Sand Fleas Are Real! (But They’re Not What You Think They Are…)

Well, it’s summer time again and millions of people will be spending lots and lots of time outdoors. They will go to the lake, they will go to the beach, they will have picnics and barbecues and luaus. All the while, they will be joined by many unwanted guests — of the arthropod kind!

Many people think about the summer in Houston a little like this:


Cartoon by Gary Larson

Bugs, or arthropods, are everywhere, and our favorite time of year to play outside just happens to be the prime of most of their little lives. Every year I hear horror stories about bugs, particularly about the beach. Perhaps it’s because creatures that inhabit such an environment are so foreign to us. The oceans are the earth’s last known frontier, and animals that live inside or near it might as well be aliens to most of us!

We are so lucky to live in the age of having information at our fingertips. Want to know something? Just Google it! The almighty “internets” can’t be wrong! But anyone is allowed to write anything about any topic they desire, so the almighty internets are sometimes wrong.

If you want to go to the beach, and you Google, say, sand fleas, you’ll very likely read articles that will keep you away from the beach for good! So allow me to fill you in on some of these mysterious critters that call the beach home.

Arthropods are the most abundant and successful animal life-form on the planet and they can be found surviving and thriving in almost any environment. Naturally, they enjoy the beach as much as we do. The warm temperatures, that nice ocean breeze… If you walk along the beach at any time of day, especially the morning or evening, you will see all sorts of activity — mussels that have been unearthed by the waves wiggling back down into the sand, little crabs skittering around, flies buzzing about, and perhaps seaweed washed ashore, covered in small creatures.


Sand hopper, a crustacean in the order Amphipoda and the family Talitridae. Many different genera have a similar appearance.

These herbivorous creatures are most likely what we sometimes call “sand fleas,” though they are actually land hoppers or in beach environments, sand hoppers. You may have heard terrible things about these little guys, that they suck your blood, leaving awful welts, or even that they burrow into your skin to lay eggs. None of these things are true of sand hoppers. They are crustaceans, cousins to the insects, with five to seven pairs of legs and two pairs of antennae. Other well-known and delicious crustaceans are crabs, shrimp, lobsters and crawfish. Sand hoppers belong to the order Amphipoda and sort of look like a cross between a giant flea and a roly-poly. They mostly live in water, but some species are terrestrial and live in damp areas. They are scavengers that feed on rotting organic matter, so a nice pile of washed-up seaweed looks really good to them. They can hop, but that’s where the similarities with actual fleas begin and end! They do not suck blood, and in fact they want nothing to do with you. If you approach them, they will jump away, the obvious origin for their common name.


Mole crab (Emerita analoga) digging in the sand.

Another crustacean incorrectly called a sand flea is a tiny little crab called a mole crab — AWWWWW!!! (Oh wait, am I the only one who thinks it’s cute?) They are filter feeders, meaning they filter plankton from seawater. They burrow down into the sand where the waves break on the shore, and they’d also prefer to stay away from humans.


True sand fleas are native to central and south America and Africa. They lay their eggs in mammalian flesh, leaving a bad infection on the hands and feet.

Now, the true sand flea, the one that is an actual flea, is a nasty parasitic insect. But, they don’t inhabit North America. You can, however, find them in Central America, South America and Africa. Sand fleas, also called the chigoe flea, are the smallest known flea species (about one millimeter across). They burrow into mammalian skin to feed and may cause an infection known as tungiasis. But this is only really an issue in areas of poor sanitation. So please folks, don’t worry yourself over sand fleas.

2006 Frank Collins Leishmaniasis is transmitted by the bite of infected female phlebotomine sandflies, injecting the infective stage (i.e., promastigotes) from their proboscis during blood meals.  Promastigotes that reach the puncture wound are phagocytized by macrophages ,and other types of mononuclear phagocytic cells, and inside these cells, transform into the tissue stage of the parasite (i.e., amastigotes), which multiply by simple division and proceed to infect other mononuclear phagocytic cells.  Parasite, host, and other factors affect whether the infection becomes symptomatic and whether cutaneous or visceral leishmaniasis results.  Sandflies become infected by ingesting infected cells during blood meals.  In sandflies, amastigotes transform into promastigotes, develop in the gut, (in the hindgut for leishmanial organisms in the Viannia subgenus; in the midgut for organisms in the Leishmania subgenus), and migrate to the proboscis. See PHIL 3400 for a diagram of this cycle.

Sand fly (Phlebotomus papatasi), but the name can refer to any species of biting, blood-sucking insect found in sandy environments.

The only arthropods that may feed on you at the beach are things that will feed on you everywhere else, mosquitoes, and biting flies (sometimes called sand flies). Unfortunately, I don’t have much to say in defense of mosquitoes you’ll find at the beach, especially salt marsh mosquitoes (Aedis sollicitans), they’re kind of the worst! They’re large, fast, and pretty relentless. They breed in inter-tidal pools of brackish water and the eggs can lay dormant for years waiting for water!


Sand midges beside a dime and a pencil point to show their relative size.

Other flies that feed on you at the beach are small midges, commonly known as “no-see-ums” (yes, really), and just like mosquitoes, only the females feed on blood in preparation to lay eggs. The most you’ll get from these are classic signs of a bite, small red bumps that itch. A good bug spray containing DEET, or even some that contain effective essential oils such as lemon and eucalyptus, are effective at repelling all of these types of insects.

So if you’re heading to the beach this summer, don’t forget the sunscreen, don’t forget the bug spray, but leave the entomophobia (fear of bugs) at home. You have nothing to fear!

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Teotihucan: A Land of Pyramids, Secret Tunnels and Robots

Archaeology is a field of study where patience is a virtue. Having a bit of luck doesn’t hurt either. In popular culture, archaeologists are seen as people who discover “lost cities,” “mysterious pyramids” and “precious treasures.” In real life, things are much more exciting.

Consider a recent development in archaeological investigations in one of Mexico’s largest pre-hispanic cities, sporting some the largest pyramids in the Americas. Never lost to the sands of time, this Mexican metropolis had a street plan laid out in a grid, very much like modern U.S. cities, and it had ethnic neighborhoods, where people were buried in the traditional ways of their homeland. Some people in this city knew how to read and write, yet we don’t know what they said. Meet Teotihuacan, where it is said the “gods were born.” This is also the story of Sergio Gomez, a Mexican archaeologist who experienced luck, when he found the entrance to a tunnel in 2009, and then displayed extreme patience excavating it.

Pyramid of the Moon at the end of the Avenue of the Dead, Teotihuacan, Mexico. (Image Wikimedia)

Pyramid of the Moon at the end of the Avenue of the Dead, Teotihuacan, Mexico. (Image Wikimedia)

With a history going back to 100 B.C., Teotihuacan was one of two major civilizations that arose in the Basin of Mexico, home to modern-day Mexico City. The other civilization we know as the Aztec. Separated by more than 1,000 years, both civilizations stand out for their monumental architecture, especially their massive pyramids.


The Aztec were fully aware of the existence of the ancient city of Teotihuacan. They even incorporated Teotihuacan ceramics as offerings in the Aztec Templo Mayor, a transfer of magic powers from an ancient power center to a new, nascent one. By 700 A.D. the city came to a violent end, but was never completely abandoned. In the centuries following the decline, migrants came and went as Teotihuacan’s pyramids continued to tower over small communities of newcomers. At present, Mexico’s capital is inching closer and closer. A modern Mexican community, San Juan Teotihuacan, now sits on top of what were once Teotihuacan’s neighborhoods.


Map showing the location of Teotihuacan in central Mexico in relation to the Aztec capital, Tenochtitlan.

Teotihuacan deserves the label metropolis. It was laid out along a north – south axis, most famously known as the “Avenue of the Dead.” At the northern end of this Avenue, we find the famous Pyramids of the Sun and the Moon.


Closer to the intersection of the Avenue with a second, East – West axis, there are the remnants of the city’s market, as well as a compound dubbed the “Ciudadela” by the Spanish. It was centered on the Temple of the Plumed Serpent, a sunken plaza large enough to hold most of the city’s inhabitants.

It was here, in front of the Temple of the Plumed Serpent, that a three-foot wide sinkhole appeared in the fall of 2003, the result of a torrential downpour. Sergio Gómez was the first person to enter this sinkhole, and found himself standing in a tunnel the extended underneath the Temple – the first person in centuries to have done so.


Early in 2004, a team of 20 archaeologists started scanning the tunnel from the surface, using ground penetrating radar. This radar map was finished in 2005 and showed that the tunnel extended for about 330 feet (100 meters); it reached the center of the Temple of the Plumed Serpent. It took until 2009 to receive government permission and funding to start working below the surface in the actual tunnel. Work was slow and progress was measured in feet per month. Shortly before writing this, the team got to the end of the tunnel. They had removed more than 1,000 tons of earth. Mixed in this dirt were approximately 75,000 artifacts. Among these discoveries were a statue of a jaguar, jaguar bones, pottery, obsidian knives, solid rubber balls, and Pacific Ocean conch shells.

The 75,000 artifacts will keep archaeologists busy for years to come. The tunnel itself requires more exploration as well. Two small remote controlled robots, named Tlaloque and Tlaloc II helped identify the presence of three buried chambers at the end of the tunnel, which still need to be investigated. Some archaeologists wonder if these chambers might contain the burial of one of the elusive Teotihuacan rulers.


Teotihuacan is slow to reveal its secrets. Archaeologists are still trying to come to grips with the ways in which it governed itself. Maya archaeologists are fascinated by the so-called Teotihuacan entrada, an intriguing episode in the history of Maya cities where there is clear evidence of Teotihuacan influence. To a large extent, the city and its namesake civilization remain a mystery. I wonder if future archaeologists will ever say similar things about our own cities…

Further reading

Berrin, Kathleen, and Esther Pasztory, 1993. Teotihuacan: Art from the City of the Gods. New York: Thames & Hudson.

Cowgill, George, 2015. Ancient Teotihuacan. Early Urbanism in Central Mexico. (Case Studies in Early Societies). New York: Cambridge University Press.

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Mark Your Calendars for these events happening at HMNS 6/13-6/19

Last week’s featured #HMNSBlockParty creation is by Kate & Hazel (ages 35 & 6): 

block party 24

Want to get your engineering handwork featured? Drop by our Block Party interactive play area and try your own hand building a gravity-defying masterpiece. Tag your photos with #HMNSBlockParty.

Lecture – They Had to Shoot the Bear: The Story of Charles Willson Peale and America’s First Museum
Tuesday, June 14
6:30 p.m.
The curious tale of America’s first museum combines mystery, pride, science and history in one package. Join Nicole Temple, Vice President of Youth Education at the Houston Museum of Natural Science, and discover how the son of a convict became a revolutionary war hero, a renowned artist and an innovator of natural history. The lecture concludes in the Museum’s new Cabinet of Curiosities.

Mixers & Elixirs
Friday, June 17
7 p.m.
Mixers & Elixirs is back and it’s better than ever! Pop on over to our place to mingle, clink your cocktail glass, and break out your best dance moves. Doors open at 7 p.m. for the live band -On The Dancefloor, dancing, cash bars, and the city’s best food trucks – Htown Streats, Pitas Bites Mediterranean Cuisine, and Los Tacos Hermanos

Summer Cockrell Butterfly Center Events 
Summer Cockrell Butterfly Center events continue through Aug. 19.

  • Wing It | Tuesdays at 10:30 a.m.
    Come fly away into the world of butterflies at the Cockrell Butterfly Center with Wing it! Introduce yourself to your favorite winged wonders and watch the release of hundreds of new butterflies into the rainforest.
  • Small Talk | Wednesdays at 11 a.m.
    Join our Cockrell Butterfly Center team as they take their live collection of insects out “for a walk” during Small Talk. Our experts will entertain and educate with all types of insects and arachnids.
  • Friday Feeding Frenzy | Fridays at 9:30 a.m., 10:30 a.m. & 11:30 a.m.
    Join us this morning in the Cockrell Butterfly Center for our Friday Feeding Frenzy! See science in action as snakes, spiders and centipedes enjoy a meal right in front of you!
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Hate Mosquitoes? Consider a Bat House! Fight Insect-Borne Illness by Partnering with Furry Fliers

The National Weather Service reported last week that 35 trillion gallons of water fell in the state of Texas during the month of May. The ground is soaked for what may well be weeks to come, our bayous have swollen far beyond their usual limits and residents in Harris and Ft. Bend counties continue to pick up the pieces after flooding pushed them from their homes. We know what 35 trillion gallons looks like in terms of disrupting the lives of Texans, but it’s difficult to imagine just exactly how much that is.


That’s a lot of water…

NBC’s Nelson Hsu put together a graphic breaking down the staggering amount of water that drenched our state — evenly distributed and dropped all at once, it’s enough to cover Texas in eight inches of water; enough to fill California’s 200 surface reservoirs to thrice their capacity, enough to cover Manhattan four times, and if we had caught all that rainwater and spread it across the globe, the world’s population would have a supply of 64 ounces of water for at least the next 27 years. And most people fail the eight-glasses-a-day challenge!

With Zika virus making headlines in the aftermath of May’s downpour, our soaking city seems like prime real estate for ground zero of the next outbreak. But fear not. Mosquitoes are ubiquitous, that’s true, but they’re easy enough to fight. They fly at less than 1.5 miles an hour, with a typical range of only about 300 feet in still weather. Their strength is in their numbers, not their speed — kind of like zombies.


America’s worst enemy, but to bats, they’re food for thought.

First, there have as yet been no locally-acquired cases of Zika virus in the United States, according to the Center for Disease Control; the 618 reported cases were all travel-associated. It’s also important to understand that while Zika poses a serious threat to developing infants during pregnancy, the disease presents no more than a few days of flu-like symptoms in adults and children.

Second, since mosquitoes are the main vector of Zika, the best way to directly combat them is to wear insect repellent. Sure it smells nasty, but Off! and other spray-on products could save you from serious symptoms and the awful itching of the world’s most annoying insect.

Third, you can stop mosquitoes from breeding by eliminating areas of shallow, stagnant water. Take a lesson from the residents of Flamingo, Fla., a community in the Everglades and home to one of the most voracious populations of mosquitoes: Get rid of aluminum cans, bottles and plastic containers, store recycling in plastic bags, don’t let water accumulate in garbage can lids or empty garbage cans, flush bird baths and plant trays twice a week, store pet food and water bowls indoors when Fido and Felix aren’t using them, and use mosquito “dunks” in areas that can’t be drained. These dunks utilize bacteria that consume mosquito larvae but leave fish and other animals unharmed.


(Yawn!!!) It it dusk yet? I’m hungry for mosquito breakfast.

For the long term, my favorite method of laying waste to mosquitoes involves enlisting the assistance of another population of flying creatures — by hanging bat houses! The Mexican free-tailed bat (Tadarida brasiliensis) is a hardy, numerous species (and they’re super cute), but their propensity to roost in a few huge colonies, like those you can find under bridges in Austin and Houston, leaves them vulnerable to habitat loss. Hanging one or two bat houses around your home keeps these adorable flying mammals close by, which means far fewer insects.


Vote Bat for Harris County Mosquito Exterminator! I eat bugs so they don’t eat you!

While female mosquitoes have an insatiable appetite for blood, which they need to lay their eggs, bats have an equally ravenous hunger for the insects. A single bat can eat around 1,000 mosquitoes every night, and a single small bat house offers shelter for up to 25 bats. Do the math with me — two shelters is 50 bats, which could eat a total of 50,000 mosquitoes a night or 350,000 mosquitoes a week. That’s not just the mosquitoes around your house; that’s probably every mosquito on the block. If you convince your neighbors to hang houses, too, you could form a bat colony coalition for an even more formidable mosquito-fighting force.


When we have a problem, we hug it out. #justbattythings

The capacity of a bat house, of course, is also adjustable according to its size. Many bat house companies, like P & S Country Crafts or Habitat For Bats offer a variety of dimensions available for purchase, or you can build one yourself. It’s an easy enough project to knock out in your garage in a few days, and an even easier project to hang up a pre-made one. Each house promotes an environmentally-friendly semi-symbiotic relationship with our adorable bat friends, which stay long enough to raise their pups and then move on when the weather cools down. And by this time, the mosquitoes will have disappeared for the season, as well.


Bat houses by, mounted on a pole. Bat houses can also be attached to the sides of houses or barns. Trees are not ideal for bat house mounting.

So do what you can to fight mosquitoes, but consider teaming up with the bats, our neighborhood insect-fighting superheroes. Check out Bat Conservation International for more information on ways to help these furry fliers.

Visit the Farish Hall of Texas Wildlife at the Houston Museum of Natural Science to learn more about bats and other native species in need of conservation.

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