Feeding preference and developmental period of some storage insect species in rice products

Relative food preference (free choice) and developmental period of tribolium castaneum (herbst),rhyzopertha dominica (f.) and trogoderma granarium everts were studied on paddy,brown and milled rice of varieties ir-6,niab-irri-9,basmati-370 and dm-25 under laboratory conditions. rice varieties responded differentially to the three insect species for feeding preference,development and grain weight loss. feeding preference,oviposition and subsequent developmental period of the beetles varied significantly in different rice products. t. castaneum and t. granarium beetles preferred paddy to brown and milled rice for oviposition. however,r dominica preferred brown rice to milled rice and paddy for feeding. t. castaneum larvae developed to adults only in brown rice,t. granarium in brown and milled rice,whereas,r. dominica in paddy and brown rice. the results also showed that highest grain weight loss was inflicted in brown rice,followed by white rice and paddy. the overall results manifested that dm-25 suffered lowest damage,followed by ir-6,basmati-370 and niab-irri-9. different factors pertaining to development of storage insects in rice products/varieties are discussed. copyright 2011 zoological society of pakistan.