Friend or foe? Differential aggression towards neighbors and strangers in the ant Liometopum microcephalum (Hymenoptera: Formicidae)

Abstract

Intra-and interspecific aggression is quite common in ants, from occasional conflicts to large-scale territorial disputes. The "nasty neighbor" phenomenon describes the differential aggressive treatment of neighbors versus foreign intruders. Due to the fact that workers of a given colony meet rival neighbors more often at food resources, they treat them as threats to their colony. The reverse can also happen: the "dear enemy" effect arises when an already known rival is treated less aggressively due to accommodation, than an unknown distant one. In the current study, we analyzed the effect of distance on the aggressiveness of Liometopum microcephalum, a territorial arboricolous ant, towards non-nestmates in two large populations. Our results show that aggression did not increase with distance, but it was higher among neighbors than among workers coming from distant nests. The results of the study are consistent with the nasty neighbor scenario, and do not support the hypothesis that the studied populations would be polydomous systems of interconnected nests.

Battles between ants (Hymenoptera: Formicidae): a review

“…Keresztes et al (2020) presented individual Liometopum microcephalum (Hymenoptera: Formicidae: Dolichoderinae) with a single ant from various colonies and measured behavior in the laboratory. Levels of aggression were highest when encountering an ant of another species, Lasius niger (Hymenoptera: Formicidae: Formicinae), and lowest among nestmates ( Keresztes et al 2020 ).…”

“…In some cases, the pattern of behavior may be established despite competition risk. For example, in tree-dwelling Liometopum microcephalum ants ( Keresztes et al 2020 ), there is likely less chance of meeting ants from neighboring colonies, given their vertical territories. Nevertheless, aggression levels were higher toward ants from neighboring nests and lower when workers were from more distant nests ( Tsuji 1988 , Sanada-Morimura et al 2003 ).…”

Not dear neighbours: Antennation and jerking, but not aggression, correlate with genetic relatedness and spatial distance in the ant Lasius niger

“…Slightly higher aggression to neighbouring nest than stranger nest in shared patch. More pronounced increase in aggression to ants from distant patches (Keresztes et al, 2020) Note: This table includes only studies of intraspecific aggression.…”