Influence of prior feeding experience and food deprivation on flour selection and utilization by the red flour beetle, &lt;i&gt;Tribolium castaneum&lt;/i&gt; (Herbst)

A.O Ojumoola,A.A Oladigbolu,E Obikwe,A.A Adesiyun

doi:10.4314/as.v19i2.7

Abstract

The influence of prior feeding experience and food deprivation on selection and utilization of wheat flour (WF), melon seed flour (MSF) and mung bean flour (MBF) by Tribolium castaneum reared on WF was investigated in this study. Flour selection, measured by percentage gravitation and acceptance of the flours by beetles (when fed and also when starved for 48 hours), was studied in choice and no-choice tests. On the other hand, T. castaneum’ s utilization of flours for growth and development was determined by monitoring population changes for three months in each flour type infested with 10 beetle pairs. Results of three-flour choice tests showed that gravitation (55.56%) and acceptance (54.44%) were significantly higher (p < 0.05) in WF than MSF and MBF. Also, MBF significantly (p < 0.05) had higher beetle gravitation (80.56%) and acceptance (72.78%) than MSF in a two-flour choice test. In no-choice tests, percentage gravitation and acceptance of beetles to the control (no flour situation) was significantly lower (p < 0.05) compared to MBF. Selection of MSF by T. castaneum was, however, not significantly different (p > 0.05) from the control in the study. Flour utilization followed a similar trend with significantly higher (p < 0.05) mean adults and larvae numbers in WF (211.33, 81.33) and MBF (87.67, 31.00), respectively compared to MSF (28.33, 7.67) at three months after infestation. The study concluded that flour selection in T. castaneum is influenced by prior feeding experience but not by food deprivation status of the beetles. Flour utilization is, however, neither influenced by prior feeding experience nor by food deprivation. Key words: Tribolium castaneum, host range, choice test, no-choice test, flour

Highlights

The rust red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is a cosmopolitan insect pest (Shafique et al, 2006) whose adult and larvae stages cause direct feeding damage to broken grains or nuts in storage (Applebaum, 1969; Johnson, 2013) and contaminate flours and other stored products with toxic secretions and exuviae (Villaverde et al, 2007; Johnson, 2013)
Higher (p < 0.05) mean percentage gravitation (55.56%) and percentage acceptance (54.44) of T. castaneum adults were recorded for wheat flour (WF) than for melon seed flour (MSF) or mung bean flour (MBF) in choice test I (Table 1a)
Prior feeding experience of T. castaneum influenced the selection of WF in this study and may pose a bias in choice tests

Summary

Introduction

The rust red flour beetle, Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae) is a cosmopolitan insect pest (Shafique et al, 2006) whose adult and larvae stages cause direct feeding damage to broken grains or nuts in storage (Applebaum, 1969; Johnson, 2013) and contaminate flours and other stored products with toxic secretions and exuviae (Villaverde et al, 2007; Johnson, 2013). Host range studies often require large numbers of the test insects necessitating continuous rearing on a suitable substrate. Such studies usually entail culturing test insects for one or more generations on a single host type in order to obtain enough insects. The use of insects reared on a particular plant host may result in a prior feeding experience bias for that host in choice tests leading to a false negative – a situation where an insect fails to accept a suitable host for food because of the presence of a more familiar one (Withers and Mansfield, 2005).

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