Influence of Queen and Diet on Nestmate Recognition and Cuticular Hydrocarbon Differentiation in a Fission- Dispersing Ant, Aphaenogaster senilis

In social insects, colony fission is a particular mode of dispersal by which an adult colony splits into two or more independent nests. In the monogynous ant Aphaenogaster senilis, field data suggest that new queens may be produced in queenless daughter nests after nest relocation. Because workers do not fly, colony fission limits dispersal distance, leading young sister colonies to compete together and with the mother queen. In the present study we analysed the effects of queen loss and diet change on nestmate recognition. Queenright colonies were separated into two queenless and one queenright fragments. One queenless group received the same food as the queenright group, while the other queenless group received a different diet for 150 days. Recognition bioassays revealed that aggression between queenright and queenless former nestmates increased progressively until day 20, when they could no longer be reunited. Different diets also induced aggression between orphaned groups. Chemical analyses indicated that cuticular hydrocarbon profiles were already different between groups after 5 days. Overall, our results are in accordance with the graded model of nestmate recognition and suggest that the loss of the mother queen progressively leads to the independence of the related nests after fission. This may also allow queenless ants to merge again with their mother colony during a short time window after fission

Limited multiple-mating in males and single-mating in females of the ant species, Paratrechina flavipes (Fr. Smith) (Hymenoptera: Formicidae)

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Reproductive conflict between laying workers in the ant Aphaenogaster senilis

International audienceSince workers of the ant Aphaenogaster senilis can lay male eggs, reproductive conflict may occur between these workers. We examined the occurrence of worker conflicts in groups of workers either with or without the queen. Intranidal aggression was observed in each nest for 10 min each day, and the immatures produced were counted once a week for two months. Pairs of workers involved in aggression were taken regularly from each nest and used for chemical, morphological and anatomical analyses. The attacker and the attacked workers differed in their cuticular hydrocarbon profiles. The attacker and the attacked ants were at the same middle-aged fertile stage. The attacker ant was significantly larger and more fertile than the attacked ant, and more mature physiologically (poison gland was darker). There was apparently no stable hierarchy between laying workers. In the first weeks under queenless conditions, most eggs and larvae were destroyed, but they were later reared to obtain males. The intranidal worker aggression in this highly evolved ant is discussed in relation to dominance and worker policing

Ontogeny of hydrocarbon profiles in the ant Aphaenogaster senilis and effects of social isolation

International audienceIn ants, cuticular hydrocarbons are used for nestmate recognition; they are stored in the postpharyngeal gland and shared among the individuals. Newly emerged ants have a very small quantity of hydrocarbons. We studied the ontogeny of the hydrocarbon profile in Aphaenogaster senilis. The total quantities of both cuticular and postpharyngeal gland (PPG) hydrocarbons increased with age from 0 to 20 days after emergence and then stabilised. These quantities are correlated with the development of the ovary. Under individual social isolation, cuticular hydrocarbons increased as normal, but the total quantity of PPG hydrocarbons never increased from the initial low level. This effect of social isolation on the PPG hydrocarbon level indicates the importance of hydrocarbon transfer between nestmates through the PPG and lends support to the gestalt model of nestmate recognition

[Photograph 2012.201.B1148.0627]

Photograph used for a newspaper owned by the Oklahoma Publishing Company

Influence of Queen and Diet on Nestmate Recognition and Cuticular Hydrocarbon Differentiation in a Fission-Dispersing Ant, Aphaenogaster senilis

International audienceIn social insects, colony fission is a particular mode of dispersal by which an adult colony splits into two or more independent nests. In the monogynous ant Aphaenogaster senilis, field data suggest that new queens may be produced in queenless daughter nests after nest relocation. Because workers do not fly, colony fission limits dispersal distance, leading young sister colonies to compete together and with the mother queen. In the present study we analysed the effects of queen loss and diet change on nestmate recognition. Queenright colonies were separated into two queenless and one queenright fragments. One queenless group received the same food as the queenright group, while the other queenless group received a different diet for 150 days. Recognition bioassays revealed that aggression between queenright and queenless former nestmates increased progressively until day 20, when they could no longer be reunited. Different diets also induced aggression between orphaned groups. Chemical analyses indicated that cuticular hydrocarbon profiles were already different between groups after 5 days. Overall, our results are in accordance with the graded model of nestmate recognition and suggest that the loss of the mother queen progressively leads to the independence of the related nests after fission. This may also allow queenless ants to merge again with their mother colony during a short time window after fission