Small pieces of fruit bodies (approximately 1 cm 1 cm) were
removed and presented to one of eight E. procera laboratory colonies,
which was previously deprived of food for 48 h (for information
on ant keeping see Witte & Maschwitz, 2008). If pieces of
fruit bodies were transported to the nest within 45 min we
considered them as accepted as a food source and classified them as
‘harvested fungi’, in contrast to ‘nonharvested fungi’.
We recorded additional fruit body characteristics, which we
considered potentially important for their acceptance or rejection
by ants, that is, their consistency, size and weight. While the consistency
of fungi may play a role in the ants’ ability to process the
fungal material, for example leathery fungi might be harder to
break up than fleshy ones, the size and weight might give us information
about the nutritional value of the food source. A fruit
body was collected for analysis only when a growth patch contained
several fruit bodies. This ensured that there were mushrooms
left for the study of growth pattern (see above). Consistency
(soft or leathery) was evaluated manually. Soft mushrooms could
be crushed while leathery ones could not. Size (umbrella diameter)
and weight measurements (fresh and dry weight; letter balance:
Maul, model 16420/02) were taken from a medium-sized specimen,
determined by eye. Fruit bodies were dried in a gas stove at
50 C for 24 h. Dried fruit bodies and spore preparations are stored
at the Faculty of Ecology of the Ludwig-Maximilians-University
Munich for later species identification.