Ecology of Two Populations of an Aquatic Isopod, Lirceus Fontinalis Raf

Abstract

Two populations of Lirceus fontinalis Rafinesque in DeKalb County, Georgia are isolated in separate river drainages and evolving in response to different environmental stresses. Drought and high temperatures seem the main ecological factors limiting the population on Mount Arabia. These factors are of little moment to the population in Lullwater Creek where biotic factors are of primary ecological significance. Behavioral patterns associated with moisture, flowing water, and temperature fluctuations contribute to the ability of Mount Arabia Lirceus to survive climatic stresses and repopulate solution pits. Behavioral patterns associated with flowing water and light add to the ability of Lullwater Creek Lirceus to maintain their position in the continuously flowing stream and to avoid predators. Although they belong to the same specie morphologically, members of these two populations are not the same species physiologically and ecologically. They differ significantly in their respiratory rates, tolerance to anaerobic conditions, and to a combination of gamma radiation, high temperature, and drought stresses. Members of the two populations are considered to be ecotypes or races of L. fontinalis.

The Effects of Habitat Structure on Winter Aquatic Invertebrate and Amphibian Communities in Pine Flatwoods Wetlands

“…Invertebrate communities are poorly studied in this habitat type, but we documented similar communities to those previously reported from other pine wetlands (Golladay et al 1997;Dietz-Brantley et al 2002). Isopods were the most abundant invertebrate group in our samples, which was unexpected given that this group is susceptible to local extinctions during drying events and does not possess many of the adaptations necessary to persist through drying events (Styron 1968). Isopods may be able to rapidly colonize ephemeral wetlands by moving across the landscape in overwash from other water bodies during precipitation events (this likely represents an important movement vector for many species in this system) or by retreating into crayfish burrows during dry periods (Wiggins et al 1980).…”

Effects of Species of Leaves and Conditioning Time on Vernal Colonization by Temperate Lotic Isopods (Lirceus sp.)

“…While numerous past studies have examined the colonization of leaf packs by larval aquatic insects, detritivorous aquatic isopods are rarely mentioned in these studies (although see [29][30][31][32][33]). However, the rate of nutrient cycling, local levels of primary productivity, and fish populations can depend on the local biomass of isopods [16,[34][35][36][37], which can act as a keystone species [38].…”

Individual Preferences and Social Interactions Determine the Aggregation of Woodlice

“…The increase in density of woodlice in a location enhances their survival in harsh conditions by reducing water losses [24] , [27] and this gregarious behaviour is considered an adaptation to terrestrial life [28] – [30] . It is important to note that aggregation is observed in numerous crustaceans [17] , for example, in the aquatic isopods Asellus communis (as a reaction to running water, Asellus seek quiet water areas; [31] ) or Lirceus fontinalis (as a reaction to harsh conditions such as drought and high temperature; [32] , [33] ).…”