Polygyny, relatedness and nest founding in the polygynous myrmicine ant Leptothorax acervorum (Hymenoptera; Formicidae)

Abstract

There is high within-nest relatedness for functional queens (with corpora lutea), nonfunctional queens (without corpora lutea), and workers in polygynous nests of Leptothorax acervorum. The high functional queen relatedness suggests that young mated queens are adopted back to their mother nest. Functional queen relatedness does not change with the number of queens present in the nest, suggesting that the number of generations of queens, on average two to three, is rather stable. Worker relatedness decreases with increasing number of functional queens per nest (Tables 5, 6). The number of queens contributing offspring to the nest (mothers), estimated from worker and functional queen relatedness, is lower than the number of functional queens, particularly in highly polygynous nests. Estimates of number of mothers in monogynous nests indicate that these nests previously were polygynous (Table 7). There is no correlation between nest relatedness and distance between nests, and budding-off, if present, thus appears to be a rare mode of nest founding (Table 8). There are no indications of inbreeding in the two populations studied since the frequency of heterozygotes is as high as expected from random mating (Table 4). Most likely, polygyny is the rule in L. acervorum and serves to secure the presence of queens in the nest.

Polymorphic social organization in an ant

“…(a) Social polymorphism in Leptothorax acervorum The social organization of our studied population strongly contrasts (table 2) with that reported from other polygynous L. acervorum populations (Stille et al 1991;Chan & Bourke 1994;Heinze et al 1995a,b;Bourke et al 1997;Hammond et al 2001Hammond et al , 2006. For example, in a UK population, Hammond et al (2006) showed that in the majority of nests (70% of colonies, n ¼ 17), skew was not significantly different from that expected if all queens reproduced equally.…”

Genetic variability and social structure of colonies in Acromyrmex heyeri and A. striatus (Hymenoptera: Formicidae)

“…In the case of polygynic species, withincolony relatedness is smaller, though it depends on relatedness between the queens (Stille et al, 1991;Ross, 1993). In polygynic colonies a hierarchy between the queens can occur (Ross, 1988;Heinze, 1990;Heinze & Smith, 1990), or a queen multiple mate, not necessarily using the sperm of all males in the same proportion (Ross, 1986).…”

Life Histories of Subarctic Ants

“…In contrast, in colonies of all species belonging to the boreal subgenus Leptothorax (sstr.) and in many boreal and alpine L. (Myrafant) several inseminated queens may be present (e.g., Buschinger, 1968;Alloway et al, 1982;Heinze and Buschinger, 1988;Stille et and openly aggressive interactions in early spring, resulting in the formation of rank orders. In each nest only the highest ranking queen began to lay eggs (Heinze and Smith, 1990;Heinze and Lipski, 1990;Heinze and Ortius, 1991).…”