scholarly journals Built to change: dominance strategy changes with life stage in a primitively eusocial bee

2020 ◽  
Author(s):  
Margarita Orlova ◽  
Erin D Treanore ◽  
Etya Amsalem
Keyword(s):  
Life Stage ◽  
Dominance Rank ◽  
Social Groups ◽  
Egg Laying ◽  
Overt Aggression ◽  
Eusocial Insects ◽  
Social Species ◽  
Chemical Signalling ◽  
Strategy Changes ◽  
Primitively Eusocial

Access to reproduction is determined by an individual dominance rank in many species and is achieved through aggression and/or dominance signalling. In eusocial insects one or several dominant females (queens) monopolize reproduction but to what extent queens rely on aggression and signalling remains obscure. Aggression is costly and its efficiency depends on the group size, whereas signalling may reduce the risks and costs of aggression. Both strategies are used to regulate reproduction in social taxa, with aggression being more common in small social groups, compared to signalling in larger societies. Here, we examine the use of aggression and chemical signalling in a social species (Bombus impatiens) where the dominant queen interacts with increasing numbers of workers as she ages. We found that the queen strategy to monopolize reproduction changes with life stage, shifting from overt aggression to chemical signalling as the queen gets older. Particularly, old queens exhibited a higher ratio of short to long cuticular hydrocarbons compared to young queens, an endogenous shift that was attributed to age, as all egg-laying queens were fecund and kept with the same number of workers. Our findings contribute to the understanding of reproductive dominance in the context of an individual life history.

scholarly journals Built to change: dominance strategy changes with life stage in a primitively eusocial bee

2020 ◽  
Vol 31 (6) ◽  
pp. 1361-1368 ◽  
Author(s):  
Margarita Orlova ◽  
Erin Treanore ◽  
Etya Amsalem
Keyword(s):  
Life Stage ◽  
Dominance Rank ◽  
Social Groups ◽  
Egg Laying ◽  
Overt Aggression ◽  
Chemical Signaling ◽  
Eusocial Insects ◽  
Social Species ◽  
Strategy Changes ◽  
Primitively Eusocial

Abstract Access to reproduction is determined by an individual’s dominance rank in many species and is achieved through aggression and/or dominance signaling. In eusocial insects, one or several dominant females (queens) monopolize reproduction but to what extent queens rely on aggression and signaling remains obscure. Aggression is costly and its efficiency depends on the group size, whereas signaling may reduce the risks and costs of aggression. Both strategies are used to regulate reproduction in social taxa, with aggression being more common in small social groups, compared to signaling in larger societies. Here, we examine the use of aggression and chemical signaling in a social species (Bombus impatiens) where the dominant queen interacts with increasing numbers of workers as she ages. We found that the queen’s strategy to monopolize reproduction changes with life stage, shifting from overt aggression to chemical signaling as the queen gets older. Particularly, old queens exhibited a higher ratio of short to long cuticular hydrocarbons compared to young queens, an endogenous shift that was attributed to age, as all egg-laying queens were fecund and kept with the same number of workers. Our findings contribute to the understanding of reproductive dominance in the context of an individual’s life history.

Pre-imaginal biasing of caste in a primitively eusocial insect

1988 ◽  
Vol 233 (1271) ◽  
pp. 175-189 ◽  
Keyword(s):  
Adult Life ◽  
Social Wasp ◽  
Caste Differentiation ◽  
Egg Laying ◽  
Ropalidia Marginata ◽  
Eusocial Insect ◽  
Eusocial Insects ◽  
Insect Societies ◽  
The Social ◽  
Primitively Eusocial

Primitively eusocial insects often lack morphological caste differentiation, leading to considerable flexibility in the social and reproductive roles that the adult insects may adopt. Although this flexibility and its consequences for social organization have received much attention there has been relatively little effort to detect any pre-imaginal effects leading to a bias in the potential caste of eclosing females. Experiments reported here show that only about 50 % of eclosing females of the tropical social wasp Ropalidia marginata build nests and lay eggs, in spite of being isolated from all conspecifics and being provided ad libitum food since eclosion. The number of empty cells in the parent nest, which we believe to be an indication of the queen’s declining influence, and a wasp’s own rate of feeding during adult life predict the probability of egg laying by eclosing females. These results call for an examination of the possibility that all females in primitively eusocial insect societies are not potentially capable of becoming egg layers and that reigning queens and possibly other adults exert an influence on the production of new queens.

scholarly journals Unreciprocated allogrooming hierarchies in a population of wild group-living mammals

2021 ◽  
Author(s):  
Catherine E Nadin ◽  
David W. Macdonald ◽  
Sandra Baker ◽  
Christina D. Buesching ◽  
Stephen Ellwood ◽  
...  
Keyword(s):  
Social Structure ◽  
Social Status ◽  
Dominance Rank ◽  
Social Groups ◽  
Group Living ◽  
Meles Meles ◽  
Social Species ◽  
Novel Approach ◽  
European Badgers ◽  
Wild Group

Allogrooming can relate to social status in mammalian societies, and thus, be used to infer social structure. This relationship has previously been investigated by examining an individual’s dominance rank and their total amount of allogrooming. This, however, does not account for the identity of allogrooming partners. We applied a novel approach, calculating the linearity and steepness of unreciprocated allogrooming hierarchies using actor–receiver matrices in European badgers (Meles meles) groups. Badgers have relatively unstructured social groups compared to most group-living carnivores and allogrooming in badgers is currently hypothesized to have a hygiene function. We examine whether allogrooming is linked to social status by investigating: 1) the presence, linearity, and steepness of unreciprocated allogrooming hierarchies; 2) the trading of unreciprocated allogrooming for the potential benefit of receiving reduced aggression from dominant individuals; and, 3) whether unreciprocated allogrooming is associated with relatedness. We found weak unreciprocated allogrooming hierarchies, with marginal linearity, steepness overall, and variation between social-group-years. Unreciprocated allogrooming was positively correlated with directed aggression, potentially providing evidence for the trading of allogrooming for reduced aggression. Allogrooming was not correlated with relatedness, possibly due to high relatedness within social groups. Our findings reaffirm that European badgers have a relatively unstructured social system; likely reflecting a relatively simple state of sociality in Carnivores, with little need for hierarchical order. Using actor–receiver unreciprocated allogrooming matrices to test for linearity and steepness of unreciprocated allogrooming hierarchies in other social species will improve knowledge of group social structure.

scholarly journals A small family business: synergistic and additive effects of the queen and the brood on worker reproduction in a primitively eusocial bee

2019 ◽  
Author(s):  
Margarita Orlova ◽  
Jesse Starkey ◽  
Etya Amsalem
Keyword(s):  
Division Of Labor ◽  
Worker Reproduction ◽  
Egg Laying ◽  
Brain Gene Expression ◽  
Worker Behavior ◽  
Social Species ◽  
Eusocial Bees ◽  
Reproductive Division Of Labor ◽  
Reproductive Division ◽  
Primitively Eusocial

AbstractThe mechanisms that maintain reproductive division of labor in social insects are still incompletely understood. Most studies focus on the relationship between adults, overlooking another important stakeholder in the game – the juvenile offspring. Recent studies from various social species show that not only the queen, but also the brood regulates reproductive division of labor between females, but how the two coordinate to maintain reproductive monopoly remained unexplored.Our study aims at disentangling the roles of the brood and the queen in regulating worker reproduction in primitively eusocial bees. We examined the effects induced by the brood and queen, separately and together, on the behavioral, physiological and brain gene expression of Bombus impatiens workers. We found that young larvae induce a releaser effect in workers, decreasing egg laying and aggressive behaviors, while the queen induces both releaser and primer effects, modifying worker aggressive and egg laying behavior and reproductive physiology. The expression of reproduction- and aggression-related genes was altered in the presence of both queen and brood, but the effect was stronger or the same in the presence of the queen.We identified two types of interactions between the queen and the brood in regulating worker reproduction: (1) synergistic interactions regulating worker physiology, where the combined effect of the queen and the brood was greater than each of them separately; (2) additive interactions regulating worker behavior, where the combined effects of the queen and the brood are the gross sum of their separated effects. In these interactions the brood acted in a manner similar to the queen but to a much smaller extent and improved the quality of the effect induced by the queen. Our results suggest that the queen and the brood of primitively eusocial bees coordinate synergistically, additively, and sometimes even redundantly to regulate worker behavior and reproduction, and the interaction between them exists in multiple regulatory levels.

scholarly journals Nutrition induced direct fitness for workers in a primitively eusocial wasp

2021 ◽  
Author(s):  
J. U. Krishnan ◽  
A. Brahma ◽  
S. K. Chavan ◽  
R. Gadagkar
Keyword(s):  
Caste Differentiation ◽  
Egg Laying ◽  
Ropalidia Marginata ◽  
Eusocial Insects ◽  
Primitively Eusocial Wasp ◽  
Direct Fitness ◽  
Queen Replacement ◽  
Eusocial Wasp ◽  
Ad Libitum ◽  
Primitively Eusocial

AbstractEusocial insects are characterised by a reproductive caste differentiation such that egg-laying is restricted to a small number of queens. The majority of the colony members function as non-reproducing workers and gain indirect fitness by rearing the offspring of the reproductives. In primitively eusocial species, some workers can also get direct fitness by sneaking in some eggs in the presence of the queens, replacing the queens and becoming new queens, or initiating new nests. Here we aimed to understand the factors that permit some workers to gain direct fitness and alter the number of workers doing so, using the primitively eusocial wasp Ropalidia marginata. We transplanted 12 naturally occurring colonies into large laboratory cages where there was adequate space for the workers to leave their natal nests and initiate new colonies. We compared six control colonies that we provided with ad libitum food placed near the nest to six test colonies in which we hand-fed the wasps in addition to the ad libitum food. Wasps in test colonies consumed more food, showed more aggression, replaced their queens, and initiated new nests significantly more often than those in control colonies. When considering all 12 colonies, the rates of queen replacement and nest foundation were significantly positively correlated with food consumption rates. The additional nutrition gained by hand-fed wasps appears to help workers in test colonies to develop their ovaries and lay eggs, implying that they are nutritionally castrated in control colonies.

Female, but not male, agonistic behaviour is associated with male reproductive success in stable bluebanded goby (Lythrypnus dalli) hierarchies

Behaviour ◽  
2014 ◽  
Vol 151 (10) ◽  
pp. 1367-1387 ◽  
Author(s):  
Tessa K. Solomon-Lane ◽  
Madelyne C. Willis ◽  
Devaleena S. Pradhan ◽  
Matthew S. Grober
Keyword(s):  
Reproductive Success ◽  
Egg Laying ◽  
Dominant Male ◽  
Male Reproductive Success ◽  
Agonistic Behaviour ◽  
Social Species ◽  
Evolution Of Sociality ◽  
Lythrypnus Dalli ◽  
Linear Hierarchies ◽  
Substantial Control

In many social species, there are important connections between social behaviour and reproduction that provide critical insights into the evolution of sociality. In this study, we describe associations between agonistic behaviour and male reproductive success in stable social groups of bluebanded gobies (Lythrypnus dalli). This highly social, sex-changing species forms linear hierarchies of a dominant male and multiple subordinate females. Males reproduce with each female in the harem and care for the eggs. Since aggression tends to be associated with reduced reproduction in social hierarchies, we hypothesized that males in groups with high rates of aggression would fertilise fewer eggs. We also hypothesized that a male’s agonistic behaviour would be associated with his reproductive success. Dominants often exert substantial control over their harem, including control over subordinate reproduction. To address these hypotheses, we quantified egg laying/fertilisation over 13 days and observed agonistic behaviour. We show that there was a significant, negative association between male reproductive success and the total rate agonistic interactions by a group. While no male behaviours were associated with the quantity of eggs fertilised, female agonistic behaviour may be central to male reproductive success. We identified a set of models approximating male reproductive success that included three female behaviours: aggression by the highest-ranking female and approaches by the lowest-ranking female were negatively associated with the quantity of eggs fertilised by males in their groups, but the efficiency with which the middle-ranking female displaced others was positively associated with this measure. These data provide a first step in elucidating the behavioural mechanisms that are associated with L. dalli reproductive success.

Behavioural consistency and group conformity in humbug damselfish

Behaviour ◽  
2017 ◽  
Vol 154 (13-15) ◽  
pp. 1343-1359 ◽  
Author(s):  
Alicia L.J. Burns ◽  
Timothy M. Schaerf ◽  
Ashley J.W. Ward
Keyword(s):  
Dominance Rank ◽  
Social Groups ◽  
Null Model ◽  
Group Level ◽  
Absolute Size ◽  
Social Hierarchies ◽  
Behavioural Type ◽  
Level Of Activity ◽  
Group Members ◽  
Dascyllus Aruanus

Abstract Humbug damselfish, Dascyllus aruanus, are a common coral reef fish that form stable social groups with size-based social hierarchies. Here we caught whole wild groups of damselfish and tested whether social groups tended to be comprised of animals that are more similar to one another in terms of their behavioural type, than expected by chance. First we found that individuals were repeatable in their level of activity and exploration, and that this was independent of both absolute size and within-group dominance rank, indicating that animals were behaviourally consistent. Secondly, despite the fact that individuals were tested independently, the behaviour of members of the same groups was significantly more similar than expected under a null model, suggesting that individual behaviour develops and is shaped by conformity to the behaviour of other group members. This is one of the first studies to demonstrate this group-level behavioural conformity in wild-caught groups.

scholarly journals Solitary bees reduce investment in communication compared with their social relatives

2017 ◽  
Vol 114 (25) ◽  
pp. 6569-6574 ◽  
Author(s):  
Bernadette Wittwer ◽  
Abraham Hefetz ◽  
Tovit Simon ◽  
Li E. K. Murphy ◽  
Mark A. Elgar ◽  
...  
Keyword(s):  
Social Behavior ◽  
Communication Systems ◽  
Group Membership ◽  
Group Living ◽  
Signal Perception ◽  
Eusocial Insects ◽  
Social Species ◽  
Solitary Living ◽  
Social Animals ◽  
Signal Production

Social animals must communicate to define group membership and coordinate social organization. For social insects, communication is predominantly mediated through chemical signals, and as social complexity increases, so does the requirement for a greater diversity of signals. This relationship is particularly true for advanced eusocial insects, including ants, bees, and wasps, whose chemical communication systems have been well-characterized. However, we know surprisingly little about how these communication systems evolve during the transition between solitary and group living. Here, we demonstrate that the sensory systems associated with signal perception are evolutionarily labile. In particular, we show that differences in signal production and perception are tightly associated with changes in social behavior in halictid bees. Our results suggest that social species require a greater investment in communication than their solitary counterparts and that species that have reverted from eusociality to solitary living have repeatedly reduced investment in these potentially costly sensory perception systems.

scholarly journals The glucocorticoid receptor in the nucleus accumbens plays a crucial role in social rank attainment in rodents

2019 ◽  
Author(s):  
Aurélie Papilloud ◽  
Meltem Weger ◽  
Alexandre Bacq ◽  
Ioannis Zalachoras ◽  
Fiona Hollis ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Glucocorticoid Receptor ◽  
Social Dominance ◽  
Dominance Rank ◽  
Social Rank ◽  
Well Being ◽  
Social Hierarchies ◽  
Social Species ◽  
High Anxious ◽  
A Cell

AbstractSocial hierarchy in social species is usually established through competitive encounters with conspecifics. It determines the access to limited resources and, thus, leads to reduced fights among individuals within a group. Despite the known importance of social rank for health and well-being, the knowledge about the processes underlying rank attainment remains limited. Previous studies have highlighted the nucleus accumbens (NAc) as a key brain region in the attainment of social hierarchies in rodents. In addition, glucocorticoids and the glucocorticoid receptor (GR) have been implicated in the establishment of social hierarchies and social aversion. However, whether GR in the NAc is involved in social dominance is not yet known. To address this question, we first established that expression levels of GR in the NAc of high anxious, submissive-prone rats are lower than that of their low anxious, dominant-prone counterparts. Furthermore, virally-induced downregulation of GR expression in the NAc in rats led to an improvement of social dominance rank. We found a similar result in a cell-specific mouse model lacking GR in dopaminoceptive neurons (i.e., neurons containing dopamine receptors). Indeed, when cohabitating in dyads of mixed genotypes, mice deficient for GR in dopaminoceptive neurons had a higher probability to become dominant than wild-type mice. Overall, our results highlight GR in the NAc and in dopaminoceptive neurons as an important regulator of social rank attainment.

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