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Building a Beetle: How Larval Environment Leads to Adult Performance in a Horned Beetle.

Reaney LT, Knell RJ - PLoS ONE (2015)

Bottom Line: The link between the expression of the signals used by male animals in contests with the traits which determine success in those contests is poorly understood.This is particularly true in holometabolous insects such as horned beetles where signal expression is determined during metamorphosis and is fixed during adulthood, whereas performance is influenced by post-eclosion feeding.Female strength was predicted by a simple path diagram where strength was determined by eclosion weight, itself determined by larval nutrition: weight gain post-eclosion was not a predictor of strength in this sex.

View Article: PubMed Central - PubMed

Affiliation: School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, United Kingdom.

ABSTRACT
The link between the expression of the signals used by male animals in contests with the traits which determine success in those contests is poorly understood. This is particularly true in holometabolous insects such as horned beetles where signal expression is determined during metamorphosis and is fixed during adulthood, whereas performance is influenced by post-eclosion feeding. We used path analysis to investigate the relationships between larval and adult nutrition, horn and body size and fitness-related traits such as strength and testes mass in the horned beetle Euoniticellus intermedius. In males weight gain post-eclosion had a central role in determining both testes mass and strength. Weight gain was unaffected by adult nutrition but was strongly correlated with by horn length, itself determined by larval resource availability, indicating strong indirect effects of larval nutrition on the adult beetle's ability to assimilate food and grow tissues. Female strength was predicted by a simple path diagram where strength was determined by eclosion weight, itself determined by larval nutrition: weight gain post-eclosion was not a predictor of strength in this sex. Based on earlier findings we discuss the insulin-like signalling pathway as a possible mechanism by which larval nutrition could affect adult weight gain and thence traits such as strength.

No MeSH data available.


Related in: MedlinePlus

Path diagrams for the final models explaining the relationship between female (A) and male (B) adult fat content, testes mass (males only) and larval nutrition, adult morphology and post-eclosion weight gain.Solid lines indicate positive relationships, dashed lines negative, double headed arrows indicate correlation (i.e. no assumptions about causality) and line width is proportional to the strength of the relationship. Numbers next to arrows indicate regression or correlation coefficients calculated from standardized predictor variables.
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pone.0134399.g002: Path diagrams for the final models explaining the relationship between female (A) and male (B) adult fat content, testes mass (males only) and larval nutrition, adult morphology and post-eclosion weight gain.Solid lines indicate positive relationships, dashed lines negative, double headed arrows indicate correlation (i.e. no assumptions about causality) and line width is proportional to the strength of the relationship. Numbers next to arrows indicate regression or correlation coefficients calculated from standardized predictor variables.

Mentions: The initial path models that were fitted to explain female body fat content and male body fat content and testes mass (see figures G and I in S1 File) were similar to the initial models used to explain maximum strength shown in Fig 1, with the differences being firstly that maximum strength for males was replaced with testes mass in the initial model, and for females this variable was removed. Secondly, the relationships between testes mass, fat content and haemolymph protein concentration were modeled as correlations rather than as causal relationships. Fig 2 shows the path diagrams for the fitted models following model refinement. In both cases the various fit measures indicate well-fitted models (females: minimum function test statistic p = 0.420, RMSEA 95% CIs 0–0.109, males: minimum function test statistic p = 0.823, RMSEA 95% CIs 0–0.135).


Building a Beetle: How Larval Environment Leads to Adult Performance in a Horned Beetle.

Reaney LT, Knell RJ - PLoS ONE (2015)

Path diagrams for the final models explaining the relationship between female (A) and male (B) adult fat content, testes mass (males only) and larval nutrition, adult morphology and post-eclosion weight gain.Solid lines indicate positive relationships, dashed lines negative, double headed arrows indicate correlation (i.e. no assumptions about causality) and line width is proportional to the strength of the relationship. Numbers next to arrows indicate regression or correlation coefficients calculated from standardized predictor variables.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4526545&req=5

pone.0134399.g002: Path diagrams for the final models explaining the relationship between female (A) and male (B) adult fat content, testes mass (males only) and larval nutrition, adult morphology and post-eclosion weight gain.Solid lines indicate positive relationships, dashed lines negative, double headed arrows indicate correlation (i.e. no assumptions about causality) and line width is proportional to the strength of the relationship. Numbers next to arrows indicate regression or correlation coefficients calculated from standardized predictor variables.
Mentions: The initial path models that were fitted to explain female body fat content and male body fat content and testes mass (see figures G and I in S1 File) were similar to the initial models used to explain maximum strength shown in Fig 1, with the differences being firstly that maximum strength for males was replaced with testes mass in the initial model, and for females this variable was removed. Secondly, the relationships between testes mass, fat content and haemolymph protein concentration were modeled as correlations rather than as causal relationships. Fig 2 shows the path diagrams for the fitted models following model refinement. In both cases the various fit measures indicate well-fitted models (females: minimum function test statistic p = 0.420, RMSEA 95% CIs 0–0.109, males: minimum function test statistic p = 0.823, RMSEA 95% CIs 0–0.135).

Bottom Line: The link between the expression of the signals used by male animals in contests with the traits which determine success in those contests is poorly understood.This is particularly true in holometabolous insects such as horned beetles where signal expression is determined during metamorphosis and is fixed during adulthood, whereas performance is influenced by post-eclosion feeding.Female strength was predicted by a simple path diagram where strength was determined by eclosion weight, itself determined by larval nutrition: weight gain post-eclosion was not a predictor of strength in this sex.

View Article: PubMed Central - PubMed

Affiliation: School of Biological and Chemical Sciences, Queen Mary, University of London, Mile End Road, London, United Kingdom.

ABSTRACT
The link between the expression of the signals used by male animals in contests with the traits which determine success in those contests is poorly understood. This is particularly true in holometabolous insects such as horned beetles where signal expression is determined during metamorphosis and is fixed during adulthood, whereas performance is influenced by post-eclosion feeding. We used path analysis to investigate the relationships between larval and adult nutrition, horn and body size and fitness-related traits such as strength and testes mass in the horned beetle Euoniticellus intermedius. In males weight gain post-eclosion had a central role in determining both testes mass and strength. Weight gain was unaffected by adult nutrition but was strongly correlated with by horn length, itself determined by larval resource availability, indicating strong indirect effects of larval nutrition on the adult beetle's ability to assimilate food and grow tissues. Female strength was predicted by a simple path diagram where strength was determined by eclosion weight, itself determined by larval nutrition: weight gain post-eclosion was not a predictor of strength in this sex. Based on earlier findings we discuss the insulin-like signalling pathway as a possible mechanism by which larval nutrition could affect adult weight gain and thence traits such as strength.

No MeSH data available.


Related in: MedlinePlus