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Quantitative differences in nourishment affect caste-related physiology and development in the paper wasp Polistes metricus.

Judd TM, Teal PE, Hernandez EJ, Choudhury T, Hunt JH - PLoS ONE (2015)

Bottom Line: In the wasp genus Polistes, colonies are founded by one or more females, and the female offspring that emerge in that colony are either non-reproducing workers or future reproductives of the following generation (gynes).A growing number of studies now indicate that workers emerge with activated reproductive physiology, whereas the future reproductive gynes do not.Although the experiment was not designed to test for worker behavior per se, our results further implicate activated reproductive physiology as a developmental response to low larval nourishment as a fundamental aspect of worker behavior in Polistes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Southeast Missouri State University, Gape Girardeau, MO, 63701, United States of America.

ABSTRACT
The distinction between worker and reproductive castes of social insects is receiving increased attention from a developmental rather than adaptive perspective. In the wasp genus Polistes, colonies are founded by one or more females, and the female offspring that emerge in that colony are either non-reproducing workers or future reproductives of the following generation (gynes). A growing number of studies now indicate that workers emerge with activated reproductive physiology, whereas the future reproductive gynes do not. Low nourishment levels for larvae during the worker-rearing phase of the colony cycle and higher nourishment levels for larvae when gynes are reared are now strongly suspected of playing a major role in this difference. Here, we present the results of a laboratory rearing experiment in which Polistes metricus single foundresses were held in environmental conditions with a higher level of control than in any previously published study, and the amount of protein nourishment made available to feed larvae was the only input variable. Three experimental feeding treatments were tested: restricted, unrestricted, and hand-supplemented. Analysis of multiple response variables shows that wasps reared on restricted protein nourishment, which would be the case for wasps reared in field conditions that subsequently become workers, tend toward trait values that characterize active reproductive physiology. Wasps reared on unrestricted and hand-supplemented protein, which replicates higher feeding levels for larvae in field conditions that subsequently become gynes, tend toward trait values that characterize inactive reproductive physiology. Although the experiment was not designed to test for worker behavior per se, our results further implicate activated reproductive physiology as a developmental response to low larval nourishment as a fundamental aspect of worker behavior in Polistes.

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Score plot for the two main principal components obtained in the PCA analysis.Data points are separated by colonies reared on the restricted (circles), and unrestricted.
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pone.0116199.g005: Score plot for the two main principal components obtained in the PCA analysis.Data points are separated by colonies reared on the restricted (circles), and unrestricted.

Mentions: Three principal components explained more than 79.8% of the variability of the data (S3 Table). The first principal component (PC1) was negatively loaded by wing length and cell height and positively loaded by ovary score and gaster lipid levels (Fig. 4, S4 Table). The second principal component had hemolymph protein levels, nest cell number, and pupation time as the variables that explained more of the data (Fig. 4, S4 Table). The third principle component (PC3) was negatively loaded by hemolymph protein levels and gaster lipid levels and positively loaded by caterpillars eaten (S4 Table). When we clustered the contribution of the variables by the experimental unit we found that PC1 significantly separated colonies in the restricted treatment from colonies in the unrestricted treatment (F = 49.11, p<0.001, ANOVA; Fig. 5). PC2 and PC3 showed no significant differences between treatments.


Quantitative differences in nourishment affect caste-related physiology and development in the paper wasp Polistes metricus.

Judd TM, Teal PE, Hernandez EJ, Choudhury T, Hunt JH - PLoS ONE (2015)

Score plot for the two main principal components obtained in the PCA analysis.Data points are separated by colonies reared on the restricted (circles), and unrestricted.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4338145&req=5

pone.0116199.g005: Score plot for the two main principal components obtained in the PCA analysis.Data points are separated by colonies reared on the restricted (circles), and unrestricted.
Mentions: Three principal components explained more than 79.8% of the variability of the data (S3 Table). The first principal component (PC1) was negatively loaded by wing length and cell height and positively loaded by ovary score and gaster lipid levels (Fig. 4, S4 Table). The second principal component had hemolymph protein levels, nest cell number, and pupation time as the variables that explained more of the data (Fig. 4, S4 Table). The third principle component (PC3) was negatively loaded by hemolymph protein levels and gaster lipid levels and positively loaded by caterpillars eaten (S4 Table). When we clustered the contribution of the variables by the experimental unit we found that PC1 significantly separated colonies in the restricted treatment from colonies in the unrestricted treatment (F = 49.11, p<0.001, ANOVA; Fig. 5). PC2 and PC3 showed no significant differences between treatments.

Bottom Line: In the wasp genus Polistes, colonies are founded by one or more females, and the female offspring that emerge in that colony are either non-reproducing workers or future reproductives of the following generation (gynes).A growing number of studies now indicate that workers emerge with activated reproductive physiology, whereas the future reproductive gynes do not.Although the experiment was not designed to test for worker behavior per se, our results further implicate activated reproductive physiology as a developmental response to low larval nourishment as a fundamental aspect of worker behavior in Polistes.

View Article: PubMed Central - PubMed

Affiliation: Department of Biology, Southeast Missouri State University, Gape Girardeau, MO, 63701, United States of America.

ABSTRACT
The distinction between worker and reproductive castes of social insects is receiving increased attention from a developmental rather than adaptive perspective. In the wasp genus Polistes, colonies are founded by one or more females, and the female offspring that emerge in that colony are either non-reproducing workers or future reproductives of the following generation (gynes). A growing number of studies now indicate that workers emerge with activated reproductive physiology, whereas the future reproductive gynes do not. Low nourishment levels for larvae during the worker-rearing phase of the colony cycle and higher nourishment levels for larvae when gynes are reared are now strongly suspected of playing a major role in this difference. Here, we present the results of a laboratory rearing experiment in which Polistes metricus single foundresses were held in environmental conditions with a higher level of control than in any previously published study, and the amount of protein nourishment made available to feed larvae was the only input variable. Three experimental feeding treatments were tested: restricted, unrestricted, and hand-supplemented. Analysis of multiple response variables shows that wasps reared on restricted protein nourishment, which would be the case for wasps reared in field conditions that subsequently become workers, tend toward trait values that characterize active reproductive physiology. Wasps reared on unrestricted and hand-supplemented protein, which replicates higher feeding levels for larvae in field conditions that subsequently become gynes, tend toward trait values that characterize inactive reproductive physiology. Although the experiment was not designed to test for worker behavior per se, our results further implicate activated reproductive physiology as a developmental response to low larval nourishment as a fundamental aspect of worker behavior in Polistes.

Show MeSH
Related in: MedlinePlus