Feeding preference and reproductive fitness of Rhyzopertha dominica (Fabricius, 1792) in a choice-based feed paradigm

T Sheeba,M Ramani Bai

doi:10.17485/ijst/v14i10.2281

Abstract

Objective: This study is designed to understand the feeding preference of R. dominica, when three grains and their flours are provided in a choice- paradigm, constructed in the form of a poly vinyl chloride tunnel, in which feed materials are made available at random. Methods and Analysis: A total of 200 beetles were released into the choice-paradigm, and the number of beetles in each feed was counted once in every 24 h. When the beetles in the choice chamber were enumerated after 96 h, 26 percent of the released beetles were found in wheat grain; 25% in wheat flour; 12 in rice; 11 in chick pea; 10 in rice and chick pea flours and 6% in the outer tunnel without opting for any feed. On the basis of the feed on which R. dominica were reared, changes were observed in selected key biological characteristics. Findings: The research findings showed that wheat and wheat flour were preferred against rice, chick-pea and their flours. The incubation period increased significantly (51%) when reared in chick pea flour. In beetles reared on this feed, total larval period increased by 39%, pupal period by 31% and total developmental period by 39%. The fecundity decreased by 11%, whereas, male and female longevities respectively by 20% and 24%. Egg hatching was not much affected by the type of feed. Hatchability was 92% for wheat flour and 97% for rice and chick pea grains. Novelty: R. dominica, a primary pest of stored wheat, seemed to possess the evolutionary plasticity to survive in a variety of feed materials when the primary diet is not available. Keywords: Rhyzopertha dominica; Triticum aestivum; Oryza sativa; Cicer arietinum; feeding preference

Highlights

Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae), the lesser grain borer, a primary pest of stored grain, mainly wheat, occurs all over the world and survives on a variety of other grains like rice, sorghum, oats, pearl, millet, malt, barley, chickpeas, peanuts and beans[1] Studies were conducted to understand the influence of the feed type on the development of R. dominica and subsequent progenySheeba & Ramani Bai / Indian Journal of Science and Technology 2021;14(10):850–857 production [2,3,4,5,6]
The number of beetles found in wheat flour is 30 ±6, the number preferred rice flour and chickpea flour is 14 ±3 and 15± 3. 38% of beetles were found as stray beetles
R. dominica adults preferred to stay in wheat grain when checked after 96 hours

Summary

Introduction

Rhyzopertha dominica (Fabricius, 1792) (Coleoptera: Bostrichidae), the lesser grain borer, a primary pest of stored grain, mainly wheat, occurs all over the world and survives on a variety of other grains like rice, sorghum, oats, pearl, millet, malt, barley, chickpeas, peanuts and beans[1] Studies were conducted to understand the influence of the feed type on the development of R. dominica and subsequent progenySheeba & Ramani Bai / Indian Journal of Science and Technology 2021;14(10):850857 production [2,3,4,5,6]. R. dominica can attack a huge variety of materials other than stored grains such as dried fruits, seeds, drugs, cork, timber and paper products. It can facilitate infestation by secondary pests and fungi [10]. The long cover in which the insects are taken is collapsed and closed in the middle region of the cover using a cloth band This enabled the beetles to remain at the bottom of the cover leaving the tip of the cover free, to be fastened to the inlet pipe. The time at which the beetles were allowed into the system was properly recorded and number of beetles preferring a particular feed material were counted after 24, 48, 72and 96 hours. Analysis of variance and Tukey’s tests were carried out to understand the attraction potential of the different feed types towards R. dominica adults

Methods

Results

Conclusion