Published online by Cambridge University Press: 31 May 2012
The time required for passage of food through various segments of the alimentary canal is important in understanding the process of digestion in insects. Abbott (1926) gave some information on this subject in connection with his study of the physiology of digestion in the Australian roach, Perqlaneta australasiae Fab. Snipes and Tauber (1937), have recorded the time required for passage and ejection of one type of food in the American cockroach, P. americana L. Later Day and Powning (1949) studied the time taken for starch paste to reach different parts of the alimentary canal of the German cockroach, Blattella germmica (L.). But any information in this respect seems to be lacking in numerous species of insects other than the cockroach. This study was undertaken to determine the time required to reach various points of the gut of small stored grain beetles, to find out the difference in the time requirement between two closely related species living on same diet and between large and small insects. Investigations were also made to locate the region of mixing in the gut of two subsequent meals, to understand the significance of certain anatomical structures in the gut in relation to the movement of food. The adult beetles used in these experiments were, Tribolium confusum Duv., T. castaneum Herbst (Fam. Tenebrionidae), Oryzaephilus surinamensis (L.), O. mercator (Fauval) and Laemophloeus pusilloides Steel and Howe (Fam. Cucujidae).