Category
Basic
Description
Regina septemvittata, commonly known as Queensnakes, are broadly distributed across eastern and central North America. In adult Queensnakes, females average a greater snout-vent length (SVL) than males. Since Queensnakes exhibit size dimorphism and have short life spans and low survival rates, it was hypothesized that neonate Queensnakes begin to display a distinct sex-related difference in SVL within their first few months of life. Our study investigated growth rates of neonate Queensnakes by conducting a capture-mark-recapture (CMR) study over a three-month period (August through October; birth to first brumation) in an urban stream in Lynchburg, VA. Captured snakes were measured (SVL), sexed using the hemipenes eversion technique, and marked with a sharpie marker. The site was visited every two weeks, and ten neonates (3 males and 7 females) were captured during the study. While neonates grew from an average of 15 to 17 cm SVL during the three months, we were unable to determine if the sexes differed in their growth rates. Size dimorphism was explored further with SVL data from the same study site collected previously on Cohorts 1 and older. Separate von Bertalanffy growth models were fit to SVL data on males (n=31) and females (n=41) using Solver in Excel. Female Queensnakes grew faster than males as they entered Cohort 2 (second full year of life). We suggest doing studies with a larger sample size to explore further whether sex-related differences are evident in neonates.
Evaluating Sexual Dimorphism in an Urban Neonate Regina septemvittata Population
Basic
Regina septemvittata, commonly known as Queensnakes, are broadly distributed across eastern and central North America. In adult Queensnakes, females average a greater snout-vent length (SVL) than males. Since Queensnakes exhibit size dimorphism and have short life spans and low survival rates, it was hypothesized that neonate Queensnakes begin to display a distinct sex-related difference in SVL within their first few months of life. Our study investigated growth rates of neonate Queensnakes by conducting a capture-mark-recapture (CMR) study over a three-month period (August through October; birth to first brumation) in an urban stream in Lynchburg, VA. Captured snakes were measured (SVL), sexed using the hemipenes eversion technique, and marked with a sharpie marker. The site was visited every two weeks, and ten neonates (3 males and 7 females) were captured during the study. While neonates grew from an average of 15 to 17 cm SVL during the three months, we were unable to determine if the sexes differed in their growth rates. Size dimorphism was explored further with SVL data from the same study site collected previously on Cohorts 1 and older. Separate von Bertalanffy growth models were fit to SVL data on males (n=31) and females (n=41) using Solver in Excel. Female Queensnakes grew faster than males as they entered Cohort 2 (second full year of life). We suggest doing studies with a larger sample size to explore further whether sex-related differences are evident in neonates.
