Comparative study of Dormancy pattern in selected Aquatic and Terrestrial organisms

Abstract

Among the various peculiar characteristics of lower animals the most prominent is avoidance to insensitive conditions as an adaptation to thrive the existing situation which is generally referred as Dormancy. Dormancy is a latent period in the life history of an organism when growth, development, and metabolic activities are provisionally clogged due to prevailing environmental conditions. The minimizations of metabolic activities facilitate an organism to conserve energy as well as life expectancy. This is the period when, an agile creature becomes inactive only to overcome the situation for an extensive period of life. Quiescence is a state of quietness or inactivity due to several reasons such as change in environment, availability of food, predator etc for a very short period. Here the creature sometimes exhibits polymorphism, one of the practices of mimicry only to avoid the available situation. Diapause, on the other hand, is a temporary slowing down of physiological activities in retort to terrible environmental conditions as such found in most of the insects. It is an extrapolative strategy, which is predetermined and inherited by an animal from its ancestors. It is a mode of change in the life style of an organism to suit its metabolic activities according to the conditions to its favor. Indeed the term Dormancy is extensive in its meaning and it includes several types of latent periods such as Quiescence, Diapause, Aestivation, Hibernation and Brumation. Present work was carried out in Wolaita Sodo University about 350 km from the capital city of Ethiopia, Addis Ababa. Aquatic organisms such as Rotifers and insects such as Sorghum chafer were taken for comparing and observing the dormancy patterns; since they were found in two different environments. An attempt was made to understand the dormancy patterns found in the life cycle of Pacnoda interrupta both in the laboratory as well as on field with respect to physical factors such as temperature, moisture, availability of food and predator, length of day light, and factors contributing for their success of overwintering for a long period. Similarly, rotifers were taken from the fresh water bodies in and around the study area for investigating their dormancy pattern in the laboratory. The authors have made an effort to define various terms of dormancy in a novel way for upcoming generations, which of course unwrap for further debate.