R

Ropalidia Independent-Founding Species

Raghavendra Gadagkar In common with most Belonogaster, ▶ Mis- Centre for Ecological Sciences, Indian Institute of chocyttarus, ▶ Parapolybia, and ▶ Polistes, inde- Science, Bangalore, India pendent-founding Ropalidia are characterized by small colonies, simple, small, open nests often suspended by a narrow petiole, relatively little Ropalidia is a large genus of social wasps in the queen-worker dimorphism, behavioral control of subfamily Polistinae. It comprises about 186 workers by the queen, and a well-developed Van known species distributed in tropical Africa, and der Vecht’s gland on the sixth gastral sternum for southern and eastern Asia to Australia [7]. It is defense against ants. As their name implies, new considered the sister-genus of Parapolybia, and colonies are founded by queens or potential these two genera together are considered the sis- queens, unaccompanied by workers. This descrip- ter-group of Polybioides + Belonogaster. The four tion of “independent-founding” is only to contrast genera together comprise the Old World tribe them with swarm-founding species, because, in Ropalidiini. However, research on taxonomy and the absence of queen-worker dimorphism, the systematics of the genus has since stagnated, question of workers accompanying queens or depriving us of a satisfactory understanding of not, does not arise [7, 13]. the diversity and taxonomic organization of the ▶ Nest Structure. Ropalidia nests may be ori- genus and even more seriously, of any reasonable ented in the vertical or horizontal plane and may phylogenetic analysis. This is a pity, because be of varying sizes. Most often, the comb is cir- Ropalidia has long been considered a crucial cular or oval in shape with many rows and col- genus for understanding social evolution in social umns of cells, but in some species there may be as wasps, especially on account of its variation in few as two long columns of cells (Fig. 1). Some- ▶ colony cycle. It is the only genus that includes times, several small combs with their individual both independent-founding and swarm-founding petioles may be clustered together to serve as a species and shows many other variations in single nest [7]. Such multicombed nests at the nesting pattern. extreme may reach thousands of combs, as in

© Springer Nature Switzerland AG 2019 C. Starr (ed.), Encyclopedia of Social Insects, https://doi.org/10.1007/978-3-319-90306-4_102-1 2 Ropalidia

Ropalidia, Fig. 1 Typical nests of Ropalidia marginata (left) and R. jacobsoni (right) in Bangalore, India. (Photos by Thresiamma Varghese)

Ropalidia, Fig. 2 A photograph of an aggregation of R. plebeiana colonies (aptly called a “town”) hanging from a large concrete pipe (left) and a close-up photo of founding female wasps that cutting a nest into two different parts (right). (Photos by Soichi Yamane)

Ropalidia plebiana in Australia (Fig. 2), although can turn-over in the tropics, nests can be occupied the adaptive significance of such massive dense by generations of wasps and are potentially aggregations is unclear [12]. immortal. Nesting Cycle. The nesting cycle depends on New nests may be initiated by one female the climate, with annual colonies in the higher (single-foundress or haplometrotic nests) or by latitudes and perennial indeterminate cycles in small groups of females (multiple-foundress or the tropics. In an indeterminate cycle, in addition pleometrotic nests). In single-foundress nests, to being initiated at any time of the year, the the lone female performs all the tasks involved duration of the cycle can be extremely variable. in building and maintaining the nest, as well as Many nests fail without producing any adult off- foraging and feeding the larvae, laying eggs, and spring, but some can last several months and defending the nest. In a multiple-foundress asso- probably years. Since both workers and queens ciation, usually only one female lays eggs, while Ropalidia 3 the remaining co-foundresses function as sterile more food and are more likely to become egg workers that perform all other tasks. However, layers. Poorly fed larvae develop into adults that one of them may sometimes replace the queen eat less even when provided ad libitum food and and take over as the next queen [7, 12]. are more likely to become non-egg laying workers The egg layer, whether in a single- or multiple- [8]. Such pre-imaginal caste bias, however, is only foundress nest, is usually inseminated and has a bias. Actual caste differentiation remains subject stored sperm in her spermatheca although she to social interactions. Dominance-subordinate may occasionally not mate until after assuming interactions before or after colony initiation help the role of principal egg layer. In long-lived nests, make the dominants into egg layers and subordi- such as those of R. marginata, queens are period- nates into workers. Even such differentiation is ically replaced by their daughters, sisters, nieces often reversible, making it possible for queens to or cousins while the rest of the individuals con- be replaced and workers to develop their ovaries tinue to work for their new queens without appar- and become queens. In some species, dominance ent disruption to the overall social organization. In hierarchies persist throughout the colony cycle the extreme case, such serial polygyny may lead and make it relatively easy to predict the identity to highly variable genetic relationships within of successive queens based on their position in the colonies. Colonies in one study were shown by hierarchy. However, the actual frequencies of pedigree analysis to consist of a complex of dominance-subordinate interactions and, indeed, mothers and daughters, sisters, nieces, cousins, the mechanisms of queen succession may vary cousins’ offspring, mother’s cousins’ offspring greatly in different species [8, 9, 12, 18, 24]. and grand offspring. The lifespans of workers Queens of at least one species (R. marginata) can be quite variable although they typically live become meek and docile within a week of assum- for a few weeks. The tenure of queens can be even ing the role of sole egg-layer and appear to regu- more variable, ranging in one study from seven late worker reproduction through pheromones. days to 236 days. Correspondingly, the productiv- There is a reproductive queue in this species, ity of queens can also be highly variable, so that even though successors cannot be identified they may have from zero to hundreds of offspring before the death or loss of the reigning queen. and lay up to ten eggs per day [7, 8]. As far as can be told, potential queens are ▶ Caste Differentiation. Independent- not different from typical workers in morphology, founding Ropalidia are classified as primitively behavior, dominance rank, residual ovarian devel- ▶ eusocial, the main implication of which is that opment, or pheromone profile. Nor is the potential there is no morphological distinction between queen predicted by her genetic relatedness to queens and workers. Thus, caste differentiation the colony members. However, there is into fertile queens and sterile workers takes place intriguing evidence that the wasps themselves after the adults eclose. Such post-imaginal caste seem to “know” the identity of their next queen, differentiation is mediated through behavioral resulting in a conflict-free succession. Older indi- interactions. This social regulation of reproduc- viduals are more likely to become future queens, tion is in stark contrast to developmental regula- but it is by no means a simple age-based suc- tion seen in highly eusocial species, presumably cession [2, 5, 8, 9, 16]. including swarm-founding Ropalidia. In most Even in the absence of morphological differ- independent-founding species, all or most ences between colony members, there may be eclosing adults may be totipotent and capable of further behavioral differentiation even among the developing their ovaries and laying eggs under workers. Using multivariate statistical analysis of appropriate social conditions, at least in the trop- the time-activity budgets of individually identified ical species [7, 8, 12]. wasps, members of colonies of R. marginata and Nevertheless, at least R. marginata appears R. cyathiformis have been classified into three to have some pre-imaginal caste bias such that behavioral castes, namely, sitters, fighters, and well-fed larvae develop into adults who consume foragers (Fig. 3). Such behavioral caste 4 Ropalidia

Ropalidia, Fig. 3 Left: Behavioral castes in R. R. marginata. Fitted polynomial regression lines for vari- marginata. Twenty wasps are shown as points in the coor- ation of the probability of task performance as a function of dinate space of the amplitudes associated with the first two absolute age. Thin broken line refers to Feed Larva, thick principal components. The points fall into three clusters (or broken line to Build, thin solid line to Bring Pulp and thick castes) by the criterion of nearest centroid. Circled dot = solid line to Bring Food. (Reprinted from [17]) centroid. (Reprinted from [10]). Right: Age polyethism in differentiation appears to go beyond mere classi- through all of these successive tasks before they fication into intranidal and extranidal workers, die. Both the frequency of performance of differ- because some of the sitters can be quite old and ent tasks as well as the probability of performing a may transition to become new queens without task in relation to other tasks is significantly ever becoming foragers. Because queens are influenced by age. The frequency and probability meek and docile and use pheromones in R. of intranidal tasks, such as feeding larva and marginata, it has been postulated that domi- building, decrease with age, while those of extra- nance-subordinate interactions have been co- nidal tasks such as bringing building material and opted for the decentralized self-organization of food increase with age. nonreproductive labor. There is a positive corre- The age-dependent performance of tasks is lation between the rate at which individuals are better explained as a function of relative age rather subject to domination and their rates of foraging. than absolute age. This permits colonies to In addition, experimental manipulation of hunger respond to unexpected changes in their demo- levels have shown that rates of dominance behav- graphic composition. Experimental removal of ior, especially toward foragers, increase in starved old individuals results in younger individuals for- colonies and decrease in well-fed colonies [8, 9]. aging at unusually early ages (precocious for- Division of Labor. Because colonies consist agers). Similarly, removal of young individuals of one or a small number of fertile queens, while makes the remaining young individuals step up the remaining females serve as sterile workers, the rates of feeding larvae. there is reproductive division of labor. Whether Such flexible age polyethism is reminiscent of nonreproductive division of labor is further highly eusocial species, such as honey bees, divided among the workers has been studied in although no swarm-founding Ropalidia has been only two species. In R. marginata, there is clear investigated in this regard. Not all independent- evidence of an age-based division of labor or age founding Ropalidia exhibit such striking age polyethism. Major tasks such as feeding larvae, polyethism. R. cyathiformis has somewhat similar building the nest, bringing building material, and age polyethism, although it appears to be rela- bringing food are initiated in this sequence with tively inflexible and based on absolute rather increasing age. Most adult females progress Ropalidia 5 than relative age. No other species of Ropalidia rather nuanced manner. Young alien workers has yet been studied in this manner [1, 8]. were allowed to freely join the resident colony, Experiments isolating one, two, or three R. older workers were not permitted to join but were marginata wasps in small plastic boxes revealed left alone if they stayed in a corner of the cage the spontaneous emergence of cooperation and away from the nest, while the alien queen was reproductive division of labor when at least two located and killed. The observation that young wasps are present. When at least three wasps were non-nestmate workers are allowed to join colonies present, nonreproductive division of labor and has been used to create genetically mixed colo- increase in colony productivity also emerge. nies. In such colonies, the young alien workers These experiments also revealed that both repro- become fully integrated into their foster colonies ductive and nonreproductive division of labor are and neither they nor members of the foster colo- mediated by dominance-subordinate interactions. nies make any discrimination between residents In pairs of wasps, the more dominant of the two and aliens. Indeed, the introduced non-nestmates becomes the egg layer and the subordinate takes go on to become foragers and even new queens in on worker roles. In triplets the most dominant their adopted colonies [8]. female becomes egg layer, and the least dominant Nestmate discrimination is facilitated by col- becomes the extra-nidal worker, while the inter- ony-specific ▶ cuticular hydrocarbon (CHC) pro- mediate wasp becomes the intra-nidal worker. The files of adult female wasps. The evidence for this role of dominance-subordinate interactions in is based on comparison of CHC profiles as well as reproductive division of labor is rather complex. from bioassays using CHC extracts from nestmate While such interactions seem to be important and non-nestmate wasps [16]. Unfortunately, no before colony foundation, queens are meek and comparable information is available for any other docile both in small and large colonies and yet species of Ropalidia. We must be cautious to maintain complete reproductive monopoly [3, 6]. generalize from one species, especially given the Nestmate Recognition. Casual observations evidence that R. marginata is perhaps somewhat suggest that wasps in all species of Ropalidia so intermediate between the primitively and the far observed recognize and resist the entry of non- highly eusocial condition [8]. nestmates into their colonies. The phenomenon of Reproductive Regulation. The mechanism by nestmate discrimination has been studied in detail which a single egg layer maintains a reproductive only in R. marginata. When presented with monopoly has been investigated in R. marginata nestmates and non-nestmates, workers in this spe- and to a lesser extent, in R. cyathiformis.InR. cies are significantly more antagonistic to non- marginata, the docile queens rub their abdomens nestmates, including outside the context of the on the nest surface and apply a ▶ pheromone nest and even when they have never before derived from their Dufour’s gland. Workers per- encountered either the nestmates or the non- ceive this apparently non-volatile pheromone and nestmates. To be able to do so, however, both thus recognize the presence of their queen. If the the discriminating wasps and the discriminated queen is lost or removed, one of the workers stops wasps should have eclosed on their respective working and becomes hyper-aggressive for about natal nests and thus have acquired their nest-spe- a week. She will immediately stop being aggres- cific recognition templates and labels. These sive and go back to behaving as a worker if the results have been interpreted to suggest that original queen is soon returned. If she is not while nestmate discrimination is well developed, returned this worker will become meek and docile intra-colony ▶ kin discrimination is unlikely, an and start laying eggs. Experimental application of interpretation that is supported by other lines a crude extract of the original queen’s Dufour’s of evidence [8]. gland on the nest elicits similar behavior, the When all the members of a colony were intro- potential queen acting as if the original queen duced into a cage containing a different colony, has returned [8, 9, 16]. the introduced (alien) wasps were treated in a 6 Ropalidia

There appears to be sufficient information in Males and Mating. Males remain poorly stud- the pheromone for both the wasps as well as a ied in most social Hymenoptera, because they discriminant function analysis on the computer to usually do not spend their whole lives in the nest correctly distinguish between fertile queen and and participate little or not at all in the social life of sterile workers [9, 16]. During the course of the the colony. That is, there are neither kings nor week in which a hyper-aggressive potential queen male workers in hymenopteran societies, unlike transforms herself into an egg-laying queen, she in termites. In most species information about reduces her levels of aggression from as many as males comes from nests and their contents col- 30–40 dominance acts per hour to nearly zero, lected opportunistically, with their presence or develops her ovaries to become indistinguishable absence and abundance in relation to colony size from the queen in this respect, and changes her and season being noted. pheromone profile from one that is statistically Behavioral knowledge of males in indepen- indistinguishable from a worker to one that is dent-founding Ropalidia is limited to a few stud- indistinguishable from a queen. The queen pher- ies of R. marginata and R. cyathiformis.InR. omone is therefore an honest signal of the queen’s marginata males leave their natal nests about a fertility [9, 16]. week after eclosion, lead a nomadic existence, and There is evidence that the queen pheromone mate with females on foraging trips, so that some contains information only about fertility and not of the workers in a colony are mated. In R. her nestmateship because potential queens will cyathiformis males seem to spend their entire reduce their aggression even when crude extracts lives on their natal colonies but keep coming and from the Dufour’s glands of non-nestmate queens going, presumably for mating. The abundance of are applied to their nests. The mechanism by males is skewed by season, with fewer males in which one and only one worker becomes the the winter months, although some may be present potential queen upon the loss of the original throughout the year [21]. queen, how such potential queens are chosen, R. marginata males, even during their short why it is not possible to predict the identity of stay on the nest and even compared to females the potential queen in the presence of the old of their age group, are not known to perform any queen even though the wasps seem to know her work. They are not observed to feed larvae in un- identity, remain elusive [8, 16]. manipulated nests, either because they (1) are In any case, R. marginata exhibits frequent incapable of feeding larvae effectively, or (2) do queen succession without overt conflict, although not have access to sufficient food, or (3) because there is underlying ▶ conflict of interests. This females perform this task more efficiently. In can be uncovered by preventing queens from testing these three hypotheses, experiments have applying their pheromone, which will result in revealed that males can indeed work. When males workers attacking them and queens retaliating are hand-fed in excess of what they can eat, they [19]. It is remarkable that such outbreaks of con- feed larvae, consistent with the hypothesis that flict are prevented under natural conditions. The they are capable of feeding larvae but do not phenomenon of reproductive regulation in R. normally have access to excess food. When marginata opens up the possibility of investigat- excess-fed males are left to care for hungry larvae ing the complex physiology of reproduction in (by removing all females), they can do so at rates social insects. It bears mention that almost nothing comparable to those of females, although larvae is known about other Ropalidia species with the under their care often appear to do poorly. It thus exception of R. cyathiformis which, true to its appears that males normally do not feed larvae typical primitively eusocial nature, has aggressive both because they do not have access to enough queens that appear to suppress worker reproduc- food and because there may not be selection on tion through physical domination and in which males to feed larvae in the presence of females queen succession is based on dominance rank, as who do a much better job, perhaps on account of in many other species of primitively eusocial glandular secretions that they may add to the food wasps [12, 24]. [20]. It remains to be seen whether males can be Ropalidia 7 similarly forced to perform other tasks such as foragers, it is expected that they should be building or repairing the nest and foraging. This familiar with the area around the nest and able area of study has hardly been touched in either to return to it reliably. Some information has Ropalidia or other genera of social wasps. begun to accumulate on homing and navigation In R. marginata an unmated female may yet in R. marginata. Individual wasps appear to be develop her ovaries and lay fertile, haploid, male- familiar with an area of about 0.73 km2, or within destined eggs and may become the sole egg layer a radius from the nest of 0.48 km, although they of a colony even in the presence of other mated can return home even when displaced to a distance females. Females that are the sole egg layers are of 1.45 km. There is evidence that with age and sometimes known to leave the nest and may thus experience the wasps actively acquire familiarity be capable of mating after taking over the role of with the landscape and the ability to home from sole egg layer. Under laboratory conditions, both places beyond those that they have visited often mated and unmated females will develop ovaries [15]. equally rapidly although unmated females lay Evolution of Eusociality. The variety of fewer eggs, which may be in anticipation of future options available to individual females around mating opportunities [8]. When paired with each the foundation of new colonies implies, especially other, both mated and unmated females have in tropical species like R. marginata, that workers equal chances of dominating their partner and have the option either to leave their natal nests and becoming the sole egg layer. found their own nests or to bide their time and It is possible to keep a pair of male and female replace their queens. With males being present R. marginata in a small beaker under controlled more or less throughout the year and some conditions to observe their courtship and mating. colonies being perennial and long lived, there is Males approach females and attempt to mount scope for many kinds of reproductive strategies. them. If successful, such mounting can result in Accordingly, these wasps are well suited to allow copulation with both individuals facing in the us to understand the evolutionary forces that mold same direction but this may be terminated rather altruistic worker behavior. More specifically, the quickly. It does not lead to sperm transfer and has contrast between wasps that leave their natal nests been labelled as short conjugation. After copula- to initiate own single-foundress nests, on the one tion the pair may remain in copula but move to hand, and those that remain on their natal nests face in opposite directions. Such “long conjuga- and contribute to their colonies by functioning as tion” is a reliable indication of sperm transfer. The sterile nonreproductive workers for their entire greatest likelihood of mating in the laboratory is lives makes these species almost ideal for tests when males and females are in the age group of of ▶ Hamilton’s rule. 5–20 days. Mating occurs without regard to R. marginata has been extensively exploited body size, ovarian development, or nestmateship. for this purpose. ▶ Inclusive fitness models When presented with two females, one with have explored the relative roles of asymmetries developed ovaries and one without, males will in genetic relatedness, ecological factors first mate with the female with developed ovaries promoting solitary nesting versus worker strate- and may subsequently also mate with the female gies and demographic predispositions. Because R. with undeveloped ovaries. Since males lead a marginata queens may mate with up to three nomadic life and mate with females on foraging males to produce genetically diverse offspring trips, they may have little choice but to mate with and because serial polygyny may result in even any female without the guarantee that she will use lower relatedness, so that colonies consist of many his sperm to produce daughters [22]. different matrilines and patrilines, this species Homing. In Ropalidia, as in all social wasps, does not appear to be predisposed to the the focus of research has been on the wasps at evolution of worker behavior on account of relat- their nests, while behaviors off the nest remain edness asymmetries alone. almost unstudied. However, as ▶ central-place 8 Ropalidia

On the other hand, the species appears to be Swarm-Founding Species more ecologically predisposed to social evolution. Individual wasps are highly variable in their abil- In contrast to independent-founding species, ity to initiate new nests and reproduce in the face swarm-founders are characterized by large colo- of ecological pressures such as the presence of nies with complex, large, usually enveloped nests parasites and predators, and uncertain food sup- that often contain many tiers of combs. Swarm ply, and it has been shown that individual wasps founders always have multiple queens and rela- appear to assess their abilities and choose their tively greater queen-worker dimorphism and, as nesting strategies accordingly. Thus, those wasps the name implies, new colonies are each founded that forgo direct reproduction stand to lose much by a mass of queen and workers, the swarm. In less by becoming workers than those that choose addition, they are distinguished by pheromonal to start nests of their own [8]. regulation of worker reproduction by queens and Finally, a demographic predisposition to the a well-developed Richards’ gland on the fifth evolution of eusociality has been assessed with a gastral sternum that helps lay an odor trail during hierarchy of models including assured fitness swarm-founding. Swarm-founding is seen in returns and delayed reproductive maturation. the small genus Polybioides and a few species Because solitary nest foundresses must necessar- of Ropalidia, while all other swarm-founding ily survive for the entire duration of development polistines are in the large New World tribe of their brood, while workers can divide labor Epiponini. The swarm-founding habit, then, is serially without losing all their investment if much more prominent among wasps in Central they die, workers have relatively more assured and South America than in Old-World tropics. returns on their investment. Calculations of The proportion of swarm-founding species expected lifespans and brood developmental within the genus Ropalidia is hard to estimate periods show that R. marginata is thus demo- from the available literature. Even so, the exis- graphically predisposed to the evolution of euso- tence of both independent founders and swarm ciality. Combining these three kinds of potential founders within the genus Ropalidia appears predispositions, a unified model for the evolution to proffer a route toward understanding the evo- of eusociality predicts that only about 5% of the lutionary origin of the swarm-founding syndrome. wasps should opt for solitary nest founding, while It must be noted, however, that swarm-founding the others should prefer the worker strategy. Esti- Ropalidia have been poorly studied, and we may mates from field colonies regarding the proportion not have recognized the existence of this habit of wasps in single foundress colonies and those in in many species. multi-female colonies closely match this theoret- On the other hand, some independent- ical prediction [8]. founding species, such as R. revolutionalis, R. Nevertheless, there appears to be much more to excavata and R. gregaria, have been investigated the evolution of eusociality in R. marginata. Even using microsatellite markers, especially because workers who appear to choose the option of ste- they appear to possess some complex features rility have several ways to obtain direct fitness. reminiscent of swarm-founding species. These These include leaving their natal nests at later species can have multiple queens and show cyclic times or replacing their queens. The potential for changes in queen number and sex ratio that founding new nests, while influenced by nutri- depend on the stage of the colony cycle, as pre- tional status and age, is not influenced by the dicted by kin selection and sex ratio theory, amount of work performed in the colony. This suggesting that key features of swarm-founding suggests that current indirect fitness is not incom- species may have their antecedents in their inde- patible with future direct fitness, making it that pendent-founding ancestors. R. romandi, a genu- much easier for selection to promote helping inely swarm-founding species, exhibits many of behavior leading to eusociality [4]. the same features [11, 23]. Ropalidia 9

Ropalidia, Fig. 4 Left panel: A nest of the swarm- also visible in the nest envelope. Right Panel: Another nest founding wasp Ropalidia montana. Numerous workers of R. montana shown with the envelope removed, reveal- are seen scattered over the surface. Near the center of the ing the nest architecture, with increasingly angled combs nest is a single Vespa tropica worker, which is a major toward the bottom. (Photos by Robert L. Jeanne) predator of R. montana. Five holes made by V. tropica are

Meager as it is, useful information about large enveloped nest containing multiple combs, swarm-founding Ropalidia comes from three many morphologically differentiated queens, and brief reports on R. montana from South India. a larger number of workers [12]. In the most detailed of these [14], four nests To understand the social dynamics of such were collected during peak season in the societies with hundreds of queens and thousands Mudumalai Wildlife Sanctuary in the Western of workers cooperating to build and repair the Ghats. The nests (Fig. 4) ranged 25–42 cm in nest, deal with predators and parasites, self-orga- length, 25–28 cm in width, with 19–27 combs – nize division of labor to forage for and feed tens of unlike in swarm-founding wasps with multi-tiered thousands of larvae and stage periodic swarms to combs, the tiers come from a spiral comb con- make new colonies, along the lines of similar struction – containing 59,000–1,45,000 knowledge of independent-founding Ropalidia, cells, 32,000–61,000 adult wasps, 0.46–1.40% would be a naturalist’s challenge even as it is a of which were queens and 1–27% were males, theoretician’s dream. Be that as it may, there isn’t the remaining being workers. Not counting the even a single account of their swarming behavior Neotropical genus Agelaia, which may sometimes and colony foundation, which is their unique fea- have a million individuals, these are among ture. Unless major corrective steps are taken, the the largest colonies of polistine wasps known. prospects of improving our knowledge in the The only other swarm-founding Ropalidia future will remain bleak, owing to large-scale with some information is R. romandi from Aus- habitat destruction and accompanying species tralia, which seems to be rather similar with a loss, dwindling of the numbers of field naturalists 10 Ropalidia and the nearly complete obsession of eusociality. Cambridge, MA: Harvard University the community of social insect researchers, with Press. 9. Gadagkar, R. (2009). Interrogating an insect society. understanding the genetic, developmental, and Proceedings of the National Academy of Sciences of molecular mechanisms of a small number of the USA, 106, 10407–10414. https://doi.org/10.1073/ phenomena in fewer than a handful of model pnas.0904317106. organisms. 10. Gadagkar, R., & Joshi, N. V. (1983). 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