Aedes species even lays its eggs on the legs of crabs, which then transport the eggs to the crab’s nest, where the eggs later hatch20.
Of course, many21 mosquitoes are just as comfortable depositing eggs in artificial containers such as gutters, tarps, birdbaths and old tires. Oddly enough, many disease-transmitting mosquito species have been found developing in artificial containers in cemeteries. The vases, toys, and flowerpots left behind by mourners prove to be ideal habitat for these sometimes-deadly insects22.
Eggs: Laid Alone or Together?
In North America, there are two primary ways that mosquitoes lay eggs: some mosquitoes, including all of the Anopheles and Aedes species, deposit their eggs one-by-one, either on the water or on moist soil at the water’s edge, whereas nearly all23 Culex species (and those of a few other groups) glue their eggs together to form an egg raft, which floats on the water and rebounds to the surface when submerged.
When female mosquitoes build an egg raft, they are nearly totally committed. According to the observations of one researcher, Culex females were so focused on building an egg raft that one could be picked up from the surface and didn’t try to fly away24. Talk about a maternal instinct!
Waiting It Out: Dormancy
If the conditions aren’t right, the eggs of some species can become dormant; dormancy can last for some time—the eggs of some Aedes species25 can remain viable for up to four years. When floodwater eggs are laid in cooler weather, the eggs remain dormant until the weather warms. This is also why Dengue fever and other diseases carried by Aedes mosquitoes often spike in spring or during the monsoon season in tropical areas.
Whereas most mosquito females simply deposit their eggs and leave, one species in South America actually broods its eggs, protecting them until they hatch26. While this is common in other insects, it’s the only mosquito species known to do so.
The Eggs Hatch and Larvae Emerge
Mosquito eggs usually hatch within a few days, but under ideal27 conditions, some species can hatch within just 30 hours. Larvae are colloquially referred to as “wigglers” thanks to their wiggly swimming motions. Larvae have two primary jobs: eating and molting. Larvae go through four molting periods, each of which is referred to as an “instar.” After hatching, the larva is in its first instar. Once it molts, it is in the second instar, and so on.
With each molting period, they get larger. Of course, to grow, they need food, and eating is their specialty. Larvae are almost always filter feeders and eat a variety of algae, single-cell organisms and plant material. In some Culex species, larvae are fierce predators, consuming many larvae of other mosquito species, and even members of their own species28.
The length of the mosquito’s larval stage depends on the species and the conditions but is usually a matter of 7–10 days29.
Let’s Go Snorkeling!
All mosquito larvae are aquatic, but they still need to breathe air. So how do they do it? Aedes and Culex mosquitoes essentially use a snorkel, which is technically called a siphon. When resting, they hang down from the snorkel. Anopheles species lack this snorkel and instead lie parallel against the water’s surface, breathing through tubes on their abdomen30.
Some larvae have even more ingenious methods of breathing. Mosquitoes in the Mansonia genus are wholly aquatic. They drill into underwater plants31 in order to obtain oxygen.
Pupation: Real-Life Transformers
Like moths and butterflies, mosquitoes pupate, but mosquitoes pupate in water. There they develop into adults and then somehow manage to emerge from the water’s surface and fly away. The transformation is like something out of science fiction; when they go in, they are worm-like aquatic creatures that get around primarily by wriggling and that eat phytoplankton and one-celled organisms. When they emerge as adults, they are six-legged flies that subsist on an entirely different diet—sugars from plants.
Pupation periods vary significantly by species and the local conditions—generally, warmer conditions speed things up, but adults usually emerge in a matter of days.
The pupae of one type of mosquito species are reported to glow in the dark. Found in Brazil, these species glow slightly in a purplish hue32.
Surprise, Adult Mosquitoes Are Vegetarians!
Once the adult mosquitoes emerge, they have two main jobs: eating and mating. Mating usually happens first and takes place at or near the site of emergence. After mating, the females forage for a blood meal; they do so because the proteins found in animal blood—specifically chains of amino acids—help them33 to produce more eggs. Without a blood meal, most species can’t produce eggs. There are a few exceptions; such species are called autogenous and can produce eggs without a blood meal34.
When most female mosquitoes seek out a blood meal, humans often aren’t their preferred species. When given the choice, mosquitoes often prefer livestock, such as sheep36. So why do they pester you at your barbecue? Because we are often the most numerous host in their habitat.
So what do mosquitoes actually eat? Sugars, usually from nectar or fruits. In the lab, scientists often feed adult mosquitoes a simple mixture of sugar water35, though research mosquitoes have also dined on corn syrup, fruit juices and raisins, among other things.
Mosquito Mating: Music (and Dancing) in the Swarm
Mosquitoes usually mate in swarms—large collections of males that are frequented by females37. As it turns out, it’s a surprisingly musical affair. The female mosquito’s characteristic buzzing sound is actually music to the male’s ears, and they are attracted to the sound. (In fact, in 1948, researchers armed only with a tuning fork tuned to the female mosquito’s frequency were able to attract male mosquitoes.)
The males in the swarm are pretty musical as well—as they “dance”38 amid the swarm, and when the male and female approach one another, they harmonize, creating the equivalent of a mosquito love song39!
The Anopheles mosquitoes don’t mate right away because they have to undergo some . . . changes40. In what must be a terrifying process, during the first 12–24 hours of the male’s adulthood, his genital organs are inverted—turning a full 180 degrees. This orients them correctly so mating can occur.
Hibernation/Overwintering
So how do mosquitoes survive the winter? It depends. Some species overwinter as adults, usually in a well-sheltered area, such as a cave or a culvert. Other species survive in the egg stage or as larvae.
