Biogeography and Biology of Bark and Ambrosia Beetles (Coleoptera: Scolytidae and Platypodidae) of a Mesic Montane Forest in Mexico, with an Annotated Checklist of Species

Abstract

We found 103 species in 33 genera of Scolytidae and five species in one genus of Platypodidae in mesic montane forest in the region of Xalapa, Veracruz, Mexico. The most distinctive elements of the fauna are the large numbers of species of ambrosia beetles in the tribe Corthylini and twig borers in the Bothrosternini. Neotropical genera, especially those typical of upland areas, formed the largest portion of the fauna. Most species in these genera are restricted to montane habitats of Mexico and Central America. Because mesic montane forest is transitional between highland temperate forests and lowland tropical forests in central Mexico, some mixing occurs and both areas contribute to the fauna. Nonetheless, the scolytid fauna includes a large component restricted to this forest type. This faunal element is derived from montane Central America, has penetrated into Mexico in favorable habitats, and is historically distinct from the predominantly South American scolytid fauna of lowland rain forest and the western North American-Mexican Plateau fauna of highland temperate forests. Most species (52%) were ambrosia beetles (which feed on ectosymbiotic fungi in galleries); phloem-feeders (21.7%) and pith-feeding twig borers (15.7%) were also abundant. The high percentage of ambrosia beetles is similar to that found in tropical rain forest in Mexico and other humid tropical areas in the Old and New World. Most ambrosia beetles and twig borers in the Xalapa fauna were extremely polyphagous, whereas most phloem-feeders were strongly monophagous. This relationship between host substrate and degree of specificity is similar to patterns observed in local scolytid faunas in temperate as well as tropical communities.