Experiment 4: Antimycotic activity of weaver ant venom
in vitro
The poison gland and reservoir were dissected from 120
P. dives workers, pooled and centrifuged. Petri dishes
(90 mm diameter) of selective media (Saboraud dextrose
agar with 0.1 g/l dodin, 0.05 g/l streptomycin sulphate and
0.1 g/l chloramphenicol) were seeded with 250 μl of a 1×
106 conidia/ml Metarhizium suspension. Doses of 3 μl of
either poison gland secretion, 0.05% Triton-X or a dilution
series of formic acid (>98%, Fisher) were applied to the
Metarhizium plates. Each 3 μl dose was applied in a 4-
mm-diameter circle, which has approximately the same
area as the body surface of a P. dives worker (ca.
13.5 mm2). After a period of 36 h at 22°C the proportion
of spores germinating was determined using a light
microscope at 400× magnification. The experiment was
repeated using media plates (without dodin) that had been
seeded with 250 μl of a suspension of 1×106 Aspergillus
flavus conidia/ml. Each treatment was repeated five times.