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Arthropoda: Insecta TABANIDAE (Contact) Please
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Most adult "horseflies" are bloodsuckers,
with females of most species feeding during the day. The larvae are mostly aquatic
or semi aquatic, feeding on various kinds of animals occurring in the medium
in which they develop. Over 4320
species have been identified in about 135 genera. One preferred food is Tipulidae larvae and other groups
inhabiting the banks of ponds and streams.
Earthworms and snails are also attacked. Tabanus stigma F.
is known to develop in drying seaweed in Puerto Rico, the larvae feeding on
sand fly larvae. Davis (1919)
recorded several species of Tabanus
as predaceous on Scarabaeidae grubs.
The eggs of most species are laid in large masses on foliage
overhanging water or on stones or other nearby objects. With some species they are found in a
single compact layer, the eggs placed vertically, side by side; while in
others they are several layers deep (Clausen 1940/62) Brachycera = "short antennae" includes larger flies with
large eyes. Tabanidae. -- <Habits>; <Adults> & <Juveniles> -- The horse
flies and deer flies
are vicious biters, and they inject toxic saliva into their hosts. The larvae
are aquatic and predaceous. The
adults may spread diseases such as Tularemia, Loiasis
and Anthrax.
Importance Primarily
important species are in the genera Tabanus,
Haematopota and Chrysops (See Distinctions). Service (2008) noted that they might
vector Anthrax, Tularemia,
Loa Loa in Africa and even Lyme
Disease. They are
especially important pests of domestic animals in their ability to transmit
bacteria, protozoa viruses and filarial worms. Tabanids are also a problem because of their painful bites,
which can result in allergic responses.
Images of important species created from collection specimens
include: Apatolestes sp., Atylotus sp., Chrysops sp.,
Diachlorus sp., Esenbeckia sp., Goniops sp., Haematopota sp., Silvius sp., Stenotabanus sp., Stonemyia sp., Tabanus sp. A critically
important disease is Loiasis that can be vectored to
humans by tabanids. It is found
mostly en the equatorial rainforests of Central Africa. Service (2008) listed Chrysops silaceus and C. dimidiatus as primary vectors, but C. distinctipennis and C. longicornis have some importance in
other parts of Africa. Behavior Adult flies
feed on sweet substances in the environment, but females also attack mammals
and humans. Some also attack
birds. Females lay eggs were the
larvae are able to survive, such as damp or aquatic sites. The waterproof eggs are glued in a
secluded fashion on the bottom of leaves, stones and rocks. Hatching can occur from four days to two
weeks depending on temperature and varying with different species. The larvae complete their
development in damp sites of standing water, which can last up to two years
even in tropical environments. Tabanus and Haematopota
species are also predaceous or cannibalistic (Service 2008). Larvae that are carnivorous inject venom
into the prey and adults can cause pain when they bite humans. Chrysops
larvae are mostly scavengers. Before
the onset of pupation the larvae will move to drier habitats adjacent to
their larval sites. Most species
females feed during the day in full sunlight, but some are also active only
at twilight. Hosts are found by sight
and olfactory stimuli. They are all
strong fliers, which allow them to fly several miles or kilometers. Their habitats are primarily in and around
forested areas. Chrysops species are especially abundant in wooded marshes and
swamps, but they can range to open fields.
Generally adults remain outdoors although a few African species may
enter dwellings. The abundance of
adults is influenced by the season in all areas where they occur. In areas with a rainy season the start of
rains will trigger activity. Control The Tabanidae are extremely difficult to
control, especially in areas where aquatic habitats cannot be practically
reduced, such as swamps and lakes.
Nevertheless, control measures
have involved draining swampland where the flies breed. Insecticidal control is also plagued by
the development of resistance and difficulties in locating principal breeding
areas. Service (2008) noted that some
control could be achieved with attractant traps for adults and the use of
repellents. = = = = = = = = = = = = = = = = = = = = Key References: <medvet.ref.htm> <Hexapoda> Anderson, J. F. 1985.
The control of horse flies and deer flies (Diptera: Tabanidae). Myia 3:
547-98. Anthony, D. W. 1962.
Tabanids as disease vectors. IN: Biological Transmission of Disease
Agents. Academic Press, NY. p.
93-107. Braga da Rosa; Gustavo
A. 2006. Predation
of hill topping horse-flies (Tabanidae) by birds in Brazil. Ornitologia Neotropical. 17:
619–622. Cheke, R. A., J. Mas & J. F. Chainey. 2003. Potential vectors of Ioiasis and other tabanids on the island
of Bioko, Equatorial Guinea. Med. Vet. Ent. 17: 221-3. Chippaux, J. P., B. Bouchite, M. Demanov, I. Morlais
& G. LeGoff. 2000. Density and dispersal of the Loiasis vector Chrysops dimidiata in southern Cameroon. Med. & Vet. Ent. 14: 339-44. Eaton,
Eric R.; Kaufman, Kenn (2007). "Deer
flies and horse flies". Kaufman Field Guide to Insects of North
America. Hillstar Editions.
p. 284. Egri, A.; Blaho, M.; Kriska, G.;
Farkas, R.; Gyurkovszky, M.; Akesson, S.; Horvath, G. 2012. "Polarotactic tabanids find
striped patterns with brightness and/or polarization
modulation least attractive: An advantage of zebra stripes". Journal of
Experimental Biology. 215 (5): 736. Foil, L. D. 1989.
Tabanids as vectors of disease agents. Parasitology Today 5:
88-95. Matheson, R. 1950. Medical Entomology. Comstock Publ. Co, Inc. 610 p. Middlekauff, Woodrow Wilson; Lane,
Robert S. 1980. Adult & Immature Tabanidae (Diptera) of California. University of California Press. pp. 1–2. Noireau, F., A. Nzoulani, D. Sinda & A. Itoua. 1990. Transmission indices of Loa
loa in the Chaillu Mountains, Congo. Amer. J. Trop. Med. 43:
382-8. Padgett, J.J.; Jacobsen, K.H. (2008).
"Loiasis: African eye worm". Transactions of the Royal Society of
Tropical Medicine and Hygiene. 102 (10): 983–9. Quercia, O.; Emiliani, F.; Foschi, F.G.; Stefanini,
G.F. The wasp-horsefly
syncrome. European Annals of Allergy
and Clinical Immunology. 40 (3): 61–63 Service, M. 2008.
Medical Entomology For Students.
Cambridge Univ. Press. 289 p Legner, E. F. 1995. Biological control of Diptera of medical and veterinary
importance. J. Vector Ecology 20(1):
59-120. Legner, E. F. 2000.
Biological control of aquatic Diptera. p. 847-870.
Contributions to a Manual of Palaearctic Diptera, Vol. 1, Science Herald, Budapest. 978 p. Thomson, M. C., V. Obsomer & J. Kamgno et
al. 2004. Mapping the distribution of Loa
loa in Cameroon in support of the African Programme for Onchocerciasis Control. Filaria J. 3: 7. Wilkerson,
R.C.; Butler, J.F.; Pechuman, L.L. (1985). "Swarming, hovering &
mating behavior of male horse flies & deer flies (Diptera:
Tabanidae)". Myia. 3: 515–546 |
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