Abstract . 1. Bark and ambrosia beetles are crucial for woody biomass decomposition
in tropical forests worldwide. Despite that, quantitative data on their host specificity
are scarce.
2. Bark and ambrosia beetles (Scolytinae and Platypodinae) were reared from 13 species
of tropical trees representing 11 families from all major lineages of dicotyledonous
plants. Standardised samples of beetle-infested twigs, branches, trunks, and roots were
taken from three individuals of each tree species growing in a lowland tropical rainforest
in Papua New Guinea.
3. A total of 81 742 beetles from 74 species were reared, 67 of them identified. Local
species richness of bark and ambrosia beetles was estimated at 80 – 92 species.
Ambrosia beetles were broad generalists as 95% of species did not show any
preference for a particular host species or clade. Similarity of ambrosia beetle communities
from different tree species was not correlated with phylogenetic distances between tree
species. Similarity of ambrosia beetle communities from individual conspecific trees was
not higher than that from heterospecific trees and different parts of the trees hosted similar
ambrosia beetle communities, as only a few species preferred particular tree parts.
5. In contrast, phloeophagous bark beetles showed strict specificity to host plant genus
or family. However, this guild was poor in species (12 species) and restricted to only three
plant families (Moraceae, Myristicaceae, Sapindaceae).
6. Local diversity of both bark and ambrosia beetles is not driven by the local diversity
of trees in tropical forests, since ambrosia beetles display no host specificity and bark
beetles are species poor and restricted to a few plant families.