D. Acosta-avalos et al., Seasonal patterns in the orientation system of the migratory ant Pachycondyla marginata, NATURWISSEN, 88(8), 2001, pp. 343-346
Route directions of migrations by the neotropical termite-hunting ant Pachy
condyla marginata at a forest reserve in Southeast Brazil were analysed by
circular statistic. Colony movement patterns were compared between the rain
y/hot and dry/cold seasons. Migrations during the dry/cold season are signi
ficantly oriented 13 degrees with the magnetic North-South axis, while rain
y/hot migrations do not exhibit a preferred direction. This result is discu
ssed considering the hypothesis that P. marginata ants may use the geomagne
tic field as an orientation cue for migrations in the dry/cold season. The
presence of magnetic iron oxides in the head and abdomen of P. marginata is
consistent with this suggestion.