Facts, Identification & Control
Family Psychodidae; Subfamily Phlebotominae
What Do They Look Like?
Sand fly adults are small flies – only about 3 mm long – and are golden, brownish or gray colored. They have long, piercing mouthparts that are well adapted for sucking blood from their selected host. Sand flies hold their hairy-looking wings in a vertical V-shape when at rest, a characteristic that distinguishes them from some other small flies. Also, the six legs on the adults are extremely long, being longer than the insect’s body.
Behavior, Diet & Habit
Female sand flies are blood feeders, but the males do not feed on blood. Females must consume a blood meal before they are able to develop eggs. However, both males and females also consume sugar-related nutrients that come from plant nectar or honeydew. Sand fly hosts vary a great deal. Some species feed on both mammals and reptiles, while Lutzomyia shannani, a common sand fly species in Florida and other coastal states feed on white-tailed deer, horses, donkeys, mules, cattle, swine, raccoons, rodents, birds and humans.
In general, sand fly bites are very painful. Most flies that bite humans feed during the evening and throughout the night. In some cases, flies will attack in the daytime, if they are disturbed while resting. Daytime resting sites include cavities close to the ground such as dry tree holes, hollow logs, palm tree crowns and the canopy of tropical and sub-tropical rain forest jungles. Another commonly found place for daytime resting is inside the home.
Sand flies develop by complete metamorphosis, which means they go through four developmental stages: egg, larvae (grub), pupae (cocoon) and adult. Sand flies complete their life cycle within 1-3 months, depending on the sand fly species and their environmental conditions. Sand fly adult females lay from about 30-70 eggs that are laid singularly in small batches on moist surfaces like soil in protected areas with high humidity and high organic matter. Eggs typically hatch about two weeks after being deposited. The larval stage may take no longer than three weeks to mature, but may also be longer if the larvae is in an area where it must survive cold weather. Before entering the pupal stage, the larvae stop feeding on the organic matter in their habitat and seek out a pupation site that is drier than its larval habitat. The pupal stage usually lasts only 1-2 weeks. After emerging from the pupal case, the adults disperse at night with the males dispersing before the females.
In general, sand fly females must consume a blood meal to develop eggs.
Signs Of A Sand Fly Infestation
The appearance of sand flies and their painful bites that can cause secondary infection are the most frequently observed sign of an infestation. Also, evidence of sand fly problems include the incidence of human and animal diseases that are transmitted by sand fly bites.
Sand flies are worldwide in distribution. However, based on their genus, distribution is categorized as either old world or new world sand flies. The genera Lutzomyia, Brumptomia and Warileya occur in the new world countries, while the genera Phlebotomus and Sergentiomyia occur in the old world countries. Lutzomyia occupy the largest distribution range in the U.S. and are found as far north as New Jersey and as far south as Florida.
Sand fly diseases are transmitted by the bite of infected female sand flies in many parts of the world. Some of the more important sand fly transmitted diseases include:
- Cutaneous leishmaniasis
- Visceral leishmaniasis
- Sand fly fever
- Carrions disease
- Pappataci fever
- Vesicular stomatitis virus
Large area control of sand flies is very difficult for homeowners and small neighborhood communities due to the hidden, cryptic nature of where sand flies develop. When sand flies become a problem, the best thing for a homeowner to do is to contact their local mosquito abatement district or other local or state agency that can accomplish area-wide sand fly control. If this is not an option, be sure to contact your pest management professional who can perform an inspection and then develop a plan to conduct small scale sand fly control around your home or business.
Preventing sand fly bites can be accomplished by using permethrin-treated clothing. Keeping exposed skin covered by clothing is helpful when venturing into sand fly habitats.