Search

The mitochondrial DNA (mtDNA) of bumblebees (Bombus) has been widely used for phylogenetic studies, but its evolution is still underexplored. Here we report a comprehensive analysis of 60 bumblebee mitogenomes, including 40 newly assembled ones, to investigate bumblebee mtDNA structure, composition, and informativeness under a phylogenetic framework. Our mtDNA dataset supports the monophyly of Bombus and its subgenera, although we found a high degree of tree discordance in deeper nodes when using different inference methods or matrix composition. Concerning mitogenome structure, our results show that tRNA genes were often rearranged, with unique rearrangements indicating shared ancestry across bumblebee subgenera, illustrating their potential for subgeneric classification. Our results also challenge the notion that faster evolving mtDNA exhibits higher gene rearrangement rates. Finally, we explicitly assessed shifts in selection constraints of mtDNA genes in obligate social parasites of subgenus Psithyrus and found that their mtDNA evolved under relaxed selective constraints. Our findings show the utility of mtDNA in providing insights into bumblebee phylogenetics, evolution, and genome trait diversification. We also highlight the potential for comparative mitogenomics to uncover previously unknown aspects of bumblebee evolution, offering exciting opportunities for future research in this field. [ABSTRACT FROM AUTHOR]

A co‐evolutionary arms race ensues when parasites exhibit exploitative behaviour, which prompts adaptations in their hosts, in turn triggering counter‐adaptations by the parasites. To unravel the genomic basis of this coevolution from the host's perspective, we collected ants of the host species Temnothorax longispinosus, parasitized by the social parasite Temnothorax americanus, from 10 populations in the northeastern United States exhibiting varying levels of parasite prevalence and living under different climatic conditions. We conducted a genome‐wide association study (GWAS) to identify single nucleotide polymorphisms (SNPs) associated with both prevalence and climate. Our investigation highlighted a multitude of candidate SNPs associated with parasite prevalence, particularly in genes responsible for sensory perception of smell including odorant receptor genes. We further focused on population‐specific compositions of cuticular hydrocarbons, a complex trait important for signalling, communication and protection against desiccation. The relative abundances of n‐alkanes were correlated with climate, while there was only a trend between parasite prevalence and the relative abundances of known recognition cues. Furthermore, we identified candidate genes likely involved in the synthesis and recognition of specific hydrocarbons. In addition, we analysed the population‐level gene expression in the antennae, the primary organ for odorant reception, and established a strong correlation with parasite prevalence. Our comprehensive study highlights the intricate genomic patterns forged by the interplay of diverse selection factors and how these are manifested in the expression of various phenotypes. [ABSTRACT FROM AUTHOR]

Due to particular vulnerabilities and environmental constraints, Alpine faunas are exposed to significant threats from climate change. However, baseline diversity and distribution data to monitor the trends of key arthropod groups are often scarce. Ants are highly diversified and key ecological actors across terrestrial ecosystems, including mountain ranges. We investigated ant diversity and distribution in the Southern European Alps to provide detailed data over wide elevational gradients and make a first assessment of potential vulnerabilities in the face of global warming. We detected 40 species from 700 to over 2600 m asl, with progressively less diversity corresponding to higher elevations and lower temperatures. Maximum temperature was weakly related to ant diversity as compared to mean and minimum temperature. In shaping ant diversity, the highest elevation species had wide elevation ranges, consistent with Rapoport's rule. We documented a fauna characterized by cold-adapted genera, species with wide geographic distributions and presumably high dispersal capabilities, no dietary specializations, and a high frequency of social parasitism. Concerning Bergmann's rule, average ant species size was not larger in the coldest environments. Red wood ants, characterized by much more populous colonies as compared to the other ant species, had the highest number of ant individuals to be found at intermediate elevations and in woodland habitats. On the other hand, grasslands and shrublands proved to be the most species-rich habitats. Our data lay the groundwork for further investigation on elevational shifts and provide context for the discussion of key aspects of the management and conservation of European alpine ants. Implications for insect conservation: The cold climate of the European Alps has so far protected its ant fauna from the incursion of alien competitors as compared to what is observed in the Mediterranean region. The scarcity of species with restricted distribution ranges or high-elevation specialists, as well as diet specialists, may grant ants of the European Alps more resilience to climate change as compared to other Alpine arthropod groups. On the other hand, many species are highly interconnected by social parasitism relationships that may be vulnerable to ecological cascade effects. While forest habitats host red wood ants, which are often protected for their important ecological role, the importance of grassland must not be overlooked as they support the highest ant species richness. [ABSTRACT FROM AUTHOR]

Social insects face many threats from predators and parasites, and so have evolved a diversity of behavioral defense strategies to evade and combat enemies. Previous research has focused extensively on the evolution of front-line defense strategies that allow social groups to successfully avoid detection by enemies, defeat them during an attack, or mitigate fitness losses upon successful invasion. However, in the case of social insects, we must also consider how colonies have evolved to alter their behavior when they survive attacks. During an attack, colony fitness can be negatively affected while the colony itself survives. There may be selective pressure for surviving individuals to respond strategically to decrease the risks of future attacks by the same enemy. In this study, we tested whether colonies of Temnothorax longispinosus acorn ants emigrate when they experience a raid by the obligate social parasite T. americanus. We found that T. longispinosus colonies that experienced a raid moved to a different nest of equal quality significantly more than genetically matched colonies that had not experienced a raid event. We also found that raided colonies moved significantly more than we would expect by random chance. This result suggests that emigration may be an induced defense against re-raiding in this host-parasite system. [ABSTRACT FROM AUTHOR]

We reported the social parasitism behavior between Vespula structor and Vl. flaviceps for the first time. These two Vespula species are both popular edible wasps in southwest China. Such a nest with these two mixed Vespula species in their natural state was found in the field, and observations both in situ and in doors were performed. Workers of the two Vespula species have distinct different looking but possess similar antennal sensilla. Mitochondrial DNA analysis proved these two Vespula were indeed two different species, with genetic difference of 14%. The queen observed in the nest belongs to Vl. structor which was supported both from morphology and DNA. The larvae collected during nest dissecting could not be distinguished which species they belong to, but DNA analysis proved that they were all Vl. structor individuals. Combined the behavior observation with the DNA data, we concluded that it was the queen of Vl. structor encroached on the nest of Vl. flaviceps, killed the queen of Vl. flaviceps, enslaved the workers in the nest, laid its own eggs, and gradually established the population of Vl. structor. Phylogenetic analysis based on complete mitochondrial genomes showed that they are close, and the Vl. structors was the more ancient species in evolution. In this case of wasp parasitism, the relatively ancient species Vl. structors parasitized the younger species Vl. flaviceps, suggesting that the social parasites (Vl. structor) were not evolved from their host (Vl. flaviceps), which rejected the Emery's rule in its strict sense. [ABSTRACT FROM AUTHOR]

Four new inquiline social parasites are described in the dolichoderine ant genus Tapinoma from the Nearctic region, and keys are provided for queens and males of the Nearctic Tapinoma species. The new social parasite species represent the first inquiline species in the genus Tapinoma and the first confirmed inquilines known from the ant subfamily Dolichoderinae. The four new species appear to be workerless inquilines that exploit a single host, Tapinoma sessile (Say), and they represent at least two distinct life history syndromes. Tapinoma incognitum Cover & Rabeling, sp. nov. is highly derived morphologically and is a host-queen-tolerant inquiline. In contrast, T. inflatiscapus Cover & Rabeling, sp. nov. shows a lesser degree of morphological modification and appears to be a host-queen-intolerant social parasite. The life history of T. pulchellum Cover & Rabeling, sp. nov. is presently unknown, but its close similarity to T. incognitum suggests that it is also a host-queen-tolerant inquiline. The life history of T. shattucki Cover & Rabeling, sp. nov. is still uncertain. Our findings provide novel insights into the complex biology of ant inquiline life history syndromes. [ABSTRACT FROM AUTHOR]

Cuckoo bumblebees (Bombus subgenus Psithyrus) are social parasites that have lost the ability to establish their own nests, and instead usurp the nest of a bumblebee host to reproduce. Accordingly, they are entirely dependent upon a host species to complete their life cycle, and are therefore vulnerable to co–extinction. Despite this, the current consensus is that there remains much we do not know about the fundamental ecology of many cuckoo bumblebee species, which is crucial for conservation.To investigate data gaps for cuckoo bumblebees, we conducted a systematic review to quantify the peer‐reviewed literature that has been produced, including which species have been most studied and which disciplines have been explored.Over half of all Psithyrus species were represented in fewer than 10 publications each, including 2 species listed as Critically Endangered by the IUCN.Research on cuckoo bumblebees is heavily weighted towards Europe and European species, while Asian species were under‐represented.Key research areas such as ecology and behaviour have received little attention for the majority of cuckoo bumblebees, which may hamper conservation effortsOur results quantitatively support observations made in other publications on the scarcity of data on cuckoo bumblebees, and highlight the need for further research on many species for whom fundamental knowledge is missing—particularly in light of the vulnerability of this subgenus to extinction. [ABSTRACT FROM AUTHOR]

Slave-making ants might exert strong pressure on their host populations by pillaging their nests and sometimes destroying the whole colonies. Consequently, host ants have evolved many adaptations reducing the probability of being attacked, resisting an assault or, as a last line of defence, minimising the losses associated with a successful slave-maker invasion. This paper presents the results of a study on a common Palearctic ant species, Formica fusca , which falls victim to slave raids organised by the congeneric F. sanguinea. Slave-making ants were placed close to the nest entrance of the host ants, and the subsequent instances of aggression were recorded. The study was carried out in the context of the influence of the dominant competitor by selecting host colonies located within and outside the territory of the wood ants (F. rufa and F. polyctena). This approach enabled the potential co-evolutionary interplay among three species performing different roles in mutual ecological interactions. The F. fusca ants reacted with aggression to the slave-making ants but not to the dominant competitors. Moreover, the avoidance of the aggression of host ants toward wood ants entails an environment-induced component, besides the presumably inherited one. The impact of the dominant competitor as a territory holder manifests itself in the reduced promptness of F. fusca ants to defend their colonies against slave-makers. The results suggest that this effect is mediated by the negative impact of wood ants on F. fusca colony size. [ABSTRACT FROM AUTHOR]

Insect social parasites are characterized by exploiting the hosts' social behaviour. Why exactly hosts direct their caring behaviour towards these parasites and their offspring remains largely unstudied. One hypothesis is that hosts do not perceive their social environment as altered and accept the parasitic colony as their own. We used the ant Leptothorax acervorum, host of the dulotic, obligate social parasite Harpagoxenus sublaevis, to shed light on molecular mechanisms underlying behavioural exploitation by contrasting tissue‐specific transcriptomes in young host workers. Host pupae were experimentally (re‐)introduced into fragments of their original, another conspecific, heterospecific or parasitic colony. Brain and antennal mRNA was extracted and sequenced from adult ants after they had lived in the experimental colony for at least 50 days after eclosion. The resulting transcriptomes of L. acervorum revealed that ants were indeed affected by their social environment. Host brain transcriptomes were altered by the presence of social parasites, suggesting that the parasitic environment influences brain activity, which may be linked to behavioural changes. Transcriptional activity in the antennae changed most with the presence of unrelated individuals, regardless of whether they were conspecifics or parasites. This suggests early priming of odour perception, which was further supported by sensory perception of odour as an enriched function of differentially expressed genes. Furthermore, gene expression in the antennae, but not in the brain corresponded to ant worker behaviour before sampling. Our study demonstrated that the exploitation of social behaviours by brood parasites correlates with transcriptomic alterations in the central and peripheral nervous systems. [ABSTRACT FROM AUTHOR]

Inquiline ant social parasites exploit other ant species for their reproductive benefit because they do not possess a worker caste. Due to their relative rarity in nature, the biology and natural history of inquilines are largely unknown. Likewise, not much research exists that details the close relationship between inquilines and their host(s), and how each organism influences the genetic structure of the other. Here, we conducted a comparative population genetics study to assess patterns of genetic structure within and among populations of inquiline Solenopsis daguerrei and its known fire ant hosts, which includes invasive Solenopsis invicta. Using nuclear and mitochondrial markers, we show that four genetically distinct groups of S. daguerrei likely exist, each with different degrees of host association. Consistent with previous inferences of the inquiline lifestyle, we find that inbreeding is common in S. daguerrei, presumably a result of intranidal mating and restricted dispersal. Results from this study, specifically host association patterns, may inform future biological control strategies to mitigate invasive S. invicta populations.

Eusocial insect colonies are vulnerable to exploitation by egg‐laying workers arising either as natal reproductive workers or as non‐natal reproductive 'drifting' workers (intraspecific social parasites). Worker egg‐laying is potentially costly to the colony, but queens and workers can counter its costs via egg eating (queen or worker policing). Bumblebee colonies exhibit egg laying by both natal and non‐natal workers: natal workers collectively lay more eggs but do so only after a specific point in the colony cycle, the 'competition point', whereas non‐natal workers potentially lay eggs throughout the colony cycle. These features create a special opportunity to investigate whether policing of worker‐laid eggs is context‐dependent (i.e. depends on worker origin of eggs and/or colony stage). We introduced artificial egg cells containing eggs laid by either natal or non‐natal workers into colonies of the bumblebee Bombus terrestris both before and after their competition points and observed the fate of introduced egg cells and eggs. In both colony stages, the majority of introduced egg cells and eggs were policed, demonstrating that policing was not activated only after the competition point. However, in the pre‐competition point stage alone, a smaller proportion of non‐natal workers' eggs (15%) remained after 20 h compared to the proportion of natal workers' eggs remaining (24%). More effective policing of non‐natal workers' eggs early in the colony cycle potentially represents an adaptive, context‐dependent response to the stage in the cycle when all worker‐laid eggs are normally unrelated to the natal colony. [ABSTRACT FROM AUTHOR]

Often, the word „marginal”, – with its derivative „marginality” – evokes a world beyond the borders of our daily existence, somewhere else, far from the center of our lives, towards the abstract territories of the geographical, social, or human periphery. But beyond its adjectival meaning, marginality sums up a series of socio-cultural, economic, political, etc. factors, capable of influencing negatively and independently of one’s own will, the life of an individual or a group, from its well-being to the loss of freedom and even suppression of life. We propose an incursion into the social geography of the marginals during Ceausescu`s regime, analyzing, briefly, certain typologies and instances of the everyday man that undermined the cohesion of the socialist life unsynchronized with the imperatives of the „new man”.

In response to anthropogenic environmental change, the cues that animals use throughout their lifecycle to optimize fitness may become unreliable, resulting in an ecological trap.Here we investigated whether commercial bumble bee Bombus impatiens colonies managed for early spring crop pollination act as ecological traps for wild nest‐searching Bombus queens by subverting their natural nest usurpation behaviour.An average of 10 dead wild queens were recovered from each standard colony during the 2‐week period of the experiment, but colonies with queen excluders were successful in preventing wild queen deaths. The use of queen excluders did not impact colony performance in terms of resident queen survival, colony reproduction, colony weight gain or worker body size.Sites where wild nest‐searching queens were small had higher rates of failed usurpation, suggesting smaller‐sized queens are disproportionately at risk from failed usurpation. Furthermore, sites where commercial colonies without queen excluders were introduced for spring crop pollination had fewer bumble bee visits to a later‐blooming crop compared to sites without commercial colonies.Synthesis and applications. Our findings reveal a novel mechanism by which commercial colonies can negatively impact wild bumble bee populations and their pollination services. At the same time, we demonstrate a simple and inexpensive risk mitigation tool—a queen excluder—was 100% effective at eliminating this risk without compromising colony performance. Commercial colonies used outdoors during the bumble bee nest‐searching period should be fit with queen excluders to prevent negative impacts on wild pollinator communities and their services. [ABSTRACT FROM AUTHOR]

The essay offers a close reading of the inaugural address Termite Craze by the entomologist Karl Escherich, the first German university president to be appointed by the Nazis. Faced with a divided audience and under pressure to politically align the university, Escherich, a former member of the NSDAP, discusses how and to what extent the new regime can recreate the egalitarian perfection and sacrificial predisposition of a termite colony. The paper pays particular attention to the ways in which Escherich tries to appease the various factions in his audience (faculty, students and the Nazi party); in doing so, it also discusses how Escherich depicts his address in the altered versions of his later memoirs. [ABSTRACT FROM AUTHOR]

Aim: One of the most consistent global biogeographic patterns is the latitudinal diversity gradient where species richness peaks within the equatorial tropics and decreases towards the poles. Here, we explore the global biogeography of socially parasitic ant species, which comprises the most diverse group of social parasites in the Hymenoptera. We test the biogeographic hypothesis that ant social parasites are distributed along an inverse latitudinal diversity gradient (iLDG) by peaking in diversity outside of the equatorial tropics, which would contrast with the biogeographic pattern observed in free‐living, non‐parasitic ant species. Location: Global. Taxon: Ants (Hymenoptera: Formicidae). Methods: We assembled a comprehensive biogeographic dataset consisting of 6001 geographic distribution records for all 371 taxonomically described socially parasitic ant species. We used phylogenetic and taxonomic studies to estimate the number of independent evolutionary origins of ant social parasitism to directly compare species richness with the number of species representing independent evolutionary origins of social parasitism across a latitudinal gradient. In addition, we compared ant social parasite diversity across biogeographic regions using rarefaction to account for different sampling efforts. Finally, we tested for a correlation between latitude and the proportion of ant social parasite species within regional ant faunae. Results: The geographic distribution records and the inferred 91 independent evolutionary origins of socially parasitic life histories in ants show that both species richness and the number of species representing independent evolutionary origins of social parasitism peak in the northern hemisphere outside of the equatorial tropics. Based on rarefaction curves, northern latitude regions harbour the most ant social parasite species, but the diversity of independent evolutionary origins is not significantly different between northern and southern hemispheres. The proportion of ant social parasite species within regional faunae is tightly correlated with latitude only in the northern hemisphere. Main conclusions The iLDG of ant social parasites contrasts with the biogeographic pattern observed in free‐living, non‐parasitic ant species and appears to be driven by large species radiations as well as by the presence of specialized life histories exclusive to the northern hemisphere. [ABSTRACT FROM AUTHOR]

The ecological success of social Hymenoptera (ants, bees, wasps) depends on the division of labour between the queen and workers. Each caste exhibits highly specialized morphology, behaviour, and life‐history traits, such as lifespan and fecundity. Despite strong defences against alien intruders, insect societies are vulnerable to social parasites, such as workerless inquilines or slave‐making ants. Here, we investigate whether gene expression varies in parallel ways between lifestyles (slave‐making versus host ants) across five independent origins of ant slavery in the "Formicoxenus‐group" of the ant tribe Crematogastrini. As caste differences are often less pronounced in slave‐making ants than in nonparasitic ants, we also compare caste‐specific gene expression patterns between lifestyles. We demonstrate a substantial overlap in expression differences between queens and workers across taxa, irrespective of lifestyle. Caste affects the transcriptomes much more profoundly than lifestyle, as indicated by 37 times more genes being linked to caste than to lifestyle and by multiple caste‐associated modules of coexpressed genes with strong connectivity. However, several genes and one gene module are linked to slave‐making across the independent origins of this parasitic lifestyle, pointing to some evolutionary convergence. Finally, we do not find evidence for an interaction between caste and lifestyle, indicating that caste differences in gene expression remain consistent even when species switch to a parasitic lifestyle. Our findings strongly support the existence of a core set of genes whose expression is linked to the queen and worker caste in this ant taxon, as proposed by the "genetic toolkit" hypothesis. [ABSTRACT FROM AUTHOR]

When risk is unpredictable, organisms may evolve induced defenses, which are activated after an indication of increased risk. In colonies with behavioural specialization, investment in defence may not be uniformly beneficial among group members. Instead, it should depend on the individual's likelihood of participating in defence. The ant Temnothorax longispinosus uses venom to defend against raids by the social parasite Temnothorax americanus . We tested whether T. longispinosus upregulate investment in venom after experiencing a raid, investigating the relationship between venom volume and worker behavioural caste. Overall, raided colonies had more venom per capita than unraided colonies. When divided into behavioural castes, foragers had more venom after experiencing a raid, while nurses did not. These results demonstrate that T. longispinosus have an induced chemical defence against parasitic raids. However, instead of this defence being deployed uniformly among all workers, the induction of the defence depends on the behavioural caste, and therefore age, of the worker, implying that plasticity in venom production increases with age. Since older social insect workers tend to perform riskier tasks, inducibility may align with an increase in expected risk of death, especially if foragers are more likely to defend the colony against parasites than younger workers.

As vital pollinators, bumble bees play an important role in ecology and agricultural economy, but the decline in diversity and abundance has received widespread attention. Bumble bees of the subgenus Psithyrus are obligate social parasites that invade the nests of other bumble bees as part of their life cycle. This dependency on other colonies may make Psithyrus bumble bees vulnerable to decline and extinction. Hence, conservation strategies and potentially suitable habitats should be identified for these vulnerable species. Here, the potential distribution of a cuckoo bumble bee endemic to China, Bombus (Psithyrus) chinensis (Morawitz 1890) (Hymenoptera, Apidae), was predicted based on species distribution data and ten bioclimatic or environmental variables. Four important variables, namely, the minimum temperature of the coldest month, growing degree days, isothermality, and mean temperature of the warmest quarter, contributed the most to the distribution model. The maximum entropy method (MaxEnt) revealed that the potential distribution of B. chinensis was fragmented under current climate conditions. The areas of potential habitat with low suitability, moderate suitability, and high suitability were 455,451 km2, 170,260 km2, and 116,111 km2, respectively. Eight provinces were evaluated as critical regions for B. chinensis conservation, especially Sichuan, Xizang, Yunnan, and Ningxia Provinces. In conclusion, the results reveal a cuckoo bumble bee’s fragmented distribution and provide a basis for its conservation strategies. The areas identified as highly suitable for B. chinensis should be considered primary conservation areas. [ABSTRACT FROM AUTHOR]

This article aims to introduce the reader to the specifics of the social phenomenon of prostitution in socialist Czechoslovakia, with an emphasis on its punishment through criminal law. The first part of the article briefly characterizes the ideologically coloured perception of prostitution in socialist states and briefly outlines the development of criminal prosecution of prostitution in Czechoslovakia since the end of World War II. The second part of the thesis is devoted to an analysis of the crime and the misdemeanour of social parasitism which were most frequently applied against prostitutes as part of the communist regime's systematic efforts to suppress this social phenomenon. The third part is devoted directly to persons who practiced prostitution in socialist Czechoslovakia. Attention is paid to both homosexual prostitution and heterosexual prostitution, the latter being further divided into certain categories. In the third part of the text, examples from the contemporary practices are given for each category of prostitutes, in particular cases of the District Court for Prague 1 which punished prostitution as a form of social parasitism offence. The aim of this article is to present the specifics of particular cases of prostitution set in the contemporary atmosphere of socialist Czechoslovakia. [ABSTRACT FROM AUTHOR]

The genus Camponotus Mayr is the second speciose ant genus after Pheidole Westwood and includes two parasitic species, Camponotus ruseni Karaman and C. universitatis Forel which are known only from Turkey to co-exist. We present new records with some biological notes of this parasitic species from Turkey and describe the hitherto unknown queen of C. ruseni. Also, the parasitism status of C. ruseni is discussed. [ABSTRACT FROM AUTHOR]

Colonies of social insects contain large amounts of resources often exploited by specialized social parasites. Although some termite species host numerous parasitic arthropod species, called termitophiles, others host none. The reason for this large variability remains unknown. Here, we report that the evolution of termitophily in rove beetles is linked to termite nesting strategies. We compared one‐piece nesters, whose entire colony life is completed within a single wood piece, to foraging species, which exploit multiple physically separated food sources. Our epidemiological model predicts that characteristics related to foraging (e.g., extended colony longevity and frequent interactions with other colonies) increase the probability of parasitism by termitophiles. We tested our prediction using literature data. We found that foraging species are more likely to host termitophilous rove beetles than one‐piece nesters: 99.6% of known termitophilous species were associated with foraging termites, whereas 0.4% were associated with one‐piece nesters. Notably, the few one‐piece nesting species hosting termitophiles were those having foraging potential and access to soil. Our phylogenetic analyses confirmed that termitophily primarily evolved with foraging termites. These results highlight that the evolution of complex termite societies fostered social parasitism, explaining why some species have more social parasites than others. [ABSTRACT FROM AUTHOR]

Uncovering the world of social parasitic ants is difficult due to their rarity and local distribution. Moreover, the more advanced the stage of parasitism, the rarer the species. Anergates atratulus (Schenck, 1852) is an extreme workerless parasite that lives with host species of the genus Tetramorium Mayr, 1855 and is locally distributed throughout large parts of the ranges of its hosts. In this study, two queenless colony fragments of A. atratulus and two of the degenerate slave-raiderStrongylognathus testaceus (Schenck, 1852) were collected in the field and kept in a laboratory. The host species, Tetramorium caespitum (Linnaeus, 1758) and T. staerckei (Kratochvíl, 1944), were identified in an integrative fashion combining worker morphometrics with COI gene identification and revealed T. staerckei as a new host species of A. atratulus. Novel sexual and host-parasitic behaviour was observed: Gynes of A. atratulus successfully obtained from breeding in laboratory nests exhibit female-female competition behaviour for males. Ten incorporation attempts to queenless mixed colony fragments of T. caespitum and S. testaceus were conducted. The workers of T. caespitum and S. testaceus killed all gynes of A. atratulus. [ABSTRACT FROM AUTHOR]

Insect societies vary greatly in their social structure, mating biology, and life history. Polygyny, the presence of multiple reproductive queens in a single colony, and polyandry, multiple mating by females, both increase the genetic variability in colonies of eusocial organisms, resulting in potential reproductive conflicts. The co-occurrence of polygyny and polyandry in a single species is rarely observed across eusocial insects, and these traits have been found to be negatively correlated in ants. Acromyrmex leaf-cutting ants are well-suited for investigating the evolution of complex mating strategies because both polygyny and polyandry co-occur in this genus. We used microsatellite markers and parentage inference in five South American Acromyrmex species to study how different selective pressures influence the evolution of polygyny and polyandry. We show that Acromyrmex species exhibit independent variation in mating biology and social structure, and polygyny and polyandry are not necessarily negatively correlated within genera. One species, Acromyrmex lobicornis, displays a significantly lower mating frequency compared to others, while another species, A. lundii, appears to have reverted to obligate monogyny. These variations appear to have a small impact on average intra-colonial relatedness, although the biological significance of such a small effect size is unclear. All species show significant reproductive skew between patrilines, but there was no significant difference in reproductive skew between any of the sampled species. We find that the evolution of social structure and mating biology appear to follow independent evolutionary trajectories in different species. Finally, we discuss the evolutionary implications that mating biology and social structure have on life history evolution in Acromyrmex leaf-cutting ants. Significance statement: Many species of eusocial insects have colonies with multiple queens (polygyny), or queens mating with multiple males (polyandry). Both behaviors generate potentially beneficial genetic diversity in ant colonies as well as reproductive conflict. The co-occurrence of both polygyny and polyandry in a single species is only known from few ant species. Leaf-cutting ants have both multi-queen colonies and multiply mated queens, providing a well-suited system for studying the co-evolutionary dynamics between mating behavior and genetic diversity in colonies of eusocial insects. We used microsatellite markers to infer the socio-reproductive behavior in five South American leaf-cutter ant species. We found that variation in genetic diversity in colonies was directly associated with the mating frequencies of queens, but not with the number of queens in a colony. We suggest that multi-queen nesting and mating frequency evolve independently of one another, indicating that behavioral and ecological factors other than genetic diversity contribute to the evolution of complex mating behaviors in leaf-cutting ants. [ABSTRACT FROM AUTHOR]

The evolution of an obligate parasitic lifestyle often leads to the reduction of morphological and physiological traits, which may be accompanied by loss of genes and functions. Slave-making ants are social parasites that exploit the work force of closely related ant species for social behaviors such as brood care and foraging. Recent divergence between these social parasites and their hosts enables comparative studies of gene family evolution. We sequenced the genomes of eight ant species, representing three independent origins of ant slavery. During the evolution of eusociality, chemoreceptor genes multiplied due to the importance of chemical communication in insect societies. We investigated the evolutionary fate of these chemoreceptors and found that slave-making ant genomes harbored only half as many gustatory receptors as their hosts', potentially mirroring the outsourcing of foraging tasks to host workers. In addition, parasites had fewer odorant receptors and their loss shows striking patterns of convergence across independent origins of parasitism, in particular in orthologs often implicated in sociality like the 9-exon odorant receptors. These convergent losses represent a rare case of convergent molecular evolution at the level of individual genes. Thus, evolution can operate in a way that is both repeatable and reversible when independent ant lineages lose important social traits during the transition to a parasitic lifestyle. [ABSTRACT FROM AUTHOR]

The restriction of rights and freedoms, the generalized shortage did not make society an ally of this law. On the contrary, a series of antisocial practices that the population resorted to in the name of survival, often placed it under its influence. The lack of goods and food in the shops of towns and villages, the time wasted waiting for them, the poor quality of the products, together with other difficulties and humiliations of everyday existence created a „black market“, a parallel supply network based on profiteering, from overpriced goods. The lack of services, including social ones, kept alive the institution of favors, a system of relationships in which access to medical services, housing, education or a job had to be additionally rewarded in order to pass the customs of corruption in the public administration. The compression of incomes, the regimentation in increasingly difficult occupations, also destroyed the civilizing myth of work. Unemployment, non-existent in official reports, became a recurrence among the youth. The „law of social parasitism" was nothing more than a way in which the state tried to re-discipline the behavior of a generation that, for a short time, had looked through the folds of the Iron Curtain. The law countered the ideological dilemmas generated by the relaxation of the 1960s and the 1970s as well as the fallout from the severe economic recession of the 1980s. [ABSTRACT FROM AUTHOR]

We conducted a survey on the Alpine fauna of one of the largest Natural Park of the Italian Alps (Stelvio National Park) in the framework of a broad ecological monitoring of Alpine biodiversity. A two-years standardized sampling employing pitfall traps along a 1200 m altitudinal gradient led to the discovery of two interesting inquiline social parasite ants of the genus Myrmica: M. myrmicoxena Forel, 1895 and M. microrubra Seifert, 1993. Myrmica myrmicoxena, which is classified as Vulnerable according to the IUCN Red List, was so far known from only three sites across a narrow geographic range between Italy and Switzerland. Our data support the previous hypothesis over its ecology and host association. Myrmica microrubra is considered an incipient species of high evolutionary interest, sometimes regarded as an intraspecific form of M. rubra. While having a wide distribution in Europe, its presence in Italy was hitherto known only from a single site, and our record extends its altitudinal distribution limit in Europe upwards by about 600 m.

We report on the occurrence of the ant Leptothorax kutteri Buschinger, 1965 in two sites in Northern and Eastern Turkey. Leptothorax kutteri is a workerless inquiline living in the colonies of L. acervorum (Fabricius, 1793) so far known from various parts of Northern and Central Europe. Our findings greatly increase the range of this small and rare ant.

The ant Acromyrmex ameliae is a social parasite of two leaf-cutting ant subspecies: Acromyrmex subterraneus subterraneus and A. subterraneus brunneus. Cytogenetic data are available for 14 species of Acromyrmex and all of them possess 2n = 38 chromosomes. In this study, chromosome number, heterochromatin detection, and detection of AT and GC-rich blocks of colonies of A. ameliae and its hosts were carried out. Additionally, the detection of nucleolus organizer regions and 18S rDNA clusters in chromosomes of the parasite and physical mapping of telomeres were undertaken. The same chromosome number and morphology were detected for the hosts 2n = 38 (10m + 14sm + 12st + 2a), while the females and males of the social parasite A. ameliae presented 2n = 36 (10m + 16sm + 8st + 2a) and n = 18 (5m + 8sm + 4st + 1a). In both A. ameliae and its hosts, the terminal region on the short arm of the largest subtelocentric pair is heterochromatic GC-rich, and this region corresponded to the 18S rDNA clusters in the parasite. The short arms of several chromosomes were heterochromatin-rich. The telomeric probe hybridized telomeres on all chromosomes of the parasite and was not detected in intrachromosomal regions. Through a comparative cytogenetic analysis, we hypothesize that the karyotype of A. ameliae (2n = 36) originated from a chromosomal rearrangement that reduced the number of chromosomes from 38 to 36; as available data on the genus Acromyrmex show that all other species possess 38 chromosomes, representing 45% of the 33 valid species in this genus. The mechanism of the chromosome rearrangement is discussed. Thus, the chromosome number observed in A. ameliae is a derivation from the genus. Our data show variation in the chromosomal number in Acromyrmex and suggest that analyses of the karyotypes of parasite species can yield novel insights with regards to the evolution of this genus. [ABSTRACT FROM AUTHOR]

Abstract Background The ants of the Formica genus are classical model species in evolutionary biology. In particular, Darwin used Formica as model species to better understand the evolution of slave-making, a parasitic behaviour where workers of another species are stolen to exploit their workforce. In his book “On the Origin of Species” (1859), Darwin first hypothesized that slave-making behaviour in Formica evolved in incremental steps from a free-living ancestor. Methods The absence of a well-resolved phylogenetic tree of the genus prevent an assessment of whether relationships among Formica subgenera are compatible with this scenario. In this study, we resolve the relationships among the 4 palearctic Formica subgenera (Formica str. s., Coptoformica, Raptiformica and Serviformica) using a phylogenomic dataset of 945 genes for 16 species. Results We provide a reference tree resolving the relationships among the main Formica subgenera with high bootstrap supports. Discussion The branching order of our tree suggests that the free-living lifestyle is ancestral in the Formica genus and that parasitic colony founding could have evolved a single time, probably acting as a pre-adaptation to slave-making behaviour. Conclusion This phylogenetic tree provides a solid backbone for future evolutionary studies in the Formica genus and slave-making behaviour.

The genetic structure of populations can be both a cause and a consequence of ecological interactions. For parasites, genetic structure may be a consequence of preferences for host species or of mating behaviour. Conversely, genetic structure can influence where conspecific interactions among parasites lay on a spectrum from cooperation to conflict. We used microsatellite loci to characterize the genetic structure of a population of the socially parasitic dulotic (aka "slave‐making") ant (Polyergus mexicanus), which is known for its host‐specificity and conspecific aggression. First, we assessed whether the pattern of host species use by the parasite has influenced parasite population structure. We found that host species use was correlated with subpopulation structure, but this correlation was imperfect: some subpopulations used one host species nearly exclusively, while others used several. Second, we examined the viscosity of the parasite population by measuring the relatedness of pairs of neighbouring parasitic ant colonies at varying distances from each other. Although natural history observations of local dispersal by queens suggested the potential for viscosity, there was no strong correlation between relatedness and distance between colonies. However, 35% of colonies had a closely related neighbouring colony, indicating that kinship could potentially affect the nature of some interactions between colonies of this social parasite. Our findings confirm that ecological forces like host species selection can shape the genetic structure of parasite populations, and that such genetic structure has the potential to influence parasite‐parasite interactions in social parasites via inclusive fitness. [ABSTRACT FROM AUTHOR]

In ants, social parasitism is an umbrella term describing a variety of life-history strategies, where a parasitic species depends entirely on a free-living species, for part of or its entire life-cycle, for either colony founding, survival, and/or reproduction. The highly specialized inquiline social parasites are fully dependent on their hosts for their entire lifecycles. Most inquiline species are tolerant of the host queen in the parasitized colony, forgo producing a worker caste, and invest solely in the production of sexual offspring. In general, inquilines are rare, and their geographic distribution is limited, making it difficult to study them. Inquiline populations appear to be small, cryptic, and they are perhaps ephemeral. Thus, information about their natural history is often fragmentary or non-existent but is necessary for understanding the socially parasitic life history syndrome in more detail. Here, we describe two new species of inquiline social parasites, Nylanderia deyrupi sp. nov. and Nylanderia parasitica sp. nov., from the southeastern United States, parasitizing Nylanderia wojciki and Nylanderia faisonensis, respectively. The formicine genus Nylanderia is large and globally distributed, but until the recent description of Nylanderia deceptrix, social parasites were unknown from this genus. In addition to describing the new social parasite species, we summarize the fragmentary information known about their biology, present a key to both the queens and the males of the Nylanderia social parasites, and discuss the morphology of the social parasites in the context of the inquiline syndrome. [ABSTRACT FROM AUTHOR]

Wingless "ergatoid" males of the ant genus Cardiocondyla have repeatedly been described as females of novel genera of workerless social parasites (Emeryia and Xenometra), which after recognition of their real nature were synonymized with Cardiocondyla. Examination of ants newly collected from Comoé National Park in Côte d'Ivoire, West Africa revealed that winged Cardiocondyla males have sparked a similar misidentification: the "winged female sexuals" of the supposed inquiline Cardiocondyla zoserka Bolton 1982, known only from the type material from Nigeria, are in fact the winged males of their presumed host, a species of the Cardiocondyla shuckardi group (sensu Seifert 2002). The types of C. zoserka are immediately recognizable by their strangely modified antennal funiculi with cup-shaped apical segments, which do not resemble any other known ant antenna. More than twenty winged individuals from two Cardiocondyla colonies from the flood plain of Comoé River exhibited the same strange modifications of their antennae and were otherwise also similar to the C. zoserka type specimens. However, these winged ants turned out to be winged males rather than winged female sexuals. The inspection of the holotype and one paratype of C. zoserka verified that they also were males: like the winged males from Comoé N.P., they have concealed male genitals and ocelli, which are considerably larger than those of the female sexuals of Cardiocondyla. All female sexuals and workers found in the colonies with the bizarre winged males from Comoé N.P. had antennae with a three-segmented club as is typical for this genus. Sequences of the mitochondrial cytochrome c oxidase subunits I (CO I) and II (CO II) of a winged male and two nestmate workers showed that they are close to C. venustula and C. shuckardi but differ from them in about 10% of the base pairs. Other samples of Cardiocondyla collected in Comoé N.P. belong to C. venustula and related species. Their males were always ergatoid or "intermorphic" (i.e., ergatoid with rudimentary wings), as previously found in other populations of C. venustula, and never winged with modified antennae. [ABSTRACT FROM AUTHOR]

Dulosis is a type of social parasitism in which a parasitic ant has become dependent on captured workers (hosts) of a closely related species. Dulosis can be either facultative or obligate depending on the degree of dependence on host workers. As parasites become more specialized over evolutionary time, their domestic abilities degenerate until they become unable to survive without the host. However, depending on the degree of specialization, the "lost" behaviors may display some degree of recovery when host workers are unavailable to do the tasks. The 12 species of the Formica sanguinea group are all traditionally considered to be facultative parasites. However, recent studies suggest that one member of the group, F. subintegra, has characteristics that are more consistent with obligate parasitism. To explore the degree to which F. subintegra has become obligate, this study examined the degree of recovery of foraging and nest excavation behaviors of parasites when hosts are removed. When parasites were isolated from hosts, they spent more time foraging and feeding regurgitated food to nestmates (oral trophallaxis), and tended to begin feeding sooner following a period of fasting than when hosts were present. Isolated parasites were able to excavate suitable tunnels and engaged in nest building behavior significantly more often than parasites in groups with hosts. These results indicate that F. subintegra demonstrates some recovery of its foraging and nest excavation abilities, and can be considered a less specialized (more primitive) obligate parasite. Formica subintegra and its facultative relatives can be used as models for studying the progression of dulotic evolution within a closely related group of social parasites, and may shed light on which factors contribute to the transition from facultative to obligate parasitism. [ABSTRACT FROM AUTHOR]

Social parasitism represents a particular type of agonistic interaction in which a parasite exploits an entire society instead of a single organism. One fascinating form of social parasitism in ants is the “inquilinism”, in which a typically worker-less parasitic queen coexists with the resident queen in the host colony and produces sexual offspring. To bypass the recognition system of host colonies, inquilines have evolved a repertoire of deceiving strategies. We tested the level of integration of the inquiline Myrmica karavajevi within the host colonies of M. scabrinodis and we investigated the mechanisms of chemical and vibroacoustic deception used by the parasite. M. karavajevi is integrated into the ant colony to such an extent that, in rescue experiments, the parasite pupae were saved prior to the host’s brood. M. karavajevi gynes perfectly imitated the cuticular hydrocarbon profiles of M. scabrinodis queens and the parasite vibroacoustic signals resembled those emitted by the host queens eliciting the same levels of attention in the host workers during playback experiments. Our results suggest that M. karavajevi has evolved ultimate deception strategies to reach the highest social status in the colony hierarchy, encouraging the use of a combined molecular and behavioural approach when studying host–parasite interactions.

Aggression toward competitors is a useful measure of resource ownership and defense in animals, but aggressive behavior is costly. Therefore, it is predicted that animals will display aggression only when the expected benefit to individual fitness exceeds the expected cost. In ants, when conspecific individuals belonging to different colonies encounter each other, fighting occurs, seemingly facultatively. However, the context that influences the expression of ants' aggressive behavior, especially in the field, is still largely unknown. We investigated the plasticity of aggressiveness toward non-nestmates in Diacamma sp. from Japan. Our field experiment clearly showed that the same foragers that were aggressive toward non-nestmates in the vicinity of their nest changed to be non-aggressive at greater distances from the nest. Furthermore, the size of the colony to which the foragers belonged weakly but significantly affected their aggressiveness: foragers belonging to larger colonies behaved more aggressively toward non-nestmates. We discuss the possible adaptive significance of the observed facultative aggression between conspecific non-nestmates. Digital video images related to the article are available at http://www.momo-p.com/showdetail-e.php?movieid=momo190618ds01a and http://www.momo-p.com/showdetail-e.php?movieid=momo190618ds02a. [ABSTRACT FROM AUTHOR]

Ant inquiline social parasites obligately depend on their hosts for survival and reproduction. Because of their shift from a eusocial to a socially parasitic life history, inquiline social parasites are interesting study systems for exploring the dynamics between conflict and cooperation in eusocial insect colonies. In addition, inquiline social parasites are of interest to evolutionary biology, because some species evolved directly from their hosts via sympatric speciation. With five described species, inquiline social parasites are relatively diverse in the fungus-growing ants. So far, four species have been reported from the leaf-cutting ant genus Acromyrmex and its closely affiliated social parasite genus Pseudoatta. In contrast, only a single parasite species was described from the lower attine genus Mycocepurus. Here, we describe a new species of inquiline social parasite, Acromyrmex fowleri sp. nov., which was discovered 27 years ago in the tropical region of Brazil (State of Bahia), living inside the colonies of its host Acromyrmex rugosus. We also report observations on the behavioral ecology and natural history of A. fowleri and its host. Our study suggests that A. fowleri is an obligate, queen-tolerant, workerless inquiline social parasite of A. rugosus and that A. fowleri represents some but not all morphological and life history characters of the inquiline syndrome, supporting the hypothesis that the complex traits of the inquiline syndrome evolve in a mosaic fashion. Considering that A. fowleri is a new social parasite species from tropical Brazil, we discuss the paradoxical biogeographic distribution of ant social parasites, which we refer to as the "Kutter–Wilson Paradox", and conclude that the Kutter–Wilson Paradox is a genuine biogeographical pattern, instead of being a mere sampling artifact. [ABSTRACT FROM AUTHOR]

1. Termitophily in some rove beetles is commonly attributed to the striking termite worker resemblance that is provided by the beetles' hypertrophic ('physogastric') abdomen. However, a termite nest may offer to a termitophile additional benefits, such as a continuously repaired shelter. 2. This could apply to Corotoca melantho (Aleocharinae: Corotocini), a viviparous obligatory termitophile staphylinid beetle species. While conferring morphological congruence to its host worker termites, its physogastry may impair mobility, leading to vulnerability and the need for a secure environment. It seems plausible to hypothesise that physogastry in C. melantho would imply in interactions between this termitophile and its host termites as well as its host termitarium. 3. This study provides evidence to build such a hypothesis by inspecting the morpho‐anatomical reproductive traits of this termitophile. It was found that a gradient of growth stages of embryos and larvae in the oviduct explains physogastry in females while pointing to iteroparity. The asynchronous development of oocytes in females, combined with a full developing sequence of sperm cells indicative of continuous spermatogenesis in males, suggests frequent matings. 4. While improving guest–host similarity, physogastry and flightlessness should confer vulnerability to pregnant females, forcing C. melantho to seek close and sheltered environments. These could facilitate the frequent male–female contacts demanded by iteroparity. It is possible, therefore, that physogastry in C. melantho is not only associated with the termites themselves but also with the physical structure of the termitarium. Thus, C. melantho can be hypothesised to be a termitariophile in addition to being a termitophile. [ABSTRACT FROM AUTHOR]

Tandem‐running is a recruitment behaviour in ants that has been described as a form of teaching, where spatial information possessed by a leader is conveyed to following nestmates. Within Temnothorax ants, tandem‐running is used within a variety of contexts, from foraging and nest relocation to—in the case of slavemaking species—slave raiding. Here, we elucidate the transcriptomic basis of scouting, tandem‐leading and tandem‐following behaviours across two species with divergent lifestyles: the slavemaking Temnothorax americanus and its primary, nonparasitic host T. longispinosus. Analysis of gene expression data from brains revealed that only a small number of unique differentially expressed genes are responsible for scouting and tandem‐running. Comparison of orthologous genes between T. americanus and T. longispinosus suggests that tandem‐running is characterized by species‐specific patterns of gene usage. However, within both species, tandem‐leaders showed gene expression patterns median to those of scouts and tandem‐followers, which was expected, as leaders can be recruited from either of the other two behavioural states. Most importantly, a number of differentially expressed behavioural genes were found, with functions relating to learning and memory formation in other social and nonsocial insects. This includes a number of up‐regulated receptor genes such as a glutamate and dopamine receptor, as well as serine/threonine‐protein phosphatases and kinases. Learning and memory genes were specifically up‐regulated within scouts and tandem‐followers, not only reinforcing previous behavioural studies into how Temnothorax navigate novel environments and share information, but also providing insight into the molecular underpinnings of teaching and learning within social insects. [ABSTRACT FROM AUTHOR]

Most social insect lineages contain socially parasitic cheater species that, rather than produce their own workers, infiltrate the nests of closely related social species and force the hosts to rear their offspring. These parasites have often lost social traits, like the ability to rear and produce workers, while retaining abilities for reproductive control and exhibiting novel parasitic innovations to capitalize on host resources. Given their close relationships with their hosts, social parasites are particularly informative to understand antagonistic coevolution and the essential components of sociality. Bumble bee social parasites are well suited to inform such evolutionary questions as they exhibit a gradation from facultative to obligate parasitism in their three independent origins of social parasitism, while also exhibiting a diverse obligately socially parasitic lineage, the subgenus Psithyrus Lepeletier, that varies across species in host use and invasion strategies. Despite the insights it can provide, cuckoo bumble bees, like most social parasites, are rare to encounter, and as such represent some of the most poorly understood bumble bee lineages. In this review, we bring together the state of our knowledge on the ecology and evolution of these rare cuckoo bees, to set a framework for further study, while also highlighting our current gaps in knowledge. In particular, we describe patterns of host breadth, geographic range, behavioral and morphological innovations, and social invasion strategies utilized across these bees to varying success. Considering their rarity, we highlight the pressing need to study these social parasites given conservation threats posed by host species declines. [ABSTRACT FROM AUTHOR]

Formica ants are not known to be prey specialists on other ant species, however, for the past 60 years, field observations on Formica archboldi in the southeastern United States have noted that their nests are scattered with body parts of Odontomachus trap-jaw ants. This study investigates the relationship between F. archboldi and Odontomachus. Through a series of behavioral experiments and a descriptive study of their chemical ecology, I find: (1) behavioral evidence that F. archboldi are more capable predators of Odontomachus in comparison to other Formica. (2) F. archboldi match the cuticular hydrocarbon profiles of the native species of Odontomachus that they occur with. This includes O. brunneus and O. relictus and the intraspecific variation found across Florida populations of O. brunneus. (3) F. archboldi do not display a prey retrieval preference towards hydrocarbon-matching Odontomachus as compared to mismatching. (4) F. archboldi that match Odontomachus hydrocarbon profiles do not receive lower levels of aggression than mismatching F. archboldi. Beyond providing natural history insights into the relationship between these species, this study expands our knowledge of an important insect chemical phenotype. The intraspecific variability in F. archboldi cuticular hydrocarbon profiles is among the greatest reported for social insects and provides a unique case of how non-parasitic species can generate parasite-like chemical-mimic phenotypes. [ABSTRACT FROM AUTHOR]

The primer and releaser effects of dominant honey bee workers' tergal gland pheromones are not known under queenless conditions. The Cape honey bee, Apis mellifera capensis, is the ideal model to investigate such question since workers normally reproductively dominate workers of all other subspecies. We determined the effects that short- and long-term exposure to pheromone blends from dominant A. m. capensis workers had on subordinate workers of A. m. scutellata. Three putative pheromonal blends, 1 (palmitic acid, oleic acid, n-heneicosene and n-tricosene), 2 (ethyl palmitate, ethyl oleate and ethyl stearate) and 3 (mixture of blends 1 + 2), were tested. All the three putative pheromonal blends elicited releaser effects in the form of retinue formation and primer effects by suppressing ovarian activation in workers. The resultant effects indicated that these pheromonal blends appear to play a role in establishing dominance among workers and hence regulating opportunities to reproduce. [ABSTRACT FROM AUTHOR]