Limits...
Queen execution increases relatedness among workers of the invasive Argentine ant, Linepithema humile.

Inoue MN, Ito F, Goka K - Ecol Evol (2015)

Bottom Line: Polygyny in social insects can greatly reduce within-nest genetic relatedness.The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies.This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biological Science Tokyo University of Agriculture and Technology 3-5-8 Saiwaicho Fuchu Tokyo 183-8509 Japan.

ABSTRACT
Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a "supercolony" that is composed of a large number of nests and is considered to contribute to the ant's invasion success. Currently, four mutually antagonistic supercolonies are contiguously distributed within a small area of Japan. Here, we analyzed the genetic structure and relatedness within and among the four supercolonies using microsatellite markers to clarify how L. humile maintains its supercoloniality. The results of AMOVA and BASP, the F ST values, and the existence of several private alleles indicated that the L. humile population in the Kobe area had a characteristic genetic structure. Within a given supercolony, there was significant genetic differentiation (F ST) among workers collected in May and those collected in September. The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies. This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution. From the perspective of kin selection, workers collectively eliminate queens, thereby increasing their own inclusive fitness. Restricted gene flow among supercolonies, together with mating with sib and queen execution, could help to maintain the unique social structure of L. humile, the distribution of which is expanding worldwide.

No MeSH data available.


Map of the study populations of Linepithema humile in the Kobe area. Population codes: KA, Kobe A; KB, Kobe B; KC, Kobe C; and JM, Japanese main.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection


getmorefigures.php?uid=PMC4588641&req=5

ece31681-fig-0001: Map of the study populations of Linepithema humile in the Kobe area. Population codes: KA, Kobe A; KB, Kobe B; KC, Kobe C; and JM, Japanese main.

Mentions: Our studies were conducted in 2009 in the four L. humile populations established in the Kobe area: the KA (Kobe A) and KB (Kobe B) supercolonies at Port Island, and the KC (Kobe C) and JM (Japanese main) supercolonies at the Maya Wharf (Fig. 1). We collected 11–20 workers from each of 19 nests in May and September 2009 for genetic analysis. Sexual production of L. humile generally occurs in the spring and early summer (M. N. Inoue et al. unpubl. data): May is just before reproduction begins and September is when the first workers are produced by the new queens. We also collected workers from 17 nests (excluding KA4 and KB5) to perform aggression tests between workers from different nests. The distance between the nests ranged from 30 to 380 m (mean ± SE, 177.50 ± 69.6 m) at the Maya Wharf and 40–1270 m (506.00 ± 29.5 m) at the Port Island site.


Queen execution increases relatedness among workers of the invasive Argentine ant, Linepithema humile.

Inoue MN, Ito F, Goka K - Ecol Evol (2015)

Map of the study populations of Linepithema humile in the Kobe area. Population codes: KA, Kobe A; KB, Kobe B; KC, Kobe C; and JM, Japanese main.
© Copyright Policy - creativeCommonsBy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC4588641&req=5

ece31681-fig-0001: Map of the study populations of Linepithema humile in the Kobe area. Population codes: KA, Kobe A; KB, Kobe B; KC, Kobe C; and JM, Japanese main.
Mentions: Our studies were conducted in 2009 in the four L. humile populations established in the Kobe area: the KA (Kobe A) and KB (Kobe B) supercolonies at Port Island, and the KC (Kobe C) and JM (Japanese main) supercolonies at the Maya Wharf (Fig. 1). We collected 11–20 workers from each of 19 nests in May and September 2009 for genetic analysis. Sexual production of L. humile generally occurs in the spring and early summer (M. N. Inoue et al. unpubl. data): May is just before reproduction begins and September is when the first workers are produced by the new queens. We also collected workers from 17 nests (excluding KA4 and KB5) to perform aggression tests between workers from different nests. The distance between the nests ranged from 30 to 380 m (mean ± SE, 177.50 ± 69.6 m) at the Maya Wharf and 40–1270 m (506.00 ± 29.5 m) at the Port Island site.

Bottom Line: Polygyny in social insects can greatly reduce within-nest genetic relatedness.The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies.This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution.

View Article: PubMed Central - PubMed

Affiliation: Department of Applied Biological Science Tokyo University of Agriculture and Technology 3-5-8 Saiwaicho Fuchu Tokyo 183-8509 Japan.

ABSTRACT
Polygyny in social insects can greatly reduce within-nest genetic relatedness. In polygynous ant species, potential rival queens in colonies with multiple queens are often executed by other queens, workers, or both. The Argentine ant, Linepithema humile, native to South America, forms a "supercolony" that is composed of a large number of nests and is considered to contribute to the ant's invasion success. Currently, four mutually antagonistic supercolonies are contiguously distributed within a small area of Japan. Here, we analyzed the genetic structure and relatedness within and among the four supercolonies using microsatellite markers to clarify how L. humile maintains its supercoloniality. The results of AMOVA and BASP, the F ST values, and the existence of several private alleles indicated that the L. humile population in the Kobe area had a characteristic genetic structure. Within a given supercolony, there was significant genetic differentiation (F ST) among workers collected in May and those collected in September. The significant deviation from Hardy-Weinberg equilibrium increased, and the relatedness among workers significantly increased from May to September in all supercolonies. This result suggested that the supercolonies replaced old queens with new ones during the reproductive season, thus supporting the plausibility of queen execution. From the perspective of kin selection, workers collectively eliminate queens, thereby increasing their own inclusive fitness. Restricted gene flow among supercolonies, together with mating with sib and queen execution, could help to maintain the unique social structure of L. humile, the distribution of which is expanding worldwide.

No MeSH data available.