Abstract:
Subterranean termites from the genus Reticulitermes are an important pest of
wood in service throughout southern Europe and elsewhere. For effective termite
control with long term protection but minimal environmental damage, new
integrated approaches to termite management are needed. Baiting-based systems
seem to be promising non-traditional methods for termite control, targeting the
colony as a whole. However, control through baiting is only feasible when it is
known that the toxicant can be transferred to all the colonies foraging on the
infested area and also throughout each individual colony. Accordingly, the work
described is specifically designed to achieve a better understanding of the
distribution and delimitation of colonies within a population of Reticulitermes,
with parallel insights into foraging behaviour and colony organization.
Initially, the species/subspecies spectrum present within the notional
Reticulitermes group in Portugal was reassessed. It was shown that Reticulitermes
grassei is the only species encountered. Foraging activity was then assessed in an
experimental woodland site over two successive annual cycles, both by the
sampling of natural lying dead wood and by a standard baiting grid. R. grassei
seem to select wood with larger diameter, with an apparent preference for material
already decayed by fungi. Both termite and fungal attack on wood seems to be
promoted by higher moisture levels, such as prevail in larger litter items and
during seasonal rains. Termites were unable to detect and direct their foraging
towards sound wood in laboratory conditions, suggesting that the network of
infochemical signals is more complex than just volatiles emanating from sound
wood. Mark-release-recapture (MRR) was used to delineate foraging groups,
which were then allocated to their parent colonies by the use of microsatellite
markers. The results suggest that resource sharing is a facultative behaviour,
specifically when food is not a limiting factor for colony development. The
implications of all these findings for bait technology and protocols are discussed,
with reference to the local population ecology of Reticulitermes.
