To appreciate the number of flies in the 25th generation, assume that the flies are packed together 1000 to a cubic inch. This number of flies would fill a ball 96 million miles in diameter, greater than the distance between the earth and the sun! Of course this is only theoretical. The natural control forces of nature will prevent this staggering fruit fly explosion from ever happening. In fact, there is a rule of nature that states "survival rate is inversely proportional to fecundity." In other words, animals with a high production of offspring (high fecundity) have a low survival rate among their offspring. In worms, insects and fish that lay thousands of eggs, only a few of their eggs will ever reach maturity.

Diploid somatic cells of Drosophila melanogaster contain three pairs of autosomes plus an X/Y pair, a total of eight chromosomes (2n = 8). The sequenced genome of 165 million base pairs contains about 14,000 protein-coding genes which comprise about 20 percent of the total genome. About 75 percent of known human disease genes have a recognized match in the genetic code of fruit flies, and 50 percent of fly protein sequences have mammalian analogues. Drosophila is being used as a genetic model for several human diseases including the neurodegenerative disorders Parkinson's, Huntington's, spinocerebeller ataxia, and Alzheimer's disease. This fly is also being used to study mechanisms underlying aging and oxidative stress, immunity, diabetes, and cancer. Research on Drosophila is also providing answers to the cause of autism.

Blood-sucking sand flies of the subfamily Phlebotominae are one of the unpleasant "No-See-Ums" that attack humans on beautiful beaches of Florida and Caribbean islands. They are primarily active in the early morning and late afternoon when the beach sands have cooled. Some species are vectors of tropical diseases.

The following two references describe cases of myiasis (infestation by fly maggots) in humans caused by the larvae of Clogmia albipunctata:

 Mohammed, N., and K.G.V. Smith. 1976. "Nasopharyngeal Myiasis Caused by the Larvae of Clogmia (= Telmetoscopus) albipunctatus Williston (Psychodidae, Diptera)." Transactions of the Royal Society of Tropical Medicine and Hygiene Vol. 70 (1): 91.

 Smith, K.G.V. 1979. "Intestinal Myiasis in Man Caused by the Larvae of Clogmia (= Telmetoscopus) albipunctatus Williston (Psychodidae, Diptera)." Transactions of the Royal Society of Tropical Medicine and Hygiene Vol. 73 (3): 349-350.

Crane flies are often mistaken for giant mosquitoes. Although crane flies and mosquitoes both belong to the insect order Diptera (true flies), they actually belong to entirely different families. They are often called "mosquito hawks," although they do not prey on mosquitoes. The soft, fragile mouthparts of crane flies make them incapable of biting. In addition, their long, clumsy legs are very fragile and break off easily. Crane flies are attracted to lights and often sit on windowsills, walls and doorways. They commonly enter houses during the evening as you walk through your doorway.

Crane flies develop from large, worm-like larvae called "leather jackets" because of the brown color of their skin. The larvae of terrestrial species live in moist soil or leaf mold where they feed on decaying wood and vegetation, fungi, mosses, and the roots of herbaceous plants. In some species the larvae are completely aquatic and live in ponds and streams. When fully grown the larvae metamorphose into pupae. They are very abundant in weedy fields in spring, especially during years with high rainfall and bountiful annual grasses and herbs. Often swarms of adults appear after mowing. Like many other insects, the adults are relatively short-lived and their main purpose is to mate and perpetuate the species.

The brown larva of a crane fly.

Size relationships used in Wayne's Word articles.

Beware Of False Pennies Used In Size Relationships

Wayne's Trivia Note #576 (23 April 2019)

It's crane fly (Tipula sp.) season in San Diego County. Erroneously called "mosquito hawks," these harmless, long-legged flies don't kill anything. In fact, they typically don't even feed as adults. They only live for a week or two, and their main purpose as adults is to find a mate and pass on their genes (DNA)! They spend the majority of their lives as larvae in grassy fields. There are literally thousands of species. For more information, go to Iowa State University, Dept. of Entomology.

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Mosquito (Order Diptera: Family Culicidae)

Well-Known Flies In Southern California

The mosquito family is readily identified, particularly if a female mosquito is sucking blood out of your arm through her long proboscis. Only the female "bites" (sucks blood), the male feeds on nectar and fruit juices or not at all. She needs the proteins from her blood meal to develop eggs. She pierces the skin with her long proboscis, tipped with minute cutting organs. An anticoagulant is secreted into the wound to keep the blood flowing. Depending on the species, mosquitoes also bite other infected host animals, such as birds horses and rodents, and are the vector of a number of dreaded diseases, including malaria, encephalitis, denge fever, yellow fever and West Nile virus.

Female house mosquito (probably the genus Culex). Males have a bushy antenna.

Close-up view of head of female mosquito.

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Fungus Gnats (Order Diptera: Family Mycetophilidae)

Fungus gnat (cf. family Mycetophilidae)

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Bee Flies (Order Diptera: Family Bombyliidae)

This little hump-backed bee fly belongs to genus Geron. It is roughly the size of a mosquito with a long, rigid proboscis and pair of short antennae typical of bee flies (Bombyliidae). Its flight is erratic with short up and down movements. It was identified by Dr. Neal Evenhuis of the Bishop Museum, Hawaii.

A species of bee fly in the very large family Bombyliidae. It belongs to the genus Villa. This interesting fly is about the size of a honey bee with a fuzzy body similar to many bees.

Bee flies have a long, rigid proboscis for sipping nectar from flowers. On warm, sunny days bee flies are often seen hovering over flowers or resting on the ground. While hovering, they probe flowers for nectar with their long proboscis, like miniature hummingbirds. They are fast-moving flyers and probably evade predators lurking in the flowers (ambush bugs and crab spiders) by not actually landing on the flower. In the following image, pupal cases can be seen in or around small holes in the ground dug by solitary bees (family Andrenidae). The larvae of bee flies are parasitic on the larvae of solitary bees within their burrows. The bee fly in the following images was identified as Bombylius montanus by Dr. Neal Evenhuis of the Bishop Museum, Hawaii. They are typically parasitic on bees of the genus Anthophora (Apidae). According to Dr. Evenhuis, this is a relatively rare species also known from Walker Pass in the southern Sierra Nevada.

Bee fly pupal cases within or near the burrows of solitary bees.

This furry fly has a long, rigid proboscis that it uses for sipping nectar from flowers.

See Bee Flies & Their Host--A Solitary Burrowing Bee

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Syrphid Flies (Order Diptera: Family Syrphidae)

Alpine daisy and syrphid fly photographed on Logan Pass, Glacier National Park.

Cactus Fly (Copestylum mexicana). The larva feeds on rotting cacti.

The following link shows a syrphid fly hovering in midair. It was taken through LCD screen at arm's length on a hand-held Sony T-9 at a distance of 4 inches (10 cm). This fast-moving fly is difficult to get close to while it is in flight. Very difficult photo.      Syrphid Fly Hovering in Midair

See Syrphid Fly Larva That Eats Aphids

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Wayne's "Remember When" #65 (23 July 2020)

I identified this beneficial metallic green fly with red eyes at my home in Twin Oaks Valley. I incorrectly thought it was the species I remembered from the 1950s in Arcadia, CA; however, The Wing Movement Of My Green Long-Legged Fly Did Not Match The Arcadia Fly From My Childhood! CORRECTION: Update 27 July 2020. The wings of Arcadia fly moved like oars in a rowboat: The fly in Arcadia was not a green long-legged fly. It was a "Boatman Fly" (Pogonortalis doclea) introduced from Australia. See following youTube video: Boatman Fly

Boatman Fly (Pogonortalis doclea) Family: Platystomatidae By Graham Wise from Brisbane, Australia CC BY 2.0, https://commons.wikimedia.org/ w/index.php?curid=40575630

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Class Insecta: Order Phthiraptera

Biting & Sucking Lice: Small, Flightless, Parasitic Flies

Biting Lice: Suborder (Order) Mallophaga

True lice are very specialized, wingless insects that live as ectoparasites on their host. They have clawilike legs that enable them to cling tenaciously to feathers and hair in spite of their host's preening and scratching. They include two very different suborders, the Mallophaga and Anoplura.

Broad-headed bird louse (Menacanthus sp.). Chewing lice belong to the insect suborder Mallophaga. The louse shown above lives on the skin of domestic fowl and game birds. Chewing lice typically gnaw on fragments of feathers, hair and skin with a pair of mandibles. Each leg is tipped with a sharp claw which can be very irritating to the host animal. The head is much broader than human lice, and they are often called broad-headed bird lice. Sucking lice (suborder Anoplura) have a set of long hypodermic-like stylets to pierce the skin and withdraw blood of mammals. They include the head lice, body lice and crab lice of humans.   Using Lice DNA To Date The First Clothing Worn By People   Sucking Lice: Suborder (Order) Anoplura Sucking lice belong to the suborder Anoplura. Human sucking lice include body lice, crab lice and head lice (Pediculus humanus). [The plant genus Pedicularis is called "lousewort" and is derived from the old belief that these plants, when ingested, were responsible for lice infestations in livestock.] Anoplurans use a set of long hypodermic-like stylets to pierce the skin and withdraw blood. After ingesting blood their body becomes swollen and shows a dark clot of blood in their abdomen. There are two forms of human sucking lice, the head louse (P. humanus capitis) and the body louse (P. humanus humanus). The head louse infests the hair of the scalp and the body louse lives in clothing near the body surface. Human lice are also known as "cooties" and their eggs attached to hairs are called "nits." Human lice cause local itching, but the discomfort is minor compared with the misery of the bacterium they can transmit called Rickettsia prowazeki. This minute bacterium causes "Epidemic Typhus," a serious disease that has devastated populations in medieval Europe. Rocky Mountain Spotted Fever is caused by Rickettsia rickettsii and is transmitted to humans by various species of ticks, most commonly the dog tick and wood ticks. Human head louse compared in size with the "eye" of an ordinary sewing needle. Photo taken with a hand held Nikon D-90 and Phoenix RF46N Ring Flash using a 60mm Micro Nikkor AF-S F/2.8G ED Macro Lens. Human head louse compared in size with cubical grains of ordinary table salt (NaCl). An average grain is about 0.3 mm on a side. Photo taken with a hand held Nikon D-90 and Phoenix RF46N Ring Flash using a 60mm Micro Nikkor AF-S F/2.8G ED Macro Lens.   See The Size Of A Grain of Table Salt   Human head louse compared in size with the "eye" of an ordinary sewing needle. Photo taken with a taken with a Sony W-300 digital camera mounted on a Bausch & Lomb stereo dissecting microscope. Magnification 20x   Size Of Sewing Needle Used In Wayne's Word Articles   Magnified view of a human head louse Photo taken with a taken with a Sony W-300 digital camera mounted on an Olympus compound laboratory grade microscope. Magnification 40x. Using Lice DNA To Date The First Clothing Worn By People One of the most novel uses for DNA sequencing is the determination of when humans first began wearing clothing. According to Mark Stoneking and his colleagues at the Max Planck Institiute for Evolutionary Anthropology in Leipzig, Germany, we started wearing clothing about 70,000 years ago. This date is based on genes of human sucking lice. It correlates with the approximate time when the body louse evolved from the human head louse and corresponds to the time when the body louse's habitat (clothing) became widespread. This is also the time when Homo sapiens sapiens began moving out of Africa into cooler regions of Europe. Stoneking and his colleagues Ralf Kittler and Manfred Kayser compared mitochondrial DNA sequences from head and body lice. The greater the difference in sequences between the two forms of lice, the older their evolutionary split. Human lice from Africa are more genetically diverse than lice from other parts of the world, indicating that the species originated in Africa. Head lice are more diverse than body lice, showing that they are the older group. By comparing the mitochondrial DNA of body lice to chimpanzee lice, Stoneking's team was able to approximate the origin of body lice to around 70,000 years ago. This date correlates well with the growing evidence that modern humans evolved in Africa and migrated northward around 100,000 years ago. Stoneking is also studying human crab lice (Pthirus pubus) which typically inhabit pubic hair. Human pubic lice are more closely related to gorilla lice than to head lice. Since this sucking louse only inhabits hairy places on the body, it might shed some light on when humans lost their heavy body hair. Crab lice are typically transferred from person to person through sexual intercourse, although they may also be picked up from infested linen, clothing and other sources. For More Information About The Origin Of Body Lice: Kittler, R., M. Kayser and M. Stoneking. 2003. "Molecular Evolution of Pediculus humanus and the Origin of Clothing." Current Biology 13: 1414 - 1417.

References: Evans, A.V. 2007. Field Guide to Insects and Spiders of North America. Sterling Publishing Co., Inc. New York, New York. Hogue, C.L. 1993. Insects of the Los Angeles Basin. Natural History Museum of Los Angeles County.

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