# Body size prediction in scorpions: a phylogenetic comparative examination of linear measurements of individual body parts
# R functions for size predictions in scorpions
# Stenio I. A. Foerster
# 12 Sep 2024
# stenio.foerster@ut.ee | stenioit@gmail.com


# This file contains four functions for predicting total lenght and carapace lenght in scorpions.
# The user has to supply the values for the linear measurements in mm. The predicted values
# are returned in mm.


# Functions ---------------------------------------------------------------

# This is the R function for predicting total lenght (in mm) using a single predictor
simple_toL <- function(values_mm, predictor = "met5l") {
  
  if (predictor == "met5l") {
    return(exp(2.126 + log(values_mm) * 0.949))
  }

  if (predictor == "carl") {
    return(exp(2.178 + log(values_mm) * 1.006))
  }

  if (predictor == "tel") {
    return(exp(2.322 + log(values_mm) * 0.903))
  }

  if (predictor == "chel") {
    return(exp(2.275 + log(values_mm) * 0.725))
  }

  if (predictor == "tew") {
    return(exp(3.286 + log(values_mm) * 0.815))
  }

  if (predictor == "chew") {
    return(exp(3.401 + log(values_mm) * 0.630))
  }

  if (predictor == "met5w") {
    return(exp(3.131 + log(values_mm) * 0.710))
  }
}

# This is the R function to predict total length (in mm) from two predictors
multi_toL <- function(met5l_mm, secPred_mm, second_predictor = "chew") {
  
  if (second_predictor == "chew") {
    return(exp(2.331 + log(met5l_mm) * 0.767 + log(secPred_mm) * 0.196))
  }
  
  if (second_predictor == "tew") {
    return(exp(2.497 + log(met5l_mm) * 0.619 + log(secPred_mm) * 0.344))
  }
  
  if (second_predictor == "met5w") {
    return(exp(2.235 + log(met5l_mm) * 0.783 + log(secPred_mm) * 0.204))
  }
  
  if (second_predictor == "tel") {
    return(exp(2.165 + log(met5l_mm) * 0.472 + log(secPred_mm) * 0.491))
  }
  
  if (second_predictor == "chel") {
    return(exp(2.041 + log(met5l_mm) * 0.739 + log(secPred_mm) * 0.218))
  }
}

# This is the R function for predicting carapace lenght (in mm) using a single predictor
simple_carL <- function(values_mm, predictor = "met5l") {
  
  if (predictor == "met5l") {
    return(exp(0.105 + log(values_mm) * 0.849))
  }
  
  if (predictor == "carl") {
    return(exp(2.178 + log(values_mm) * 1.006))
  }
  
  if (predictor == "tel") {
    return(exp(0.235 + log(values_mm) * 0.839))
  }
  
  if (predictor == "chel") {
    return(exp(0.222 + log(values_mm) * 0.658))
  }
  
  if (predictor == "tew") {
    return(exp(1.116 + log(values_mm) * 0.775))
  }
  
  if (predictor == "chew") {
    return(exp(1.222 + log(values_mm) * 0.603))
  }
  
  if (predictor == "met5w") {
    return(exp(0.946 + log(values_mm) * 0.711))
  }
}

# This is the R function to predict carapace length (in mm) from two predictors
multi_carL <- function(tel_mm, secPred_mm, second_predictor = "met5w") {
  
  if (second_predictor == "chew") {
    return(exp(0.390 + log(tel_mm) * 0.681 + log(secPred_mm) * 0.172))
  }
  
  if (second_predictor == "tew") {
    return(exp(0.576 + log(tel_mm) * 0.493 + log(secPred_mm) * 0.362))
  }
  
  if (second_predictor == "met5w") {
    return(exp(0.337 + log(tel_mm) * 0.653 + log(secPred_mm) * 0.224))
  }
  
  if (second_predictor == "met5l") {
    return(exp(0.188 + log(tel_mm) * 0.727 + log(secPred_mm) * 0.131))
  }
  
  if (second_predictor == "chel") {
    return(exp(0.147 + log(tel_mm) * 0.702 + log(secPred_mm) * 0.150))
  }
}