Going out! Blood Sucking flies!

We are all in the “compfy” chairs at the College of Charleston’s New Science Center getting ready to listen to a lecture about Blood Sucking Flies.  This is the first lecture in the Darwin Week series.

We are all here.  It is the first time AR and BW have attended a lecture. We are large and in charge.

The Wildlife of a Fly: Evolutionary Interactions Between Blood-feeding Flies and Their Vertebrate Hosts.

Dr. Peter Adler, Clemson University Biology Department


Blood feeding flies are ubiquitous.  13,000 species  (perhaps 2x that to yet be discovered) in the world.

Four Main Categories of Blood Sucking Flies

  1. Horse Fly,
  2. Biting Midge,
  3. Black Fly,
  4. Mosquito

The northern, northern hemisphere is the most difficult area for these creatures.

(mosquitoes) standing water – 30,000,000 per hectare per day
(black flies) running water – 1 billion per km of river per day

Profound changes in roosting sites of the Great-horned Owls
Nesting abandonment in Common Loons
Nestling deaths in Eastern Bluebird  (toxic shock in the baby’s blood stream from repeated biting)

The great question is what blood sucking flies feed on what creature.  So the creation of a Mesh Net attached to a car roof.  A soda bottle is attached at the vertex of the bottle.  Driving around catching flies.

67,000 female black flies and 200 contained vertebrate blood.
DNA extracted from vertebrate blood in flies  – cytochrome b gene amplified  there by vertebrate hosts were identified
17 species of black flies
25 vertebrate-host species identified:  12 mamal 13 bird
moose and grouse are the most common hosts
Host specificity is greatest for mammal-feeding black fles.
Host type bird vs. mammal observation: corresponds 100% with claw structure.
Rodent specialists are active later in the evening – more than likely that the rodents are more active in the afternoon.
Large, abundant hosts are used most frequently.

What did we learn:

Grouse is a large bird and has the most bites. Yet the smaller the bird the fewer the bites.


Zoos – blood-feeding flies are at the interface of captive and native animals, including humans.  What species of animals are serving as hosts for what species of mosquitoes?

We collected at Riverbank Zoo, Columbia, SC.

Five species of Mosquitoes

1. Aedes albopictus (asian tiger mosquito) (3)

2. Culex quinquefasciatus (transmits causal agents for elephantiasis) (46)
Charleston SC was the only place in the US that has shown any elephantiasis.  The last case was 1944.
Chipping sparrow
Northern cardinal
Eurasian eagle owl
King vulture
Thick-billed parrot

3. Culex erraticus (17)
Northern cardinal
Turkey vulture
Toco toucan
Thick-billed parrot
African Fire salamander


Looking Northward to Canada

The bloodsucking flies can be so bad some years it alters migration routes.  It caused me to wonder about flies driving species to extinction.

Research moments:

Case 1:  Attwater’s Prairie Chicken is a critically endangered birds  – there are only 40 birds left now. Its habitat is prairies in Texas.

I looked at the samples of black flies.  I tested them to see if they had specific avian toxins – Leucocytozoon (protozoan).  It had them.  It infects birds and when the birds are stressed,  the birds suffer and might cause them to go over to extinction.

Case 2:  Whooping Crane – critically endangered 1941 – 15 birds , 2010 266 birds

10 years attempt to reintroduce the species into eastern North America: failure
Nest failure: 10 years: 59 attempts, 3 young fledged
You can hear the flies as you approach the next.
400 flies withdraw 1.2 mili-liters of blood in 5 minutes from a whooping crane
black flies entrapping in broken eggs whooping crane 2,272 black flies – the birds accidentally break their eggs as they try to remove the flies from their bodies.

What is the Role in the Black Flies in Nest Failure?

1. Monitor Black Fly Populations – make a black fly trap so 7 carbon-dioxide traps run every day for three months

2.  Determine Relation of Crane Behaviors at Nests to Black Fly Numbers in Carbon Dioxide Traps – infrared cameras at nests did not work as birds would abandon the nests immediately.  Bird blinds work.

After three months on total trapped – 293,235 black flies

25 to 30 species of flies but only 3 attack cranes.  6 year time frame.

Findings:  Any nesting before the third week of April abandoned their nest.  Black flies don’t appear until after the 3rd week in April.

Whooping Crane rearing versus reintroduction.  The cranes are raised in MD at a different – latitude from where the reintroduction site is located.

Multidimensional scaling indicates strong association of black flies with 3 “comfort behaviors” (head-shaking, bill flick, and head-rub) of whooping cranes on nests. 75% fewer comfort behaviors when not on the nest.

The reintroduction area is the only traditional nesting area that is in a dense black fly area.  The nesting areas traditionally are below the black fly area.

Where do the black flies breed?

Breeding distribution of Black Flies in Wisconsin reintroduction area:  130 larvae per square inch on debris submerged in flowing water.

Next Phase: Possible black fly suppression by biological control agent (bacterium) to evaluate role of black flies in nest failures.


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Filed under AR, AV, Biology, BR, BW, DW, Science

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