Parasites, Worker Polymorphism, and Queen Number in Social Insects

Wingless males of the ant genus Cardiocondyla engage in fatal fighting for access to female sexual nestmates. Older, heavily sclerotized males are usually capable of eliminating all younger rivals, whose cuticle is still soft. In Cardiocondyla sp. A, this type of local mate competition (LMC) has turned the standard pattern of brood production of social insects upside down, in that mother queens in multi-queen colonies produce extremely long-lived sons very early in the life cycle of the colony. Here, we investigated the emergence pattern of sexuals in two species with LMC, in which males are much less long-lived. Queens of Cardiocondyla obscurior and Cardiocondyla minutior reared their first sons significantly earlier in multi-queen than in single-queen societies. In addition, first female sexuals also emerged earlier in multi-queen colonies, so that early males had mating opportunities. Hence, the timing of sexual production appears to be well predicted by evolutionary theory, in particular by local mate and queen–queen competition.

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Regulation of Queen Number by Workers in Colonies of Social Insects

Science ◽

10.1126/science.219.4582.312 ◽

1983 ◽

Vol 219 (4582) ◽

pp. 312-314 ◽

Cited By ~ 72

Author(s):

D. J. C. FLETCHER ◽

M. S. BLUM

Keyword(s):

Social Insects ◽

Queen Number

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Reproductive inhibition among nestmate queens in the invasive Argentine ant

Scientific Reports ◽

10.1038/s41598-020-77574-1 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Sílvia Abril ◽

Crisanto Gómez

Keyword(s):

Social Insects ◽

Cuticular Hydrocarbon ◽

Argentine Ant ◽

Chemical Interactions ◽

Queen Number ◽

Queen Pheromones ◽

Social Species ◽

Reproductive Inhibition ◽

Insect Societies ◽

Insight Into

AbstractIn social species, the presence of several reproductive individuals can generate conflict. In social insects, as queen number increases, individual oviposition rate may decrease because of direct and indirect behavioural and/or chemical interactions. Understanding the factors that mediate differences in queen fecundity should provide insight into the regulation and maintenance of highly polygynous insect societies, such as those of the invasive Argentine ant (Linepithema humile). In this study, we investigated (1) whether differences in the oviposition rates of Argentine ant queens exposed to polygynous conditions could result from interactions among them; (2) whether such differences in fecundity stemmed from differences in worker attention; and (3) whether polygynous conditions affected the cuticular hydrocarbon profiles of queens (CHCs). We found that differences in queen fecundity and CHC profiles observed under polygynous conditions disappeared when queens were exposed to monogynous conditions, suggesting some form of reproductive inhibition may exist when queens cohabit. These differences did not seem to arise from variation in worker attention because more fecund queens were not more attractive to workers. Levels of some CHCs were higher in more fecund queens. These CHCs are associated with greater queen productivity and survival. Our findings indicate that such compounds could be multifunctional queen pheromones.

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