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Nest relocation and excavation in the Florida harvester ant, Pogonomyrmex badius.

Tschinkel WR - PLoS ONE (2014)

Bottom Line: Relocation is probably intrinsic to the life history of this species, and the causes of relocation remain obscure--the architecture of old and new nests was very similar, and neither the forest canopy nor the density or size of neighbors was correlated with relocation.Colonies moving more than once in two years lost more size than those moving less often, suggesting that moving may bear a fitness cost.Colony relocation is a dramatic and consistent feature of the life history of the Florida harvester ant, inviting inquiry into its proximal and ultimate causes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America.

ABSTRACT
The Florida harvester ant (Pogonomyrmex badius) excavates deep nests in the sandy soils of the Gulf and Atlantic coastal plains. Nest relocations of over 400 colonies in a north Florida coastal plains pine forest were tracked and mapped from 2010 to 2013. Individual colonies varied from one move in two years to four times a year, averaging about one per year. Almost all moves occurred between May and November peaking in July when more than 1% of the colonies moved per day. Move directions were random, and averaged 4 m, with few moves exceeding 10 m. Distance moved was not related to colony size. Over multiple moves, paths were random walks around the original nest location. Relocation is probably intrinsic to the life history of this species, and the causes of relocation remain obscure--the architecture of old and new nests was very similar, and neither the forest canopy nor the density or size of neighbors was correlated with relocation. Monitoring entire relocations (n = 20) showed that they were usually completed in 4 to 6 days. Moves were diurnal, peaking in the mornings and afternoons dipping during mid-day, and ceasing before sundown. Workers excavated the new nest continuously during the daytime throughout the move and beyond. A minority of workers carried seeds, charcoal and brood, with seeds being by far the most common burden. The proportion of burdened workers increased throughout the move. Measured from year to year, small colonies gained size and large ones lost it. Colonies moving more than once in two years lost more size than those moving less often, suggesting that moving may bear a fitness cost. Colony relocation is a dramatic and consistent feature of the life history of the Florida harvester ant, inviting inquiry into its proximal and ultimate causes.

Show MeSH
Colonies sometimes cleared visible trails during moves.The charcoal covered nest disc is the old nest, and the clear, sandy one is the new.
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pone-0112981-g011: Colonies sometimes cleared visible trails during moves.The charcoal covered nest disc is the old nest, and the clear, sandy one is the new.

Mentions: Relocations in their early stages were identifiable through the very small nest disc around the new nest, and a trail between the old and new nests. This early trail was usually much less active than later in a move, at which time the ants occasionally formed conspicuous cleared trails between the new and old nests (Fig. 11), but most trails were not conspicuously cleared. During every day of the move, workers at the new nest brought pellets of sand to the surface and deposited them on the growing nest disc. All trail activity began no earlier than about 8:30 or 9 a.m. and ceased no later than about 6 or 7 p.m. Trail activity often diminished or ceased during the hottest part of the day (noon to 3 p.m.). Substantial rain inhibited trail activity, but light rain often did not. In all cases, trailing and excavation ceased before sunset at which time the ants closed the nest entrances of both nests, to resume surface activity the next morning Trails were most likely when the minimum surface temperature on the trail was above about 25°C and the maximum was less than about 45°C (Fig. 12).


Nest relocation and excavation in the Florida harvester ant, Pogonomyrmex badius.

Tschinkel WR - PLoS ONE (2014)

Colonies sometimes cleared visible trails during moves.The charcoal covered nest disc is the old nest, and the clear, sandy one is the new.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4237378&req=5

pone-0112981-g011: Colonies sometimes cleared visible trails during moves.The charcoal covered nest disc is the old nest, and the clear, sandy one is the new.
Mentions: Relocations in their early stages were identifiable through the very small nest disc around the new nest, and a trail between the old and new nests. This early trail was usually much less active than later in a move, at which time the ants occasionally formed conspicuous cleared trails between the new and old nests (Fig. 11), but most trails were not conspicuously cleared. During every day of the move, workers at the new nest brought pellets of sand to the surface and deposited them on the growing nest disc. All trail activity began no earlier than about 8:30 or 9 a.m. and ceased no later than about 6 or 7 p.m. Trail activity often diminished or ceased during the hottest part of the day (noon to 3 p.m.). Substantial rain inhibited trail activity, but light rain often did not. In all cases, trailing and excavation ceased before sunset at which time the ants closed the nest entrances of both nests, to resume surface activity the next morning Trails were most likely when the minimum surface temperature on the trail was above about 25°C and the maximum was less than about 45°C (Fig. 12).

Bottom Line: Relocation is probably intrinsic to the life history of this species, and the causes of relocation remain obscure--the architecture of old and new nests was very similar, and neither the forest canopy nor the density or size of neighbors was correlated with relocation.Colonies moving more than once in two years lost more size than those moving less often, suggesting that moving may bear a fitness cost.Colony relocation is a dramatic and consistent feature of the life history of the Florida harvester ant, inviting inquiry into its proximal and ultimate causes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, Florida, United States of America.

ABSTRACT
The Florida harvester ant (Pogonomyrmex badius) excavates deep nests in the sandy soils of the Gulf and Atlantic coastal plains. Nest relocations of over 400 colonies in a north Florida coastal plains pine forest were tracked and mapped from 2010 to 2013. Individual colonies varied from one move in two years to four times a year, averaging about one per year. Almost all moves occurred between May and November peaking in July when more than 1% of the colonies moved per day. Move directions were random, and averaged 4 m, with few moves exceeding 10 m. Distance moved was not related to colony size. Over multiple moves, paths were random walks around the original nest location. Relocation is probably intrinsic to the life history of this species, and the causes of relocation remain obscure--the architecture of old and new nests was very similar, and neither the forest canopy nor the density or size of neighbors was correlated with relocation. Monitoring entire relocations (n = 20) showed that they were usually completed in 4 to 6 days. Moves were diurnal, peaking in the mornings and afternoons dipping during mid-day, and ceasing before sundown. Workers excavated the new nest continuously during the daytime throughout the move and beyond. A minority of workers carried seeds, charcoal and brood, with seeds being by far the most common burden. The proportion of burdened workers increased throughout the move. Measured from year to year, small colonies gained size and large ones lost it. Colonies moving more than once in two years lost more size than those moving less often, suggesting that moving may bear a fitness cost. Colony relocation is a dramatic and consistent feature of the life history of the Florida harvester ant, inviting inquiry into its proximal and ultimate causes.

Show MeSH