Scarcity of sites suitable for nesting promotes plesiobiosis in ants (Hymenoptera: Formicidae)

Plesiobiosis is a rudimentary form of social symbiosis. It consists of the close proximity of nests of different social insect species. Numerous cases of plesiobiosis between ant species observed in a successional series of rocky habitats in S Finland are listed and themost interesting of them are described in detail. Among all Lasius colonies found within the whole successional series studied, as many as 8.4% were plesiobiotically associated with other ants. In the two earliest successional stages: the shoremeadow and the open rocky outcrop, the proportion was nearly 12% and 10% respectively. The finding of numerous plesiobiotically related nests there is discussed in the context of the unique local habitat conditions

Behavioural and socially parasitic relations between Polyergus rufescens (Latr.) and Formica polyctena Först. (Hymenoptera: Formicidae)

Polyergus rufescens (Latr.), an obligate slave-maker, and Formica polyctena Först., an aggressive, territorial wood ant species, rarely co-occur in the field, and there are almost no data on their mutual relations under natural conditions. These interactions were studied in the Bialowieza Forest (NE Poland), based on two P. rufescens colonies (with Formica fusca L. slaves) nesting within the territories of F. polyctena. The wood ants routinely searched the immediate vicinity of P. rufescens nests, whereas P. rufescens ants raided F. fusca colonies very close to F. polyctena nests or their columns passed right next to them, they eventually crossed wood ants’ foraging and removal routes, and even directly attacked F. polyctena colonies and robbed their brood. Interspeciflc relations in these particular situations are described and discussed in the contexts of supposed chemical camouflage/mimicry of P. rufescens and interspecific competition hierarchy in ants

Structure and succession of Lasius s. str. (Hymenoptera: Formicidae) assemblages in a Finnish sand dune area – reassessment after taxonomic revisions of the subgenus

Gallé (1991) described the structure of ant assemblages along a successional gradient of sand dune habitats in southern Finland. The work was immediately succeeded by two revisions where two of the most abundant species on the sand dunes were split into two and three species respectively (Seifert 1991, 1992). On the basis of the revised taxonomy and our present work, Gallé’s Lasius (s. str.) alienus (Först.) on the dunes is L. psammophilus Seifert, and his L. (s. str.) niger (L.) includes two sibling species, L. niger and L. platythorax Seifert. We reassess the relative abundances of the Lasius s. str. species and their nest sites in the successional habitats of the dunes in the light of the present taxonomic knowledge

Collapse of the invasive garden ant, Lasius neglectus, populations in four European countries

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Ants trapped for years in an old bunker; survival by cannibalism and eventual escape

Successful evacuation of a peculiar 'colony' of the wood ant Formica polyctena Forst., for years trapped within an old bunker previously used for storing nuclear weapons (see Czechowski et al. 2016), is reported. Using an experimentally installed boardwalk, the imprisoned ants managed to get through the ventilation pipe to their maternal nest on the top of the bunker. In our previous report, we left open the question of how the 'colony' could survive seemingly without food. Here we show that the 'colony' in the bunker survived and grew thanks to an influx of workers from the source nest above the bunker and mass consumption of corpses of the imprisoned nestmates.Peer reviewe

Alate gyne of the ant Dolichoderus quadripunctatus (L.) (Hymenoptera, Formicidae) follows foraging trail to aphids

The first observation of alate gyne of Dolichoderus quadripunctatus (L.) visiting aphids is described. A gyne walked along a foraging trail to the aphid Panaphis juglandis Goeze colony where it imbibed honeydew excreted on the leaf by the aphids, after which it returned to the trail. This recurred during two more days, always a single alate gyne at a time; hence the total number of gynes, one or more, remained open. The phenomenon, hitherto practically unknown in ants, is presented against the background of the biology of the species and discussed in the context of specific environmental circumstances and the colony dynamics.Peer reviewe

Living beyond the limits of survival: wood ants trapped in a gigantic pitfall

A unique accumulation of workers (‘colony’) of the wood ant Formica polyctena Först., trapped within an old bunker for storing nuclear weapons, is described. The source of the ‘colony’ is a large colony nesting outdoors, on top of the bunker. Individuals that have fallen down through a ventilation pipe are not able to find their way back to the mother nest. In total darkness, they have constructed an earthen mound, which they have maintained all-year-round by moulding it and keeping the nest entrances open. Judging from the huge deposits of wood-ant corpses in the bunker, the ‘colony’ has survived for years. Through these years, the mortality has been more than compensated by new workers that fall down during the active season of the free-living colony outside, and at present the number of the bunker workers is counted in hundreds of thousands. The ‘colony’ has evidently produced no offspring, which is due to low (though relatively stable) temperatures and scanty food in the bunker

Wood ants in the Bialowieza Forest and factors affecting their distribution

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