Mosquito (Culex sp.)
There are over 100 species of mosquitoes in North
America and close to 3000 worldwide. Mosquito adults must
maintain their food in the form of a liquid. The food may be
plant juices (nectar, fruit juices, sap). Only female mosquitoes
of some species have mouthparts adapted for feeding on blood.
This blood may come from warm-blooded or cold-blooded animals.
Mosquito eggs must be laid in or very near
water. Some mosquitoes lay their eggs in masses known as
rafts. These egg rafts float on the top of the water and contain
as many as several hundred eggs each. Under optimum conditions,
eggs usually htach within one to five days. The larval stage is
aquatic, feeding on bacteria, algae, and other tiny organisms found in
the water. Most mosquito larvae have breathing tubes located at
the base of their tail. They must expose the tail to the surface
of the water in order to take in air and breathe. The body is
covered with brushy hairs that help it swim and prevent it from
sinking. Larvae undergo four growth periods known as
instars. For most species the entire larval stage lasts one to
three weeks. After the fourth instar in the larval stage, the
larva rises to the surface of the water and undergoes a process known
as pupation. This process lasts about three to five
minutes. The mosquito sheds the larval exoskeleton and is now
shaped like a comma (large head region, tiny tail region.) The
pupa can be very active, wiggling the tail to swim in rapid
jerks. The pupa's breathing tubes are at its head region, so its
tail typically dangles downward when the pupa is at rest at the
surface. The pupal stage lasts one to three days, depending
primarily on water temperature; warm temperature speeds
development. When it is time for the adult to emerge, the pupa is
at the surface of the water, where the exoskeleton splits open.
Emergence takes about five minutes to complete. The adult floats
on the surface of the water until its exoskleton sclerotizes.
Availability: Mosquitoes are
available now. Contact Liz (firstname.lastname@example.org)
to schedule a pickup time (right after class is convenient). We will
provide you with an egg raft. They will come in a small plastic
container with water, so make sure your
container at home is set up and ready to go BEFORE you pick them up.
Housing: Mosquito larvae are
aquatic and should be kept in a shallow pan with water. Make sure
the water is dechlorinated. Once the larvae are 10 days old, you
should change the water in the pan. You can transfer larvae to a
new container with a plastic pipet, or you can pour all of the water
through a fine mesh net to collect all of the larvae that way.
The net straining will stress your larvae more than the pipet
will. Once you have pupae, you should move them to a smaller jar
of water that you can put inside of a mesh cage, or a larger jar with a
mesh lid. This will keep the adult from flying away if you are
out of the room when it emerges. If you keep your mosquitoes at
room temperature, it should take two to three days for the eggs to
hatch, ~15 days for larvae to molt to pupae, five to six days for pupae
to molt to adults, and adults may live for several days or weeks.
Food: We will provide you a
powdered mosquito diet to feed your larvae. You should add one
pinch every three days. Add a small amount of fresh water to the
pan every time you add food. If you do not use the diet, mosquito
larvae also feed
well on powdered milk dissolved in water. If not enough powederd
milk is used, the larvae grow very slowly. If too much milk is
used, a film develops on the surface and suffocates the larvae, so film
must then be broken up. If the film is a continual problem, the
solution should be changed. The amount of powdered milk to use
depends on the volume of water and number of larvae to be reared.
Adults need a cotton ball soaked in water, and a cotton ball soaked in
a 10% sugar solution to feed on. Females require a blood meal to
lay eggs, but it is entirely up to you if you want to take your rearing
to that level.