Age and body size in four introduced populations of the American bullfrog, Lithobates catesbeianus (Ranidae)

Abstract

The American bullfrog, native to the eastern half of North America including southern Quebec, is considered one of the most invasive species in the world. It has been introduced in America, Asia and Europe, mainly for food purposes. A study on the age and body size of this species was carried out on individuals obtained from four introduced populations (one from Western Canada and three from France), using the skeletochronological method. Adults did not differ between sexes in mean body size or mean age, with the exception of one population in France where males were younger than females. Several differences in the mean age and body size were observed, with the individuals from the population in Canada exhibiting the highest values for both sexes. The scarcity of studies in the native range prevents the comparison of introduced versus native populations, and we focus on comparisons between introduced populations.

Life History Traits and Longevity of the Invasive Asian Common Toad Duttaphrynus melanostictus (Schneider, 1799) in Madagascar

“…Species’ life history traits can be mismatched between invasive and native populations due to different environmental conditions (e.g., a lack of competitors and lower predatory pressure). On the other hand, trait mismatches can result from pre-existing differences in the native source populations and can emerge during acclimatization through genetic drift and local adaptation [ 37 , 38 ]. The study of life history traits, including growth rate, age, and size at maturity, of an invasive population can be useful for understanding how each trait may have contributed to successfully colonizing a new area.…”

Phenotypic variation in American bullfrogs (Lithobates catesbeianus) bred under intensive systems in Mexico: A preliminary report

“…22,23 Gonadal maturation in female bullfrogs begins at one year of age, but do not reach full maturity until year two. 24 This could explain the lack of differences in weight and body condition between male and female juvenile bullfrogs. Also, juvenile amphibians use nutrients mainly for body growth, and a redistribution of these resources towards the gonads occur as they mature sexually to favor reproduction.…”