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Pigeon Fly

Figure 1-2: Dorsal and Ventral images of the Pigeon fly (Pseudolynchia canariensis) Image Credit: Leshon Lee


Name

Binomial name: Pseudopynchia canariensis (Macquart, 1840)

Vernacular name: Pigeon fly

Synonyms: Lynchia simillima Speiser, 1904  

Olfersia capensis Bigot, 1885      

Olfersia exornata Speiser, 1900

Olfersia falcinelli Rondani, 1879

Olfersia lividicolor Bigot, 1885   

Olfersia maura Bigot, 1885         

Olfersia rufipes Macquart, 1847

Olfersia testacea Macquart, 1843

Classification

Kingdom: Animalia

Phylum: Arhtropoda

Class: Insecta

Order: Diptera

Family: Hippoboscidae

Genus: Pseudolynchia

Species: canariensis


Figure 3: Video of 3 Pigeon flies on a male Pink Necked Green Pigeon (Treron vernans). Video Credits: Chiu Sein Chiong


Introduction

Pseudolynchia canariensis (Macquart, 1840), commonly known as a Pigeon Fly is a biting fly in the family Hippoboscidae. Like most flies from the family Hippoboscidae, the Pigeon Fly specifically parasitizes on birds from the family Columbidae, such as pigeons and doves, thus its common name.


Distribution

Pigeon flies are found is most part of the world (mainly subtropical and tropical) where pigeons can be found. Areas include Africa, Mediterranean Sub-region, Afghanistan, India, Bangladesh, Nepal, Taiwan, and across Southeast Asia.


Identification

    

Figures 4-8: Illustrations of  a Pigeon fly and its morphology. Image Credit: Smithsonian National Museum of Natural History, Department of Entomology.1

Pigeon flies are brown and dorsoventrally flattened. This allows the fly to hide in between the feathers of its hosts to avoid detection.  Additionally, it has a hard exoskeleton which makes it more difficult for the birds to crush the flies using their beaks when preening.


Life cycle

Pigeon flies  have a very unique life cycle. Unlike most flies, they “gives birth” to its offspring instead of laying eggs. A single egg will hatch inside the fly’s uterus and feed on the mother’s “milk glands”. After the larva forms a prepupa or a puparium, the mother will “give birth” to it. Shortly after leaving the mother’s body, it will harden to form a pupa. Finally, it will undergo complete metamorphosis and emerge as a young adult.

Disease Vector

Pigeon flies have been known to be a carrier of Haemoproteus columbae, the protozoan that causes pigeon malaria.

Figure 9: General life cycle of Haemoproteus. Picture credit: ???

Pigeons will be infected when bitten by a Pigeon fly that carries Haemoproteus columbae. The sporozoites from the saliva of the fly enters the blood stream and invade the endothelial cells of the blood vessels of the lungs, liver and spleen. They then congregate to form schizonts. Each schizont will multiply to form 15 or more small, unpigmented bodies known as cytomeres, each with a single nucleus. Each cytomere grows still further, and its nucleus undergoes multiple fission. Eventually, the host cell becomes considerably hypertrophied (enlarged) and is filled with a number of multinucleate cytomeres. The endothelial cells break down, releasing the cytomeres, which accumulate in the capillaries, ocassionally resulting in complete blockage. They are irregularly shaped and tortuous, and may send out branches along the capillaries, becoming bifurcate, trifurcate or even multiradiate. Each cytomere produces an enormous number of merozoites, which infects the ethyrocytes (Red blood cells) of the pigeon and develop into gametocytes.2 Another Pigeon fly may feed of the infected bird's blood, resulting in the Pigeon fly being a vector. The gametocytes will then continue its life cycle in the midgut of the fly by maturing and sexually reproducing to form an encapsuled zygote known as an oocyst. The oocyst will rupture and infect the salivary glands of the pigeon fly, ready to infect its next pigeon host.

Phoresy

Phoresy is a type of commensalism where one species hitches a ride on another species to ensure its dispersal. Pigeon flies have a phoretic association with mite species, such as Myialges spp. and Ornitocheyletia hallae volgin, and amblyceran and ischnoceran lice. This allows the mites and lice to be dispersed throughout a wide range of pigeons. This is especially important for these parasites as the hosts will eventually die, thus the Pigeon fly is an escape route for them to travel to another host to propagate and survive to pass on its genes to the next generation.


Do Pigeon flies feed on humans?

It may seem like an obvious answer but a daring study in 1931 done by G. Robert Coatney found that the Pigeon fly is able to feed on humans! Coatney recruited 2 friends to carry this experiment out by forcing the flies to bite them and suck their blood, effectively becoming the host for the flies. However, they only feed on humans blood when there is a lack of choice, on in this case, when being forced to. By having a diet of only human blood, the flies could not survive for long or reproduce. This effectively shows that these Pigeon flies are very host specific, as only by feeding on pigeons will they be able to survive and reproduce. Therefore fret not! Unless pigeons have been wiped out throughout the world, we, humans, do not have to worry about these little critters sucking our blood and potentially transmitting deadly diseases to us.


Type Information

It does not have a holotype. However, it has a syntype stored at the Muséum National d'Histoire Naturelle in Paris.


Figure 9-11: Image of Pseudolynchia canariensis syntype. Image credits: Muséum National d'Histoire Naturelle.3


Phylogeny


Figure 12: Phylogenetic tree of Hippoboscoidea.


4

As seen in fig. 10, viviparity, which is the retention and growth of the fertilized egg within the maternal body until the young animal, as a larva or newborn, is capable of independent existence, has evolved very early on in the phylogenetic tree, resulting in presence of viviparity in all organisms within Hippoboscidea. However, at that time, the larvae were still able to move. It was only when "true" ectoparasitism evolved, then the larvae had reduced movement, resulting in the change from the larvae burrowing into the soil to pupate like the flies in the Glossinidae family to becoming incapable of burrowing and in some cases pupate within the mother's body. The host shift to bird evolved independently in the tree, thus showing convergent evolution. 


DNA Barcoding

A 421 base pair barcode from the cytochrome oxidase 1 gene was sequenced and uploaded onto GenBank (Ascension number: KF453425.1) by Duron et al. (2014).

Figure 13: Screenshot of details on Cytochrome Oxidase 1 gene on GenBank.5

References

Footnotes
Ref Notes
1 Figure 4-8.  Illustrations of Pseudolynchia canariensis. From Illustration Archive, by Smithsonian National Museum of Natural History, Department of Entomology. http://n2t.net/ark:/65665/34020751f-6dca-492f-8a49-8bd11d652a06. Reprinted with permission.
2 Huff, C. (1942). Schizogony and Gametocyte Development in Leucocytozoon simondi, and Comparisons with Plasmodium and Haemoproteus. The Journal of Infectious Diseases, 71(1), 18-32. Retrieved from http://www.jstor.org/stable/30093867
3 Macquart J., 1839 - Animaux articulés recueillis aux Îles Canaries par MM. Webb et Berthelot. Diptères. Histoire Naturelle des Îles Canaries. II (2ème partie), 13 : 97-119.
4 Petersen, F. T., Meier, R., Kutty, S. N., & Wiegmann, B. M. (2007). The phylogeny and evolution of host choice in the Hippoboscoidea (Diptera) as reconstructed using four molecular markers. Molecular Phylogenetics and Evolution45(1), 111–122. https://doi.org/10.1016/j.ympev.2007.04.023
5 Duron, O., Schneppat, U. E., Berthomieu, A., Goodman, S. M., Droz, B., Paupy, C., … Tortosa, P. (2014). Origin, acquisition and diversification of heritable bacterial endosymbionts in louse flies and bat flies. Molecular Ecology23(8), 2105–2117. https://doi.org/10.1111/mec.12704

This page was authored by Leshon Lee (A0166748M)
Last curated on 6 October 2018

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