An uneasy alliance: a nesting association between aggressive ants and equally fierce social wasps

Abstract

Although the Neotropical territorially dominant arboreal ant Azteca chartifex Forel is very aggressive towards any intruder, its populous colonies tolerate the close presence of the fierce polistine wasp Polybia rejecta (F.). In French Guiana, 83.33% of the 48 P. rejecta nests recorded were found side by side with those of A. chartifex. This nesting association results in mutual protection from predators (i.e., the wasps protected from army ants; the ants protected from birds). We conducted field studies, laboratory-based behavioral experiments and chemical analyses to elucidate the mechanisms allowing the persistence of this association. Due to differences in the cuticular profiles of the two species, we eliminated the possibility of chemical mimicry. Also, analyses of the carton nests did not reveal traces of marking on the envelopes. Because ant forager flows were not perturbed by extracts from the wasps' Dufour's and venom glands, we rejected any hypothetical action of repulsive chemicals. Nevertheless, we noted that the wasps "scraped" the surface of the upper part of their nest envelope using their mandibles, likely removing the ants' scent trails, and an experiment showed that ant foragers were perturbed by the removal of their scent trails. This leads us to use the term "erasure hypothesis." Thus, this nesting association persists thanks to a relative tolerance by the ants towards wasp presence and the behavior of the wasps that allows them to "contain" their associated ants through the elimination of their scent trails, direct attacks, "wing-buzzing" behavior and ejecting the ants.

Notes on an interspecific interaction between distant taxa: Observation of active cohabitation and communal nesting resources between Gehyra mutilata (Wiegmann, 1834) and two vespid wasp species

“…One or all species positively benefitting from the ecological interaction likely indicates a mutualistic (+, +) or commensal (+, 0) ecological interaction. These interactions could be considered mutualistic, with reciprocal fitness benefits for the species establishing the nesting site experienced no obvious detrimental fitness cost, but likely benefited from additional protection and maintenance of a nesting site or mechanical barriers reducing parasites and pathogens (Doody et al, 2009; Servigne et al, 2020; Veiga et al, 2013a) and the two other species benefiting from utilizing an existing nesting resource.…”

“…A colony consisting of two Polistes species, O'Donnell & Jeanne, 1991) and arboreal ants (e.g. A nesting association between arboreal ant species Azteca chartifex and Polistine wasp Polybia rejecta , Servigne et al, 2020). However, interspecific active nesting associations between distant taxa are even less reported (see Rodriguez‐Prieto et al, 2010; Gory, 2011; Veiga et al, 2013a, 2013b for some known examples).…”

“…Polistine wasps have been previously observed to have interspecific nesting associations (e.g. with other tropical social wasps, O'Donnell & Jeanne, 1991; and arboreal ants, Servigne et al, 2020).…”

New records of the association between Polybia rejecta (Fabricius, 1798) (Hymenoptera: Vespidae) and Azteca chartifex Emery, 1896 (Hymenoptera: Formicidae) for the Caatinga and Amazon forest

“…Most occurrence records of the association between P. rejecta and A. chartifex are in the Amazon biome (Jeane 1978;Corbara et al 2009;Somavilla et al 2013;Servigne et al 2018), but this seems to be changing. This association has been previously recorded in areas of transition between cerrado and amazon (Richards 1978), atlantic forest (Souza et al 2013) and in areas of transition between atlantic forest and caatinga (Virgínio et al 2015) (Tab.…”

“…Thus, further studies in ethology and ecology should be undertaken to assess whether this relationship is merely a case of tolerance between the two hymenopteran species or there is some kind of symbiosis between them. Virgínio et al (2015) 18 Petit Saut, French Guiana Amazon Forest 05°03′39″N; 53°02′36″W Corbara et al (2009) 05 Petit-Saut, Sinnamary and Kourou, French Guiana Amazon Forest 05°03'39"N, 53°02'36"W Servigne et al (2018)…”