Hot Topics
Could you be raising mosquitos in your backyard?
Are you finding dead birds? Here's what to do...
What is the district doing to fight West Nile Virus?
See the California summaries of West Nile Virus Activity
View the current U.S. West Nile Virus human case counts as reported by the CDC...
Search for Material Safety Data Sheets
Terrestrial Predators of Mosquitoes
Predatory Animals
There is much to be said about bats, but here the discussion will be mostly limited to their relevance to mosquito suppression. Bats belong to the order Chiroptera, a Greek word meaning “hand wing”. They are mammals, meaning they feed their young with milk produced in mammary glands. All bats are warm-blooded, have fur and give birth to live young. No other mammal has the ability to fly. Since there are approximately 925 living species of bats in the world, one can imagine that they eat a variety of foods. Worldwide, about 70% of bats eat flying insects. Fruit makes up the diet of nearly all of the remaining bats. A few species are carnivorous, consuming frogs, lizards, other bats, mice and fish. The infamous vampire bat does indeed get its nourishment from the blood it takes from other animals. In the United States almost all of the 42 bat species (23 in California) feed after dark or at dusk on available flying insects. Because of the effort required for flight, bats must consume large quantities of food. Some experts have estimated that a single bat can consume between 600 and 1,000 insects in one hour. Bats either catch insects in their mouth or scoop them into their tail or wing membranes. Then they can reach down and take the insect into their mouth. Bats drink by skimming close to a body of water, gulping a mouthful. As cold winters set in and insects become less abundant, bats either migrate to warmer areas or go into hibernation. In contrast to the beneficial behaviors of bats, they do present some public health issues. You can read about them on our Bats and public health page.
Many species of birds prey on flying insects. No omnivorous bird singles out the adult mosquito as their only food source. Birds are generally opportunistic feeders, consuming whatever food presents itself or is unusually abundant, although some birds may have preferences influencing their dietary choices. Scientific studies that catalogue the stomach contents of smaller, omnivorous birds show that mosquitoes represent only a small portion of the total content. In environments or areas where unusually high numbers of mosquitoes proliferate, birds that have been collected from these areas and then examined, reveal a greater percentage of mosquitoes in their total stomach contents, up to 70% and higher. It is also important to note that water fowl consume mosquito larvae in their normal diets. Aquatic invertebrates, including mosquito larvae, make up a portion of these omnivorous birds' food intake. The relatively small numbers of mosquitoes consumed by birds does not create a significant impact in controlling mosquitoes. But every little bit has to help- right?
Predatory Insects
Adult dragonflies are a familiar sight during warm summer months. Commonly they are called darning needles or mosquito-hawks. They belong to the insect order Odonata, suborder Anisoptera. Sixty-three species have been identified in California. Dragonflies have 3 distinct life stages: egg, naiad and adult. The life span of an adult dragonfly is relatively short, lasting 6 to 8 weeks during the summer months. Adults appear to be constantly hunting. Prey is scooped out of the air and consumed in flight. During their life time, dragonflies can consume large numbers of mosquitoes.
Damselflies belong to the order Odonata, suborder Zygoptera. Thirty-eight species of damselflies have been identified in California. Damselflies have 3 distinct life stages: egg, naiad and adult. Sometimes mistaken for their close relative, the dragonfly, damselflies are not as active or graceful in flight. They are feeble flyers compared to the powerful flight of the dragonfly. Instead of actively hunting flying insects, damselflies position themselves on a branch or other suitable perch, darting out to catch prey as it passes by. Adults emerging in the spring or summer die during the ensuing winter months.
Home | Sitemap | Contact Us