Social organization in experimentally assembled colonies of Ropalidia marginata : comparison of introduced and natal wasps (original) (raw)
Related papers
Oecologia, 1998
In the primitively eusocial wasp, Ropalidia marginata, low levels of intra-colony genetic relatedness, lack of intra-colony kin discrimination and acceptance of young wasps into alien colonies, prompted us to investigate whether or not there exists a cost of such high genetic variability. Freshly eclosed wasps were paired either with their nestmates or with their non nestmates and their performance in nest building and brood care were compared. There was no demonstrable dierence between nestmate and non nestmate pairs in terms of success in raising adult ospring, time required for nest initiation, brood developmental period and productivity. There was also no dierence in the eciency of cooperation and division of labour between the nestmate pairs and non nestmate pairs. These results reinforce the idea that the haplodiploidy hypothesis is insucient to explain the prevalence of worker behaviour in R. marginata and emphasize the importance of factors other than genetic relatedness in the evolution of eusociality.
Emergence of cooperation and division of labor in the primitively eusocial wasp Ropalidia marginata
Proceedings of the National Academy of Sciences, USA, 2018
In most primitively eusocial wasps new nests are initiated by a single female or by small groups of females. To study the emergence of division of labor (DOL) among the nest foundresses and to determine its possible effect on nest productivity we maintained newly eclosed females of Ropalidia marginata in small boxes with one, two, or three nestmate wasps of the same age per box. Only one wasp developed her ovaries and laid eggs in each box, while the other wasp(s) built the nest, brought food, and fed larvae, demonstrating the spontaneous emergence of reproductive DOL in the presence of more than one wasp. In nests with three wasps there was also a strong negative correlation between intranidal and extranidal work performed by the two nonreproductive workers, suggesting the spontaneous emergence of nonreproductive DOL; such nonreproductive DOL was absent in nestswith two wasps. Both reproductive and nonreproductive DOL were modulated by dominance behavior (DB). In nests with two wasps the egg layer showed significantly more DB than the non-egg layer before nest initiation; in nests with three wasps queens showed significantly more DB than intranidal workers, which in turn showed significantly more DB than extranidal workers. Productivities of nests (as measured by total brood on the day of eclosion of the first adult) initiated by one or two wasps were not different from each other but were significantly lower than that of three wasps. Thus, nonreproductive DOL, and not merely reproductive DOL, is necessary for increase in productivity.
Oecologia, 1998
In the primitively eusocial wasp, Ropalidia marginata, low levels of intra-colony genetic relatedness, lack of intra-colony kin discrimination and acceptance of young wasps into alien colonies, prompted us to investigate whether or not there exists a cost of such high genetic variability. Freshly eclosed wasps were paired either with their nestmates or with their non nestmates and their performance in nest building and brood care were compared. There was no demonstrable dierence between nestmate and non nestmate pairs in terms of success in raising adult ospring, time required for nest initiation, brood developmental period and productivity. There was also no dierence in the eciency of cooperation and division of labour between the nestmate pairs and non nestmate pairs. These results reinforce the idea that the haplodiploidy hypothesis is insucient to explain the prevalence of worker behaviour in R. marginata and emphasize the importance of factors other than genetic relatedness in the evolution of eusociality.
Australian Journal of Entomology, 2000
Studies of primitively eusocial Hymenoptera have often been used to examine the relationship between individual behavioural flexibility and the evolution of eusociality. Within this group, species of the genus Ropalidia (Vespidae) have been used extensively, in part because of the ease in which they can be observed in the field (e.g. relatively small colonies, the lack of an outer nest envelope and the absence of a caste system based on morphological differences in the majority of species facilitate observation of individual behaviours and the process by which reproductive division of labour is attained . and used principal component analyses to examine division of labour in two monomorphic species of Ropalidia (subgenus Icariola), R. cyathiformis (Fabricius) and R. marginata (Lepeletier), respectively. Both species are independently founding and construct combs without an external envelope. By analysing individual time budgets, they demonstrated that the individuals in both species formed three distinct behavioural castes, termed 'Sitters', 'Fighters' and 'Foragers'. Yet the relationships between behavioural castes and the mechanism by which reproductive dominance may be obtained appeared to differ. In R. cyathiformis, reproductive individuals were members of the fighter class and were the most behaviourally dominant individuals, while in R. marginata queens were members of the sitter class and did not display the most frequent dominance behaviours. The regulation of worker activity through aggressive behaviour and individual reproduction are disassociated in this species . The reasons for these interspecific differences are unclear. In this paper we use similar techniques to examine division of labour in a third monomorphic species of the same subgenus, the independently founding Ropalidia revolutionalis (de Saussure), in order to provide more details on the relationship between behavioural castes, dominance and reproductive output in this group of primitively eusocial wasps.
Behavioral Ecology and Sociobiology, 1988
We have demonstrated that females of widespread phenomenon. The ability to discrimithe primitively eusocial tropical wasp Ropalidia nate kin from non-kin has been reported in marine marginata can discriminate nestmates from non-invertebrates, subsocial arthropods, sweat bees, nestmates outside the context of their nests. This honey bees, several species of ants and wasps, was accomplished by recording all behavioural in-fishes, frogs, toads, iguanas, birds and a variety teractions in a neutral arena and comparing toler-of mammals (reviews in Fletcher and Michener ance levels. In order for these wasps to make such 1986; Gadagkar 1985b; Gamboa et al. 1986a; a discrimination, howeyer, it was essential that Hepper 1986; Holldobler and Michener 1980; Linafter eclosion both the discriminated and the dis-senmair 1985; Sherman and Holmes 1985; Waldcriminating animals were exposed to their respec-man 1987); for the iguana see Werner et al. ; tive natal nests and nestmates. The results suggest for the fish see Quinn and Busack (1985); for the that both recognition labels and templates are ac-marine invertebrates see Grosberg and Quinn quired by the animals from sources outside their (1986) and Keough (1984). body, perhaps from their nest or nestmates. It is
Behavioral Ecology and Sociobiology, 1996
In mature post-emergence colonies of the tropical primitively eusocial polistine wasp Ropalidia marginata, the queen is not a behaviourally dominant individual. Nevertheless, she completely suppresses reproduction by the workers and becomes the sole egg-layer in the colony. Mechanisms by which a female is able to establish her exclusive reproductive status in the colony can be investigated by examining dominance-submission relationships and hierarchy formation at particular stages of the colony cycle when reproductive competition is behaviourally manifest. Observations on the behaviour of R. marginata females (1) during early stages of colony-founding, (2) when potential queens challenge the existing queen, and (3) immediately after queen replacement show that these wasps use highly aggressive dominance interactions to establish their reproductive status. Both the frequency and the intensity of dominance behaviours are significantly higher at these stages than those observed at phases of the colony when there is no apparent reproductive strife. Once her position as the only egg-layer of the colony has been established, the levels of dominance interactions initiated by the queen decrease and the nature of these interactions also becomes comparatively milder. Thus, the mechanisms by which a queen establishes her social status in her colony and those by which she continues to suppress reproduction of her nestmates in the absence of overt physical dominance may be quite different.
Arathi and Gadagkar 1996 Can genetically unrelated individuals join colonies of Ropalidia marginata
New Age International Limited, New Delhi, 1996
Field and laboratory investigations of the primitively eusocial wasp Ropalidia marginata suggest that worker behaviour cannot be explained satisfactorily either by intra-colony genetic relatedness or by parental manipulation. Besides, polyandry and serial polygyny lead to high levels of intra-colony genetic variability. For these reasons, an attempt was made to explore the role of mutualistic interactions in social evolution. Artificially mixed colonies were created introducing 4-12 one day old unrelated female wasps into six semi-natural colonies of Ropaiitlia marginata. Wasps naturally eclosing on the colonies during the period of introduction were used as controls. All introduced animals were accepted without any significant aggression. The introduced animals stayed on their foster colonies as long as the controls did. There was no evidence of any differential treatment or recognition of the introduced animals by the older animals in the foster colonies. Five out of 56 introduced animals went on to become foragers, and brought food to their foster~ colonies within 25 days of introduction. This is not significantly different from the fact that six oUt of 38 control animals also became foragers during the same period. More importantly, in two of the six colonies where there were natural queen turn overs, an introduced animal became the replacement queen in both cases. These results lend support to mutualistic theories of social evolution.
Division of Labour and Organization of Work in the Primitively Eusocial Wasp Ropalidia marginata
Proc. Indian natn. Sci. Acad. , 2001
Ropalidia marginata is a primitively eusocial polistine wasp with the expected lack of morphological caste differentiation between queens and workers. The lack of morphological caste differentiation appears to be compensated by a system of behavioural caste differentiation. The wasps in a colony may be classified into three behavioural castes which we have called Sitters, Fighters and Foragers and the queens are almost always in the Sitters caste. Consistent with this and unlike in most other primitively eusocial species studied, R. marginata queens are relatively inactive, behaviourally subordinate individuals. There is no evidence that they regulate activities of their workers. The workers continue to remain active, bring food and feed the larvae, even if the queen is removed. WorJ<er activity appears to be regulated by the workers themselves through the use of dominance behaviours which are hypothesized to have come to represent larval and adult hunger signals, to the foragers. In undisturbed colonies, intranidal workers who also unload food and pulp bearing foragers, appear to regulate foraging rates. In the absence of unloaders, the foragers themselves feed the larvae and apparently obtain first-hand information about larval hunger levels. In spite of its primitively eusocial status, R. marginata has a well developed age polyethism. Workers show strong preferences to feed larvae, build the nest, bring pulp and bring food, in that order, as they age. However, the relative position of a wasp in the age distribution of the colony, rather than her absolute age, is a stronger predictor of her task performance. Soliciting behaviour (a form of trophallaxis) provides a plausible mechanism for the wasps to assess their relative ages. A computer simulation model, adapting the verbal activator-inhibitor model proposed for honey bees, demonstrates that a relative-age based rule for division of labour provides the necessary flexibility for colonies to respond adaptively to changing colony demography or varying demands for food. Thus, morphologically identical individuals, and in spite of retaining some reproductive options, have access to a variety of mechanisms to efficiently divide labour and organize work.