Phoretic mites in uni- and bivoltine populations of Ips typographus: a 1-year case study

Abstract

Members of the order Mesostigmata frequently use other animals to colonize suitable habitats, and thus their phoretic exploitation of bark beetles is not exceptional. We compared the abundance and species spectrum of phoretic mites in univoltine and bivoltine populations of the European spruce bark beetle Ips typographus. Two localities with high population densities of Ips typographus in the eastern part of the Czech Republic (400 and 1100 m a.s.l.) were studied. Beetles were sampled with pheromone traps baited with IT Ecolure (5 per locality). In total, 1268 I. typographus individuals were captured, from which 1662 mite individuals were collected and 8 species of phoretic mites were identified. The most numerous species were Dendrolaelaps quadrisetus and Trichouropoda polytricha. Trichouropoda polytricha was dominant at the higher elevation (1100 m a.s.l.). Neither the number of phoretic mites per beetle nor the percentage of beetles carrying the mites differed between the localities. At the locality with bivoltine beetle populations, however, the number of phoretic mites per beetle was greater in the spring generation than in the summer generation.