Host-seeking female tabanid flies, that need mammalian blood for the development of
their eggs, can be captured by the classic canopy trap with an elevated shiny black
sphere as a luring visual target. The design of more efficient tabanid traps is important
for stock-breeders to control tabanids, since these blood-sucking insects can cause
severe problems for livestock, especially for horse- and cattle-keepers: reduced meat/milk
production in cattle farms, horses cannot be ridden, decreased quality of hides due
to biting scars. We show here that male and female tabanids can be caught by a novel,
weather-proof liquid-filled black tray laid on the ground, because the strongly and
horizontally polarized light reflected from the black liquid surface attracts water-seeking
polarotactic tabanids. We performed field experiments to reveal the ideal elevation
of the liquid trap and to compare the tabanid-capturing efficiency of three different
traps: (1) the classic canopy trap, (2) the new polarization liquid trap, and (3)
the combination of the two traps. In field tests, we showed that the combined trap
captures 2.4-8.2 times more tabanids than the canopy trap alone. The reason for the
larger efficiency of the combined trap is that it captures simultaneously the host-seeking
female and the water-seeking male and female tabanids. We suggest supplementing the
traditional canopy trap with the new liquid trap in order to enhance the tabanid-capturing
efficiency.
