Size and shape changes of Ips typographus L. (Coleoptera: Scolytinae) in relation to population level

摘要: 1 High intraspecific competition is known to occur during Ips typographus outbreaks, and thought be the main factor regulating epidemic populations by affecting beetle population productivity. However, little about consequences of on quality although it could have dynamics. 2 Ips morphological variations among localities, years levels were investigated in 10 Norway spruce (Picea abies) stands having various damage intensities. Beetle size shape estimators based wing length, using isometric log-shape ratios, employed. Field-caught beetles compared with emerging from controlled breeding at different densities, performed laboratory. Beetles this colony also used check influence densities estimator. 3 Size occurred localities consistent or latent status populations. Controlled confirmed negative effect encountered field offspring size. Two hypotheses are formulated explain increase an outbreak, but our data support host change between populations. 4 Shape unrelated levels. No groups a geographical structure found, suggesting low genetic variation for I. France.