DOI: 10.5061/dryad.tb2rbp076
title: Effects of mite load on growth and body condition in Sceloporus undulatus

description: Parasitism is nearly ubiquitous in animals and is frequently associated
 with fitness costs in host organisms, including reduced growth, foraging,
 and reproduction. In many species, males tend to be more heavily
 parasitized than females and thus may bear greater costs of parasitism.
 Sceloporus undulatus is a female-larger, sexually-size dimorphic lizard
 species that is heavily parasitized by chigger mites (Eutrombicula
 alfreddugesi). In particular, the intensity of mite parasitism is higher
 in male than in female juveniles during the period of time when sex
 differences in growth rate lead to the development of sexual size
 dimorphism (SSD). Sex-biased differences in fitness costs of parasitism
 have been documented in other species. We investigated whether there are
 growth costs of mite ectoparasitism, at a time coinciding with sex
 differences in growth rate and the onset of SSD. If there are sex-biased
 growth costs of parasitism, then this could suggest a contribution to the
 development of SSD in S. undulatus. We measured growth and mite loads in
 two cohorts of unmanipulated, field-active yearlings by conducting
 descriptive mark-recapture studies during the activity seasons of 2016 and
 2019. Yearling males had consistently higher mid-summer mite loads and
 consistently lower growth rates than females. However, we found that
 growth rate and body condition were independent of mite load in both
 sexes. Furthermore, growth rates and mite loads were higher in 2019 than
 in 2016. Our findings suggest that juveniles of S. undulatus are highly
 tolerant of chigger mites and that any costs imposed by mites may be at
 the expense of functions other than growth. We conclude that sex-biased
 mite ectoparasitism does not contribute to sex differences in growth rate
 and, therefore, does not contribute to the development of SSD.
description: These datasets were collected in Colliers Mills Wildlife
 Management Area in the New Jersey Pinelands (June-July 2016 and
 2019). Details for each dataset are provided in the
 README file.
description: # Mites Loads and Effects on Growth
 [https://doi.org/10.5061/dryad.tb2rbp076](https://doi.org/10.5061/dryad.tb2rbp076) ### Datasets included: 1) 2016/2019 Lizard Captures * Lizard toe clip IDs with their associated sex and age classes * First capture date with measurements of snout-vent length (mm), body mass (g), and mite load (# of mites) * Second capture date with measurements of snout-vent length (mm), body mass (g), and mite load (# of mites) * Growth rate calculations for each lizard (mm/day) 2) Verification of Growth Rate Calculations * Lizard toe clip IDs with their associated sex and age classes * Growth rate calculations for each lizard (mm/day) using field calculations of snout-vent length * Growth rate computed as the slope of SVL plotted as a function of date of recapture for each lizard 3) Quantifying the Accuracy of Mite Load Counts * Lizard IDs with associated photos of body regions containing mites * Mite loads when counted using photos and ImageJ computer software * Mite loads when counted using a hand lens 4) 2016/2019 Body Conditions * Body condition and mite load (# of mites) for each each yearling female and male lizard Missing values are denoted by "null".