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Worker policing

Worker policing is a conflict-mediating behavior observed in eusocial insect societies, particularly among ants, bees, and wasps, in which non-reproductive workers suppress the reproductive attempts of other workers—most commonly by rapidly consuming worker-laid eggs—to prioritize the production and rearing of the queen's offspring, thereby reducing intra-colony conflict over male parentage. This phenomenon exemplifies how cooperative societies enforce altruism despite potential incentives for individual selfishness, as workers in many species retain the physiological ability to reproduce but face evolutionary pressures to forgo it. Key examples include the honeybee (Apis mellifera), where workers preferentially remove over 95% of worker-laid eggs within hours while sparing queen-laid ones, and the common wasp (Vespula vulgaris), in which genetic analyses of adult males confirm near-total absence of worker-derived sons due to effective egg-eating policing. Similar patterns occur in other vespine wasps like Dolichovespula saxonica and across multiple ant and bee genera, with policing documented in at least 50 species spanning Hymenoptera. The evolutionary origins of worker policing have been modeled through evolutionary stable strategy (ESS) analyses and , revealing that it stabilizes under conditions of multiple queen mating (typically three or more patrilines), where relatedness asymmetries alone are insufficient without gains in colony-level efficiency, such as reduced disruption to and brood care from unchecked worker . In single-mated queen colonies, policing may still invade if it boosts overall by even a small margin (e.g., 1%), but its persistence requires monotonic efficiency improvements with higher policing intensity. Across taxa, worker policing correlates more strongly with mitigation of "tragedy of the commons" costs—such as lowered colony output from reproductive conflicts—than with haplodiploid relatedness differences, underscoring its role in promoting eusociality's .

Overview

Definition and Core Concept

Worker policing is a reproductive mechanism observed in eusocial societies, particularly among , where non-reproductive workers actively suppress reproduction by other workers to favor the production of males by the queen. This behavior primarily manifests through , the targeted consumption of eggs laid by workers, thereby enforcing the queen's monopoly on male production and promoting colony-level reproductive harmony. The concept of worker policing was first proposed theoretically by Francis L. W. Ratnieks in 1988, who argued that in colonies with multiple-patriline , workers benefit from policing each other's due to lower relatedness to worker-derived males compared to queen-derived ones. This theoretical framework was empirically validated the following year through experiments on honeybees (Apis mellifera), where workers were observed to preferentially consume worker-laid eggs over queen-laid ones, confirming the policing behavior in a natural setting. In practice, worker policing operates rapidly: within the first few hours after laying, worker-laid are detected and removed by policing workers, with survival rates dropping to less than 1% in queenright colonies, while queen-laid exhibit survival rates around 59-61%. This selective egg destruction effectively limits worker to negligible levels, often resulting in worker-derived males comprising only about 0.1% of the colony's male output. By minimizing intraspecific conflict over male parentage, worker policing enhances overall colony efficiency, as resources are directed toward queen-produced offspring that benefit the majority of workers through higher under principles.

Role in Maintaining Colony Harmony

Worker policing plays a crucial role in resolving reproductive conflicts within eusocial colonies by suppressing individual workers' attempts to lay male-producing eggs, thereby preventing the spread of selfish reproductive behaviors that could undermine colony cohesion. In haplodiploid , this conflict arises from relatedness asymmetries, where workers are more closely related to their own sons (r = 0.5) or nephews (r = 0.375 on average) than to the queen's sons (r = 0.25), potentially favoring worker over queen production of males. However, through mutual policing—where workers destroy eggs laid by other workers—this enforces reproductive restraint, ensuring that the majority of males are queen-produced and aligning individual actions with colony-level interests. The primary benefit of worker policing to the colony lies in enhancing by prioritizing the production of higher-relatedness and minimizing energy expenditure on worker-laid eggs that are often removed or fail to develop. This reduces wasteful to doomed and promotes the of fitter queen-produced males, which can contribute more effectively to . Theoretical models demonstrate that such policing can yield significant colony-level gains; for instance, policing can evolve even in single-mated queen colonies if it increases colony-level by at least 20%, particularly in larger colonies where the costs of unchecked worker reproduction are amplified by increased competition and resource demands. Beyond immediate reproductive efficiency, worker policing contributes to broader colony harmony by stabilizing the division of labor, as non-reproductive workers devote more time to essential tasks like , , and rather than competing for reproductive opportunities. This suppression of individual fosters cooperative behaviors that are foundational to the evolution and maintenance of , allowing colonies to achieve higher levels of organization and productivity compared to those without effective mechanisms. Empirical observations in species exhibiting strong worker policing reveal rates of worker ovarian activation ranging from 6% to 43% in queenright , which correlates with elevated overall colony productivity and reproductive success. For instance, in honeybees, this limited activation ensures that worker-laid eggs constitute a negligible of male production, supporting sustained colony growth and efficiency.

Evolutionary Foundations

Kin Selection and Relatedness Asymmetry

Kin selection theory provides the foundational evolutionary explanation for worker policing in eusocial , where workers altruistically destroy eggs laid by other workers to favor the queen's reproduction. According to , a social behavior evolves if the inclusive fitness benefit to the recipient, weighted by relatedness r_b, exceeds the cost c to the actor: r_b b > c. In the context of worker policing, r_b represents the policing worker's relatedness to the queen's sons (the beneficiaries), b is the fitness benefit from promoting the queen's male offspring over worker-laid males, and c is the cost of policing, such as time or energy expended in egg removal. This rule predicts that policing is favored when workers are more related to queen-laid males than to worker-laid males, which occurs primarily under queen polyandry. Haplodiploid sex determination in creates a key relatedness asymmetry relevant to policing. Under single queen-mating, workers are related to their full sisters by r = 0.75, to the queen's sons (brothers) by r = 0.25, to their own sons by r = 0.5, and to nephews (sons of other workers) by r = 0.375. A laying worker prefers her own sons (r = 0.5) over the queen's sons (r = 0.25), but other workers are more related to nephews (r = 0.375) than to brothers (r = 0.25), creating an asymmetry that favors rearing worker-laid males over queen-laid ones under single mating. Multiple mating by the queen reduces average worker-worker relatedness, lowering the average relatedness to nephews below 0.25, which then favors policing to promote queen's higher-related sons and suppress worker . Worker policing exemplifies by resolving conflicts over male parentage, as workers collectively increase their through the production of the queen's offspring when relatedness favors it. Foundational models demonstrate that policing behaviors are evolutionarily stable when average worker relatedness to the queen's sons exceeds that to worker-produced males, particularly under . Empirical comparative analyses across species confirm that policing is more prevalent where relatedness asymmetry favors queen's sons (e.g., in polyandrous lineages), supporting the framework.

Theoretical Predictions and Models

The foundational theoretical framework for worker policing was developed by Ratnieks in 1988, who modeled it as a mechanism to resolve reproductive conflicts in eusocial . The model predicts that policing evolves when workers are more closely related to queen-laid male eggs (relatedness r_q = 0.25) than to worker-laid male eggs (relatedness r_w, which averages lower under queen due to reduced average relatedness among workers). This asymmetry arises because multiple mating dilutes worker-worker relatedness below the threshold where workers prefer nephews over brothers, making it beneficial for workers to remove worker-laid eggs to favor queen production. The condition for policing to spread is r_q > r_w, leading to fixation when the inclusive fitness benefits outweigh costs. Subsequent simulations extended this framework to incorporate colony-level dynamics, particularly the role of colony size in modulating policing costs. In a comprehensive analysis, Wenseleers, Helanterä, and Ratnieks (2004) used individual-based models to show that policing becomes advantageous in large colonies because the per-worker cost of policing is diluted across many individuals, allowing efficient suppression of without substantial penalties to any single worker. In smaller colonies, higher costs make policing less viable, permitting higher levels of worker . These simulations predict near-complete worker sterility in large-colony like honeybees, where policing efficiency approaches 98%, aligning with observed low reproductive rates (0.01–0.1%). More recent theoretical updates have refined these predictions by integrating variable degrees of , showing that moderate multiple reduces relatedness asymmetry and shifts the policing threshold toward weaker enforcement. For instance, in with effective queen frequencies q = 2-3, models indicate that the benefit of policing diminishes, often resulting in "selfish" or facultative policing driven by intra-worker competition rather than harmony with the . This is because r_w remains relatively high, making full policing less stable unless supplemented by dominance hierarchies. Empirical tests of these models reveal strong concordance with phylogenetic patterns: worker policing is prevalent in polyandrous species like honeybees (effective q \approx 10-20), where asymmetry favors it, but rare or absent in singly mated species with q = 1 (e.g., many bumblebees), and variably present in highly polyandrous ants (q > 5), where extreme dilution of r_w reinforces policing despite potential costs. A comparative analysis across approximately 100 hymenopteran species confirms that policing frequency correlates positively with effective mating frequency, supporting the asymmetry hypothesis over alternatives like queen control.

Recognition Mechanisms

Chemical Cues from Queen and Workers

Queens produce distinct blends of cuticular hydrocarbons (CHCs) that serve as fertility signals, marking their eggs for against worker policing in social . These queen-specific CHCs, transferred to eggs during oviposition, include high proportions of certain alkenes and methyl-branched alkanes that workers recognize as legitimate. In honeybees (Apis mellifera), for instance, queens exhibit elevated levels of (Z)-9-hentriacontene and related compounds in their CHC profiles, which correlate with egg viability and inhibit policing behaviors. Reproductively active workers, in contrast, display shifted CHC profiles characterized by increased relative abundance of n-alkanes, rendering their eggs recognizable as targets for destruction. This chemical distinction arises from physiological changes associated with ovarian activation, where fertile workers produce fewer fertility-signaling compounds and more neutral n-alkanes compared to or sterile workers. Such profiles facilitate rapid identification by policing workers, ensuring the selective removal of worker-laid eggs to favor reproduction. Workers detect these chemical differences through antennal contact, assessing the ratios of key CHCs on egg surfaces to determine maternity. Eggs lacking sufficient queen-like cues—typically those with low alkene-to-n-alkane ratios—are promptly eaten, typically within the first hour of detection, minimizing the potential for worker-derived males to develop. This sensory process relies on specialized antennal receptors tuned to CHC blends, enabling efficient policing without visual or positional cues. Experimental evidence supports the role of these chemical signals in policing. Visscher and Dukas (1995) demonstrated that workers recognize and preferentially attack individuals with developed ovaries, a that is less frequent due to queen pheromones suppressing worker ovarian development. More recently, a 2023 study on the African carpenter ant Camponotus maculatus confirmed distinct CHC chemotypes on eggs in policed colonies, with workers consistently removing those deviating from profiles despite colony-level variations.

Behavioral and Contextual Recognition

In worker policing, behavioral recognition plays a key role in identifying and suppressing by subordinate workers, often through direct rather than solely relying on removal. Workers may attack or immobilize egg-laying individuals using antennation, biting, or holding appendages to prevent oviposition, thereby addressing the source of potential selfish before eggs are laid. For instance, in the Harpegnathos saltator, subordinate workers cooperatively bite and immobilize dominant reproductive workers, effectively reducing the number of egg-layers and enforcing reproductive . This proactive complements egg-eating behaviors and is observed across various , where it inhibits ovarian activation in targeted individuals. Contextual factors, such as the location of egg-laying within the , further modulate policing decisions by providing environmental cues that signal appropriate reproductive contexts. Eggs laid in worker-dominant brood areas, like peripheral , are more likely to be policed than those in central queen-laying regions, where pheromones dominate and suppress worker . Experimental introductions of eggs into different nest positions demonstrate that such spatial cues influence removal rates, with brood-area eggs facing higher scrutiny due to reduced -signal . Additionally, policing intensity varies with colony context, including nestmate , where foreign eggs from non-natal workers experience stronger rejection. A 2023 study on bumblebees () found that non-natal worker eggs were removed at a rate of 85% (15% after 20 hours) in early colony stages, compared to 76% removal (24% ) for natal eggs, highlighting kin-biased contextual discrimination. Age and behavioral state also affect policing efficacy, with older forager workers exhibiting heightened toward reproductive attempts, though no dedicated "policeman caste" exists. Instead, policing is distributed among a of workers across age classes, ensuring colony-wide enforcement without specialization. In like the ant Pachycondyla inversa, a behavioral performs policing tasks, including toward layers, but this is not strictly age-bound, allowing flexible responses to reproductive threats. Older workers, having transitioned to roles, contribute disproportionately to these interactions due to their and experience in nest monitoring.

Examples in Hymenoptera

Honeybees

In the honeybee Apis mellifera, worker policing manifests as the rapid and selective removal of worker-laid eggs by other workers, ensuring that reproduction is predominantly controlled by the queen. Experimental studies have demonstrated that workers remove the majority of worker-laid eggs within hours, with approximately 85% removed within 1 day in queenright colonies, while queen-laid eggs are typically left intact. This high efficiency restricts successful worker reproduction to less than 0.1% of eggs in queenright colonies, where only about 0.01–0.1% of workers develop active . The queen mandibular pheromone (QMP), produced by the queen's mandibular glands, plays a dual role by suppressing ovary development in workers—preventing most from becoming reproductively active—and facilitating the recognition of legitimate queen-laid eggs through chemical cues that mark them as non-worker-derived. Seminal cage experiments by Ratnieks (1993) provided key evidence for policing efficiency in queenright colonies, where worker-laid eggs introduced into drone cells were preferentially eaten by nestmates, with removal rates of approximately 85% within one day, compared to minimal removal of -laid controls. These studies involved isolating groups of workers with or without a and monitoring egg fate, revealing that policing operates even in the absence of brood or full colony context, underscoring its robustness as a mechanism to enforce reproductive division of labor. In such setups, the low incidence of worker-laid eggs in natural drone comb (fewer than 1 per 10,000 cells) further confirms that policing effectively curbs selfish reproduction under normal conditions. Policing dynamics vary with colony state; in queenless colonies, the breakdown of policing allows worker reproduction to increase dramatically. Without QMP, worker ovaries activate progressively over 2–3 weeks, and egg removal rates decline, enabling laying workers to produce viable male offspring as the colony attempts to rear a new queen. Additionally, genetic factors such as queen mating frequency influence policing strength across strains; in populations with lower (fewer effective patrilines), the relatedness between workers and nephews versus brothers is reduced, weakening the selective for policing and resulting in higher of worker-laid eggs compared to highly polyandrous strains.

Ants

Worker policing in ants (family Formicidae) manifests as the selective oophagy or removal of worker-laid eggs by nestmate workers, a process that unfolds over hours to days, contrasting with the more immediate responses in other hymenopterans. This behavior helps resolve genetic conflicts over male production, favoring the rearing of queen's sons, and is influenced by colony structure, including queen mating frequency and the presence of alternative reproductives. In monandrous species, such as Formica exsecta, policing is highly efficient, with worker-produced males comprising only 0.4% of total males, indicating near-complete suppression of worker reproduction. A key example comes from the African carpenter ant Camponotus maculatus, where a 2023 study identified distinct cuticular (CHC) profiles on worker-laid eggs relative to queen-laid eggs in certain chemotypes, prompting selective removal by workers; in queenless assays, worker-laid eggs experienced significantly higher rates, with low survival after 24 hours across colony variants. In contrast, polyandrous species like Lasius niger exhibit reduced policing intensity, with worker-produced males accounting for about 3.9% of total males due to decreased relatedness asymmetry among workers. Mechanisms in ants often involve chemical recognition of egg surfaces, but are complicated in species featuring gamergates—mated workers that assume queen-like roles and produce cuticular cues akin to those of alate queens—leading to targeted aggression against unauthorized reproductives rather than routine egg policing; workers nonetheless aggressively eliminate foreign eggs to enforce reproductive hierarchies. Evolutionarily, worker policing has arisen multiple times across ant subfamilies, driven by in response to relatedness asymmetries, yet it is notably absent in slave-making species such as rufescens, where 100% of males derive from workers, reflecting adaptations to interspecific host conflicts that prioritize parasitic brood raiding over internal regulation.

Wasps

Worker policing has convergently evolved in wasps, particularly within the family, paralleling the egg-eating behavior observed in honeybees to resolve genetic conflicts over male production. In the common wasp , workers rapidly remove nearly all worker-laid eggs, with 97% (116 out of 120) destroyed within one hour, while accepting 88% of queen-laid eggs. This results in virtually no worker-derived males (0% in genetic analyses of 270 males from nine colonies), demonstrating effective policing that favors the queen's sons over workers' nephews due to higher relatedness asymmetry in singly mated queens. Unlike honeybees, which rely on a potent queen mandibular pheromone for suppression, wasps lack such a centralized chemical signal; instead, recognition of reproductive eggs depends on shifts in cuticular hydrocarbons (CHCs) produced by fertile workers, which serve as fertility cues targeted by policing behaviors. regulates both ovarian activation in workers and the production of these egg-marking pheromones, enabling precise discrimination and destruction of worker-laid eggs in queenright colonies. Policing intensity is context-dependent, waning after queen death as workers' ovaries activate and reproduction surges, shifting colony dynamics toward worker-derived males. In more primitive paper wasps like species, policing deviates from the universal egg destruction seen in advanced vespines, relying instead on dominance hierarchies where the queen and high-ranking subordinates suppress subordinates' reproduction through physical aggression and selective . For instance, in and P. dominulus, workers produce up to 51% of males with minimal worker policing (0% incidence), as queen policing maintains her monopoly, though workers occasionally aid in egg removal. This hierarchical control reflects the smaller colony sizes and lower in Polistes compared to . Recent studies highlight facultative aspects of policing in tropical wasps, particularly swarm-founding Epiponini, where worker control over reproduction strengthens in larger colonies (>100 workers) to maintain high relatedness. In the epiponine Brachygastra mellifica, collective worker policing in colonies averaging 7,951 adults suppresses individual selfishness, aligning with kin selection benefits in high-paternity contexts. These findings underscore how colony size modulates policing efficiency across vespid diversity.

Extensions to Other Social Insects

Termites

In (order Isoptera), worker policing manifests as the targeted destruction of eggs laid by neotenic reproductives—worker- or nymph-derived individuals that attempt reproduction within the —primarily carried out by workers and soldiers to enforce reproductive division of labor. Unlike haplodiploid , termites exhibit diplodiploid inheritance with symmetric relatedness among colony members (r = 0.5 between workers and siblings), eliminating the genetic asymmetry that drives policing in bees and ; instead, this behavior is thought to evolve via colony-level selection, enhancing overall colony fitness by preventing disruptive proliferation of secondary reproductives and maintaining efficient toward and nest maintenance. Policing mechanisms in termites combine physical aggression and chemical cues. In the lower termite , older neotenics initiate attacks by biting conspecific neotenics, accompanied by vibrational alarm signals that recruit workers to cannibalize the victims, resulting in over 75% mortality of unprotected neotenics within 90 days and limiting their numbers to fewer than three per under natural conditions. Chemical suppression via pheromones further inhibits neotenic development, with physical policing serving as a backup to eliminate any that emerge. In higher such as Macrotermes species, overt policing is rarer due to more specialized castes and stronger preemptive chemical inhibition, where neotenic reproductives occur in only about 13% of genera compared to over 60% in lower , achieving near-complete suppression of worker-derived to sustain the primary king- pair's monopoly. This policing behavior underscores evolutionary convergence with , having arisen independently multiple times in lineages to resolve intracolonial reproductive conflicts, with particularly robust enforcement in large, mound-building higher where colony sizes exceed millions of individuals, ensuring long-term stability of the royal pair's reproduction.

Blattodea and Related Groups

In wood-feeding of the genus , which exhibit subsocial family structures with biparental care, dominant individuals suppress among subordinates through aggressive interactions, maintaining reproductive skew via size hierarchies and in these primitive groups. This behavior is analogous to worker policing in more advanced eusocial , as it prevents disruptive by non-dominant family members and promotes colony cohesion in subsocial settings without distinct castes. Mechanisms of this suppression involve tactile aggression, such as physical during oviposition, and pheromonal cues that inhibit subordinate ovarian , as observed in laboratory studies of family dynamics. A 2020 analysis of neotropical in the Melyroidea group, including like Melyroidea magnifica, revealed varying degrees of with cooperative brood care and reproductive division of labor, where a single dominant female monopolizes reproduction while subordinates forgo laying eggs, supported by group defense and foraging. In these groups, qualitative observations indicate reproductive skew.

Exceptions and Variations

Anarchic Syndromes

Anarchic syndromes represent exceptional cases in honeybee (Apis mellifera) colonies where the mechanisms of worker policing break down, permitting substantial worker reproduction despite the presence of a functional . This rare behavioral anomaly, often termed the "anarchic syndrome," arises primarily in selected laboratory strains like the (anarchistic) line, where genetic mutations disrupt the normal suppression of worker oviposition and egg removal. In such colonies, workers evade policing by producing eggs with altered marking pheromones that closely mimic those of -laid eggs, resulting in low detection and removal rates. The causes of anarchic syndromes trace to heritable genetic factors that impair -based recognition and inhibition. Seminal experiments by Oldroyd and Ratnieks (2000) revealed that anarchic workers lay eggs that are removed at only about 20% the rate of typical worker eggs, allowing 1–5% of workers to actively oviposit while 5–10% develop active ovaries. These mutations lower sensitivity to queen mandibular , which normally inhibits worker reproduction, and may involve specific quantitative trait loci influencing sterility enforcement. Consequently, worker-derived males can constitute 20–30% of emerging drones in these colonies, far exceeding the 0.1% observed in standard queenright hives. This failure of policing imposes severe fitness costs on affected colonies, including reduced worker and elevated resource diversion to rearing excess drones, which can diminish overall brood production and lead to colony instability or collapse without human intervention. Anarchic workers exhibit lower and rates, contributing to a colony-level productivity decline that offsets any individual reproductive gains. The remains evolutionarily unstable, as with non-anarchic workers rapidly restores effective policing through superior egg removal. In wild populations, queen polyandry—mating with multiple drones—bolsters among workers, enhancing policing efficiency and thereby increasing tolerance to potential anarchic outbreaks by diluting the spread of selfish reproductive traits. Studies indicate that higher paternity diversity suppresses worker ovary activation and selfish laying, stabilizing colonies against such disruptions.

Selfish or Context-Dependent Policing

In queenless phases of bumblebee colonies, such as those of Bombus terrestris, dominant workers engage in policing by consuming the eggs laid by subordinate workers, thereby monopolizing reproduction for their own direct fitness gains rather than promoting the production of queen's offspring. This selfish policing arises from intense reproductive competition among workers, where only a few dominant individuals successfully rear males, suppressing rivals to enhance their personal reproductive success. Worker policing in bumblebees exhibits strong context-dependency, varying with colony stage and egg origin. A 2023 study demonstrated that in early-stage colonies (pre-competition point), policing is significantly more effective against non-natal worker eggs (15% survival rate) than natal worker eggs (24% survival rate), allowing natal workers a biased opportunity for selfish reproduction while collectively policing potential parasites. This bias diminishes in later stages (post-competition point), where survival rates equalize (27% for non-natal vs. 28% for natal), reflecting shifts in conflict dynamics as colonies mature. Policing is notably reduced or absent in very small, early colonies with fewer workers, where low reproductive skew limits the incentives for aggressive suppression. Similar selfish and context-dependent policing occurs in certain , exemplified by Diacamma sp., where gamergates—reproductive workers functioning as —aggressively consume eggs laid by non-reproductive workers to enforce their dominance and elevate the average relatedness of males to their own . In small Diacamma colonies, mutual worker policing broadly suppresses subordinate reproduction to favor , but in larger, mature colonies, dominant workers shift to selfish policing, tolerating their own laying while eliminating rivals' eggs to secure personal gains. These cases highlight how worker policing often deviates from pure altruism, incorporating selfish elements that prioritize individual worker interests, particularly in queenless or high-conflict contexts. Theoretical models, such as evolutionary stable strategy analyses, predict that in facultative policing systems with variable relatedness, a substantial portion of policing behavior evolves to resolve intra-worker conflicts, blending selfish restraint of rivals with colony-level benefits.

Policing Without Underlying Genetic Conflict

In diploid social insects such as , worker policing enforces reproductive division of labor without the genetic conflicts driven by haplodiploid sex determination or multiple paternity. In the eastern subterranean termite , workers and older neotenic reproductives cooperatively eliminate excess neotenics—pluripotent workers that develop into secondary reproductives—through targeted , thereby maintaining a single breeding pair and optimizing colony efficiency. This behavior is initiated when older neotenics detect and bite potential reproductives, producing alarm vibrations that recruit additional workers to join the attack and consume the victim, resulting in substantial suppression of neotenic development (e.g., survival of female ergatoids reduced to approximately 22% of potential levels over 90 days). Soldiers play no role in this process, underscoring that enforcement relies on worker rather than specialized castes. Such policing aligns with colony-level selection for social harmony, as workers are equally related to all siblings (relatedness r = 0.5) and lack asymmetries in that might favor selfish reproduction. A similar mechanism operates in certain lacking genetic variation among workers. In the clonal Platythyrea punctata, which reproduces via thelytokous , workers aggressively police newly emerging reproductives by biting and dragging them, often causing ovarian regression or death, to restrict reproduction to a single dominant individual per colony. Workers detect targets through chemical cues like cuticular hydrocarbons associated with ovarian development, with aggression rates increasing significantly after colony fission and reunification (e.g., up to fivefold in experimental groups). This mutual enforcement prevents resource competition and brood care disruption, enhancing overall colony productivity without any underlying relatedness differences. Theoretical models support the stability of these non-conflict policing systems through , where cooperative enforcement evolves via mutual benefits in diploid societies, independent of Hamilton's rule. For example, simulations demonstrate that policing sustains reproductive monopolies in clonal or equally related groups by punishing deviation, leading to higher fitness for participants compared to unchecked . Recent analyses of eusocial evolution in diploids, including and , further predict convergent policing as a response to ecological pressures like resource limitation, reinforcing division of labor without kin-biased conflicts.