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The sociometry and sociogenesis of reproduction in the Florida harvester ant, Pogonomyrmex badius.

Smith CR, Tschinkel WR - J. Insect Sci. (2006)

Bottom Line: Therefore, there is a trend of increasing male bias in the sex ratio with increasing colony size (although a single outlier complicates this conclusion).We interpret our results in the light of sexual and natural selection as documented in related species.We also report the first documentation of male production by workers in the genus Pogonomyrmex .

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA. crsmith@life.uiuc.edu

ABSTRACT
The colony is the functional unit of natural selection for most social insects including the Florida harvester ant, Pogonomyrmex badius . To address reproduction in the species variables were evaluated relevant to the colony-level (sociometry), and social growth (sociogenesis). Colonies become reproductively mature when the worker population reaches approximately 700 individuals. The production of males and gynes (reproductive females) occurs only in spring, and is highly synchronized from its onset, which in turn allows synchronization of mating in early summer. Worker production follows sexual production, and continues until colonies go dormant in winter. Once mature, colony investment into reproduction is a constant proportion of colony size (isometric), regardless of the sex ratio produced. As individual male body size increases, they become leaner, whereas the amount of fat stored by gynes is highly variable. Larger colonies produce larger males, but gyne size is a constant across the range of colony sizes. As colony size increases, investment into males increases faster than investment into gynes. Therefore, there is a trend of increasing male bias in the sex ratio with increasing colony size (although a single outlier complicates this conclusion). We interpret our results in the light of sexual and natural selection as documented in related species. We also report the first documentation of male production by workers in the genus Pogonomyrmex .

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Weight and numeric allometries of reproductive production. Filled symbols (with solid line) are weights and open symbols (with dashed line) numbers. The independent axis is the number of mature workers in a colony (colony size). The slope (scaling exponent) of the weight-colony size relationship is 1.06 and for numeric data is 1.37. Neither slope is statistically different than 1.
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i1536-2442-6-32-1-f03: Weight and numeric allometries of reproductive production. Filled symbols (with solid line) are weights and open symbols (with dashed line) numbers. The independent axis is the number of mature workers in a colony (colony size). The slope (scaling exponent) of the weight-colony size relationship is 1.06 and for numeric data is 1.37. Neither slope is statistically different than 1.

Mentions: Investment into sexuals, by both weight and number, was isometric with colony size (Fig. 3). Colony investment into individual male qualities (head width, dry weight, and fat content) increased more slowly than colony size (Table 3). Gyne qualities, however, were not associated with colony size at all. Total production of males, the number produced and their summed weight, increased faster than colony size. Total gyne production, numerically, increased at the same rate as colony size, but their summed weight was not associated with changes in colony size (Table 4). Therefore, colonies invested proportionally more in total male production by increasing both the total number produced and the quality of individuals. On the other hand, investment into gyne quality was constant, regardless of colony size, but the total number produced increased proportionately to colony size.


The sociometry and sociogenesis of reproduction in the Florida harvester ant, Pogonomyrmex badius.

Smith CR, Tschinkel WR - J. Insect Sci. (2006)

Weight and numeric allometries of reproductive production. Filled symbols (with solid line) are weights and open symbols (with dashed line) numbers. The independent axis is the number of mature workers in a colony (colony size). The slope (scaling exponent) of the weight-colony size relationship is 1.06 and for numeric data is 1.37. Neither slope is statistically different than 1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC2990325&req=5

i1536-2442-6-32-1-f03: Weight and numeric allometries of reproductive production. Filled symbols (with solid line) are weights and open symbols (with dashed line) numbers. The independent axis is the number of mature workers in a colony (colony size). The slope (scaling exponent) of the weight-colony size relationship is 1.06 and for numeric data is 1.37. Neither slope is statistically different than 1.
Mentions: Investment into sexuals, by both weight and number, was isometric with colony size (Fig. 3). Colony investment into individual male qualities (head width, dry weight, and fat content) increased more slowly than colony size (Table 3). Gyne qualities, however, were not associated with colony size at all. Total production of males, the number produced and their summed weight, increased faster than colony size. Total gyne production, numerically, increased at the same rate as colony size, but their summed weight was not associated with changes in colony size (Table 4). Therefore, colonies invested proportionally more in total male production by increasing both the total number produced and the quality of individuals. On the other hand, investment into gyne quality was constant, regardless of colony size, but the total number produced increased proportionately to colony size.

Bottom Line: Therefore, there is a trend of increasing male bias in the sex ratio with increasing colony size (although a single outlier complicates this conclusion).We interpret our results in the light of sexual and natural selection as documented in related species.We also report the first documentation of male production by workers in the genus Pogonomyrmex .

View Article: PubMed Central - PubMed

Affiliation: Department of Biological Science, Florida State University, Tallahassee, FL 32306-4370, USA. crsmith@life.uiuc.edu

ABSTRACT
The colony is the functional unit of natural selection for most social insects including the Florida harvester ant, Pogonomyrmex badius . To address reproduction in the species variables were evaluated relevant to the colony-level (sociometry), and social growth (sociogenesis). Colonies become reproductively mature when the worker population reaches approximately 700 individuals. The production of males and gynes (reproductive females) occurs only in spring, and is highly synchronized from its onset, which in turn allows synchronization of mating in early summer. Worker production follows sexual production, and continues until colonies go dormant in winter. Once mature, colony investment into reproduction is a constant proportion of colony size (isometric), regardless of the sex ratio produced. As individual male body size increases, they become leaner, whereas the amount of fat stored by gynes is highly variable. Larger colonies produce larger males, but gyne size is a constant across the range of colony sizes. As colony size increases, investment into males increases faster than investment into gynes. Therefore, there is a trend of increasing male bias in the sex ratio with increasing colony size (although a single outlier complicates this conclusion). We interpret our results in the light of sexual and natural selection as documented in related species. We also report the first documentation of male production by workers in the genus Pogonomyrmex .

Show MeSH