Spatial occurrence and abundance of five phloeophagous beetle species (Coleoptera) in Scots pine trees (Pinus sylvestris) growing on sandy soils

Abstract

Spatial occurrence and abundance of Ips sexdentatus, Phaenops cyanea, Pissodes piniphilus,
Tomicus minor and Ips acuminatus (Coleoptera: Curculionidae, Buprestidae) were examined in
mature Scots pine trees (Pinus sylvestris) growing on poor sandy soils in Záhorská nížina lowland
in western Slovakia, Central Europe. In the study area, the five given phloeophagous species are
secondary pests of Scots pine spatially separated in pine trunks. Early in March 2006, each of
them was recorded in 10 different Scots pine trees, in the lower, middle and upper parts (sections)
of the trunks, each section being 4.0 m long. The study was made to clarify in more detail (1) as to
whether and to which extent studied species occur in the middle trunks and (2) how their abundance
(density) is differing among particular trunk sections of infested trees. All studied species were
recorded in the middle trunk sections. However, the four of them, I. sexdentatus, P. piniphilus, T.
minor and I. acuminatus, were less frequent here than in the other sections (lower or upper) they
were preferring. Abundance of each species per 1,000 cm 2 significantly differed among the trunk
sections (p < 0.001, Kruskal-Wallis anova ). Particular species avoided extreme situations, that is,
species inhabiting the lower trunks (I. sexdentatus and P. cyanea) were not recorded in the upper
trunks and those colonizing the upper trunks (P. piniphilus, T. minor, I. acuminatus) were not
documented to be developing in the lower trunks. In each species, variability in abundance was
greatest in most densely colonized (preferred) parts of the trunks. The results give the evidence
that high number of individuals of studied species are developing in dying mature pine trees in a
mixed oak-pine forest in Central Europe.