House Flies--Natures Pesky Pest

Shoofly! Shoo! How many of us have said those words, or heard someone say them? They become part of our spring and summertime vocabulary as we try to keep pesky flies away from our food, drinks, and… well, US! It is a constant battle; that we are sure the flies are winning. House flies rank right up there with mosquitoes and ticks as being loathsome and unwanted. Where do they all come from and what good are they?

House flies (Musca domestica) are probably the most common fly encountered by humans. Even their genus name of domestica hints at their domesticated nature, and their association with humans, livestock and pets. In fact it has been reported that up to 90% of all flies encountered by humans will be the house fly. House flies are in the order Diptera, which means Two-Wings, and like all flies they only have one set of wings, or “two-wings.” All other winged insects have two sets of wings, or “four-wings.”

House flies are relatively small at approximately ¼ of an inch. They have gray bodies with four longitudinal stripes on their thorax (behind the head). Their bodies are covered with hair-like projections. Females are slightly larger than males. How do you tell a male from a female? Look at the eyes; the females have eyes that are wide set, whereas males will have eyes that practically meet in the middle, or touch each other.

Females are capable of laying up to 500 hundred eggs in their lifetime. These tiny white eggs will be laid on garbage or animal dung and usually hatch in less than 24 hours. It will take the maggots approximately 5 days to reach their full size, then they will drop to the ground and burrow into the soil. They will remain in this underground chamber to pupate and will emerge in a few days as fully grown adult flies. So we can easily see how we end up with so many flies…with each female producing hundreds of eggs, and those eggs going from maggot to adult in less than 1 ½ weeks, and then they are ready to mate in less than 3 days and start the cycle all over again. It has been estimated that if all the offspring of a single pair of house flies were to survive throughout one breeding season beginning in April and ending in August, they would have produced 191,010,000,000,000,000,000 progeny. Thankfully though, not all will live, many are consumed by other insects, birds, and frogs or are outwardly killed by humans. A typical adult house fly will live up to 25 days, but may live up to 2 months if suitable food can be found. They are particularly fond of sugars. According to a study conducted in Texas, breeding site suitability (in descending order), was horse manure, human excrement, cow manure, fermenting vegetable, and kitchen waste. However, another study found that structures containing swine, horse, sheep, cattle, and poultry varied in fly abundance, with swine facilities containing the most and poultry the least. Fruit and vegetable cull piles, partially incinerated garbage, and incompletely composted manure also are highly favored sites for breeding.

House flies have the potential to spread many diseases, including typhoid, cholera, dysentery, viral hepatitis, cocci, salmonella, and many other unsavory pathogens. These are spread to humans through indirect contact, meaning it is passed through their feces, vomit and from the hairs on their bodies. Think about where a fly hangs out….then he comes to join your family picnic and lands on your food. The fly will vomit, defecate or sometimes both right on Aunt Mabel’s potato salad. Then we consume Aunt Mabel’s potato salad and voila….we get sick! So the next time someone in your family yells Shoofly! Shoo! There is good reason for it……these little beasties should be kept away from food meant for human consumption. The transmission of diseases is more prevalent in areas where hygiene is poor. Washing and cooking raw vegetables controls the spread of these pathogens. When outside, keep food covered to deny the fly access. Remember, that fly has been crawling around on garbage and manure, then landing on your food….!

Controlling flies is a difficult endeavor that involves removing animal waste, garbage and other materials they find suitable for mating and laying eggs. Killing the adults will help, but remember one fly can produce 500 eggs, so if you do not remove the areas where eggs are laid, an infestation will occur. This is especially true near livestock farms.

When being asked where do they all come from, and what good are they; I point out their prolific lifestyle and their ability to produce numerous offspring. I try to find something good in all manner of creatures, including flies. They are instrumental in breaking down waste which aids in adding nutrients back in the soil. They are also a food source to numerous other creatures. So not all is bad where house flies are concerned, but it is still best to keep them at a distance.

Tumblebugs----Earths Manure Spreaders

Poop, Poop, everywhere Poop, much to the delight of the dung beetle or tumblebug as it is sometimes called, which consumes dung with as much enthusiasm as we show to an ice cream sundae. These beetles range in size from very small to quite large at over an inch in length, and all are incredibly robust looking. These are stout beetles and are unmistakable when spotted. They may be black, green, brown, or even iridescent in coloration. Males have a distinctive horn on their head, presumably to fight for the right to mate with available females.

These industrious beetles are in the family of beetles called scarabs. Many of us are familiar with the significance of the dung rolling scarab beetle in Egyptian historical culture. The activity of rolling dung was thought to be a symbol of Ra rolling the sun across the sky each day. Scarabs, especially the dung rolling variety are depicted in Egyptian culture often and for many reasons. In Gothland, Sweden’s largest island it was believed that if you encountered a dung beetle on its back and righted it, you would be purged of all sin. In African folklore it is told that butterfly and dung beetle were best friends. One day while resting in the shade, first man and first woman came by. They admired the butterfly but ignored the beetle. After declaring to the butterfly that he did not like being ignored, the butterfly encouraged the beetle to become the strongest beetle ever. The beetle worked hard to gain strength and once again first man and first woman came by. They witnessed the feats of strength the beetle exhibited by rolling his dung ball. They were so impressed that for the first time they ignored the butterfly it all its beauty. The beetle was so proud of his accomplishment that to this day he continues to roll dung. While this may be folklore, the strength of the dung beetle is in fact quite remarkable. Most can move ten times their weight, and one species in particular can move 1,141 times its own weight! That would be like an average sized man pulling six double decker buses full of people! 

Dung beetles come in three classifications. There are rollers, tunnelers and dwellers. Rollers are the ones we are all most familiar with and get the most attention. They use an extremely sensitive sense of smell to locate dung, remove a portion of the “cake,” and tamp it into a ball which they roll to another location to bury. Males are usually the ones moving the ball, while females either walk behind or hitch a ride on top of the ball, and just hang on for the ride.

Most of us have watched a video or two of these beetles racing across the landscape rolling their prized ball with them at what seems like remarkable speeds when moving something so cumbersome. They are not trying to set land speed records, these energetic movers are trying to protect their ball from lazy dung rollers who mean to steal their hard work. 

The tunnelers on the other hand dig a burrow right below the cake and bury it in place. The dwellers took the easy route and just live inside the cake. These beetles utilize the dung of herbivores and omnivores with the former be their preference. Plant material is difficult to digest in its entirety which means bits, and pieces are passed through the digestive track of large herbivores such as cattle or in Africa it is often elephants and rhinos. The indigestible bits are then deposited inside a nutrient rich pile of poo that dung beetles find quite tasty. This habit of eating leftover plant material out of fecal matter also gives them clout as seed dispersers. As they roll the prized dung ball across the landscape and bury it, seeds are transferred to new locations and often sprout into new plants. Because dung contains all the nutrients and moisture these beetles need, they do not seek other forms of food or water. However, there are some species of these beetles that prefer fungi and decaying fruit.

All three types use dung as a food source for their offspring. Eggs are laid within the fecal matter, and when the eggs hatch the larvae feed on the provided meal. In the case of those that bury the dung, often both parents stay with the offspring and guard them from potential predation. Once the larvae form pupas the parents eat much of what is left of the dung ball.

In our area they are most likely to occur in feed lots where cattle are kept or in pastures with horses or cows. But worldwide may be found in a wide variety of habitats including deserts, woodlands, savannas and grasslands.

These beetles are important components in the environment, and they play a significant role in breaking down organic matter (dung) and returning it back to the soil as a nutrient rich substance. They aerate the soil, compete for underground nesting sites with several different species of flies, as well as remove the availability of dung for the flies to feed on or lay eggs in at the surface (which greatly reduces the fly populations). Thus reducing the number of flies that pester your livestock, keeping them healthier. Their habits add nutrients back to the soil which helps prevent pasture fouling. Pasture grasses will yield better stands and provide more fodder for cattle and horses, thus reducing the amount of hay that needs to be purchased to supplement their diet. Not to mention an estimated 380 million dollars annually is saved in the cattle industry by these beetles and their dispersal of dung. The use of chemical control of flies in cattle lots has had a dramatic impact on populations of dung beetles. Many individuals are beginning to understand the detrimental result of this practice and have eliminated the use of such chemicals or have greatly reduced the amount used. Chemicals that kill flies often kill beetles and many other insects.

There are species that navigate using the milky way, still others that use moonlight to traverse their habitats. They occur on all continents except Antarctica. These unique beetles are beneficial by aiding in a healthier environment for all of us. They should be encouraged and marveled at, and never destroyed. If you want a chance to watch these beetles in action, they are more active in the late evening and nighttime hours. Grab a flashlight and head to the nearest pasture, scan the piles of dung and you may just get to see one of these beetles forming and burying their dung ball.

Inchworms

Who doesn’t have fond memories of childhood, capturing “bugs” such as ladybugs, roly-poly’s, or the intriguing inchworm? Harmless insects such as these have fascinated children for generations. I can remember capturing inchworms and letting them crawl over my hand or across my arm, fascinated by their movement. Legend has it that an inchworm crawling on you, is measuring you for your coffin. After 50 years, I can attest to the falsehood of this claim.  Inchworms get their name from their unique mobility. This creative movement is possible because of the absence of middle legs. Their legs instead are located at the front and rear of the caterpillar. They essentially clasp with the front legs and draw up the hind end then clasp with the hind legs, giving them a humpback appearance. Before reaching out again with those front legs to clasp onto something else, repeating their motility. This unique movement gives the impression they are measuring their journey; thus, the name “inchworm” was attributed to them.

The first inchworm found in Baltic amber was discovered in 2019 and was given the name Eogemeter. It was estimated to date back 44 million years ago! So, they have been around a very long time. Currently there are approximately 24,000 species of inchworms found Worldwide, 1400 of which live in North America, there is no shortage of these fascinating caterpillars. They belong to the family of moths called the Geometer moths. This name is derived from the Latin word geometra and translates loosely into “earth measurer.” Which is also a descriptive term for their unique movement. They may be green, gray or a shade of brown, with some species being nearly black. Some may have spots, or stripes, but all are masters of camouflage. These small, thin caterpillars resemble twigs and blend in well with their environment. When disturbed many species will bungie jump from their vantage point via a piece of silk string they release. This silk string will harden, allowing the caterpillar to climb back up to continue feeding once danger has passed. Some parasitic wasps, however, are aware of the trickery of these caterpillars. They can locate the silk line and either reel up a desperate caterpillar or maneuver themselves down the silken line to inject eggs inside the horrified inchworm…. which hatch into tiny wasp larvae that feed on the caterpillar from the inside out. Other insects, like yellow jackets and paper wasps paralyze the inchworm with special enzymes and masticate them, only to serve them up as a tasty meal for their offspring in a form of inchworm vomit.  With all the birds, and predatory insects out there that feed on these caterpillars I am certain they are kept busy reeling themselves down and climbing back up multiple times daily. Other species of inchworms will stand erect on their hindlegs completely motionless, giving the appearance of a small twig. These enterprising caterpillars manage to avoid being eaten by freezing in place. 

Inchworms, like all caterpillars, are herbivores and feed on a wide variety of plant material. There is an exception though. In Hawaii lives an inchworm that is carnivorous and feeds on insects and spiders. They have a specially adapted mouth and lightning-fast reflexes and can capture an insect in 0.1 seconds. These meat-eating inchworms are referred to as pugs. At this point, these are the only known predatory caterpillars living today.

 Inchworms are considered a social insect and will often gather in relatively large groups but will feed as loners away from their brethren. Inchworms are boom and bust insects. Meaning there are years of plenty and years of few. Their cycle is typically two to seven years of higher populations, then thirteen to eighteen years of low population. The last significant, damaging population explosion occurred in the 1970’s. These explosions in population can cause significant damage to fruit trees, and deciduous shade trees, which are their typical foods of choice. If higher populations remain for three years or more, the continued defoliation of trees may lead to extremely stressed trees that end up dying.

 Many people may know these caterpillars by their other common name ofcankerworm. There are two types of cankerworms, the spring and fall species.  The spring cankerworm spends the winter in the soil as a mature caterpillar until spring when they will form a cocoon and pupate into the adult form that will emerge in a few weeks. Typically, it will be early April through mid-May when the adults appear. Fall cankerworms emerge as adult moths in October after a hard freeze. The males appear first, followed by females a few days later. Mating takes place and females will lay eggs in clusters that overwinter and hatch the following spring. Adults die shortly after mating. They hatch in spring, usually to coincide with the budding of trees. In about four weeks they will drop to the ground and finish their lifecyle to the adult stage. Both spring and fall cankerworms typically begin feeding at the same time each spring, even though their lifecycles are a little different from each other. In years of excessive population numbers, control measures may be needed. Assess your trees and try to start any treatment when the caterpillars are in their earliest stages, older caterpillars are more difficult to impossible to control. In most cases, however, control is not needed, and natural predators will take care of the problem. If you do need to use chemicals, find those with Bt (Bacillus thuringiensis) as a key ingredient, it is the safest and has the most effect on the caterpillars.

 Historically other control measures were implemented which resulted in a whole other problematic issue. In the 1850’s immigrants from Europe found our country devoid of familiar wildlife. They drastically missed the birds they had lived with back home. It was also during this time that a huge outbreak of cankerworms appeared and were destroying the Linden trees in New York City. An enterprising individual by the name of Nicholas Pike, had a plan. He bought eight pairs of English sparrows, or house sparrows as they are more commonly referred to as. These birds were released in New York and did a fabulous job of eating the caterpillars causing all the havoc. It is believed those initial birds are the ancestors of all house sparrows living in the United States today. Others claim those initial sixteen birds did not reproduce and subsequent purposeful releases did the trick. Either way, this is a case of the cure, being arguably worse than the problem at hand.

Finding yourself in the middle of a plague of inchworms, often dangling in an unsightly manner like pendants on a string only to drop on your head, can be a bit annoying. Not to mention watching as they defoliate your orchard, leaving behind a barren