Nests Of Social Insects Research Articles

The Worker Flow at the Hive Entrance Predicts When Nest Cleaning is Intensified in Stingless Bees

Waste produced by living organisms is commonly disposed of as a prophylactic measure to avoid the spread of diseases and parasite infestation. For social insects, a proportion of workers is allocated to dispose the waste material outside the colony’s nest. However, most nests of social insects have a single entrance, where a high flow of individuals may create congestion, potentially compromising normal foraging activities and colony growth/health. Here, we investigated how two species of stingless bees (Tetragonisca fiebrigi and Plebeia droryana) deal with waste disposal and regular foraging activities, and the impacts of these activities on traffic flow at nest entrances. First, we compared the average traffic of bees assigned to waste removal activities. Following this, we investigated probabilities for waste removal as bee traffic increases. Then, we estimated a cutoff value to predict the likelihood that waste removal activities will be intensified over foraging trips. We found that, on average, the number of bees performing waste removal activities was lower than those undertaking foraging trips for both species. In addition, we observed that as overall bee traffic increases, the number of workers engaged in waste removal reduces or even ceases. Our models indicate that bee traffic of approximately 15 individuals/time is a cutoff score, below which, colonies invest in waste removal and above which, foraging trips are increased. It suggests that both species use the entrances of their colonies in an optimized way by adjusting which tasks should be intensified as the traffic of individuals increases.

The emergence of collective knowledge and cumulative culture in animals, humans and machines.

The emergence of collective knowledge and cumulative culture in animals, humans and machines.

Mitogenomic data elucidate the phylogeny and evolution of life strategies in Dermestidae (Coleoptera)

AbstractDermestidae (Bostrichoidea) exploit diverse food sources including fungal mycelia, but notably they as saprophagous, feeding on decomposing and dried flesh and keratin of animals and plants. Some of them live in spider webs, vertebrate and social insect nests, while others cause damage in human dwellings. Here, we use mitogenomics to reconstruct their phylogeny and evolution of life history strategies. We recovered serial splits of Orphilinae, Thorictinae + Dermestinae, Attageninae, Trinodinae and Megatominae, and we dated the origins of all subfamilies between the Middle Jurassic and Upper Cretaceous. Extant genera started their diversification in the Middle Cretaceous, except for Dermestes that originated in the Eocene. Mycetophagy, the likely feeding style of the common ancestor with Endecatomidae, was retained only by Orphilinae. Since the Late Jurassic, most dermestids have been saprophagous with the preference for desiccated tissue. We infer a scenario of feeding preferences from mycetophagy moving to saprophagy, always depending on food with low water content, followed by the shift from cryptic life in crevices and wood, to commensalism with social Hymenoptera, and ultimately feeding on angiosperm pollen as adults. The dependence on spider larders evolved already in the Early Cretaceous, but lineages with this specialized strategy remained species‐poor. We date the origin of exploitation of vertebrate carcasses to the Eocene when modern mammalian fauna became dominant. The diversification of Megatominae (62% of known dermestids) and Attagenus Latreille (17%) coincides with the radiation of angiosperms.

An outlook on the evolutionary history of Carabid beetles (Coleoptera, adephaga)

The paper is an attempt to take stock of recent research on the evolutionary history of the megadiverse beetle family Carabidae. First, the evolution of the carabid body is presented in its fundamental characteristics, in relation to the thoracic structure and locomotory and morphofunctional constraints, taking into account also what we know about fossil findings. Changes are described in the ten fundamental life forms that are recognizable in the larval body, from primitive surface runner to the arboreal tree/bark dweller and the parasitoid life style. The influence of biotic factors, first of all the food preferences, are examined for the best-known subfamilies/tribes, and a synthetic frame is presented of relationships between prey and age of the lineages in the three types of feeding modes: fluid, fragment and mixed feeders. On the whole, Harpalinae lineages seem more adapted to preys that appeared in recent times after the angiosperm flourishing, though exceptions have found. The availability of the biomasses of social insect nests, ants and termites, was of fundamental importance for several carabid stems. The influence of predators surely contributed to the refinement of chemical defenses, and some avoidance behaviours as gregariousness and müllerian mimcry. Ordering the relevant fossil findings by age and taxon the absence of modern carabid fossils in the first part of mesozoic appears clearly, only in the Cretaceous some extinct forms belonging to the actual suprageneric taxa have been found. Thus, Cenozoic era should be retained the age of modern forms, even if extinct taxa are recorded at least until the late miocene. Concerning the old question of ancestral habitat of adephaga, if terrestrial or aquatic, the intermediate hypothesis of Erwin seems still valid, that is a waterside life on shores rich of animal biomass, from which both directions into inland waters and subaerial ecosystems may have started. Finally, the taxonomic position of Rhysodidae has examined in the light of recent studies. morphology of adult and larval beetles is poorly in accordance with a place in Scaritinae (Clivinini), the preimaginal features remember that of archostemata also in the probable presence of a fused labrum, molecular evidence is mainly indicating a position within Carabidae but still not conclusive. a place as separate family within basal Geadephaga should be maintained.

New social insect nests from the Upper Jurassic Morrison Formation of Utah

This paper reports a new assemblage of social insect ichnofossils from the Brushy Basin Member of the Upper Jurassic Morrison Formation near Green River, Utah. At least seven distinct nests are visible in the locality horizon, identifiable at the outcrop scale by loci of anastomosing, and orthogonally connected hor-izontal burrows and vertical shafts. A boulder-sized block from the in situ horizon has eroded and rolled downhill, revealing the ventral aspect of the nest, showing a view of the overall nest architecture. Burrow and shaft clusters are organized into mega-galleries which have branching arms and ovate, bulbous cham-bers. The organization of distinct trace morphologies is consistent with ethological complexity of the social insects. A small sample was collected and analyzed by serial sectioning and petrographic thin sectioning to observe small-scale morphological features. Centimeter-scale analysis shows chamber, gallery, and burrow walls have complex topography. Pebble-sized, hollow, ellipsoid features are distributed throughout the up-permost facies of the nest and have undergone complete silicification of their outer surfaces. The ellipsoids share similarity with pellet structures made of mud or carton produced by modern termites. This trace fossil assemblage suggests it is possible that termites had acquired subterranean nesting behavior, and mud or carton utilization in nest construction in seasonally arid habitats by the Late Jurassic.

Modern termites inherited the potential of collective construction from their common ancestor.

Animal collective behaviors give rise to various spatial patterns, such as the nests of social insects. These structures are built by individuals following a simple set of rules, slightly varying within and among species, to produce a large diversity of shapes. However, little is known about the origin and evolution of the behavioral mechanisms regulating nest structures. In this study, we discuss the perspective of inferring the evolution of collective behaviors behind pattern formations using a phylogenetic framework. We review the collective behaviors that can be described by a single set of behavioral rules, and for which variations of the environmental and behavioral parameter values produce diverse patterns. We propose that this mechanism could be at the origin of the pattern diversity observed among related species, and that, when they are placed in the proper conditions, species have the behavioral potential to form patterns observed in related species. The comparative analysis of shelter tube construction by lower termites is consistent with this hypothesis. Although the use of shelter tubes in natural conditions is variable among species, most modern species have the potential to build them, suggesting that the behavioral rules for shelter tube construction evolved once in the common ancestor of modern termites. Our study emphasizes that comparative studies of behavioral rules have the potential to shed light on the evolution of collective behaviors.

The effect of nest topology on spatial organization and recruitment in the red ant Myrmica rubra.

Nests of social insects are an important area for the exchange of food and information among workers. We investigated how the topology of nest chambers (as opposed to nest size or environmental factors) affects the spatial distribution of nestmates and the foraging behavior of Myrmica rubra ant colonies. Colonies were housed in artificial nests, each with same-sized chambers differing in the spatial arrangement of galleries. A highly connected central chamber favored higher occupancy rates and a more homogeneous distribution of ants across chambers. In contrast, a chain of successive chambers led to a more heterogeneous distribution of ants, with the occupancy of a chamber chiefly mediated by its distance to the entrance. Irrespective of nest topology, the entrance chamber housed the largest proportion of ants, often including the queen, which exhibited a preference for staying in densely populated chambers. Finally, we investigated how nest topology influenced nestmate recruitment. Surprisingly, a highly connected chamber in the center of the nest did not promote greater recruitment nor activation of ants. At the onset of foraging, the largest number of moving ants was reached in the topology where the most connected chamber was the nest entrance. Later in the process, we found that a chain of successive chambers was the best topology for promoting ant's mobilization. Our work demonstrates that nest topology can shape the spatial organization and the collective response of ant colonies, thereby taking part in their adaptative strategies to exploit environmental resources.

Effects of high CO2 on mating success, mating duration, and sperm transfer in the West Indian sweet potato weevil, Euscepes postfasciatus

AbstractMost terrestrial animals live in natural atmospheric conditions, but some are also adapted to low oxygen (hypoxic) or high‐carbon dioxide (hypercapnic) conditions, such as in social insect nests, soil, caves, wood, and decaying material. Although it is possible that individuals adapt their behaviour to the environmental condition of their habitats, mating behaviour under ecologically possible ranges of CO2 has not been well studied. We compared walking activity, duration of mating behaviour, and sperm transfer ability in the West Indian sweet potato weevil, Euscepes postfasciatus Fairmaire (Coleoptera: Curculionidae), in high CO2 (10 000 p.p.m.) vs. normal atmospheric conditions (laboratory air, ca. 800 p.p.m.). We found that high CO2 enhanced walking activity and mounting frequency. Under such circumstances, we predicted that enhanced activities under a high‐CO2 environment would increase the risk of sperm competition, which induces an extended copulation period and an increase in sperm transfer. However, weevils shortened the mating period and did not alter their sperm transfer ability under high CO2. These findings are, as far as we are aware, the first report of the effect of ecologically relevant high CO2 on insect mating behaviour under mass‐rearing conditions. The effect of ambient conditions on mating behaviour and sperm transfer is discussed in relation to the intensity of female refusal behaviour directed against males.

Strategies of the beetle Oochrotus unicolor (Tenebrionidae) thriving in the waste dumps of seed‐harvesting Messor ants (Formicidae)

1. A diverse group of arthropods have adapted to the niches found inside the nests of social insects. Studies mostly focused on very specialised parasites residing in the brood chambers. However, the biology and strategies of symbionts occupying other niches, such as waste dumps, are underexplored.2. Using a series of complementary experiments, this study demonstrated that the Mediterranean beetle Oochrotus unicolor has adapted to the waste dump niche found in the nests of Messor harvester ants.3. Laboratory experiments confirmed field observations that the beetle preferentially resided in the refuse pits. Next, it was shown that the beetles readily consumed seeds and flour, whereas other food sources were poorly accepted and ant brood was never even eaten. The beetles did not elicit a strong aggression response in Messor ants, and they could tolerate very high densities of workers without clear costs. The beetles modestly mimicked the nest recognition cues of their Messor host. This imperfect mimicry could promote the adoption of the beetle in the ant colony, in concert with mechanical defence generated by its tank‐like body. Isolation of the beetle from its host did not significantly affect the beetle's chemical cuticular profile nor did it provoke elevated ant aggression, indicating that the beetle does not acquire the chemicals passively from its host.4. This paper discusses the fact that waste dumps in social insect nests are hotspots for arthropod symbionts. It shows that symbionts in this niche may employ behavioural, trophic and chemical strategies that are different from those found in other niches of social insect nests.

Characterization of Nest Architecture of an Indian Ant Diacamma indicum (Hymenoptera: Formicidae).

Nests are physical entities that give shelter to the inhabitants from natural adversities, predators and act as a platform for organization of tasks particularly in social insects. Social insect nests can range from simple structures consisting of a single entrance leading to a chamber to complex nests containing hundreds of connected shafts and chambers. This study characterizes nest architecture of a tropical ponerine ant Diacamma indicum (Hymenoptera: Formicidae), which has small colony sizes and is known to be a scavenger. We also examined if these nests vary seasonally. By examining the microhabitat in the vicinity of the nest, the nest entrance characteristics and casting 77 natural nests of D. indicum across a year, we found that this species occupies relatively simple nests consisting of a single entrance that leads to a single chamber. This chamber progressed to a secondary tunnel that terminated at a greater depth than the chamber. The nest volume was not correlated to the number of adult members in the colony. Even though the microhabitat around the nest and the entrance itself change across seasons, principle component analysis showed that the nest architecture remained similar. Only one parameter, the entrance tunnel showed significant difference and was longer during postmonsoon. Nests of colonies living in the immediate vicinity of human habitation were comparable to other nests. We conclude that D. indicum found in the Gangetic plains live in relatively simple nests that do not vary across seasons.

Contrasting Global Patterns of Spatially Periodic Fairy Circles and Regular Insect Nests in Drylands

AbstractNumerical analysis of spatial pattern is widely used in ecology to describe the characteristics of floral and faunal distributions. These methods allow attribution of pattern to causal mechanisms by uncovering the specific signatures of patterns and causal agents. For example, grassland‐gap patterns called fairy circles (FCs) in Namibia and Australia are characterized by highly regular and homogenous distributions across landscapes that show spatially periodic ordering. These FCs have been suggested to be caused by both social insects and competitive plant interactions. We compared eight Namibian and Australian FC patterns and also modeled FCs to 16 patterns of social insect nests in Africa, Australia, and America that include the most regular termite mound patterns known. For pattern‐process inference, we used spatial statistics based on both nearest‐neighbor analysis and neighborhood‐density functions. None of the analyzed insect‐nest distributions attain the spatially periodic ordering that is typical of FCs. The inherently more variable patterns of termite and ant nests are commonly attributable to well documented aspects of the faunal life‐history. Our quantitative evidence from drylands shows that the more variable insect‐nest distributions in water‐limited environments cannot explain the characteristic spatial signature of FCs. The analysis demonstrates the interpretation of scale‐dependent neighborhood‐density functions and that it is the identification of unique spatial signatures in regular patterns that need to be linked to process. While our results cannot verify a specific hypothesis, they support the hypothesis that FCs in these drylands are more likely an emergent vegetation pattern caused by strong plant competition for water.

The modern and fossil record of farming behavior

AbstractFarming is a behavior in which an organism promotes the growth and reproduction of other organisms in or on a substrate as a food source. A number of trace fossils have been suggested to record the occurrence of farming behavior. These include the deep-sea graphoglyptid trace fossils, proposed to be microbial farms on the seafloor, and terrestrial fossil social insect nests thought to represent fungicultural behavior. The presumed farming behavior of graphoglyptids is the basis of the ethological category agrichnia. Four criteria have been proposed as diagnostic of farming behavior, and these can be applied to both observed modern and proposed trace fossil examples of farming behavior. The evidence for farming behavior in the social insect trace record is strong but is much weaker in the case of graphoglyptids. The use of agrichnia as an ethological category should be limited to well-supported cases.

The brood parasite's guide to inclusive fitness theory.

Hamilton's theory of inclusive fitness provides a framework for understanding the evolution of social behaviour between kin, including parental and alloparental care. Brood parasitism is a reproductive tactic in which parasites exploit the care of other individuals of the same species (conspecific parasitism) or different species (interspecific parasitism) to rear their brood. Here, drawing from examples in birds and social insects, we identify two insights into brood parasitism that stem from inclusive fitness theory. First, the kin structure within nests, or between neighbouring nests, can create a niche space favouring the evolution of conspecific parasitism. For example, low average relatedness within social insect nests can increase selection for reproductive cheats. Likewise, high average relatedness between adjacent nests of some birds can increase a female's tolerance of parasitism by her neighbour. Second, intrabrood conflict will be high in parasitized broods, from the perspective of both parasite and host young, relative to unparasitized broods. We also discuss offspring recognition by hosts as an example of discrimination in a kin-selected social behaviour. We conclude that the inclusive fitness framework is instructive for understanding aspects of brood parasite and host evolution. In turn, brood parasites present some unique opportunities to test the predictions of inclusive fitness theory. This article is part of the theme issue 'The coevolutionary biology of brood parasitism: from mechanism to pattern'.

Reproductive aspects of the Purple-throated Euphonia, Euphonia chlorotica (Aves: Fringillidae) in southeastern Brazil, and first record of the species nesting inside a vespiary

Despite the fact thatE. chlorotica(Linnaeus, 1766) is common and widely distributed in South America, the reproductive aspects of the species are poorly documented. Here we present data on 18 active nests found from August to February, between 2007 and 2012. Nests were globular with a lateral entrance, and measured 97.9 ± 14.4 mm in outside height, 110.6 ± 11.6 mm in outside diameter, and were 4.88 ± 2.09 m above ground. They were often supported from bellow and were composed mainly of tiny dry leafs and leaflets, fine petioles, and plumed seeds, all compacted with spider web silk. Eggs were laid on consecutive days or with one day interval, and clutch size varied from 1–3 eggs (2.1 ± 0.6, n = 9 nests). Only females incubated the eggs, but both sexes were involved in nest construction and nestling attendance at similar rates. Incubation and nestling periods were 14 and 21 days, respectively, and overall nest survival probability was 5%. A vespiary used for nesting was not occupied by wasps and nest material was deposited only to form the incubatory chamber. Although nesting near wasps or bees is a widespread strategy among birds in general, nesting inside the nests of social insects is a poorly documented behavior.

When social behaviour is moulded in clay: on growth and form of social insect nests

The nests built by social insects are among the most complex structures produced by animal groups. They reveal the social behaviour of a colony and as such they potentially allow comparative studies. However, for a long time, research on nest architecture was hindered by the lack of technical tools allowing the visualisation of their complex 3D structures and the quantification of their properties. Several techniques, developed over the years, now make it possible to study the organisation of these nests and how they are built. Here, we review present knowledge of the mechanisms of nest construction, and how nest structure affects the behaviour of individual insects and the organisation of activities within a colony.

Stigmergic construction and topochemical information shape ant nest architecture

The nests of social insects are not only impressive because of their sheer complexity but also because they are built from individuals whose work is not centrally coordinated. A key question is how groups of insects coordinate their building actions. Here, we use a combination of experimental and modeling approaches to investigate nest construction in the ant Lasius niger. We quantify the construction dynamics and the 3D structures built by ants. Then, we characterize individual behaviors and the interactions of ants with the structures they build. We show that two main interactions are involved in the coordination of building actions: (i) a stigmergic-based interaction that controls the amplification of depositions at some locations and is attributable to a pheromone added by ants to the building material; and (ii) a template-based interaction in which ants use their body size as a cue to control the height at which they start to build a roof from existing pillars. We then develop a 3D stochastic model based on these individual behaviors to analyze the effect of pheromone presence and strength on construction dynamics. We show that the model can quantitatively reproduce key features of construction dynamics, including a large-scale pattern of regularly spaced pillars, the formation and merging of caps over the pillars, and the remodeling of built structures. Finally, our model suggests that the lifetime of the pheromone is a highly influential parameter that controls the growth and form of nest architecture.

A Brazilian Social Bee Must Cultivate Fungus to Survive

The nests of social insects provide suitable microenvironments for many microorganisms as they offer stable environmental conditions and a rich source of food [1-4]. Microorganisms in turn may provide several benefits to their hosts, such as nutrients and protection against pathogens [1, 4-6]. Several examples of symbiosis between social insects and microorganisms have been found in ants and termites. These symbioses have driven the evolution of complex behaviors and nest structures associated with the culturing of the symbiotic microorganisms [5, 7, 8]. However, while much is known about these relationships in many species of ants and termites, symbiotic relationships between microorganisms and social bees have been poorly explored [3,4, 9, 10]. Here, we report the first case of an obligatory relationship between the Brazilian stingless bee Scaptotrigona depilis and a fungus of the genus Monascus (Ascomycotina). Fungal mycelia growing on the provisioned food inside the brood cell are eaten by the larva. Larvae reared invitro on sterilized larval food supplemented with fungal mycelia had a much higher survival rate (76%) compared to larvae reared under identical conditions but without fungal mycelia (8% survival). The fungus was found to originate from the material from which the brood cells are made. Since the bees recycle and transport this material between nests, fungus would be transferred to newly built cells and also to newly founded nests. This is the first report of a fungus cultivation mutualism in a social bee.

Insights on the association of American Cetoniinae beetles with ants

AbstractCetoniinae beetles (Coleoptera: Scarabaeoidea: Scarabaeidae) can occupy the nests of social insects. In many cases the beetles located within the colonies of social insects encounter a place of shelter and food resources for both adults and immatures. Despite the numerous cohabitation records, the relationship of Cetoniinae beetles with their ant hosts remains mostly unexplored. In this review we provide hypotheses explaining this ant–beetle association. A conceptual model is presented on the processes underpinning the occupation of the nest and the consequences that unfold after occupation, including: (i) death of the ant colony; (ii) death of beetles; and (iii) coexistence. We also provide an exhaustive list of American Cetoniinae beetle species found associated with ants and discuss the symbiotic relationships occurring between the beetles and their host ants.

Recognition of nestmate eggs in the ant Formica fusca is based on queen derived cues

Abstract Inclusive fitness benefits depend on recognizing the right individuals to interact with. Social insect nests protect themselves from non-kin intruders through nestmate recognition based on chemical cues. The recognition cues on adult individuals are from a mixture of genetic and environmental sources, but the ontogeny and use of recognition cues on eggs has not been previously assessed. We studied recognition by workers of eggs that were either nestmates or non-nestmates. and the ontogeny of recognition cues on eggs in the ant Formica fusca, a species with precise egg recognition abilities. Workers were able to discriminate among freshly laid eggs with no nest derived cues on them, and the egg surface chemicals varied among nests in these eggs, suggesting that queen derived cues are used in nestmate recognition. The results are discussed in the light of their implications on deceptive social parasite strategies and within colony conflicts.

Mite species inhabiting commercial bumblebee (Bombus terrestris) nests in Polish greenhouses

Nests of social insects are usually inhabited by various mite species that feed on pollen, other micro-arthropods or are parasitic. Well-known negative effects of worldwide economic importance are caused by mites parasitizing honeybee colonies. Lately, attention has focused on the endoparasitic mite Locustacarus buchneri that has been found in commercial bumblebees. However, little is known of other mites associated with commercial bumblebee nests. Transportation of commercial bumblebee colonies with unwanted residents may introduce foreign mite species to new localities. In this study, we assessed the prevalence and species composition of mites associated with commercial bumblebee nests and determined if the mites are foreign species for Poland and for Europe. The study was conducted on 37 commercial bumblebee nests from two companies (Dutch and Israeli), originating from two greenhouses in southern Poland, and on 20 commercial bumblebee colonies obtained directly from suppliers. The species composition and abundance of mites inhabiting commercial bumblebee nests were determined. Seven mite species from three families were found in nests after greenhouse exploitation. The predominant mite species was Tyrophagus putrescentiae (Acaridae) that was a 100-fold more numerous than representatives of the family Laelapidae (Hypoaspis marginepilosa, H. hyatti, H. bombicolens). Representatives of Parasitidae (Parasitellus fucorum, P. crinitus, P. ignotus) were least numerous. All identified mite species are common throughout Europe, foreign species were not found. Mites were not detected in nests obtained directly from suppliers. We conclude that probably bumblebee nests are invaded by local mite species during greenhouse exploitation.