TY - JOUR
T1 - Intraspecific competition in the ant Camponotus cruentatus
T2 - should we expect the 'dear enemy' effect?
AU - Boulay, Raphaël
AU - Cerdá, Xim
AU - Simon, Tovit
AU - Roldan, María
AU - Hefetz, Abraham
N1 - Funding Information:
We thank Alain Lenoir and two anonymous referees for their helpful comments on this manuscript. Javier Juste kindly advised us for statistical analyses. Elena Angulo, Aaron Gove, Isabel Luque, Alberto Tinaut and Merav Vonshak provided important assistance in various aspects of the fieldwork. We are also grateful to Naomi Paz for editorial assistance. This work was supported by a grant from ‘Ecodoca’ (European Community-Access to Research Infrastructure action of the Improving Human Potential Programme in Doñana Biological Station) to A. H.
PY - 2007/10
Y1 - 2007/10
N2 - The mechanisms of competition and resource domination were analysed in the Mediterranean ant Camponotus cruentatus. In a plot located in southern Spain mature colonies are overdispersed, which is indicative of territoriality in other species. Unexpectedly, however, workers from neighbouring colonies commonly foraged in areas that overlapped by more than 44%. This suggests that while mature colonies possibly prevent the establishment of new colonies in the vicinity of their nests, they do not limit the intrusion of alien foragers. In contrast, rich food sources located in common foraging areas are aggressively defended, generally leading to their domination by the nest that discovered them first. Resource exploitation further requires rapid recruitment of foragers and soldiers to transport food as well as to exclude competitors. Complementary to the field experiments we conducted laboratory bioassays to assess intercolonial aggression. Group encounters showed that workers of C. cruentatus were equally aggressive towards alien ants irrespective of whether they were sympatric neighbours (and had possibly had contact), sympatric nonneighbours (which had probably had no contact), or allopatric. This was corroborated by analysis of the hydrocarbons that generally serve as colony recognition cues. This mixture, which contains an unusual proportion of trimethylalkanes, showed important colony specificity. The high intraspecific aggression shown indiscriminately by workers indicates that the 'dear enemy' effect does not exist in this species and suggests that scarce resources are worth defending against intraspecific competitors. We discuss several proximate and ultimate constraints that may prevent the general occurrence of this process in ants.
AB - The mechanisms of competition and resource domination were analysed in the Mediterranean ant Camponotus cruentatus. In a plot located in southern Spain mature colonies are overdispersed, which is indicative of territoriality in other species. Unexpectedly, however, workers from neighbouring colonies commonly foraged in areas that overlapped by more than 44%. This suggests that while mature colonies possibly prevent the establishment of new colonies in the vicinity of their nests, they do not limit the intrusion of alien foragers. In contrast, rich food sources located in common foraging areas are aggressively defended, generally leading to their domination by the nest that discovered them first. Resource exploitation further requires rapid recruitment of foragers and soldiers to transport food as well as to exclude competitors. Complementary to the field experiments we conducted laboratory bioassays to assess intercolonial aggression. Group encounters showed that workers of C. cruentatus were equally aggressive towards alien ants irrespective of whether they were sympatric neighbours (and had possibly had contact), sympatric nonneighbours (which had probably had no contact), or allopatric. This was corroborated by analysis of the hydrocarbons that generally serve as colony recognition cues. This mixture, which contains an unusual proportion of trimethylalkanes, showed important colony specificity. The high intraspecific aggression shown indiscriminately by workers indicates that the 'dear enemy' effect does not exist in this species and suggests that scarce resources are worth defending against intraspecific competitors. We discuss several proximate and ultimate constraints that may prevent the general occurrence of this process in ants.
KW - Camponotus cruentatus
KW - Mediterranean ant
KW - aggressive interactions
KW - colony integrity
KW - cuticular hydrocarbons
KW - intraspecific competition
KW - nestmate recognition
KW - social insects
UR - http://www.scopus.com/inward/record.url?scp=35148856561&partnerID=8YFLogxK
U2 - 10.1016/j.anbehav.2007.02.013
DO - 10.1016/j.anbehav.2007.02.013
M3 - ???researchoutput.researchoutputtypes.contributiontojournal.article???
AN - SCOPUS:35148856561
SN - 0003-3472
VL - 74
SP - 985
EP - 993
JO - Animal Behaviour
JF - Animal Behaviour
IS - 4
ER -