Figure - available from: Journal of Hymenoptera Research
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The boardwalk just assembled, to provide the ants a means to reach the ventilation pipe. Photo taken on 18.09.2016 (Wojciech Stephan).
Source publication
Successful evacuation of a peculiar ‘colony’ of the wood ant Formica polyctena Först., 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 th...
Citations
... The subject of the present paper is the case of F. polyctena colony and its odd filial nest -odd due to its peculiar origin, history and extremely unfavourable, in seemingly every respect, location: deep underground at the bottom of a concrete bunker (see Czechowski et al. 2016, Rutkowski et al. 2019; see also Material and methods). The aim of our research was (1) to reveal the further fate of this, unusual in every respect, auxiliary nest, (2) to answer the question of whether and how ants could benefit from such an unfortunate nest location, and (3) determine possible importance of this nest as a component of the polydomous wood ant system for the colony, and therefore the reasons for its -undoubtedly energetically expensive -maintenance by the colony. ...
... Therefore, ants from this nest were constantly accidentally falling down this pipe straight from the nest into one of the rooms of the bunker. Over the years, living mostly by cannibalism on their dead (see Rutkowski et al. 2019), the bottom 'colony' has been growing due to the constant influx of individuals falling from the maternal nest; in 2015, the size of the colony was estimated at several thousand alive workers. Moreover, apart from the polydomous system mentioned above, within a 1.5 km radius there were two other F. polyctena polydomous systems: the larger one (13 nests; hereafter the system B; Fig. 1b), located 1384 m in a straight line from the closest nest of the bunker system, and the smaller one (5 nests; hereafter the system C; Fig. 1c), located 995 m from the nearest bunker system nest. ...
... Here we present new observations and research conducted in the years 2017-2019, i.e. after the experimental installation of a wooden structure ('ladder' in the bunker in autumn 2016, which allowed the ants trapped in the bunker to return to their maternal nest (see Rutkowski et al. 2019), while giving them the opportunity to move freely between the 'upper' and 'lower' nests. Our particular goal was to determine the role of the bunker nest in the life of the over-bunker colony at that time. ...
... Even though the food-searching behavior of F. rufa is primarily related to the abundance of the psyllids, and approximately 85% of the dry mass of the F. rufa diet consists of honeydew from them [75][76][77], a higher relative abundance of psyllids did not induce an increased population of F. rufa ants in the canopies of treated stands. However, the increased psyllid population might have a stimulating effect on the increased prevalence of the epigeal F. rufa ants, which are characterized by their adaptation and ability to navigate through different ecological strata, including the forest canopy, understory, and forest floor, as much as needed [78][79][80][81][82]. Given that F. rufa has long been valued for its role in controlling insect pest outbreaks in temperate and boreal forests [83], it is possible that an increase in their arboreal population during the outbreaks of L. monacha could naturally contribute to pest management. ...
Outbreaks of Lymantria monacha are of great concern, as their occurrence is predicted to become more intense and frequent due to a warming climate. A frequent treatment to control mass outbreaks of the pest is with the bioinsecticide Foray 76B. However, knowledge of how this treatment affects non-target insect species is limited. We surveyed the assemblages of non-target epigeal and arboreal insects in Pinus sylvestris forests in the year following bioinsecticide application. A collection of insects using sweep nets and pitfall traps was carried out in L. monacha-infested pine stands, (i) treated with Foray 76B and (ii) untreated, in three regions of Lithuania from May to October 2021. The results revealed that, in Neringa forests, species richness of the epigeal insects was lower in treated than in untreated sampling plots, with 36 and 41 different insect species, respectively. The relative abundance of epigeal Coleoptera in treated plots was 3.6%, while in untreated it was 53.2%. There was a significant decrease in the relative abundance of Carabus arcencis in Kapčiamiestis (by 7.4%) and Marcinkonys (by 16.7%). Treated plots were distinguished by lower relative abundance of arboreal Hymenoptera at all three study locations.
... Moreover, foreign ant corpses can be used even as a typical food source by several ant species (Marikovsky, 1963;Howard and Tschinkel, 1976;Mori et al., 2000). Such resources, although not sufficient to reach normal colony size and reproduction (see Rutkowski et al., 2019), butby flexibly adapting the life strategy to the current environmental conditionsmay allow the colonies to survive while maintaining relatively large nest densities. In this light, our results support the context-dependent effect of the territorial ants on other ant species (see Adams, 2016;Johansson and Gibb, 2016;Stuble et al., 2017;Trigos-Peral et al., 2020). ...
The hierarchical organization of multi-species ant communities can be determined by the colony size and worker density-dependent differences in behaviour, recruitment efficiency, and aggressiveness between colonies of different species. In this study, we compared the competitive effects of two territorial wood ant species, Formica rufa and F. polyctena, on the ant species subordinated to them (encounterers and submissives) that nest close-by their mounds. The nests of subordinates were mapped in 10 m2 plots around the mounds of each of the two wood ant species, situated at a distance of 10, 20 and 30 m in four directions. The most abundant subordinate species were two Myrmica species: M. rubra and M. ruginodis. Interestingly, the nests of subordinates had an even diversity, density and distribution along with the distance from the wood ant mounds. The wood ant presence had a species-specific negative effect on some of the subordinate species, which can be in relation with the smaller mound sizes in F. rufa compared to F. polyctena. Based on our results it seems that subordinate species, due to their adaptability, might tolerate the circumstances close-by the wood ant mounds by changes in their strategies, foraging behaviour, and switching to the use of alternative food sources, like corpses of wood ants present in high abundance. Although these might not allow reaching normal colony size and reproduction, they may allow the colonies to survive while maintaining relatively large nest densities.
... In our study, we aimed to examine experimentally the modulating effect of pathogen contamination and starvation on cannibalistic necrophagy behaviour among nestmates. We chose Formica polyctena, as this species is already known to be cannibalistic 15,16,36,37 and the need for protein can be continuously present in a huge colony containing several (even thousands) queens 38,39 . Although cannibalistic necrophagy can ensure the survival of workers in conditions of food shortage 37 , the characteristics and drivers of corpse necrophagy were not investigated experimentally. ...
... We assumed this based on the weight loss of the paint-marked corpses and the presence of gnawed-out holes in their gasters. However, this finding is consistent with earlier observations on a F. polyctena 'bunker colony' living in extreme starvation 37 , as well as with those of Mabelis 15 , who also found that the conspecific corpses (victims of the wood ant wars) retrieved into the nest were twice as heavy as those dumped on the waste piles. Moreover, he also proved that the contents of the corpse gasters were consumed and fed to the larvae through regurgitation 6,15 . ...
... Moreover, he also proved that the contents of the corpse gasters were consumed and fed to the larvae through regurgitation 6,15 . Field observations also confirm the presence of gnawed-out holes in the gasters of consumed corpses 37 and suggest that the consumption rate of conspecific corpses is consistent with the current needs of the colony 15,16,37 -higher in the spring and autumn, when other food sources are scarce. ...
Abstract Cannibalistic necrophagy is rarely observed in social hymenopterans, although a lack of food could easily favour such behaviour. One of the main supposed reasons for the rarity of necrophagy is that eating of nestmate corpses carries the risk of rapid spread of pathogens or parasites. Here we present an experimental laboratory study on behaviour indicating consumption of nestmate corpses in the ant Formica polyctena. We examined whether starvation and the fungal infection level of the corpses affects the occurrence of cannibalistic necrophagy. Our results showed that the ants distinguished between corpses of different types and with different levels of infection risk, adjusting their behaviour accordingly. The frequency of behaviours indicating cannibalistic necrophagy increased during starvation, although these behaviours seem to be fairly common in F. polyctena even in the presence of other food sources. The occurrence and significance of cannibalistic necrophagy deserve further research because, in addition to providing additional food, it may be part of the hygienic behaviour repertoire. The ability to detect infections and handle pathogens are important behavioural adaptations for social insects, crucial for the fitness of both individual workers and the entire colony.
Simple Summary
The red wood ants are considered to be one of the main ecosystem engineers and keystone species of the habitats in which they exist. Most of the species from this species group inhabit coniferous forests, which, due to the consequences of anthropogenic climate change, are continuously cut down. Therefore, the main habitat of these important species is rapidly disappearing. We investigated the consequences of the absence of conifers (clear-cut area and deciduous forest) on one of the members of this species group, namely Formica polyctena. We have found that compared with the mixed-coniferous forest stand, the absence of coniferous species resulted in significant changes in the colony and nest structure of F. polyctena. In addition, the colony size was also smaller in these sites. These changes suggest that although F. polyctena is able to survive in suboptimal habitats, still their population decline is expected and urges conservation managers to apply necessary action plans for their protection.
Abstract
The consequences of anthropogenic climate change are one of the major concerns of conservation biology. A cascade of negative effects is expected to affect various ecosystems, one of which is Central European coniferous forests and their unique biota. These coniferous forests are the primary habitat of many forest specialist species such as red wood ants. Climate change-induced rising of temperature allows trees to skip winter hibernation, making them more vulnerable to storms that cause wind felling, and in turn, promotes bark beetle infestations that results in unscheduled clear-cuttings. Red wood ants can also be exposed to such habitat changes. We investigated the effects of bark beetle-induced clear-cutting and the absence of coniferous trees on colonies of Formica polyctena, including a mixed-coniferous forest as a reference. Our aim was to investigate how these habitat features affect the nest characteristics and nesting habits of F. polyctena. Our results indicate that, in the absence of conifers, F. polyctena tend to use different alternatives for nest material, colony structure, and food sources. However, the vitality of F. polyctena colonies significantly decreased (smaller nest mound volumes). Our study highlights the ecological flexibility of this forest specialist and its potential to survive under extreme conditions.
