The effect of food source (mung bean Vigna radiata vs. black-eyed pea Vigna unguiculata) on relative inhibition of acetylcholinerase due to malaoxon in bean beetle Callosobruchus maculatus
The effect of food source (mung bean Vigna radiata vs. black-eyed pea Vigna unguiculata) on relative inhibition of acetylcholinerase due to malaoxon in bean beetle Callosobruchus maculatus
Background and Hypotheses:
Recent studies, most notably Gbaye et al. (2011, 2012), have investigated the sensitivity of bean beetles in the genus Callosobruchus to organophosphate insecticides (OPs). Economically this is important work given that these beetles are pests that threaten agricultural yields of legumes. OPs work by inhibiting the enzyme acetylcholinerase (AChE) in the beetles. Without this enzyme, the neurotransmitter acetylcholine can't be broken down and its overflow leads to the eventual death of the beetle. Results obtained by Gbaye et al. (2011, 2012) suggest that there are indeed differences in AChE sensitivity to malaoxon – a popularly used OP – amongst different geographical strains of Callosobruchus maculatus, one particular species of Callosobruchus. This difference may be due to environmental factors such as temperature and food source.
In our study, we asked whether the food source (e.g. type of bean) will affect the sensitivity of the beetles' AChE to malaoxon. Our alternative hypothesis was that AChE extracted from beetles of the species Callosobruchus maculatus will exhibit different sensitivity to malaoxon depending on whether they were bred on mung beans (Vigna radiata) or black-eye peas (Vigna unguiculata). Our null hypothesis, then, was that there will be no such difference in sensitivity to malaoxon.
Experimental design:
To test this hypothesis, we set up a manipulative experiment attempting to isolate the effect of the food source on the sensitivity of AChE in C. maculatus to malaoxon. Our independent variable was the type of bean on which the beetles were bred. We required two treatment levels: one using beetles bred on mung beans and the other using beetles bred on black-eye peas. There is no control group in the experiment.
Background and Hypotheses:
Recent studies, most notably Gbaye et al. (2011, 2012), have investigated the sensitivity of bean beetles in the genus Callosobruchus to organophosphate insecticides (OPs). Economically this is important work given that these beetles are pests that threaten agricultural yields of legumes. OPs work by inhibiting the enzyme acetylcholinerase (AChE) in the beetles. Without this enzyme, the neurotransmitter acetylcholine can't be broken down and its overflow leads to the eventual death of the beetle. Results obtained by Gbaye et al. (2011, 2012) suggest that there are indeed differences in AChE sensitivity to malaoxon – a popularly used OP – amongst different geographical strains of Callosobruchus maculatus, one particular species of Callosobruchus. This difference may be due to environmental factors such as temperature and food source.
In our study, we asked whether the food source (e.g. type of bean) will affect the sensitivity of the beetles' AChE to malaoxon. Our alternative hypothesis was that AChE extracted from beetles of the species Callosobruchus maculatus will exhibit different sensitivity to malaoxon depending on whether they were bred on mung beans (Vigna radiata) or black-eye peas (Vigna unguiculata). Our null hypothesis, then, was that there will be no such difference in sensitivity to malaoxon.
Experimental design:
To test this hypothesis, we set up a manipulative experiment attempting to isolate the effect of the food source on the sensitivity of AChE in C. maculatus to malaoxon. Our independent variable was the type of bean on which the beetles were bred. We required two treatment levels: one using beetles bred on mung beans and the other using beetles bred on black-eye peas. There is no control group in the experiment.