Let’s begin this discussion with some light-hearted fun but also the cautionary statement that you can’t always judge a book by its cover.
Many things are categorized as insignificant or simply annoying because of appearance, size, background and other factors. However, initial impressions can be very deceptive.
Beginning with a human example that references animals we’ll be discussing, let us consider someone who, from an early age, was nicknamed “La Pulga” or “La Pulguita” — translated as “the flea” or “the little flea.”
This individual was called a flea because of his diminutive stature compared to others players in his sport, but his nickname also alluded to quickness and difficulties opponents encountered defending against him. La Pulga is the nickname of Lionel Messi, a player who developed into a famous, worldwide legend of futbol or soccer!
Flea-ridden literature
Many comparisons, proverbs and metaphors referring to fleas are found in literature, including King David comparing his significance to a flea and Augustus Morgan’s statement, “Great fleas have little fleas upon their backs to bite ‘em, and little fleas have lesser fleas, and so ad infinitum … .”
William Shakespeare alluded to daring action accomplished by diminutive forces in his play “Henry V” by stating, “That’s a valiant flea that dares eat his breakfast on the lip of a lion.”
Benjamin Franklin cast fleas in a more negative way by stating, “He that lieth down with dogs shall rise up with fleas.” And William Butler Yeats asked, “But was there ever dog that praised his fleas?”
The poet John Donne represented fleas in both negative and satirically positive ways. In his “Devotions Upon Emergent Occasions,” Donne portrayed fleas negatively by stating that, “The flea, though he kill none, he does all the harm he can …” — but also in positive, metaphysical ways in the poem “The Flea” by representing a flea as a sacred cloister facilitating union between two lovers.
Ancient fleas were ambushers
Nicknames and literary devices aside, fleas are an ancient insect order that perhaps began their ectoparasitic behaviors upon feathered dinosaurs and ancestral mammals. Compared to modern species, ancient fleas were huge — 10 times the size of today’s fleas — and lacked pronounced leaping abilities.
Instead, they relied upon ambush methods to crawl upon their prey and secure a blood meal with long, sharp siphons.
Fleas in our times
Most modern fleas are 3 mm or less in length and have become more specialized for ectoparasitic lifestyles. Their bodies are laterally compressed, or flattened, and their legs have enlarged coxae which help store energy for incredible leaps that are perhaps 200 times their body lengths.
Antennae fit neatly into grooves upon the flea’s head, and piercing-sucking mouthparts are enclosed within a beak. Numerous, backward facing bristles are located on the body, and one or more bristly ctenidia, or combs, may be found on the head and/or thorax. Most adult fleas are tan to reddish-brown. Fleas have simple eyes or may lack eyes and rely upon sensing a potential host’s body heat.
The flea’s small size, laterally compressed body and backward facing bristles allow it to easily move through a host animal’s fur or feathers. Hardened, pressure-resistant sclerites cover the flea’s body and likely are survival adaptations against a host’s scratching efforts. Flea feet, or tarsi, also have pronounced claws and bristles enabling a secure grip upon their host.
Jumping abilities
The flea’s extraordinary leaping abilities are not strictly attributable to muscles but are also based upon energy release from elastic, body proteins called resilins. Body pads containing resilin are compressed, and fleas cock their hind legs to store the potential energy prior to leaping.
This action is similar to drawing a bow, and fleas even have a catch mechanism in their hind leg tendons and joints to prevent the premature release, or firing, of their legs.
Who and what fleas like to bite
Some fleas have specific hosts, for example, bats, birds and even armadillos) whereas many others are less particular regarding sources of blood meals and parasitize rabbits, rodents, carnivores and many other terrestrial mammals and birds.
Although there are specific fleas known as “dog fleas,” almost all fleas found upon dogs in the United States are “cat fleas.” And cat fleas are also the likely culprits of most human flea bites! Adult fleas depend upon blood meals for nutrition and successful egg production — usually several dozen eggs per batch and several batches per annum.
Flea life cycle
Fleas have holometabolous lifecycles, and tiny, worm-like larvae hatch from eggs, grow and spin silken cocoons around themselves to pupate into adults. Depending upon environmental conditions, lifecycles may be completed within a few weeks or more extended time periods.
Eggs are deposited within burrows, nests, bedding and other locations as well as directly upon hosts; however, eggs laid on host animals ultimately fall off, and most end up in one or more of the aforementioned locations. Newly hatched flea larvae feed upon detritus, food waste and also upon adult flea fecal matter.
Flea fecal matter contains partially digested blood which facilitates larval growth and development. Therefore, thorough cleaning of pets, pet bedding and surrounding areas helps disrupt the flea’s lifecycle.
Fighting fleas
Now let us consider a few reasons why fleas are far from insignificant.
Residents of the United States spend billions of dollars per annum on prevention and treatment strategies to reduce or eliminate fleas on pets, livestock, properties and public spaces. These measures are necessary because fleas are well-known disease vectors of bubonic plague, typhus, cat scratch disease and tungiasis.
Fleas can also transmit tapeworms to pets and humans and cause dermatitis and anemic conditions in pets, people and livestock. Regular, timely cleaning and use of various systemic and topical medicines help prevent flea infestations on pets and livestock, and various options are available for flea prevention around and within homes as well as pet housing and livestock holding areas. Applying insect repellants during outdoor activities also discourages fleas.
Controlling or eliminating rodent populations near pets, people and livestock helps reduce flea-borne diseases. Rodents, such as old-world rats and mice, woodrats, white-footed mice and deer mice, may harbor fleas carrying the Yersinia pestis bacterium responsible for bubonic plague, and concern recently arose regarding prevalence of plague in prairie dog colonies.
However, additional research revealed that prairie dogs quickly succumb to the disease (greater than 90% of a colony may die off within 72 hours of infection. Therefore, although prairie dogs might amplify the disease somewhat during an outbreak, prairie dog towns are more useful in indicating presence of bubonic plague within an area.
As we’ve discussed, the tiny flea can have a definitive impact despite its small size. Application of good, preventative practices aids in avoiding these little blood-suckers in our communities and region!
Jim Goetze is a retired professor of biology and former chairperson of the Natural Sciences Department of Laredo College with an avid interest in all aspects of the natural world. He can be contacted at gonorthtxnature@gmail.com.
This article originally appeared on Abilene Reporter-News: Tiny fleas have a big impact on health and pets | Opinion
Reporting by Jim Goetze, Abilene Reporter-News / Abilene Reporter-News
USA TODAY Network via Reuters Connect
