Honors Theses
Date of Award
Spring 5-10-2025
Document Type
Undergraduate Thesis
Department
Biology
First Advisor
Michel Ohmer
Second Advisor
Christopher Leary
Third Advisor
Ryan Garrick
Relational Format
Dissertion/Thesis
Abstract
Amphibians are facing the most drastic biodiversity declines of all vertebrates, with an estimated 41% of amphibians threatened with extinction. Captive breeding programs employ a variety of assisted reproductive technologies including environmental manipulation, hormonal therapies, artificial fertilization, and gamete preservation to augment vulnerable populations and optimize genetic diversity. Amphibians require a species-specific combination of environmental, social, and physiological cues to reproduce, which makes universal and successful captive breeding programs especially elusive. Here, I investigate assisted reproductive technologies for a small frog species, the southern cricket frog (Acris gryllus). Establishing successful methods for southern cricket frogs may yield promising results for a closely-related threatened species, the northern cricket frog (Acris crepitans). I intraperitoneally injected various dosages of luteinizing hormone-releasing hormone (LHRH) and co-injected with metoclopramide to hormonally induce natural mating and produce fertilized eggs in captivity. I also tested an in vitro fertilization (IVF) protocol with LHRH and human chorionic gonadotropin (hCG) injection regimen where females received a three-dose priming sequence and males received a spermiation dose before spermic urine was collected via catheter. Although each induced mating treatment yielded similar results, I found that a female’s gravid state upon collection was the main determinant of successful oviposition, highlighting the importance of developing priming regimens that prompt oocyte maturation. However, the female priming regimens tested did not cause females to become gravid. Additionally, IVF was not found to be an effective method for the southern cricket frog due to a limited volume of urine output from males and non-reluctance of gravid females to release eggs in captivity. I describe specific considerations for cricket frog breeding programs and suggest criteria for selecting appropriate assisted reproductive technologies for amphibians. Optimizing and specifying methods for amphibian assisted reproductive technologies will supplement captive breeding programs, which have the potential to decrease the risk of extinction for threatened amphibian taxa.
Recommended Citation
Koltz, Audrey Grace, "Assisted Reproductive Technologies for Southern Cricket Frogs (Acris gryllus)" (2025). Honors Theses. 3599.
https://egrove.olemiss.edu/hon_thesis/3599
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