Seasonal patterns in the orientation system of the migratory ant Pachycondyla marginata.
Route directions of migrations by the neotropical termite-hunting ant Pachycondyla marginata at a forest reserve in Southeast Brazil were analysed by circular statistic. Colony movement patterns were compared between the rainy/hot and dry/cold seasons. Migrations during the dry/cold season are significantly oriented 13 degrees with the magnetic North-South axis, while rainy/hot migrations do not exhibit a preferred direction. This result is discussed considering the hypothesis that P. marginata ants may use the geomagnetic 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.
Acosta-Avalos
D
D
Centro Brasileiro de Pesquisas Físicas, Rua Xavier Sigaud 150, 22290-180, Rio de Janeiro, RJ, Brazil. darci@cbpf.br
Esquivel
D M
DM
Wajnberg
E
E
de Barros
H G
HG
Oliveira
P S
PS
Leal
I
I
D000818:Animals; D001000:Ants / Q000502:physiology*; D001938:Brazil; D003080:Cold Temperature; D055593:Geological Phenomena; D005844:Geology; D006358:Hot Temperature; D008280:Magnetics; D009949:Orientation / Q000502:physiology*; D011891:Rain; D012621:Seasons