Byers, J.A. & Löfqvist, J. 1989. Flight initiation and
survival in the bark beetle Ips typographus
(Coleoptera: Scolytidae) during the spring dispersal.
Holarctic Ecology 12:432-440.
Abstract--
Temperatures in the forest litter of Norway spruce Picea abies were
recorded throughout the day to obtain environmental parameters that
could be used to design realistic flight-activity experiments in the
laboratory. Flight activity and survival were monitored
electronically in plastic chambers where the conditions were
controlled by an environmental chamber. Flight attempts of the bark
beetle Ips typographus were initially lower in chambers with forest
duff but were prolonged compared with those of beetles in chambers
with a metal screen substrate. Small bark slabs and spruce twigs in
the duff were utilized as food and extended the period of flight and
survival. A thermal gradient in duff from 25 degrees C at the surface
down to 13.8 degrees C at a depth of 4 cm also slightly increased the
survival of beetles compared with a constant 25 degrees. A daily
ambient temperature cycle as well as the duff thermal gradient
increased the survival from about 3 d to more than 8 d. The latter
length in the laboratory agreed with survival rates of caged beetles
in a clearcut forest area, while beetles caged in the forest survival
for more than 14 d. Temperatures were monitored at the duff surface
of the caged beetles and compared with the catches of beetles that
were attracted to a pheromone trap and collected with an electronic
fraction collector. Information on flight and survival during the
dispersal period is necessary to the design of ecologically sound
management programs for control of bark beetles.
Chemical Ecology