Mosquitoes
There are over 35 species of mosquitoes on the Swan Coastal Plain alone. Different species need different habitats. Some species only breed in specific aquatic habitats while others are able to breed in a wide range of habitats - including both fresh and saline water - and some are even found in heavily polluted water, such as in septic tanks.
The larval and pupal stages in a mosquito's life cycle occur in water. Only female mosquitoes feed on blood. They get protein from the blood so that they can lay a lot of eggs. To survive, both males and females feed on plant sugars and starches. Also, each species feeds on certain vertebrates. For example, some species feed only on frogs, others only on birds. Other species feed on a whole lot of different animals. Some species will travel large distances to find a blood meal (one species will go up to 100 kilometres), but usually they travel less than ten kilometres.
Most mosquito species are active for only part of the year. When they're active depends on whether breeding sites are available. Other species breed whenever the opportunity arises, such as after rains or high tides or in artificial situations such as septic tanks.
Killing all mosquitoes and destroying the places where they breed and live is not an easy way to solve the problem. The places where mosquitoes breed are important feeding areas for birds. Whatsmore, some birds eat a lot of mosquitoes. A balance must be found between controlling mosquitoes for the comfort of people and protecting the habitat of birds. The goal of control is to keep mosquito populations down so that they aren't a nuisance or health risk, rather than total eradication, which is rarely possible.
Three types of mosquito control are commonly used.
Pesticides are a short-term solution. Pesticides aren't very effective anymore. This is because mosquitoes are becoming resistant. It also costs a lot of money and takes a long time to develop new pesticides and have them tested and registered. Also, pesticides can harm other parts of the ecosystem, not just mosquitoes.
Changing the environment by removing or altering the places where mosquito larvae grow can sometimes work. For example, one way to alter an environment is to dig channels on the foreshore so that water flows back into the waterway after high tide, rather than lying on the ground. Mosquitoes then don't have enough time to breed.
Mosquito larvae are eaten by a lot of aquatic animals. They also get infections from parasites, bacteria, viruses and fungi. Invertebrate predators, such as dragonflies and beetles, also eat mosquito larvae. Native fish, such as pygmy perch, eat them, too. Biological control means adding animals, viruses or bacteria to where mosquitoes live. These organisms interrupt the life cycle of the mosquito so that there are less breeding.