation of populations.

Key words: Batocera lineolata, feeding preference, morphological characteristics, genetic variation, mating