Hello and Happy August! My favorite time of the year because the end of the summer is hot and dry which is perfect weather for being outside and enjoying nature.
Anyway, here is a picture of me in the lab counting the mosquito eggs at the microscope.
(It has been very wet and rainy throughout July. I just wish it was sunny outside, but its okay being in the lab too!)
Over the past few weeks, I have been doing more with the egg collection from the ovitraps and hatching the mosquitoes in the incubation closet. Once the larvae are a 3rd or 4th instar (largest larval size before pupation), I can look at them under the microscope and identify the mosquito species. The most common (I have found) and easiest to spot is Ochlerotatus japonicus (JAP) because the siphonal tuft is within the pecten teeth on the siphon (used to breathe air at the water's surface) and there are many bunches of hair on the head capsule of the larva.
Image of the siphon of an Oc. japonicus larva with the visible siphonal tuft in the pectin teeth.
The next mosquito is Aedes albopictus (ALB) which is not extremely common but is present in high numbers at one of our trap locations in Chatham. I have found over 200 eggs at one location and when they have hatched about 50 % of the larvae hatched are this species (the other being Oc. japonicus).
The circles on the egg paper each contain one or many individual eggs that have been counted. There are 186 eggs across the two papers.
I have also found a few Oc. triseriatus (TRI) which has larva with the distinct features of dorsal pair of anal gills longer than the ventral pair and an incomplete saddle on the anal segment. This species was only found in small numbers at 2 locations.
This is my larval identification set up. I remove the larvae from the incubation cups and place them into the petri dish. Then I add ethanol to kill the larvae which makes it easier to handle and move them around to get a better view. With the mircoscope I zoom in close enough to see the anal segment or the head capsule to throughly inspect and identify the morphology. After, I dispose of the larvae because we do not want to spread more mosquitoes!
A picture of the incubation cup with a heating light casting purple light into the contents. There is cut sections of the egg paper and hatched mosqutio larvae. These larvae are 2nd instar and need a little more time to mature. I will give them fish food so they will grow into a 3rd instar and be ready for identification.
Having lots of fun,
David
Very cool descriptions! Pictures are awesome as well!
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