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I am looking for an ID of this fly at genus or preferably species level.
Location: The Netherlands.
Size: approx. 7-8mm Habitat: indoors, attic.
Timing: usually appears late winter, early spring
Apparently, this is a Pollenia sp https://forum.waarneming.nl/smf/index.php?topic=447650.0.
One of the common species from this genus, Pollenia rudis, is often found overwintering in groups in attics and is therefore known as the cluster fly or attic fly.
Bacteria of the Flies: Tracing the Spread of Disease-Controlling Wolbachia
Wolbachia, a bacterium commonly found in insects that has the potential to combat and control mosquito-borne diseases, is revealing its movement across host species to a team of researchers led by geneticists at UC Davis and the University of Melbourne.
In a study appearing in Current Biology, Michael Turelli, distinguished professor of genetics in the Department of Evolution and Ecology, and his colleagues traced the spread of closely related Wolbachia across Drosophila fly species. They found that while the flies evolutionarily diverged tens of millions of years ago, their Wolbachia bacteria diverged only tens of thousands of years ago.
The new research is helping scientists further understand the spread of Wolbachia infections, which may help control diseases spread by mosquitoes.
“If you move the Wolbachia from the model species Drosophila melanogaster into the mosquito Aedes aegypti, a common disease transmitter, those mosquitoes don’t transmit Dengue, Zika or Yellow fever,” said Turelli, who is also a member of the Center for Population Biology.
Jumping from species to species
Distinguished Professor Michael Turelli is exploring the evolutionary strategies of the bacterium Wolbachia, pictured here, and its spread among fly species. Scott O'Neill
Of the Drosophila melanogaster species group, which comprises some 190 fly species, eight species harbored a strain of Wolbachia similar to wRi, a bacteria variant that co-author Professor Ary Hoffmann, of the University of Melbourne, and Turelli first discovered in California populations of Drosophila simulans.
“This means that on an evolutionary timescale, somehow Wolbachia moves between closely and distantly related hosts,” said Turelli. “We think of biological species as being reproductively isolated, and yes, they are, but closely related species are often not completely isolated.”
Turelli said Wolbachia moved between fly species, like D. anomalata and D. pandora, almost certainly through fly interbreeding, but how the bacteria jumped between distantly related species, like D. simulans and D. ananassae, which cannot interbreed, remains a mystery. He suggested one plausible way the bacteria could spread is through parasitoids and mites, which can infect a range of host species and potentially transfer the bacteria between them.
“We’ve known that Wolbachia are pervasive, but no one had any idea how rapidly they were moving from host to host,” Turelli said. “Those fly species diverged on the order of 12 million years ago, yet they have essentially identical Wolbachia.”
Scientists are using mosquitoes infected with Wolbachia to prevent the spread of diseases, like Yellow Fever. CDC
A natural control for diseases
Wolbachia provides some benefits to its hosts. In D. melanogaster, the bacteria protects its host from naturally occurring viruses and other potentially harmful microbes.
But Wolbachia has another more significant effect. They can manipulate host reproduction through a process called cytoplasmic incompatibility. When infected females mate with either infected or uninfected males, their offspring are infected. However, when uninfected females mate with infected males, the resulting embryos often die.
In mosquitoes, cytoplasmic incompatibility leads to the death of all embryos produced when uninfected females mate with infected males. While the yellow fever mosquito, A. aegypti, doesn’t host Wolbachia naturally, Wolbachia from either Drosophila or from other mosquitoes can be introduced in the laboratory. If a virus-suppressing Wolbachia is introduced into A. aegypti, the Wolbachia-infected individuals will increase in frequency and suppress the spread of diseases like Dengue fever and Zika.
This population-transformation approach is being conducted in many countries, including Australia, Brazil and Indonesia, by the World Mosquito Program. Turelli and Hoffmann are members of the project.
In an alternative approach, only infected males are introduced into an uninfected natural population. The native uninfected females are effectively sterilized, leading to suppression of the local A. aegypti population, without pesticides. This method is being tested in Fresno County, where 20 million Wolbachia-infected mosquitoes were released last summer.
Funding for Turelli’s study of basic Wolbachia biology was provided by the National Institutes of Health.
The spotted lanternfly, Lycorma delicatula, is an invasive species to the United States, first discovered in Pennsylvania in 2014. It was originally from China and southern Asian countries such as India. It is likely to become a serious agricultural pest without natural enemies to keep populations low. It was accidentally introduced into South Korea in 2006 and has spread dramatically to become a major agricultural pest, especially for grape production.
The risk of spread in the northern US was once believed to be low due to cold winters. More recently, however, many eggs and newly hatched nymphs have survived the winter. While not yet in New York, the spotted lanternfly is on the border with Pennsylvania and if it does move into NY and become established, it has the potential to become a significant agricultural pest causing untold physical and economic damage.
Spotted lanternfly, Lycorma delicatula, adult. [Photo: Holly Raguza, Bugwood.org] Spotted lanternfly, Lycorma delicatula, adult. [Photo: Holly Raguza, Bugwood.org] This map shows documented sightings of the spotted lanternfly since it was first found through Oct. 17, 2017. (Courtesy Pennsylvania Department of Agriculture
Spotted lanternfly eggs hatch as nymphs in April and May during the early hours of the day. The black bodied nymphs go through 4 growth phases (instars) before becoming a winged adult. Instars 1-3 have white spotted black bodies, while the 4 th instar develops black and red mottling under the white spots. Adult lanternflies have grayish forewings with black spots the hind wings are red and black spotted on the lower portion and grey and black with a bold white stripe on the upper portion. Adult females are about an inch in length males are about 4/5ths of an inch. Adults are strong hoppers but weak fliers. In the fall, adults often shift to feeding the invasive Tree of Heaven (Ailanthus altissima). In late September until early winter, adults lay oothecas, or egg sacs, which house up to 30-50 brown seedlike eggs with a shiny, light orange/brown waxy coating. The egg sacs have a smooth, shiny surface. While lanternflies often lay eggs on Tree of Heaven, they will use any smooth, vertical surface including other smooth-barked trees, stones, vehicles, outdoor furniture and other manmade surfaces. Eggs in Pennsylvania overwintered successfully in 2014 once eggs hatch the waxy coating is removed, leaving parallel lines of hatched egg sacs behind.
Lanternfly female caudal View. [Photo: Lawrence Barringer, Pa Dept. of Agriculture, Bugwood.org] Lanternfly juvenile stage. [Photo: Lawrence Barringer, Pa Dept. of Agriculture, Bugwood.org] Lanternfly juvenile stage. [Photo: Lawrence Barringer, Pa Dept. of Agriculture, Bugwood.org]
Both adults and nymphs use their piercing and sucking mouthparts to eat the phloem tissue of a wide variety of plants in order to obtain nutrients. The insects also excrete a sugary fluid similar to aphid honeydew, which encourages mold and disease growth. In the native range of the spotted lanternfly, these impacts does not normally kill host plants absence of natural predators, however, can lead to overinfestaton and cause sickness and death in infested plants. Overfeeding by the lanternflies can extract a damaging percentage of the plant’s nutrients, and the dripping sap from lanternfly feeding wounds combined with sugary lanternfly excretia can lead to mold and disease damage.
Spotted lanternflies feed on over 65 species of plants, preferring plants that have high sugar content and toxic metabolites. These include many agricultural species such as fruit vines (grapes), fruit trees (apples, cherries, peaches, pears, plums) and maple trees. Ornamental plants and forestry species including dogwoods, lilacs and pines are also susceptible. The spotted lanternfly has the potential to become a serious agricultural pest and stressor on natural systems.
Honeydew secretions building up at tree base. This is a sign of heavy lanternfly infestation. [Photo: Lawrence Barringer, PA Dept. of Agriculture, Bugwood.org] Bark damage done by lanternflies. [Photo: Lawrence Barringer, PA Dept. of Agriculture, Bugwood.org]
In the spring, look for the white-spotted black-bodied nymphs and white-spotted, mottled red-and-black fourth instar nymphs feeding on any of the wide variety of host species, both woody and non-woody. In the summer, adults are visible while feeding. Indicators of lanternfly damage are seeping sap wounds on non-woody and woody species, and patches of blackened soil around the plant base. Other insects and molds are also attracted by the sugary secretions caused by the sap and honey dew, including ants, bees and wasps. In the fall, brownish egg sacs can be seen plastered to tree trunks (especially Tree of Heaven) or other smooth surfaces such as stones, vehicles, farm equipment or outdoor furniture.
Lanternfly egg mass. [Photo: Holly Raguza, Bugwood.org]
Spotted lanternfly management will vary based on whether the insect is found inside or outside existing quarantine areas. To date, several towns in Pennsylvania including District, Earl, Hereford, Pike, Rockland and Washington and the boroughs of Bally and Bechtelsville are under quarantine. Quarantine areas may expand if the spotted lanternfly is found elsewhere in the US.
Egg sacs should be scraped off the host surface, soaked in alcohol or hand sanitizer and thrown away.
Catherine A. Hill and John F. MacDonald, Department of Entomology
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Horse and deer flies are annoying biting pests of wildlife, livestock, and humans. Their blood sucking habits also raise concerns about possible transmission of disease agents. You are encouraged to learn more about the biology of horse and deer flies to avoid being bitten and to understand the public health risk posed by these insects.
Are Horse and Deer Flies Public Health Risks?
The bites of female horse and deer flies are painful and, if numerous enough, can disrupt recreational activities and even the harvesting of some agricultural crops. Their mouthparts include two pairs of cutting “blades” that lacerate skin and cause flow of blood out of the wound, which females lap up with a sponge-like mouthpart. Males have similar, but much weaker mouthparts. They are not capable of biting and do not feed on blood.
The blood sucking behavior of females together with their possible role in the transmission of disease agents have been studied extensively. Numerous viruses, bacteria, and protozoa have been isolated from the bloody, sponge-like mouthpart of females and from their digestive system, but there are no studies showing conclusively that they are capable of transmitting disease agents to humans, with one exception. There is evidence that a deer fly in the western U.S. is involved in the transmission of a bacterium that causes the disease “tularemia,” which also is known as “deer fly fever” and “rabbit fever.” The role of deer flies in transmission is minor, however, compared to transmission by ticks and via contact with infected small game animals, especially rabbits.
How Many Types of Horse and Deer Flies Are There?
Horse and deer flies are “true” flies in the insect Order Diptera, and comprise the Family Tabanidae known as “tabanid flies” or “tabanids.” There are an estimated 4, 300 species of horse and deer flies in the world, approximately 335 of which occur in the continental U. S. Of these, over 160 species are horse flies, and over 110 species are deer flies. It is estimated that at least 45 species of horse flies and 30 species of deer flies occur in Indiana. The vast majority of horse flies are in two genera, Tabanus and Hybomitra. Nearly all deer flies are in the genus Chrysops.
How Can I Recognize a Horse Fly or Deer Fly?
Adult horse flies (Fig. 1) and deer flies (Fig. 2) are relatively large to very large (approximately 0.25 to 1.25 inches long), robust flies with a pair of huge eyes known as “compound eyes.” Those of some horse flies have colorful purple or green bands against a blue or yellowish-green background. The mouthparts are large and prominent, projecting downward and forward in front of the head. They have large, fan-shaped wings and are capable of rapid flight and flying long distances.
Figure 1. A horsefly, Tabanus sp. (Diptera: Tabanidae), adult female. (Photo by: Drees, Univ. of Texas)
Figure 2. A deer fly, Chrysops sp. (Diptera: Tabanidae), adult female. (Photo by: Drees, Univ. of Texas)
What Is the Life Cycle of Horse and Deer Flies in Indiana?
Similar to all flies, horse and deer flies develop from egg to adult via a process of “complete metamorphosis.” This means the last larval stage passes through a non-feeding pupal stage, from which the adult eventually emerges.
The summarized life cycle of horse flies (Fig. 3) and deer flies (Fig. 4) begins with the emergence of adults from late spring into summer, depending on the species. Upon becoming active, adults of both sexes feed on energy-rich sugars in nectar, plant sap, or honey dew produced by sap-sucking insects such as aphids and scale insects. Mating of the few species that have been observed takes place in flight. Females of some species are capable of developing an initial batch of eggs without taking a blood meal, otherwise blood is required for the development of eggs. Females search for a place to lay a single mass of eggs consisting of 100-800 eggs, depending on species. Egg masses of most species that have been studied are laid on the underside of leaves or along the stems of emergent vegetation growing in wetlands. Hatching occurs in approximately 2-3 days, and newly emerged larvae drop down into water or saturated soil in which they feed and develop.
Figure 3. Summarized life cycle of horse flies. (Drawing credit: Scott Charlesworth, Purdue University, based in part on Pechuman, L.L. and H.J. Teskey, 1981, IN: Manual of Nearctic Diptera, Volume 1)
Figure 4. Summarized life cycle of deer flies. (Drawing credit: Scott Charlesworth, Purdue University, based in part on Pechuman, L.L. and H.J. Teskey, 1981, IN: Manual of Nearctic Diptera, Volume 1
The sites in which horse and deer fly larvae develop are known for only about a third of the species in the U. S. Deer fly larvae appear to be limited to aquatic habitats, including marshes, ponds, and streams. Developmental sites of horse fly larvae are more varied. Larvae of most species are found in freshwater and saltwater marshes, some in streams, some in moist forest soils, and a few in moist decomposing wood. Larvae of all species of horse flies that have been studied are predators. They feed primarily on other soft-bodied animals such as insect larvae and worms, but larvae of some large species of horse flies feed on small vertebrates, including tadpoles, frogs, and toads. Horse fly larvae appear to possess a toxin in their saliva that is involved in subduing their prey. Much less is known about the feeding behavior of deer fly larvae, and there is no consensus as to whether they are predators or scavengers.
The larval stages of horse and deer flies range in number from 6-13. The last larval stage passes winter in the site in which it developed and molts into a pupa the following spring. Most species complete one generation per year. However, small species of deer flies can complete 2-3 generations per year and very large species of horse flies require 2-3 years in which to complete larval development.
What Should I Know About the Feeding Behavior of Adult Horse and Deer Flies?
Only females take a blood meal, and, with rare exception, they feed during the daytime. Unlike numerous other groups of blood sucking flies, female horse and deer flies do not enter structures and thus do not feed on humans indoors. Female horse flies feed primarily on large mammals, including stationary hosts, and they typically bite the legs and body, rarely on the head. Although there are species of horse flies that feed on humans, Indiana species rarely do. In contrast to horse flies, female deer flies typically feed on moving hosts and usually bite on the shoulders and head. They have a wide host range, attacking mammals of all sizes, including humans, and some species feed on birds and reptiles. Females of both horse and deer flies are aggressive, persistent feeders that quickly return to bite again if they are interrupted before they take a complete blood meal.
Similar to other blood sucking insects, female horse and deer flies respond to chemical and visual cues associated with a potential host. Carbon dioxide given off by warm-blooded animals provides a long-range cue, attracting females into the vicinity of a host. There, visual cues such as motion, size, shape, and dark color serve as attractants. Female horse and deer flies are deterred very little by repellents, including DEET, and humans entering infested areas have little protection against them.
How Do Humans Influence Horse and Deer Fly Development?
Humans generally do not influence horse and deer fly development because habitats that support larval development are “natural,” including freshwater wetlands, saltwater marshes, and open areas within forests. However, there is one type of habitat associated with human activity that can be a source of horse flies. Larvae and pupae of a few species are able to complete development in low areas of pastures or cultivated fields that support standing water or at least consist of heavily saturated soils.
Are There Effective Methods of Controlling Horse and Deer Flies?
Controlling horse and deer flies is nearly impossible. The use of insecticides to kill larvae is not an option because the vast majority of species develop in natural habitats in which insecticides cannot be applied due to environmental concerns. Even if they could be used, insecticides would be ineffective in controlling larvae because they are widely dispersed in a developmental site. The use of insecticides against adult horse and deer flies is not a realistic option because they are relatively large to very large and unaffected by the rate of insecticide that can be applied according to product label. At best, an insecticide application aimed at adults might produce a minor and temporary reduction in biting. A number of trapping devices have been used to capture adults, but their value is limited to sampling. At best, trapping devices produce temporary, minor relief from female horse flies.
Again, repellents, including those containing DEET, have very little or no effect in deterring adult horse and deer flies. Wearing a thick long sleeve shirt, thick pants, and a heavy hat may provide some protection against bites when entering habitats that support large numbers of adult horse and deer flies, but females can be very annoying as they attempt to take blood meals.
Where Can I Find More Information About Horse and Deer Flies?
There is surprisingly little information about horse and deer flies on university and governmental Web sites. There is, however, a recent textbook (2002) by G. Mullen and L. Durden, Medical and Veterinary Entomology, that includes an excellent chapter devoted to horse and deer flies, covering biology, behavior, and medical and veterinary risk. It also includes a section that evaluates various methods used in attempts to control horse and deer flies.
READ AND FOLLOW ALL LABEL INSTRUCTIONS. THIS INCLUDES DIRECTIONS FOR USE, PRECAUTIONARY STATEMENTS (HAZARDS TO HUMANS, DOMESTIC ANIMALS, AND ENDANGERED SPECIES), ENVIRONMENTAL HAZARDS, RATES OF APPLICATION, NUMBER OF APPLICATIONS, REENTRY INTERVALS, HARVEST RESTRICTIONS, STORAGE AND DISPOSAL, AND ANY SPECIFIC WARNINGS AND/OR PRECAUTIONS FOR SAFE HANDLING OF THE PESTICIDE.
It is the policy of the Purdue University Cooperative Extension Service that all persons have equal opportunity and access to its educational programs, services, activities, and facilities without regard to race, religion, color, sex, age, national origin or ancestry, marital status, parental status, sexual orientation, disability or status as a veteran. Purdue University is an Affirmative Action institution. This material may be available in alternative formats.
This work is supported in part by Extension Implementation Grant 2017-70006-27140/ IND011460G4-1013877 from the USDA National Institute of Food and Agriculture.
How flies are flirting on the fly
Valentine’s Day is traditionally a day to let someone know you’re interested in them, often with a card or bunch of roses. But how would you go about this if you were a fly? Research published today in BMC Biology reveals a previously unrecognized mate recognition system where female flies dazzle potential suitors with light flashes from their wings.
Sexual communication signals are relied upon by mate-seeking animals to facilitate mate encounters. These signals come in diverse forms such as visual, olfactory and acoustic, with different species using specific signals or specific combinations.
A study published today in BMC Biology finds a previously unrecognized visual mate recognition system in common green bottle flies Lucilia sericata. By video-recording wing movements, researchers found that with each wing-beat a single flash of light is reflected.
Male common green bottle flies appear to be able to detect the frequency of these flashes and are strongly attracted to a wing-flash frequency of 178Hz, a characteristic of free flying young female flies.
In the eye of the beholder
The compound eyes of flies play a key role not only in flight, but also in mate recognition.
With females ‘flirting’ with these wing-flash signals how are males expected to pick up on them?
Flies have some of the most advanced visual systems among insects. The fast visual processing that they are capable of is thought to be an adaptation that evolved to support their advanced flight abilities.
There is also sexual dimorphism, with males having larger eyes that feature ‘bright zones’ to help capture light. This would allow males to better detect the wing flashes of female flies, suggesting that the compound eyes of flies play a key role not only in flight, but also in mate recognition.
Examining the attraction
Researchers recorded wing movements of abdomen-mounted flies at 15,000 frames per second under direct light which revealed the wing flashes. They then went on to record flies in free flight, placing 50 young or old male flies or 50 young or old female flies in a wire mesh cage. They found the young females to have a wing-flash frequency of 178Hz, significantly lower than young males (212Hz), old females (235Hz) or old males (265Hz).
To test if these flashes contributed to mate recognition and if male flies are attracted to the visual wing-flash of young females, researchers mounted two live females with immobilized wings to aluminum T bars and illuminated each female with LEDs. One emitted light at the flash frequency of a free flying female whilst the other produced constant light. When these were placed in a cage containing 50 males, the males alighted towards the female with a flashing light significantly more times.
The sphere flashing at 178Hz received significantly more alighting responses from males than any other frequency.
This experiment was then repeated but with a live male fly illuminated by the flashing LED to eliminate the phenotypic effects of female flies. The male flies still alighted with the fly exposed to the pulsing light.
The researchers also ran the experiment with spheres containing LEDs replacing the female flies. This would isolate the light flash effects as a test variable. The sphere flashing at 178Hz received significantly more alighting responses from males than any other frequency.
Sunshine of your love
During the study, the researchers found that under diffuse light and when photographs of the flies were taken outside on a cloudy day, the light reflections on the wings were not evident. This finding fits with the low mating propensity of common green bottle flies on cloudy days where direct illumination from the sun becomes diffuse, reducing the wing-flash effect. This indicates that the sexual communication of these flies is synchronized with environmental conditions to optimize the communication signals.
The findings of this study demonstrate a previously unrecognized visual mate recognition system in common green bottle flies that suggests that the advanced visual systems of flies support both agile flying and mate recognition. It could well be that this form of mate recognition occurs in other insects, this could pave the way for potential applications such as optimized light traps to capture nuisance insects.
But for now, the next time you see flies buzzing about in the sunshine, before reaching for a fly swat, spare a thought, they may just be looking for love.
A syrphid fly, (Diptera: Syrphidae), adult. Photo by Drees.
Common Name: Syrphid fly, hover fly, flower fly
Scientific Name: Varies
Description: This is a large group of medium to large flies, ranging from 1/4 to 3/4 inch long. Most adult hover flies are black or brown with yellow banded abdomens and body markings, superficially resembling bees and wasps except that they have only two wings that are not held over the back of the body when at rest. Some species are hairy and have a long, thin abdomen. Antennae are short (not elbowed) and the last segment bears a strong hair (seta). Larvae of most species are legless spindle-shaped maggots and vary in color from creamy-white to green or brown.
Hover flies can be distinguished from other groups of similar flies by studying the wing venation: they have a isolated (spurious) vein in the wing between the third (radius) and the fourth (media) longitudinal veins.
A syrphid fly, (Diptera: Syrphidae), maggot preying on yellow pecan aphid. Photo by Drees.
Life Cycle: Biology and developmental times vary between species and because of environmental conditions and availability of food. In general, females lay single white eggs on leaves near aphid infestations or near other suitable food source for that species. Larvae or maggots hatch from eggs in about 3 days. Larvae develop through several stages (instars) over a period of 2 to 3 weeks before pupating, either on the host plant or in the soil. The skin of the last stage larva forms the tan-brown teardrop shaped puparium. Adults emerge in one to two weeks unless the pupal stage remains through the winter. Up to seven generations occur annually.
Habitat and Food Source(s): Larvae have chewing (teasing) mouthparts adults have sponge-type mouthparts similar to house flies. Adult flies can be found hovering around flowers, feeding on nectar and pollen. They are often attracted to honeydew covered leaves characteristic of infestations of sucking insects such as aphids. Legless larvae of these (Syrphinae) species are slug-like, adhering to leaf surfaces of infested plants while searching for aphids and other suitable prey (small caterpillars, thrips, etc.). Each larva can consume up to 400 aphids during development. Larvae of other species feed in the nests of ants, termites or bees, and others live in decaying vegetation and wood. One group, Eristalis spp., are called rattailed maggots because of an unusually long breathing tube from the back of their bodies used to breath as they dwell in highly polluted water. Adults of this genus resemble bees and are known as drone flies. Larvae of a few species feed on live plants. Larvae and pupae can be found by inspecting aphid-infested plants or searching through other suitable habitats (e.g., decaying wood, algal mats).
Pest Status: Generally considered beneficial because the larval stages of many species are predaceous on insect pests such as aphids and adults pollinate flowers medically harmless adults and larvae of most species larvae of one group of syrphid flies, called “rattailed maggots,” can survive in human digestive tracts.
For additional information, contact your local Texas A&M AgriLife Extension Service agent or search for other state Extension offices.
Origin of Species
Macroevolution is evolution over geologic time above the level of the species. One of the main topics in macroevolution is how new species arise. The process by which a new species evolves is called speciation. How does speciation occur? How does one species evolve into two or more new species?
To understand how a new species forms, it&rsquos important to review what a species is. A species is a group of organisms that can breed and produce fertile offspring together in nature. For a new species to arise, some members of a species must become reproductively isolated from the rest of the species. This means they can no longer interbreed with other members of the species. How does this happen? Usually they become geographically isolated first.
Assume that some members of a species become geographically separated from the rest of the species. If they remain separated long enough, they may evolve genetic differences. If the differences prevent them from interbreeding with members of the original species, they have evolved into a new species. Speciation that occurs in this way is called allopatric speciation. An example is described in the Figure below.
Allopatric Speciation in the Kaibab Squirrel. The Kaibab squirrel is in the process of becoming a new species.
Less often, a new species arises without geographic separation. This is called sympatric speciation. The following example shows one way this can occur.
- Hawthorn flies lay eggs in hawthorn trees (see Figurebelow). The eggs hatch into larvae that feed on hawthorn fruits. Both the flies and trees are native to the U.S.
- Apple trees were introduced to the U.S. and often grow near hawthorn trees. Some hawthorn flies started to lay eggs in nearby apple trees. When the eggs hatched, the larvae fed on apples.
- Over time, the two fly populations&mdashthose that fed on hawthorn trees and those that preferred apple trees&mdashevolved reproductive isolation. Now they are reproductively isolated because they breed at different times. Their breeding season matches the season when the apple or hawthorn fruits mature.
- Because they rarely interbreed, the two populations of flies are evolving other genetic differences. They appear to be in the process of becoming separate species.
Sympatric Speciation in Hawthorn Flies. Hawthorn flies are diverging from one species into two. As this example shows, behaviors as well as physical traits may evolve and lead to speciation.
Species of Trypanosoma | Microbiology
The following points highlight the four important species of Trypanosoma for which man is host. The species are: 1. Trypanosoma Gambiense 2. Trypanosoma Rhodesiense 3. Trypanosoma Cruzi 4. Trypanosoma Rangeli.
Species # 1. Trypanosoma Gambiense:
It was discovered by Forde in 1901. Sir David Bruce reported that sleeping sickness is transmitted by tseitseily. T. gambiense is the causative agent of African sleeping sickness or Gambian trypanosomiasis. This species is confined to West and Central parts of Africa, particularly Nigeria and Congo.
T. gambiense in the blood of man is long and slender. It measures about 25 x 2 um with a flagellum. The parasite multiply by longitudinal binary fission. It migrates through the body by way of blood. Normal habitats are the blood plasma, cerebrospinal fluid, lymph nodes and spleen.
The chief vector hose which transmits the trypanosome from one man to another is the tse tse fly, Glossina palpalis, which bites man and feeds on his blood. Occasionally, Glossina tachinoides also acts as a vector. Domestic and wild animals like buffaloes, pig, antelopes and reed bucks serve as reservoir or temporary hosts.
There is no developmental cycle in these hosts, but simply waits for its introduction into the man. Tse tse fly is a common ectoparasite of both principal host and reservoir hosts. In the intestine of tse tse fly, Trypanosoma reproduces and forms both epimastigotes and trypomastigotes.
After two weeks or more in the gut of the fly the flagellates migrate to salivary glands where they become attached to the epithelium and develop into infective slender trypanosome forms, known as metacyclic forms.
By the bite, tse tse fly inoculates trypanosomes into human blood. In addition to development in blood, parasite migrate to other parts. Chronic form of Gambien sleeping sickness primarily involves the nervous system and the lymphatic system. After an incubation period of one or two weeks, fever, chills, headache and loss of appetite occur.
As time goes on, enlargement of the spleen, liver and lymph nodes occurs, accompanied by weakness, skin eruptions, disturbed vision and reduced pulse rate. As the nervous system is invaded by the parasites, the symptoms include weakness, apathy, headache and definite signs of “sleeping sickness”. A patient readily falls asleep at almost any time. In advanced stage the patient falls in coma. Death is always the ultimate fate.
Sometimes congenital infection occurs through the damaged placenta of mother. The infection may also be transmitted through the mother’s milk. The parasite may also enter through the mucous membrane of the upper part of the alimentary canal.
Gambian trypanosomiasis can be treated successfully during early stages before the parasite invade cerebrospinal fluid. The drugs effective in the early stages are Atoxyl, Bayer 205, Suramin sodium, Antripol, Germanin, Tryparsamide, arsenic and antimony compounds. Pentamidine, Lomidine, butyric acid and Parsenophenyl are useful for prevention and treatment of human infection. If the central nervous system is affected by infection, Orsanine is quite effective. Melarsen oxide is quick in action without side effects. If proper treatment is not given to the patient, it will result in death.
1. Destruction of tse tse flies.
2. Reduce contacts between tse tse fly and human population.
3. Transmission should be checked.
4. Spraying of DDT over bushy areas in the vicinity of villages to control tse tse flies.
5. Sanitary conditions should be improved.
6. Susceptible persons should take injection of Suramin (dose 1 grm.) every two or three months.
Species # 2. Trypanosoma Rhodesiense:
It is closely related to T. gambiense. It is identical in appearance and has the same type of life cycle, but it also occurs in antelope and cattle. It is the causative agent of Rhodesian trypanosomiasis. This species is confined to East and Central parts of Africa, particularly Rhodesia. The insect vectors are tse tse flies mainly Glossina morsitans and G. pallidipes.
T. rhodesiense cause the Rhodesian sleeping sickness. As compared to Gambien type, this is acute and more rapid type of human sleeping sickness. This disease usually results in death within a year. The incidence of infection is less than that with T. gambiense. The parasite is restricted to a much more limited area. Willett (1965) consider T. rhodesiense as a virulent type of T. gambiense.
Species # 3. Trypanosoma Cruzi:
This species is the causative agent of South American trypanosomiasis or Chaga’s disease. The adult flagellate lives in the blood and reticuloendothelial tissues of man, monkey, dog, cat, rat armadillos, opossum and other mammals. Within the mammalian host T. cruzi enters tissue cells especially muscle and glia and changes to amastigote forms (rounded, no external flagellum), that multiply rapidly.
Amastigotes develop into promastigote and epimastigote stages and finally to trypomastigote forms. They destroy the host cell and enter the blood and lymphatic vessels. Multiplication does not occur in the blood stream.
T. cruzi is transmitted by bugs of the family Reduviidate. The common vector bug in Brazil is Panslrongylus megistus. With a meal of blood the trypanosomes are taken to the posterior part of gut of bug. There they develop into amastigote forms with a short flagellum. These are spheromastigotes. They are infective stages to man.
When a man is bitten by a bug, the insect usually defaecates and thus deposits the infective metacyclic forms on the skin. Parasite enter the body by penetrating through skin. Animals and man are sometimes infected by eating bugs or bug faeces or by eating other infected animals.
Chaga’s disease is found mainly in Central and South America, and is more common in children. At least seven million people have the disease. Symptoms of Chaga’s disease are varied. Mostly the bug bites the area of eye especially in children. The eye becomes puffy and is often closed. Both eyes and even the whole face may become involved.
As parasite invade body organs, enlargements of the spleen, lymph nodes and liver occur with head aches, fever and anemia. In serious condition, enlargement of oesophages and colon occur. The heart, urinary bladder muscles, striated muscles and nervous system may also be affected. Intramuscular forms are mostly amastigote stages. Anemia and injury to heart muscles lead to death.
There is no permanent cure of Chaga’s disease. Primaquine and Puromycin are used for temporary relief.
1. Destruction of vector bugs.
2. Reduce contacts between bug and human population.
3. Man should prevent themselves from contamination.
Species # 4. Trypanosoma Rangeli:
It occurs in man, monkeys, dogs and possibly opossums in Central and South America. The insect vector is the triatomid bug, Rhodnius prolixus. It transmits the flagellate during the act of biting the host, through saliva. In the vertebrate host, the parasite multiplies only in the trypomastigote stage. It is nonpathogenic to vertebrates, but damages it’s insect hosts.
What species is this fly? - Biology
Mole cricket damage is primarily mechanical: tunneling through the soil near the surface,
severing the roots and uprooting the grass.
Mole crickets spend most of their lives underground. The types of soils that they occupy depend upon the species in question, though light soils are easier for them to dig into, such as sandy soils, heavier soils that are made friable by cultivation, and mud. Their front legs are strong and adapted for digging, and they can dig into light soils remarkably rapidly. Their digging action is called tunneling, but they make three kinds of cavities in the ground. Tunnels are the deeper mines they make in the ground. Galleries are the horizontal mines made just below the soil surface, causing the soil to bulge upward above the surface. The third kind of cavity is the egg chamber made by females.
Galleries are made mainly at night, apparently as the mole crickets are foraging in search of food, just below the soil surface. Galleries made in sandy soils are collapsed by rain. Heavy rains clear sandy areas of galleries, so that galleries appearing after a heavy rain are evidence of fresh mole cricket activity. Galleries in golf course greens are viewed as damage by golfers because these galleries can deflect the roll of a putted golf ball.
Mole crickets deposit their eggs in chambers hollowed out in the soil. Most chambers are found 4 to 12 inches below the soil surface, and are about the size of a golf ball. When a female mole cricket excavates a chamber, she lays one clutch of eggs in it. The number of eggs in the clutch varies among species, and varies with the physiological condition of individual females. When eggs have been laid in a chamber by a Neoscapteriscus mole cricket, the mother does not revisit it, and the entrance to the chamber closes. However, Gryllotalpa females revisit the chamber many times and take care of the eggs and hatchlings.
Mole cricket eggs in chamber. The two large dots on each egg are the eyes of the maturing first instar nymph. The two smaller dots are the mandibles.
Hatching and Development
So far as is known, mole cricket eggs of the 10 species mentioned in this knowledgebase incubate for about three weeks. Eggs take longer to incubate if they are subjected to a period of lower temperature. Mole cricket nymphs then hatch from the eggs. Nymphs look like adults but are very much smaller and they lack wings. It takes the nymphs many weeks of feeding and growing before they reach adult size, and they molt six to eight times as they grow.
Mole cricket hatchlings (first instar nymphs).
Life History and Seasonality
The month or months in which mole cricket eggs are laid varies among species and varies with latitude, and the same is true of the length of time that it takes mole cricket nymphs to develop. Some latitudinal variation is to be expected. For example, if the oviposition period of a mole cricket species is April–May in Florida, it is likely to be May–June in North Carolina, and October–November for the same species in northern Argentina, where seasons are six months out of phase. If the same mole cricket species occurs at intermediate latitudes, its oviposition period there may differ again. For these reasons, seasonality of mole crickets is described below for particular places, and it should not be expected that the seasonality will be identical at distant places.
Effects of Temperature and Moisture
Mole crickets are cold-blooded. They cannot move at freezing temperatures, so must remain dormant underground. The temperature must be still higher before they can fly.
Neoscapteriscus mole crickets caused problems first in Florida and Georgia because those are the states where they arrived first. Southern and tawny mole cricket populations continue to spread north and west, though spread of shortwinged mole cricket populations has not been noted. Colder temperatures ultimately will limit the spread of southern and tawny mole crickets to the north. There is no evidence that they will not spread farther west, though arid conditions may hinder them. In drought, mole crickets risk desiccation and seek moister locations or moister conditions deeper in the soil. They dig to the surface of flooded soil and move to higher ground.
Wings, Flight, and Songs of Mole Crickets
Typically, adult mole crickets have wings and can fly. However, in some species such as the shortwinged mole cricket, the wings grow only to a small size, not nearly big enough for flight. In other species, such as the northern mole cricket, adults in some geographic areas do not develop large wings and cannot fly, though in other areas most or all of the adults develop full-sized wings. Mole cricket nymphs are wingless, but the larger nymphs have wing buds that will develop into wings at the final molt to the adult phase.
It may be that most flights by mole crickets are short, but a flight of 5 miles by a paint-marked mole cricket has been recorded. Furthermore, mole crickets arrived at lights on a fishing boat many miles off Florida’s east coast one night in March 1992, according to Harold Jones, Duval County extension agent, but the species of mole cricket and exact location were not recorded.
Mole crickets fly at night. Flights begin soon after sunset and end after little more than an hour in both the tawny mole cricket and southern mole cricket. They fly clumsily, though they dig very well in sandy soils. The body is covered by a dense mat of short setae, which seems to trap a layer of air around the body when a mole cricket is in water. Consequently, mole crickets are buoyant, not easily wetted, and they can swim well enough to reach the shore if they fall or land accidentally in canals and rivers.
Adult mole crickets have two pairs of wings (forewings and hind wings). Wings are covered by a network of veins that are tough tubes supporting the wing membranes. Spaces between the veins are called cells. Forewings of males and females differ slightly. Forewings of the males have a pair of large cells, the anterior of which has been described as harp-shaped. In fact it is shaped like a tiny outline map of Florida. The two cells together are called the stridulatory area. Females lack such large cells.
In males, one of the veins on each wing is modified with a line of tiny teeth to form a stridulatory file. This file is drawn across a scraper on the other wing as the wings close, and this makes a noise. Males make this noise — song — by opening and closing the wings. They amplify the song by widening the mouth of their gallery into a funnel shape, much like the speaker of a radio. The arrangement of the teeth in the stridulatory file differs from species to species, so the song differs from species to species. Males open and close the wings many times in rapid succession to sing, but sound is produced only as they close. Females do not sing. The songs are species-specific and unvarying. Tawny and southern mole cricket songs are continuous trills that differ in tone (carrier frequency, measured in kHz) and pulse rate (pulses/second). The song of the southern mole cricket is 2.7 kHz and 50 pulses/second, whereas that of the tawny mole cricket is 3.3 kHz and 130 pulses/second. The loudness of the songs varies but is typically about 70 dB at 15 cm from the source. The hearing organs of mole crickets are on the tibiae of the front legs.
Attraction of Mole Crickets to Mole Cricket Song
Mole cricket males of most species sing to attract females of the same species. The UF/IFAS mole cricket program contracted with an electronics specialist to design sound emitters that synthesize these songs and are powered by a 12-volt battery. The emitters, now produced by a small electronics company, will play either of the two songs, and the volume is adjustable. When played at 105 dB, the emitter is much more attractive to mole crickets than when played at 70 dB. Females and some males sometimes are attracted in large numbers to the synthetic song of their own species.
Attraction of Mole Crickets to Light
Winged, adult insects of many species fly at night. A lot, but not all, are attracted to incandescent and fluorescent light. Moths flying around a porch light are a familiar sight. Mole crickets likewise fly at night and are attracted to fluorescent lights at gasoline stations and to floodlights on tennis courts. In general, the brighter the light, the more attractive it is. Investigation has shown that attractiveness of light for insects of various species varies by wavelength. Ultraviolet light is especially attractive for many insects. The wavelength most attractive for Neoscapteriscus mole crickets has not been investigated.
How Far Will A Mole Cricket Travel?
People who enjoy running may run 5 miles daily, whereas marathon runners may run farther, and some people do not run at all. We could estimate an average distance run daily for all members of a human population of a city by asking all the people to complete a survey form, tabulating the answers of those who bothered to complete the form and calculating the result. The resulting average, perhaps 0.25 mile, would not be very useful and would not be entirely accurate because some people did not bother to complete the form. The variance might be more interesting, for example, knowledge that 90 percent of the people who replied did not run at all and 0.05% ran 10 miles. If we had asked the right questions we might also find that none of the very young or very old ran 10 miles, that weather too hot or too wet made a difference, and that sick people did not run or only made a token effort.
We cannot easily do this same exercise for mole crickets because mole crickets do not complete survey forms. If we had plenty of funds, we could have hired several people to carry out a lengthy series of experiments over several years to gain the answers, but such funds have never been available. What we do know is that mole crickets cannot fly if the weather is too cold because their flight muscles will not work. We also know that when the air is very dry they tunnel into the soil to find moisture, so will not fly. By definition, they will not fly if they are too sick. It is likely that mole crickets younger than a certain age will not fly, much less likely that age alone will inhibit them from flight, but extremely likely that reproductive status will influence flight. They fly at night, especially in the early hours of the night, and the amount of moonlight probably makes a difference, as it seems to do so for nocturnally flying insects of numerous species.
The average distance flown, which we do not know, probably would be no more useful than the average distance run by a human population. The influence of previous flights is not clear: if a mole cricket flew last night, is it less or more likely to fly again tonight? We are left with extreme measurements: (a) on one occasion a marked mole cricket was captured in a trap 5 miles from the point where it was released, and (b) that mole crickets have turned up at lights on fishing boats at sea, dozens of miles from shore. These extreme measurements cannot be taken as typical. Perhaps mole crickets that happen to venture over the sea may be reluctant to touch down until they sense land below, so these may keep going until they drop from exhaustion.
The distance tunneled by mole crickets also is problematic. All we can say is that galleries of over 20 feet in total length have been found on the surface of sand without vegetation, and each of these 20 foot galleries appeared to have been made by one adult mole cricket. We suspect that these galleries would have been shorter if the sand had been vegetated, because the vegetation might have provided food and might have interfered mechanically with their tunneling activity.
Mole crickets are not strict vegetarians. Dissection of their guts to reveal the contents has shown that southern mole crickets feed largely on a diet of insects and other soil-inhabiting animals, and only to a slight extent on plants — perhaps when animal material is in short supply. In contrast, tawny and shortwinged mole crickets feed largely on plant material, and only to a slight extent on insects and other animals. Relatively very little damage is caused to plants by southern mole crickets as a consequence of this diet.
Since 1978, concentrated research has been conducted by University of Florida researchers in the following areas: basic research on life cycles, behavior, ecology, sampling methods, physiology, biochemistry, and taxonomy, biological control, resistant grass varieties, and chemical control.
There are no open-source textbooks to introduce sand flies to a wider audience. The following documents are recommended:
Maroli M, Feliciangeli MD, Bichaud L, Charrel RN, Gradoni L. Phlebotomine sand flies and the spreading of leishmaniases and other diseases of public health concern. Medical and Veterinary Entomology. 2013 Jun27(2):123-47.
Ready PD. Biology of phlebotomine sand flies as vectors of disease agents. Annual Review of Entomology, Vol 58. 2013 201358:227-50. doi: 10.1146/annurev-ento-120811-153557
Dvorak V, Shaw J, Volf P. Parasite biology: the vector. In: F Bruchi, L Gradoni, eds. The Leishmaniases: old neglected tropical diseases. Cham, Switzerland: Springer 2018. pp. 31-76. ISBN: 978-3-319-72385-3.