Selected Aspects of the Larval Ecology of the Marbled Salamander Ambystoma opacum in the Southern Portion of Its Range

• Published in: The American midland naturalist 1980-10, Vol.104 (2), p.352-363
• Main Authors: Petranka, James W., Petranka, John G.
• Format: Article
• Language: English
• Subjects: Ecology; Food; Hatching; Invertebrates; Larvae; Larval development; Metamorphosis; Plankton; Salamanders; Water temperature
• ISSN: 0003-0031; 1938-4238
• DOI: 10.2307/2424876

Selected aspects of the larval ecology of Ambystoma opacum were studied from 1977-1979 in S-central Alabama. Differences were found in the length of the larval period, time of metamorphosis, stratification behavior and feeding patterns of larvae when compared to other populations. Substantial differences in hatching dates and growth periods occurred between local pools. In addition, estimated differences in hatching dates of as much as 2 months occurred within one pool that filled incrementally. In general, the larval period was shorter, the time of metamorphosis earlier, and the size at metamorphosis smaller than those of northern populations. Larval growth was relatively slow during the 1st 6 weeks after hatching, but accelerated during the remainder of the larval stage. Increases in weight were proportionately greater than increases in body length during the last 6 weeks of growth. Copepods, cladocerans, ostracods, isopods and amphipods were important food items of larvae. Strong shifts to alternate food items did not occur as larvae grew. Instead, larvae maintained a generalist feeding habit throughout their development. Larvae fed continuously throughout the day and did not limit their feeding to the stratification period. The diurnal aggregation of larvae on pool bottoms and their upward movements at night often corresponded to similar movements of macrozooplankton. Stratification was not strongly associated with changes in physical factors other than light and was observed in all size classes of larvae except those nearing metamorphosis.