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!

Bug Geeks

Report from the yearly gathering of bug geeks…

I recently got back from the annual “Bugs in Bondage” conference held in southern Arizona.  The actual name is the more politically correct “Invertebrates in Education and Conservation,” recently updated from the original “Invertebrates in Captivity” – thus the humorous nickname.  But for those of us who have attended for many years (this was the conference’s 15th consecutive year), the nickname will always come first to mind. 

This is a great conference.  Who goes?  It’s a fairly small group, about 125-150 people, including representatives from most of the US facilities that display live insects and/or butterflies, as well as those who supply insects and butterflies to our facilities.  Several international attendees often participate as well – especially from Canada and Mexico but also from as far away as Scotland, Costa Rica, Singapore, and Malaysia. 

Hosted by the Sonoran Arthropod Studies Institute (SASI), it’s a week of workshops, collecting field trips, formal and informal presentations and roundtable discussions – with a strong social aspect as well.  The “Insect Trivia” contest is one of my favorite rituals; the photography contest is always fun, too; and of course, nothing can beat the final banquet.  Outside the meeting room, several vendors set up their wares – whether live arthropods, insect books, toys, and jewelry or collecting equipment.  As an example, BioQuip has a large display and also helps to sponsor the conference.

It may seem crazy to meet in southern Arizona in the middle of the summer, but the time (late July/early August) was chosen for a reason.  Although it’s hot and sunny during the day, this is “monsoon season” in the Sonoran desert, a time when – most days – clouds build up late in the afternoon, followed by dramatic lightning storms that are accompanied by brief but torrential rains. 

Shortly after nightfall, it is usually clear again (the stars are great there in the desert skies).  Because of all the rain at this season, the desert is teeming with plant and insect life.  It’s a great time to find cactus longhorn beetles, giant centipedes, vinegaroons, sunburst diving beetles, jewel beetles, and much more.  Some participants go blacklighting almost every night, choosing a spot off the beaten path and setting up a white sheet with UV and mercury vapor lamps to draw in flying insects.  I’ve seen sheets completely covered with moths, including some large and spectacular ones, along with tons of beetles, adult ant lions and owl flies, and much more.  

This year, a former colleague and I led a workshop on “plant identification for entomologists.”  One of my favorite workshops in the past was one on “cooking with bugs” – we made a number of dishes using different insects and then served them at the icebreaker that night!  The talks I most enjoyed this year included one on leaf cutter ants, another on a monitoring program for the endangered burying beetle, and one on how to keep and display bumblebees

The other attendees are fun, unique people brimming with knowledge and experience – along with some “newbies” who are there to learn the ropes.  We all come away from the conference full of new ideas for displays, new arthropod possibilities, and a sense of community.  It’s not often you can be in a room of over 100 people where every one is a major insect enthusiast (aka bug geek)! 

Are you a bug geek? Learn more:
What butterfly are you most likely to see in the wild?
Could you raise a tiny baby mantis?
Discover the Black Swallowtail.