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Ropalidia marginata is a social wasp in which colonies consist of a single fertile queen and several sterile workers. If the queen is removed, one of the workers, potential queen (PQ), becomes hyperaggressive and becomes the next queen. The identity of the PQ cannot be predicted in the presence of the queen. The probability of a worker succeeding the queen is uncorrelated with her body size, dominance rank, ovarian or mating status, but imperfectly correlated with her age. Here, we investigate whether genetic relatedness help to predict the queen’s successors. We constructed models based on successors being (i) most closely related to the queen, (ii) most closely related to the immediate predecessor queen/PQ, or (iii) having the highest relatedness to the majority of the workers; and (iv) having the highest average relatedness to all the workers. We predicted five successors from each of these models using pair-wise genetic relatedness estimated from polymorphic microsatellite loci. We independently performed serial queen/PQ removal experiments and compared the observed sequence of successors with the predictions from the models. The predictions of none of the models matched the experimental results; on an average 5-6 individuals predicted by the models were bypassed in the experiment. Thus, genetic relatedness is inadequate to predict the queen’s successors in this species. We discuss why relatedness sometimes predicts the patterns of altruistic behaviour and sometimes not, and argue that the cost and benefit terms in Hamilton’s rule, i.e. ecology, should be vigorously investigated when relatedness does not have adequate explanatory power. [ABSTRACT FROM AUTHOR]

Insects that use ephemeral resources must rapidly digest nutrients and simultaneously protect them from competitors. Here we use burying beetles (Nicrophorus vespilloides), which feed their offspring on vertebrate carrion, to investigate the digestive and defensive basis of carrion utilization. We characterize gene expression and microbiota composition in the gut, anal secretions, and on carcasses used by the beetles. We find a strict functional compartmentalization of the gut involving differential expression of immune effectors (antimicrobial peptides and lysozymes), as well as digestive and detoxifying enzymes. A distinct microbial community composed of Firmicutes, Proteobacteria and a clade of ascomycetous yeasts (genus Yarrowia) is present in larval and adult guts, and is transmitted to the carcass via anal secretions, where the yeasts express extracellular digestive enzymes and produce antimicrobial compounds. Our results provide evidence of potential metabolic cooperation between the host and its microbiota for digestion, detoxification and defence that extends from the beetle's gut to its nutritional resource. [ABSTRACT FROM AUTHOR]

Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We studied queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioral strategies involved in the resolution of this conflict. Previous work has shown that in this species, experimental queen removal always results in only one worker becoming hyper-aggressive and taking over the colony as its next queen, without ever being challenged. Here we show that even during natural queen turnover, one and only one worker becomes hyper-aggressive and takes over as the next queen, without being challenged. During natural queen turn-over, aggression of the successor may sometimes begin before the loss of the old queen and may sometimes decline more rapidly, unlike in the case of experimental queen removal. The successor begins to lay eggs sooner after a natural queen turn-over as compared to experimental queen removal. This is expected because workers might detect the gradual decline of the queen preceding her disappearance. Because queen succession is expected to be more prevalent in tropical perennial species, we expect natural selection to have favored such an orderly queen succession so that a route to direct fitness is available without significant reduction in cooperation.Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We studied queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioral strategies involved in the resolution of this conflict. Previous work has shown that in this species, experimental queen removal always results in only one worker becoming hyper-aggressive and taking over the colony as its next queen, without ever being challenged. Here we show that even during natural queen turnover, one and only one worker becomes hyper-aggressive and takes over as the next queen, without being challenged. During natural queen turn-over, aggression of the successor may sometimes begin before the loss of the old queen and may sometimes decline more rapidly, unlike in the case of experimental queen removal. The successor begins to lay eggs sooner after a natural queen turn-over as compared to experimental queen removal. This is expected because workers might detect the gradual decline of the queen preceding her disappearance. Because queen succession is expected to be more prevalent in tropical perennial species, we expect natural selection to have favored such an orderly queen succession so that a route to direct fitness is available without significant reduction in cooperation.Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We studied queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioral strategies involved in the resolution of this conflict. Previous work has shown that in this species, experimental queen removal always results in only one worker becoming hyper-aggressive and taking over the colony as its next queen, without ever being challenged. Here we show that even during natural queen turnover, one and only one worker becomes hyper-aggressive and takes over as the next queen, without being challenged. During natural queen turn-over, aggression of the successor may sometimes begin before the loss of the old queen and may sometimes decline more rapidly, unlike in the case of experimental queen removal. The successor begins to lay eggs sooner after a natural queen turn-over as compared to experimental queen removal. This is expected because workers might detect the gradual decline of the queen preceding her disappearance. Because queen succession is expected to be more prevalent in tropical perennial species, we expect natural selection to have favored such an orderly queen succession so that a route to direct fitness is available without significant reduction in cooperation.Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We studied queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioral strategies involved in the resolution of this conflict. Previous work has shown that in this species, experimental queen removal always results in only one worker becoming hyper-aggressive and taking over the colony as its next queen, without ever being challenged. Here we show that even during natural queen turnover, one and only one worker becomes hyper-aggressive and takes over as the next queen, without being challenged. During natural queen turn-over, aggression of the successor may sometimes begin before the loss of the old queen and may sometimes decline more rapidly, unlike in the case of experimental queen removal. The successor begins to lay eggs sooner after a natural queen turn-over as compared to experimental queen removal. This is expected because workers might detect the gradual decline of the queen preceding her disappearance. Because queen succession is expected to be more prevalent in tropical perennial species, we expect natural selection to have favored such an orderly queen succession so that a route to direct fitness is available without significant reduction in cooperation.Insect societies are hallmarks of cooperation because one or a few queens monopolize reproduction and several non-reproductive workers cooperatively raise brood. However, the loss of the queen exposes a colony to potential reproductive conflict, which is resolved only after a new queen takes over. We studied queen succession in natural and experimental colonies of the primitively eusocial wasp Ropalidia marginata to understand the proximate behavioral strategies involved in the resolution of this conflict. Previous work has shown that in this species, experimental queen removal always results in only one worker becoming hyper-aggressive and taking over the colony as its next queen, without ever being challenged. Here we show that even during natural queen turnover, one and only one worker becomes hyper-aggressive and takes over as the next queen, without being challenged. During natural queen turn-over, aggression of the successor may sometimes begin before the loss of the old queen and may sometimes decline more rapidly, unlike in the case of experimental queen removal. The successor begins to lay eggs sooner after a natural queen turn-over as compared to experimental queen removal. This is expected because workers might detect the gradual decline of the queen preceding her disappearance. Because queen succession is expected to be more prevalent in tropical perennial species, we expect natural selection to have favored such an orderly queen succession so that a route to direct fitness is available without significant reduction in cooperation. [ABSTRACT FROM AUTHOR]