scholarly journals Novel cooperative antipredator tactics of an ant specialized against a snake

2019 ◽  
Vol 6 (8) ◽  
pp. 190283
Author(s):  
Teppei Jono ◽  
Yosuke Kojima ◽  
Takafumi Mizuno
Keyword(s):  
Eusocial Insects ◽  
Ant Eating ◽  
Eusocial Species

Eusocial insects can express surprisingly complex cooperative defence of the colony. Brood and reproductive castes typically remain in the nest and are protected by workers' various antipredator tactics against intruders. In Madagascar, a myrmicine ant, Aphaenogaster swammerdami , occurs sympatrically with a large blindsnake, Madatyphlops decorsei . As blindsnakes generally specialize on feeding on termites and ants brood by intruding into the nest, these snakes are presumably a serious predator on the ant. Conversely, a lamprophiid snake, Madagascarophis colubrinus , is considered to occur often in active A . swammerdami nests without being attacked. By presenting M . colubrinus , M . decorsei and a control snake, Thamnosophis lateralis , at the entrance of the nest, we observed two highly specialized interactions between ants and snakes: the acceptance of M . colubrinus into the nest and the cooperative evacuation of the brood from the nest for protection against the ant-eating M . decorsei . Given that M . colubrinus is one of the few known predators of blindsnakes in this area, A . swammerdami may protect their colonies against this blindsnake by two antipredator tactics, symbiosis with M . colubrinus and evacuation in response to intrusion by blindsnakes. These findings demonstrate that specialized predators can drive evolution of complex cooperative defence in eusocial species.

scholarly journals Chemical Variation among Castes, Female Life Stages and Populations of the Facultative Eusocial Sweat Bee Halictus rubicundus (Hymenoptera: Halictidae)

2021 ◽  
Author(s):  
Iris Steitz ◽  
Robert J Paxton ◽  
Stefan Schulz ◽  
Manfred Ayasse
Keyword(s):  
Chemical Communication ◽  
North American ◽  
Specific Chemical ◽  
Eusocial Insects ◽  
Queen Signal ◽  
Ovarian Activation ◽  
Chemical Profiles ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

AbstractIn eusocial insects, chemical communication is crucial for mediating many aspects of social activities, especially the regulation of reproduction. Though queen signals are known to decrease ovarian activation of workers in highly eusocial species, little is known about their evolution. In contrast, some primitively eusocial species are thought to control worker reproduction through physical aggression by the queen rather than via pheromones, suggesting the evolutionary establishment of chemical signals with more derived sociality. However, studies supporting this hypothesis are largely missing. Socially polymorphic halictid bees, such as Halictus rubicundus, with social and solitary populations in both Europe and North America, offer excellent opportunities to illuminate the evolution of caste-specific signals. Here we compared the chemical profiles of social and solitary populations from both continents and tested whether (i) population or social level affect chemical dissimilarity and whether (ii) caste-specific patterns reflect a conserved queen signal. Our results demonstrate unique odor profiles of European and North American populations, mainly due to different isomers of n-alkenes and macrocyclic lactones; chemical differences may be indicative of phylogeographic drift in odor profiles. We also found common compounds overproduced in queens compared to workers in both populations, indicating a potential conserved queen signal. However, North American populations have a lower caste-specific chemical dissimilarity than European populations which raises the question if both use different mechanisms of regulating reproductive division of labor. Therefore, our study gives new insights into the evolution of eusocial behavior and the role of chemical communication in the inhibition of reproduction.

scholarly journals Experimental increase of worker diversity benefits brood production in ants

2021 ◽  
Author(s):  
Marina N. Psalti ◽  
Dustin Gohlke ◽  
Romain Libbrecht
Keyword(s):  
Division Of Labor ◽  
Genetic Relatedness ◽  
Lasius Niger ◽  
Brood Production ◽  
Eusocial Insects ◽  
Colony Performance ◽  
Positive Correlations ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

AbstractThe reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on fitness in eusocial insects still await validation. In this study, we experimentally increased worker diversity in the ant Lasius niger while controlling for typical confounding factors. We found that experimental colonies composed of workers coming from three different source colonies produced more larvae and showed more variation in size compared to groups of workers coming from a single colony. We propose that the benefits of increased diversity stemmed from an improved division of labor. Our study confirms that worker diversity enhances colony performance, thus providing a possible explanation for the evolution of multiply mated queens and multiple-queen colonies in many species of eusocial insects.

scholarly journals What Can Mechanisms Underlying Derived Traits Tell Us About the Evolution of Social Behavior?

2020 ◽  
Author(s):  
Erin Treanore ◽  
Nathan Derstine ◽  
Etya Amsalem
Keyword(s):  
Social Behavior ◽  
Social Evolution ◽  
Female Reproduction ◽  
Task Specialization ◽  
Major Transitions ◽  
Eusocial Insects ◽  
Morphological Differences ◽  
Underlying Mechanisms ◽  
Eusocial Species ◽  
Primer Pheromones

Abstract Social behavior, although rare, is a highly successful form of living that has reached its most extreme forms in eusocial insects. A tractable framework to understand social evolution is the study of major transitions in social behavior. This includes the transitions between solitary to social living, from species exhibiting intermediate degrees of sociality to species exhibiting true sociality, and from primitive to advanced eusocial species. The latter transition is characterized by the emergence of traits not previously found in primitive eusocial species, such as fixed morphological differences between castes and task specialization within the sterile caste. Such derived traits appear to exist in a binary fashion, present in advanced eusocial species, and absent or rare in primitive ones, and thus do not exist in a gradient that is easily tracked and compared between species. Thus, they may not be viewed as valuable to explore ultimate questions related to social evolution. Here, we argue that derived traits can provide useful insights on social evolution even if they are absent or rare in species with a lower social organization. This applies only if the mechanism underlying the trait, rather than the function it regulates for, can be traced back to the solitary ancestors. We discuss two examples of derived traits, morphological differences in female castes and primer pheromones regulating female reproduction, demonstrating how their underlying mechanisms can be used to understand major transitions in the evolution of social behavior and emphasize the importance of studying mechanistic, rather than functional continuity of traits.

scholarly journals Experimental increase of worker diversity benefits brood production in ants

2021 ◽  
Vol 21 (1) ◽  
Author(s):  
Marina N. Psalti ◽  
Dustin Gohlke ◽  
Romain Libbrecht
Keyword(s):  
Division Of Labor ◽  
Genetic Relatedness ◽  
Lasius Niger ◽  
Brood Production ◽  
Eusocial Insects ◽  
Colony Performance ◽  
Positive Correlations ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Eusocial Species

Abstract Background The reproductive division of labor of eusocial insects, whereby one or several queens monopolize reproduction, evolved in a context of high genetic relatedness. However, many extant eusocial species have developed strategies that decrease genetic relatedness in their colonies, suggesting some benefits of the increased diversity. Multiple studies support this hypothesis by showing positive correlations between genetic diversity and colony fitness, as well as finding effects of experimental manipulations of diversity on colony performance. However, alternative explanations could account for most of these reports, and the benefits of diversity on performance in eusocial insects still await validation. In this study, we experimentally increased worker diversity in small colonies of the ant Lasius niger while controlling for typical confounding factors. Results We found that experimental colonies composed of workers coming from three different source colonies produced more larvae and showed more variation in size compared to groups of workers coming from a single colony. Conclusions We propose that the benefits of increased diversity stemmed from an improved division of labor. Our study confirms that worker diversity enhances colony performance, thus providing a possible explanation for the evolution of multiply mated queens and multiple-queen colonies in many species of eusocial insects.

scholarly journals Eusociality and Senescence: Neuroprotection and Physiological Resilience to Aging in Insect and Mammalian Systems

2021 ◽  
Vol 9 ◽  
Author(s):  
Ysabel Milton Giraldo ◽  
Mario L. Muscedere ◽  
James F. A. Traniello
Keyword(s):  
Dna Damage ◽  
Cell Death ◽  
Social Evolution ◽  
Brain Cell ◽  
Antioxidant Defenses ◽  
Physiological Indicators ◽  
Eusocial Insects ◽  
Eusocial Species ◽  
Selection Of

Are eusociality and extraordinary aging polyphenisms evolutionarily coupled? The remarkable disparity in longevity between social insect queens and sterile workers—decades vs. months, respectively—has long been recognized. In mammals, the lifespan of eusocial naked mole rats is extremely long—roughly 10 times greater than that of mice. Is this robustness to senescence associated with social evolution and shared mechanisms of developmental timing, neuroprotection, antioxidant defenses, and neurophysiology? Focusing on brain senescence, we examine correlates and consequences of aging across two divergent eusocial clades and how they differ from solitary taxa. Chronological age and physiological indicators of neural deterioration, including DNA damage or cell death, appear to be decoupled in eusocial insects. In some species, brain cell death does not increase with worker age and DNA damage occurs at similar rates between queens and workers. In comparison, naked mole rats exhibit characteristics of neonatal mice such as protracted development that may offer protection from aging and environmental stressors. Antioxidant defenses appear to be regulated differently across taxa, suggesting independent adaptations to life history and environment. Eusocial insects and naked mole rats appear to have evolved different mechanisms that lead to similar senescence-resistant phenotypes. Careful selection of comparison taxa and further exploration of the role of metabolism in aging can reveal mechanisms that preserve brain functionality and physiological resilience in eusocial species.

scholarly journals Polymorphism and division of labour in a socially complex ant: neuromodulation of aggression in the Australian weaver ant, Oecophylla smaragdina

2015 ◽  
Vol 282 (1811) ◽  
pp. 20150704 ◽  
Author(s):  
J. Frances Kamhi ◽  
Kelley Nunn ◽  
Simon K. A. Robson ◽  
James F. A. Traniello
Keyword(s):  
Social Systems ◽  
Division Of Labour ◽  
Oecophylla Smaragdina ◽  
Minor Worker ◽  
Task Specialization ◽  
Territorial Defence ◽  
Weaver Ant ◽  
Eusocial Insects ◽  
Worker Size ◽  
Pharmacological Manipulations

Complex social structure in eusocial insects can involve worker morphological and behavioural differentiation. Neuroanatomical variation may underscore worker division of labour, but the regulatory mechanisms of size-based task specialization in polymorphic species are unknown. The Australian weaver ant, Oecophylla smaragdina , exhibits worker polyphenism: larger major workers aggressively defend arboreal territories, whereas smaller minors nurse brood. Here, we demonstrate that octopamine (OA) modulates worker size-related aggression in O. smaragdina . We found that the brains of majors had significantly higher titres of OA than those of minors and that OA was positively and specifically correlated with the frequency of aggressive responses to non-nestmates, a key component of territorial defence. Pharmacological manipulations that effectively switched OA action in major and minor worker brains reversed levels of aggression characteristic of each worker size class. Results suggest that altering OA action is sufficient to produce differences in aggression characteristic of size-related social roles. Neuromodulators therefore may generate variation in responsiveness to task-related stimuli associated with worker size differentiation and collateral behavioural specializations, a significant component of division of labour in complex social systems.

scholarly journals A death pheromone, oleic acid, triggers hygienic behavior in honey bees (Apis mellifera L.)

2017 ◽  
Author(s):  
Alison McAfee ◽  
Abigail Chapman ◽  
Immacolata Iovinella ◽  
Ylonna Gallagher-Kurtzke ◽  
Troy F. Collins ◽  
...  
Keyword(s):  
Oleic Acid ◽  
Honey Bees ◽  
Complex Behavior ◽  
Hygienic Behavior ◽  
Larval Food ◽  
Odorant Binding Proteins ◽  
Eusocial Insects ◽  
Low Levels ◽  
Odorant Binding ◽  
Crowded Environment

Eusocial insects live in teeming societies with thousands of their kin. In this crowded environment, workers combat disease by removing or burying their dead or diseased nestmates. For honey bees, we found that hygienic brood-removal behavior is triggered by two odorants – β-ocimene and oleic acid – which are released from brood upon freeze-killing. β-ocimene is a co-opted pheromone that normally signals larval food-begging, whereas oleic acid is a conserved necromone across arthropod taxa. Interestingly, the odorant blend can induce hygienic behavior more consistently than either odorant alone. We suggest that the volatile β-ocimene flags hygienic workers’ attention, while oleic acid is the death cue, triggering removal. Bees with high hygienicity detect and remove brood with these odorants faster than bees with low hygienicity, and both molecules are strong ligands for hygienic behavior-associated odorant binding proteins (OBP16 and OBP18). Odorants that induce low levels of hygienic behavior, however, are weak ligands for these OBPs. We are therefore beginning to paint a picture of the molecular mechanism behind this complex behavior, using odorants associated with freeze-killed brood as a model.

scholarly journals Stable eusociality via maternal manipulation when resistance is costless

2015 ◽  
Author(s):  
Mauricio González-Forero
Keyword(s):  
Mathematical Model ◽  
Resource Allocation ◽  
Maternal Care ◽  
Honest Signaling ◽  
Queen Pheromones ◽  
Honest Signals ◽  
Long Run ◽  
Maternal Manipulation ◽  
Selection For ◽  
Eusocial Species

In many eusocial species, queens use pheromones to influence offspring to express worker phenotypes. While evidence suggests that queen pheromones are honest signals of the queen's reproductive health, here I show that queen's honest signaling can result from ancestral maternal manipulation. I develop a mathematical model to study the coevolution of maternal manipulation, offspring resistance to manipulation, and maternal resource allocation. I assume that (1) maternal manipulation causes offspring to be workers against offspring's interests; (2) offspring can resist at no direct cost, as is thought to be the case with pheromonal manipulation; and (3) the mother chooses how much resource to allocate to fertility and maternal care. In the coevolution of these traits, I find that maternal care decreases, thereby increasing the benefit that offspring obtain from help, which in the long run eliminates selection for resistance. Consequently, ancestral maternal manipulation yields stable eusociality despite costless resistance. Additionally, ancestral manipulation in the long run becomes honest signaling that induces offspring to help. These results indicate that both eusociality and its commonly associated queen honest signaling can be likely to originate from ancestral manipulation.

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