INVESTIGADORES
FARJI-BRENER Alejandro Gustavo
artículos
Título:
Nocturnal resource defence in aphid-tending ants of northern Patagonia
Autor/es:
LESCANO, N.; FARJI-BRENER, AG; GIANOLI, ERNESTO
Revista:
ECOLOGICAL ENTOMOLOGY
Editorial:
WILEY-BLACKWELL PUBLISHING, INC
Referencias:
Lugar: Londres; Año: 2014 vol. 39 p. 203 - 209
ISSN:
0307-6946
Resumen:
1. Interspecific competition plays a key role in the organisation of ant
communities. In ant?plant interactions, individual host plants are usually occupied
by a single ant colony, and co-occurring ant species compete for hosts. Here indirect
evidence of competition between three dominant ant species that tend aphids on two
biennial thistles in northern Patagonia is described, and a novel defensive behaviour
in temperate ant assemblages is reported.
2. This study has found that: (i) dominant ant species were not spatially segregated,
thus enhancing the probability of fights and invasions of host plants; (ii) ant species
did not show preferences for a thistle species or for any plant characteristic, and
thus all plants have similar chances of being colonised by all dominant ant species;
(iii) the resident ant species remained on the same plant during the whole plant life
cycle, monopolising plant resources (aphids); and (iv) all dominant species, whose
nests are on the ground, assigned some ants to stay on the host plant during the
night, when the low temperatures typical of this temperate environment greatly reduce
foraging activities. When these ?nocturnal guards? were experimentally removed from
the host plant, other ants from the same colony rapidly appeared showing aggressive
behaviours.
3. Taking all these findings together, it is suggested that interspecific competition
influences the distribution of ants on their host plants and involves nocturnal defensive
behaviours despite unfavourable thermal conditions. This illustrates how habitat
features, such as the short life cycle of thistles and the low night-time temperatures
that reduce ant foraging and thus make plants more vulnerable to invasion, might
affect the distribution and behaviour of ants.