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Chigger mite (Eutrombicula alfreddugesi) ectoparasitism does not contribute to sex differences in growth rate in eastern fence lizards (Sceloporus undulatus)
  • Nicholas Pollock,
  • Hailey Conrad,
  • Henry John-Alder
Nicholas Pollock
University of Texas Arlington Department of Biology

Corresponding Author:[email protected]

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Hailey Conrad
Virginia Tech
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Henry John-Alder
Rutgers University
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(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 tested whether a sex-biased growth cost of parasitism contributes 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 must 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 the development of SSD.
30 Jan 2023Submitted to Ecology and Evolution
06 Feb 2023Submission Checks Completed
06 Feb 2023Assigned to Editor
15 Feb 2023Reviewer(s) Assigned
01 Mar 2023Review(s) Completed, Editorial Evaluation Pending
17 Mar 2023Editorial Decision: Revise Minor
17 Jul 20231st Revision Received
18 Jul 2023Submission Checks Completed
18 Jul 2023Assigned to Editor
18 Jul 2023Review(s) Completed, Editorial Evaluation Pending
18 Jul 2023Reviewer(s) Assigned
18 Aug 2023Editorial Decision: Revise Minor
07 Sep 20232nd Revision Received
16 Sep 2023Submission Checks Completed
16 Sep 2023Assigned to Editor
16 Sep 2023Review(s) Completed, Editorial Evaluation Pending
22 Sep 2023Editorial Decision: Accept