body condition index (Ambystomatidae)

Knowledge graph centered on body condition index (Ambystomatidae) with 35 nodes and 132 connections. Top connected: aquatic insects, Ambystoma, phenotypic plasticity, Ambystoma tigrinum, Ambystoma tigrinum nebulosm.

Method synopsis

Calculation of body condition metrics (mass/SVL³) and derived fitness proxies including condition-weighted reproductive opportunities for males and estimated egg production for females based on body size relationships.

Synthesized from method descriptions across 3 papers using this protocol.

Procedure from a recent peer-reviewed implementation

Steps below were extracted from the most recent peer-reviewed implementation of this protocol in the corpus — Lifetime Fitness, Sex-Specific Life History, and the Maintenance of a Polyphenism (2019), The American Naturalist. Implementations in other papers (listed below) may differ.

1. Body condition measurement
   Body condition was calculated by dividing mass by SVL cubed for each individual. Larval condition was measured in the third summer of development when morph determination occurred. Adult condition was averaged across all adult captures for each individual. For larvae captured multiple times in their third summer, larval condition measures were averaged.
   Quantities: Condition calculated as mass/SVL³, with SVL measured to nearest millimeter and mass to nearest gramDuration: Measured at each capture event throughout individual lifetimesConditions: Measurements taken during capture events in summer months
   Equipment: measuring devices for SVL, scales for mass measurement
2. Reproductive opportunity quantification
   Reproductive opportunities were counted as the number of years each individual was captured in breeding condition (swollen cloaca). For males, condition-weighted reproductive opportunities were calculated by standardizing each male's condition relative to other males in reproductive condition that year, with males in higher condition receiving higher weights based on expected mating advantage.
   Quantities: Reproductive opportunities ranged from 0-10 per individual, with 75% of adults having zero or one reproductive opportunityDuration: Tracked annually across individual lifetimes from first reproduction until death or final captureConditions: Assessed during breeding season when individuals were in reproductive condition
   Equipment: visual assessment tools for breeding condition determination

Typical Equipment

• measuring devices for SVL
• scales for mass measurement
• statistical analysis tools for regression calculations

Output Measurements

• body condition
• condition-weighted reproductive opportunities
• estimated egg production
• lifetime fitness metrics

Papers Using This Protocol (3)

Species Studied With This Protocol