Abstract

The study was aimed at evaluating the influence of winter mortality and predator larvae abundance on breeding performance of bivoltine populations of Ips. typographus colonizing felled spruce trees in Croatia. A low colonization density of I. typographus expressed as a number of maternal galleries per square meter of bark, usually reflects high reproductive success, defined as a number of daughters per mother beetle (female/female). Regarding this study, the mean gallery density on felled trees varied between 27 and 146 per m(2) of bark, while the lowest reproduction rate was only 0.5 female/female. Althought differently suggested by previous findings, the cause of such a low reproduction rate can be explained by high abundance of predator larvae and high winter mortality of larvae, pupae and callow beetles. The results suggest that predators, primarily long-legged flies-of the genus Medetera (Fischer von Waldheim) (Diptera: Dolichopodidae), have huge ecological impact on bark beetle populations at endemic levels. At low attack densities, the majority of males (74%) copulate with two females, following the evolutionary trait of avoiding intraspecific larval competition.

Keywords

breeding; low attack; gallery; intraspecific; Medetera

Published in

Sumarski List
2018, Volume: 142, number: 9-10, pages: 473-479
Publisher: CROATIAN FORESTRY SOC

SLU Authors

• Lindelöw, Åke

  • Department of Ecology, Swedish University of Agricultural Sciences
    

UKÄ Subject classification

Ecology
Forest Science


Publication identifier

DOI: https://doi.org/10.31298/sl.142.9-10.2

Permanent link to this page (URI)

https://res.slu.se/id/publ/97317