Week 7: (7/15-7/19)

 

Bioassay number four was completed this week! On Monday, we set up for this bioassay, and 72 hours later on Friday we were able to record the results. The larvae for this bioassay were hatched from egg papers the Friday the previous week, and yet we still noticed some pupae in the experiment. Besides that, everything went as planned, and the results are mostly in line with what has occurred so far with the other runs. I also made more voucher slides from this bioassay, which were all Aedes albopictus. Then, we happened to find an abandoned gravid trap that had mosquito larvae in the water naturally. We measured the water to 5L and then treated it with 5mL of Natular SC like in the mesocosm studies we did previously. By the next day, all of the larvae were dead! Then, we took the dead organisms and looked at them under the microscope. There were Anopheles, Aedes japonicus, and some Cluex. This was my first time looking at anything other than Aedes mosquitoes under the microscope, so I thought it was interesting to learn the identifying traits of other genus types. There was also many interesting organisms in the water we collected such as a spider and a nematode (pictured below).

As I said previously, on Friday of this week we recorded the results of the fourth bioassay. We also ran the data through a probit analysis software. I also had the idea to run all of the trials together this time, just to see where we are at. Most of the data looked really good except for the concentration of 0.08. I believe this is because of an error on our second bioassay, but that is just my hypothesis. The LD50 for all of the trials together so far was 0.06, which is right around what we have seen in the separate trials. Below is a table of the percent mortality for each concentration. 

Concentration (µl/L)	Percent Mortality
0.01	5
0.0265	24
0.05	34
0.08	83*
0.1	65
0.265	84

As you can see, that concentration is a little odd, so we hope to run another bioassay next week to solidify the data. The heterogeneity is almost 20 for this data set, which is not optimal at all. Additionally, if the second bioassay is taken out, the percent mortality decreases to 73%, but that is still not what I would like to see. On Friday, I made more test solutions as well as hatched more egg papers for next Monday. This time, we hatched them in the afternoon in hopes that they will be third and not fourth instars. Additionally, we are testing a hypothesis that the larvae will develop slower in one room rather than the other because of the location of the air conditioner. 

This week, I also went out to treat the river with BTI for black flies! I went to four different sites on Wednesday of this week, and it was incredibly hot. Luckily it rained later in the week, and it looks like the heatwave that NJ was experiencing has come to an end (for now). I also went on a trap run as well as learned how to make pins for adult mosquitoes! I enjoyed making the pins because it was sort of therapeutic to delicately handle them. Next week is my last full week before I go away, so I am excited to get some more data with another bioassay!!