scholarly journals Workers influence royal reproduction

2010 ◽  
Vol 278 (1711) ◽  
pp. 1524-1531 ◽  
Author(s):  
Richard J. Gill ◽  
Robert L. Hammond
Keyword(s):  
Sex Ratio ◽  
Social Insects ◽  
Cooperative Breeding ◽  
Parentage Analysis ◽  
Egg Laying ◽  
Male Production ◽  
Leptothorax Acervorum ◽  
Worker Brood ◽  
Breeding Groups ◽  
Animal Societies

Understanding which parties regulate reproduction is fundamental to understanding conflict resolution in animal societies. In social insects, workers can influence male production and sex ratio. Surprisingly, few studies have investigated worker influence over which queen(s) reproduce(s) in multiple queen (MQ) colonies (skew), despite skew determining worker-brood relatedness and so worker fitness. We provide evidence for worker influence over skew in a functionally monogynous population of the ant Leptothorax acervorum . Observations of MQ colonies leading up to egg laying showed worker aggressive and non-aggressive behaviour towards queens and predicted which queen monopolized reproduction. In contrast, among-queen interactions were rare and did not predict queen reproduction. Furthermore, parentage analysis showed workers favoured their mother when present, ensuring closely related fullsibs (average r = 0.5) were reared instead of less related offspring of other resident queens ( r ≤ 0.375). Discrimination among queens using relatedness-based cues, however, seems unlikely as workers also biased their behaviour in colonies without a mother queen. In other polygynous populations of this species, workers are not aggressive towards queens and MQs reproduce, showing the outcome of social conflicts varies within species. In conclusion, this study supports non-reproductive parties having the power and information to influence skew within cooperative breeding groups.

The origins of societies

1997 ◽  
Author(s):  
John Maynard Smith ◽  
Eors Szathmary
Keyword(s):  
Carbon Dioxide ◽  
Sex Ratio ◽  
Human Body ◽  
Somatic Cells ◽  
Egg Laying ◽  
The Body ◽  
Narrow Channels ◽  
The Individual ◽  
Animal Societies

The heat generated within a mound of the termite Macrotermes is carried upwards by a central air duct. The air then travels down along narrow channels close to the surface of the mound, where it is cooled, and where, as in a lung, oxygen and carbon dioxide are exchanged. The whole mound is an airconditioning system. Although the mound resembles a human building in having features ensuring the comfort of its inhabitants, it differs in that not one of its builders had a picture of the completed structure before building started. The structure emerged from the rule-governed behaviour of tens of thousands of interacting workers. In this, the mound resembles a human body rather than a human building. The body is built by the rule-governed actions of millions of cells. Nowhere is there anything resembling a blueprint of the body. At most, the genome is a set of instructions for making a body: it is not a description of a body. The resemblance between the development of an insect colony and of an organism has led to the concept of a ‘superorganism’. The analogy has some value. To the extent that individual ants, bees or termites have lost the capacity to reproduce, they can propagate their genes only by ensuring the success of the colony, just as somatic cells can propagate theirs only by ensuring the success of the organism. Hence, the colony can be expected to have features adapted to ensure its success, and it is reasonable to apply concepts of optimization to it, rather than to the individual—as was done, for example, by Oster & Wilson (1978) in their book on insect caste systems. But for our purposes the concept of a super organism is of little use. To understand the origins of animal societies, we must ask how individuals capable of reproduction came to cooperate to the extent that most of them lost the ability to reproduce. To understand their maintenance, we must explain why they are not disrupted by cheating. Unlike somatic cells, the individual workers, although related, are not genetically identical. We would therefore expect within-colony conflict to be widespread, as indeed it is: examples discussed below concern egg laying by workers, and conflict over the sex ratio.

scholarly journals Unexpected resilience of species with temperature-dependent sex determination at the Cretaceous–Palaeogene boundary

2010 ◽  
Vol 7 (2) ◽  
pp. 295-298 ◽  
Author(s):  
Sherman Silber ◽  
Jonathan H. Geisler ◽  
Minjin Bolortsetseg
Keyword(s):  
Climate Change ◽  
Sex Ratio ◽  
Sex Determination ◽  
Volcanic Eruptions ◽  
Egg Laying ◽  
Molecular Clocks ◽  
Temperature Dependent ◽  
Hell Creek Formation ◽  
Male Preponderance ◽  
Genotypic Sex Determination

It has been suggested that climate change at the Cretaceous–Palaeogene (K–Pg) boundary, initiated by a bolide impact or volcanic eruptions, caused species with temperature-dependent sex determination (TSD), including dinosaurs, to go extinct because of a skewed sex ratio towards all males. To test this hypothesis, the sex-determining mechanisms (SDMs) of Cretaceous tetrapods of the Hell Creek Formation (Montana, USA) were inferred using parsimony optimizations of SDMs on a tree, including Hell Creek species and their extant relatives. Although the SDMs of non-avian dinosaurs could not be inferred, we were able to determine the SDMs of 62 species; 46 had genotypic sex determination (GSD) and 16 had TSD. The TSD hypothesis for extinctions performed poorly, predicting between 32 and 34 per cent of survivals and extinctions. Most surprisingly, of the 16 species with TSD, 14 of them survived into the Early Palaeocene. In contrast, 61 per cent of species with GSD went extinct. Possible explanations include minimal climate change at the K–Pg, or if climate change did occur, TSD species that survived had egg-laying behaviour that prevented the skewing of sex ratios, or had a sex ratio skewed towards female rather than male preponderance. Application of molecular clocks may allow the SDMs of non-avian dinosaurs to be inferred, which would be an important test of the pattern discovered here.

Contribution of adult sex ratio to trauma and reproductive output in large breeding groups of rhesus macaques (Macaca mulatta)

2021 ◽  
Vol 30 (4) ◽  
pp. 479-492
Author(s):  
J Crast ◽  
MA Bloomsmith ◽  
CM Remillard ◽  
T Meeker
Keyword(s):  
Sex Ratio ◽  
Macaca Mulatta ◽  
Social Dynamics ◽  
Rhesus Macaques ◽  
Well Being ◽  
Primate Research ◽  
Adult Males ◽  
Adult Sex Ratio ◽  
Breeding Groups ◽  
Financial Burdens

Maintaining stable breeding groups of rhesus macaques (Macaca mulatta) can be challenging due to the complex social dynamics and despotic nature of the species. Trauma from aggression is a common problem in rhesus colonies and can cause social disruption, strain veterinary and animal management resources, and potentially affect reproduction. Previous research has shown that increasing the number of non-natal adult males in a breeding group can improve group stability, reduce trauma, and increase reproduction. Here, we used mixed-effects regression models to examine the effects of sex ratio and other factors on trauma and reproduction at the Yerkes National Primate Research Center using a historical dataset made up of four large rhesus groups over an eleven-year period (2003–2013). As expected, sex ratio was a significant predictor for both trauma and reproduction. However, group age since formation was a stronger predictor of trauma frequency and the amount of space available was a slightly better predictor of reproduction than sex ratio or trauma. These results indicate that improving sex ratios can be a viable management strategy to reduce trauma and improve reproduction, particularly when it is difficult to manipulate the group compositions and/or their housing situations. Reducing trauma is a primary goal for rhesus breeding colonies, as it directly impacts the monkeys' health and psychological well-being. Such improvements are necessary for the ethical treatment and care of the animals themselves, but also to reduce financial burdens and maintain a healthy colony for research purposes.

scholarly journals Ecological and social constraints combine to promote evolution of non-breeding strategies in clownfish

2020 ◽  
Vol 3 (1) ◽  
Author(s):  
Rebecca Branconi ◽  
Tina A. Barbasch ◽  
Robin K. Francis ◽  
Maya Srinivasan ◽  
Geoffrey P. Jones ◽  
...  
Keyword(s):  
Cooperative Breeding ◽  
Wild Population ◽  
Social Constraints ◽  
Bargaining Theory ◽  
Breeding Strategies ◽  
Ecological Constraints ◽  
Amphiprion Percula ◽  
Outside Options ◽  
Risk Of Mortality ◽  
Animal Societies

Abstract Individuals that forgo their own reproduction in animal societies represent an evolutionary paradox because it is not immediately apparent how natural selection can preserve the genes that underlie non-breeding strategies. Cooperative breeding theory provides a solution to the paradox: non-breeders benefit by helping relatives and/or inheriting breeding positions; non-breeders do not disperse to breed elsewhere because of ecological constraints. However, the question of why non-breeders do not contest to breed within their group has rarely been addressed. Here, we use a wild population of clownfish (Amphiprion percula), where non-breeders wait peacefully for years to inherit breeding positions, to show non-breeders will disperse when ecological constraints (risk of mortality during dispersal) are experimentally weakened. In addition, we show non-breeders will contest when social constraints (risk of eviction during contest) are experimentally relaxed. Our results show it is the combination of ecological and social constraints that promote the evolution of non-breeding strategies. The findings highlight parallels between, and potential for fruitful exchange between, cooperative breeding theory and economic bargaining theory: individuals will forgo their own reproduction and wait peacefully to inherit breeding positions (engage in cooperative options) when there are harsh ecological constraints (poor outside options) and harsh social constraints (poor inside options).

scholarly journals Sex-biased dispersal, haplodiploidy and the evolution of helping in social insects

2011 ◽  
Vol 279 (1729) ◽  
pp. 787-793 ◽  
Author(s):  
Rufus A. Johnstone ◽  
Michael A. Cant ◽  
Jeremy Field
Keyword(s):  
Sex Ratio ◽  
Social Insects ◽  
Family Relationships ◽  
Nest Building ◽  
Kin Discrimination ◽  
Sterile Female ◽  
Sex Ratio Bias ◽  
Non Local ◽  
Reproductive Altruism ◽  
Existing Data

In his famous haplodiploidy hypothesis, W. D. Hamilton proposed that high sister–sister relatedness facilitates the evolution of kin-selected reproductive altruism among Hymenopteran females. Subsequent analyses, however, suggested that haplodiploidy cannot promote altruism unless altruists capitalize on relatedness asymmetries by helping to raise offspring whose sex ratio is more female-biased than the population at large. Here, we show that haplodiploidy is in fact more favourable than is diploidy to the evolution of reproductive altruism on the part of females, provided only that dispersal is male-biased (no sex-ratio bias or active kin discrimination is required). The effect is strong, and applies to the evolution both of sterile female helpers and of helping among breeding females. Moreover, a review of existing data suggests that female philopatry and non-local mating are widespread among nest-building Hymenoptera. We thus conclude that Hamilton was correct in his claim that ‘family relationships in the Hymenoptera are potentially very favourable to the evolution of reproductive altruism’.

scholarly journals Causes and consequences of adult sex ratio imbalance in a historical U.S. population

2017 ◽  
Vol 372 (1729) ◽  
pp. 20160314 ◽  
Author(s):  
Ryan Schacht ◽  
Ken R. Smith
Keyword(s):  
Biological Sciences ◽  
Sex Ratio ◽  
Life History Traits ◽  
Male Mating ◽  
Age At First Birth ◽  
The Social ◽  
Adult Sex Ratio ◽  
Sex Ratio Imbalance ◽  
Animal Societies

The responsiveness of individuals to partner availability has been well-documented across the literature. However, there is disagreement regarding the direction of the consequences of sex ratio imbalance. Specifically, does an excess of males or females promote male–male mating competition? In an attempt to clarify the role of the adult sex ratio (ASR) on behaviour, here we evaluate both competing and complimentary expectations derived from theory across the social and biological sciences. We use data drawn from a historical, nineteenth century population in North America and target several life-history traits thought to be affected by partner availability: age at first birth, relationship status, completed fertility and longevity. Furthermore, we assess the role of various contributors to a population's ASR. We find that both the contributors to and consequences of sex ratio imbalance vary over time. Our results largely support predictions of greater male pairbond commitment and lesser male mating effort, as well as elevated bargaining power of women in response to female scarcity. After reviewing our findings, and others from across the literature, we highlight the need to adjust predictions in response to ASR imbalance by the: (i) culturally mediated mating arena, (ii) variable role of demographic inputs across time and place, (iii) constraints to behavioural outcomes across populations, and (iv) ability and accuracy of individuals to assess partner availability. This article is part of the themed issue ‘Adult sex ratios and reproductive strategies: a critical re-examination of sex differences in human and animal societies’.

Dieldrin reduces male production and sex ratio in Daphnia galeata mendotae

1999 ◽  
Vol 15 (1-2) ◽  
pp. 193-200 ◽  
Author(s):  
Christine M. Merritt ◽  
Laura Torrentera ◽  
Katherine M. Winter ◽  
Christopher K. Tornehl ◽  
Kristin Girvin ◽  
...  
Keyword(s):  
Sex Ratio ◽  
Male Production ◽  
Daphnia Galeata ◽  
Daphnia Galeata Mendotae

scholarly journals Direct assessment of queen quality and lack of worker suppression in a paper wasp

2005 ◽  
Vol 272 (1570) ◽  
pp. 1339-1344 ◽  
Author(s):  
Jürgen Liebig ◽  
Thibaud Monnin ◽  
Stefano Turillazzi
Keyword(s):  
Reproductive Output ◽  
Ovarian Development ◽  
Inclusive Fitness ◽  
Reproductive Activity ◽  
Egg Laying ◽  
Paper Wasp ◽  
Polistes Dominulus ◽  
Queen Policing ◽  
Reproductive Conflicts ◽  
Animal Societies

Assessing a conspecific's potential is often crucial to increase one's fitness, e.g. in female choice, contests with rivals or reproductive conflicts in animal societies. In the latter, helpers benefit from accurately assessing the fertility of the breeder as an indication of inclusive fitness. There is evidence that this can be achieved using chemical correlates of reproductive activity. Here, we show that queen quality can be assessed by directly monitoring her reproductive output. In the paper wasp Polistes dominulus , we mimicked a decrease in queen fertility by regularly removing brood. This triggered ovarian development and egg-laying by many workers, which strongly suggests that brood abundance is a reliable cue of queen quality. Brood abundance can be monitored when workers perform regular brood care in small size societies where each brood element is kept in a separate cell. Our results also show that although the queen was not manipulated, and thus remained healthy and fully fertile, she did not control worker egg-laying. Nevertheless, when workers laid eggs, the queen secured a near reproductive monopoly by selectively destroying these eggs, a mechanism known as ‘queen policing’. By contrast, workers destroyed comparatively few queen-laid eggs, but did destroy each other's eggs.

REPRODUCTIVE CONFLICT IN SOCIAL INSECTS: MALE PRODUCTION BY WORKERS IN A SLAVE-MAKING ANT

Evolution ◽  
2005 ◽  
Vol 59 (11) ◽  
pp. 2480
Author(s):  
Elisabeth Brunner ◽  
Andreas Trindl ◽  
Karl H. Falk ◽  
Juergen Heinze ◽  
Patrizia D'Ettorre
Keyword(s):  
Social Insects ◽  
Male Production ◽  
Reproductive Conflict
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