Goal: Perform a pilot study to gauge the efficacy of chlorine dioxide gas's ability to kill cockroaches and red flour beetles (RFB). The gas has previously been show to be effective against soft bodied insects (wax worms), but its effect on insects with exoskeletons has yet to be well characterized. I wish to perform an exposure assay using a relatively high concentration of chlorine dioxide gas. This will give me an idea of whether or not the gas will be lethal at all. However, I need to keep in mind that if lethality isn't observed it doesn't mean the gas did not effect the insects in some other way, only that there may have not been an acute observable effect.
ClO2 & Cockroaches
A number of cockroaches were exposed to ClO2 gas in the 925 mL volume container that had been previously used in the wax worm pilot studies ( 3-30-15). For this experiment, five juvenile Madagascar hissing cockroaches were placed into the container. I did not intend to use the Madagascar roaches, but I didn't notice my mistake in cockroach species until after the gas was added. I intended to use the Blaptica dubia roaches instead as the Madagascar are more valuable and difficult to rear and should not be squandered on a preliminary study such as this!
I modified a 1.5 Eppendorf tube similarly to how PCR tubes were modified in the wax worm pilot study. Six small holes were made on the sides of the Eppendorf tube using a heated inoculating needle. Four more holes were made in the lid of the tube. A total of 3 grams of chlorine dioxide reagent (1.5 grams from each of the two parts A and B) were mixed in the modified Eppendorf tube.
There were only two groups for this pilot experiment- a negative control and an experimental group. Modified Eppendorf tubes were places into each of the containers with roaches, but only the experimental group's was filled with the chlorine dioxide reagent. The containers were incubated at room temperature, protected from light, for 24 hours. After the 24 hours, I will remove the modified Eppendorf tubes and air out the containers for five minutes. The containers will be incubated at room temperature for an additional 24 hours to allow the insects to recover (if they will) before survival is quantified.
ClO2 & RFB
I also exposed ClO2 gas to a large amount of red flour beetles (RFB). The RFB were exposed to the gas inside of a modified 50 mL conical tube. The same modified PCR tube method was used in this experiment as was used in the wax worm exposure experiment. In order to expose the RFB, and in order to keep the RFB from coming into direct contact with the gas reagents, a modification was made to the cover of the 50 mL conical tube. The modified PCR tube was placed inside of the 50 mL tube cover by creating a small hole in it. Images of this modification is seen below.
I also exposed ClO2 gas to a large amount of red flour beetles (RFB). The RFB were exposed to the gas inside of a modified 50 mL conical tube. The same modified PCR tube method was used in this experiment as was used in the wax worm exposure experiment. In order to expose the RFB, and in order to keep the RFB from coming into direct contact with the gas reagents, a modification was made to the cover of the 50 mL conical tube. The modified PCR tube was placed inside of the 50 mL tube cover by creating a small hole in it. Images of this modification is seen below.
The above modification will ensure that the RFB will not come into direct contact with the gas reagents, but still experience the full effect of the gas (ClO2 is heavier than air and will sink to the bottom of the tube once it is generated).
Between 25 - 30 RFB were added to each container using a metal scoopula. No larval stages of RFB were added. A small amount of wheat flour was also added to the tube. An image of what this looked like is seen above. Only a total of 100 mg of chlorine dioxide reagent was used in this experiment as I was limited due to the size of the PCR tube. The reagents were mixed inside of the modified PCR tube. The modified PCR tube was secured using masking tape and the tube was sealed very thoroughly using Parafilm.
For this experiment, only a negative control and experimental treatment group was used. The tubes were incubated at room temperature, protected from light, for 24 hours. After 24 hours, the health of the RFB will be evaluated.
For this experiment, only a negative control and experimental treatment group was used. The tubes were incubated at room temperature, protected from light, for 24 hours. After 24 hours, the health of the RFB will be evaluated.
//EWW
What were the results of this study?
ReplyDeleteDid you ever do a follow up very curious on the RFB study. Very odd that a higher ppm was used than the amount used on the roach with zero effect?
ReplyDelete