Bark and ambrosia beetles are a diverse group that causes widespread mortality of deciduous and coniferous trees. The present study aimed to investigate the species compositions and richnesses of bark and ambrosia beetles in six species of plant hosts in East Java, Indonesia. Bark and ambrosia beetles were sampled using bottle traps baited with ethanol. Studies were conducted at two sites of monoculture and polyculture systems for each host plant species. At each site, 20 ethanol-baited traps were deployed on a linear transect along the forest. Six host tree species examined were used, namely Tectona grandis (Teak), Syzygium aromaticum (Clove), Swietenia mahagoni (Mahogany), Pinus merkusii (Sumatran Pine), Paraserianthes falcataria (Moluccan Albizia), and Mangifera indica (Mango). The data were analyzed using R software. A total of 4823 beetles were collected, representing 26 ambrosia beetle and eight bark beetle species. The abundance of bark and ambrosia beetles was significantly highest at the sites of T. grandis (F = 13.88, P < 0.01). Xylosandrus crassiusculus showed a strong attraction to the ethanol lure and was the dominant beetle species (50.65% of the total number of individuals). The Shannon-Wiener diversity index of all beetles captured in this study was the highest in the S. mahogany polyculture (2.28) and the lowest in the T. grandis polyculture (0.47). According to Bray-Curtis analysis, the T. grandis monoculture and T. grandis polyculture had a high similarity value of bark and ambrosia beetle species compositions (91% similar). There were no significant differences between two cultural systems of host plants in the compositions of bark and ambrosia beetle species (ANOSIM, R = -0.1537, P = 0.961).
Keywords: Ambrosia beetles; Cultural system; Ethanol-baited; NMDS; Species richness.