Thermal acclimation in the fresh water planarians, Dugesia tigrina and D. dorotocephala

Abstract

The planarians Dugesia tigrina and D . dorotocephala show well developed resistance adaptation responses following transfer from 5 to 25 ° C or the reverse . Their rates of thermal acclimation are typical of most organisms, but the magnitudes of their responses are impressively large . Thermal acclimation in these two species is generally similar, although somewhat more rapid and perhaps more extensive in D. tigrina. Forward and reverse acclimation rates are similar and there is evidence of overshoot and undershoot time course patterns respectively. Our heat resistance data, although based on a different methodology (the CTM method, using loss of equilibrium as the end point criterion) agree well with published values for these triclads . The temperature tolerance and thermal acclimation responses of D . tigrina and D. dorotocephala correlate well with their apparent eurythermy and their widespread distributions .

Critical Thermal Maxima of aquatic macroinvertebrates: towards identifying bioindicators of thermal alteration

“…Of the 27 families assessed, four families were ranked as both thermally sensitive and highly suitable, whilst five were ranked as moderately thermal sensitive and highly suitable. Previously published CTM studies (Table 5) on aquatic macroinvertebrates are largely limited to flatworms (Claussen & Walters, 1982;Claussen et al, 2003), Table 3 Behavioural responses (Point of Thermal Reactivity-PTR and Critical Thermal Endpoint-CTE) of a subset of families giving Suitability Rank (SR: 1 = highly suitable; 2 = suitable but with limitations; 3 = unsuitable) and Thermal Sensitivity Rank (TSR: 1 = highly thermally sensitive; 2 = moderately thermally sensitive; 3 = not thermally sensitive)…”

Seasonal Variation in the Time Course of Thermal Acclimation in the Crayfish Orconectes rusticus

“…Although some exceptions have been noted among ectothermic invertebrates and vertebrates (Claussen & Walters 1982;Edney 1964;Hutchison & Rowlan 1975;Senius 1977), the gain in heat tolerance usually occurs at a faster rate than does the reciprocal loss of heat tolerance (for a review see Claussen 1980). Moreover, the time courses of homeoviscous adaptations, which have been implicated in the thermal acclimation process, show a similar thermal dependence (Cossins, Friedlander & Prosser 1977).…”

Physiological evaluation of the behavior and epidermis of freshwater planarians (Girardia tigrina and Girardia sp.) exposed to stressors

“…The water temperature is an important factor involved in the distribution and abundance of the different planarian species (Claussen and Walters, 1982). Planarians possess thermo-sensory structures throughout their bodies which are activated by ion channels of the melastatin TRP family (TRPM).…”

“…The freshwater planarians Girardia tigrina (Girard, 1850) and Girardia dorotocephala (Woodworth, 1897) were studied on how they adapted to variation in water temperature and thermal acclimatization. They demonstrated that the adaptation and resistance responses of Girardia tigrina due to temperature changes, 5°C to 25°C or 25°C to 5°C, were faster compared to those of G. dorotocephala (Claussen and Walters, 1982). In 1985, Tsukuda and Ogoshi evaluated three groups of Dugesia japonica (Ichikawa and Kawakatsu, 1964), that were acclimatized for 6 months at 13°C, 18°C and 20°C using a platform on which the temperature increased gradually from 9°C to 27°C.…”

“…The adoption of the CTM parameter allowed researchers to evaluate the thermal tolerance of different organisms (Cowles and Bogert, 1944; Lutterschmidt and Hutchison, 1997; Zhang and Kieffer, 2014). Limnic planarians exposed to the CTM, show signs of contortions, sluggishness, and an injured epidermis, losing their ability to move properly before dying (Claussen and Walters, 1982; Tsukuda and Ogoshi, 1985). …”