Background for Teachers

Introduce the “Bloodsuckers” topic with a short story, as a read-aloud or as assigned reading. However you use it, make sure students come away knowing the following facts:

  1. Only female mosquitoes drink blood. 
  2. Female mosquitoes need fats and proteins from blood to help develop their eggs.
  3. Female mosquitoes eat blood meals just before reproducing.
  4. As annoying as people find mosquitoes, some animals do depend on them for survival.
  5. When female mosquitoes do not need blood, they eat nectar. Males always eat nectar.
  6. Female mosquitoes do not bite; they poke, using a "proboscis" similar to a straw.
  7. While females suck blood through part of their proboscis, they send an anti-coagulant through the other part, to keep the blood from thickening.
  8. Female horseflies and deer flies also need blood meals before laying eggs. Like males of their species, when they don’t need  blood, they eat nectar.

Why Do Bloodsuckers Suck Blood?

Bloodsuckers don’t suck blood to be mean. When they take blood from an animal, it is because they need it to survive. As you help students understand this, make an analogy. We don’t eat hamburgers to be mean to cows. We don't chomp on poultry to be mean to chickens. We eat meat (sometimes including residual blood) because we need protein and other food value it contains.

The proteins found in meat (including blood) contain amino acids, the building blocks of all living things. We could not survive without them, nor could any other animal.

How Do Bloodsuckers Get the Blood Out?

Bloodsuckers use different kinds of mouth parts to get blood from hosts. Leaches are an exception; they have none.

Check out these two groups of bloodsuckers and the two major types of mouth parts:

Poke and Suck Mouth Parts

Some poke with a needle-like proboscis then use it as a straw to suck blood.

KISSING BUG Kissing Bug - Tx Dept State Health Services

Kissing bugs get their name because they often bite near lips.  When animals sleep, they exhale carbon dioxide. This attracts kissing bugs to the host’s mouth.

Kissing bugs are also called “Assassin bugs” because they can kill other bugs. That can actually help people, because the bugs they kill and eat are often those that damage our crops. Unfortunately, kissing bugs only need to eat about once every three weeks!

Where do they live? They often live where crops are grown, or near houses. We tend to find them most often in south Texas.

Lone Star Tick male - Tx Dept State Health ServicesTICKS

Lone Star Tick female - Tx Dept State Health Services

Ticks don’t have true heads, just a barbed mouth part, which they stick into their host. Ticks create a cement-like substance, to glue themselves on, and they can’t leave until they fill up, even if they want to!  

Two types of ticks live in Texas: hard ticks and soft ticks. People see more hard ticks, since soft ticks live in burrows and places where birds live. Some ticks can live up to 200 days without food or water, and some can live for up to two years!

Learn more about ticks at:  PestWorldforKids.org

Four kinds of hard ticks live in Texas. The Lone Star Tick is the main "vector" for Lyme Disease, which means they can carry and transmit it, but they are not affected by it.

Tick-borne diseases in Texas are rising. Please be aware of the signs of these diseases. Here is a resource to identify the Lone Star Tick in its various stages of growth: http://www.tickencounter.org/tick_identification/lone_star_tick

Please teach your students these important tick safety tips:

·         Before you visit wooded or grassy areas, ask an adult to help you put on bug repellent with DEET.

·         Stop often to check for ticks. Wear lighter colors to make them easier to spot.

·         Check pets for ticks, especially in hot weather.

·         If a tick has attached itself to you, tell an adult right away. Don’t squish it, and don't try to remove it yourself. There’s a special way to remove ticks, and you don’t want any parts of it to stay on your or in you.

·         If you get a rash that looks like a bullseye, or your feel like you have the flu, tell an adult. 

PLEASE also be careful with how you discuss ticks with children. Avoid scaring them about the outdoors.  Diseases from ticks can lead to serious health issues, but the risk  decreases when we correctly these tips.

Where do ticks live?

Soft ticks live in nests, burrows, and caves

Hard ticks live in bushes and on mammals, including deer.

Asian Tiger Mosquito - Tx Dept State Health ServicesMOSQUITOES

Next time a mosquito makes you itch, say “Ouch, she poked me!” because, like many other bloodsuckers, the females need a blood meal before they can lay their eggs. The rest of the time they suck plant juices with males. Males live about a week. Ladies can last 4-8 weeks.  

Check out this photo of a female proboscis by artist/photographer Dennis Kunkel: http://www.astrographics.com/GalleryPrintsIndex/GP2108.html. Amazing, isn’t it?  Mr. Kunkel used a special lens to take the picture.

This video is interesting for kids, and it's also short: https://video.nationalgeographic.com/video/00000144-0a42-d3cb-a96c-7b4fe7c50000

Where do they live?

Mosquitoes live in water, until they are adults. One way to decrease mosquito populations is to eliminate all standing water sources from yards and community areas.

Cat Flea - Tx Dept State Health ServicesFLEAS

The most common flea in Texas is the cat flea; they’ll gladly suck blood from dogs and people too! Fleas are expert jumpers. They can even leap from one end of a cat’s tail to the other!

Their specially shaped flat bodies help them move easily through the hair of their hosts. Adult fleas eat blood, but first meal for babies is their parents’ poop. Yum, yum! NOT!

Where do they live?

Baby fleas live on cats, dogs, and deer until they can jump off. Adults live in grass or carpets, where they wait until they are hungry again. Whens  host comes near, adults jump onto it and eat until they are full, then they jump off again and lay low for a while.

Bed Bug - H.J. Harlan, AFPMBBED BUGS

Ever heard the saying, “Sleep tight and don’t let the bed bugs bite?” That’s because bed bugs only come out at night, while we sleep.

It takes a bed bug about 10 minutes to fill up (become engorged) and it won’t eat again for days. Adults can survive for up to an entire year without blood!

Females lay 3-4 sticky eggs every day near where people sleep. Our blood is their favorite feast.

It used to be unusual to find bed bugs in the United States, but today it is a problem. Health experts don't know exactly why. One theory is the rise in international travel, which spreads infestation of rooms, suitcases, and even clothing People travel to and from from infested faster and more often, spreading insects across the world like before. 

Where do they live? Bed bugs live in tiny cracks in walls, under carpets, and under mattress seams.

"Slash and Lap" Mouth Parts
Some make a slash with a sharp mouth part and lap up blood like sponges soak up water.

HORSEFLIES: See photo at http://insects.tamu.edu/images/insects/common/images/cd-43-c-txt/cimg224.html>

Horseflies look like huge super-flies. Guess where they get their name....but, hold those reins...horseflies dine on cattle more than horses. Brown and black cows beware! Moving and dark objects are their favorite targets. Only females about to lay eggs eat blood. Otherwise they dine on nectar with the guys.

 

Where do they live?
 Horseflies like to live around farms and stalls and places where we keep cows.

 

DEER FLIES:

Deer Fly - John Moore, AFPMBDeer Fly - AFPMB

Only females chomp on hosts, and only when it's time to lay eggs – up to 1000 at one time! Otherwise, girls eat nectar with the boys. They get their name from their favorite host: deer.

Check out this photo and learn more about deer flies: http://kids.yahoo.com/animals/insects/3781--Deer+Flies

Where do they live?
Deer flies prefer to live near plants, especially those that produce flowers.

LICE

“Lice” is a plural word, meaning “more than one” louse.

Head Louse - Tx Dept State Health ServicesEach louse is about as big as a period on a written sentence. That makes them tough to find. Some types live only on people (in our hair), while others live on different animals. People can’t get lice from a dog or cat. A louse cannot hop or fly from one host to another. To move they must crawl.
 

Lice that live in human hair are called head lice. They feed on human blood and  die within 24 hours (1 day) if they fall off your scalp. Chances are they won’t fall off. People need a special shampoo and comb. Avoid sharing brushes or combs with other people. 

Each louse lays 8-10 eggs per day!  An egg is called a “nit.”  The nits make your scalp itch a lot!

Check out this site to learn more about lice:  http://www.headlice.org/kids/animations/index.htm

Where do they live?

Head lice that eat human blood live in our scalp, where hair grows. Since they live on another animal, we also call them parasites. 

No Mouthparts

LEECHES

Leeches are different from other bloodsuckers. They don’t use mouths to get blood from hosts. They use super suckers to attach to a host and suck on skin until blood comes through.

As painful as that sounds, leeches actually don’t really harm skin, and you can easily pull them off. Not all leeches in Texas suck blood, but those that do like fish and turtle blood best.

Where do they live?
Leeches live in water and look like slugs. 

How Do Bloodsuckers Find Hosts?

Most bloodsuckers have special carbon dioxide detectors that help them find hosts. Carbon dioxide is what animals exhale. When a bloodsucker detects carbon dioxide in the air, it knows an animal with blood is nearby.

Have you noticed that one minute there are no mosquitoes, and the next minute it seems like there are millions of them all over you? That’s because some types of mosquitoes can detect carbon dioxide from up to 200 feet away!

Why Do Bloodsucker Bites Sometimes Itch?

When bloodsuckers eat blood, they leave spit (saliva) behind. You itch because your body has a small allergic reaction to the saliva.

Do Bloodsuckers Carry Diseases?

Some sure do! Ticks, for example, carry Lyme Disease and Rocky Mountain Spotted Fever,  which are among the most serious.

Here is a picture of a Lone Star Tick

Do you notice the light colored “star” on its back? That’s how it got its name. Lone Star Ticks are little – about the size of the end of a pencil – making them hard to spot.

You can review safety steps and/or have students try this interactive activity:

http://www.dshs.state.tx.us/kids/lessonplans/lymedisease.shtm
The level of difficulty is about 3rd grade.

NOTE: If a child is bitten by a tick, remove it, put it in a jar, and send it to the Texas Department of State Health Services, Infectious Disease Control Unit for testing. They can test for diseases. For more information please call (512) 458-7676 or visit: http://www.dshs.state.tx.us/idcu/disease/lyme/.