Apocephalus borealis

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Apocephalus borealis
Adult female Apocephalus borealis.png
Adult female A. borealis with visible ovipositor alongside grains of sugar for size comparison
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Diptera
Family: Phoridae
Genus: Apocephalus
Species:
A. borealis
Binomial name
Apocephalus borealis
Brues, 1924

Apocephalus borealis is a species of North American parasitoid phorid fly that attacks bumblebees, honey bees, and paper wasps. This parasitoid's genus Apocephalus is best known for the "decapitating flies" that attack a variety of ant species, though A. borealis attacks and alters the behavior of bees and wasps. [1] These flies are colloquially known as zombie flies and the bees they infect are colloquially known as zombees. [2] Association with honey bees has so far only been documented from California, South Dakota, Oregon, Washington, British Columbia (Vancouver Island), and Vermont. [3] [4]

Contents

History

This phorid fly is native to North America, attacking bumble bees and paper wasps. [1] The infection of European honey bees in North America by A. borealis is a recent development that was first discovered by Dr. John Hafernik, who collected some dead specimens near a light source at San Francisco State University's campus. These were placed in a vial and forgotten. About a week later larvae emerged from the dead bees. [5]

It is hypothesized that the bumble bee is A. borealis’s native host but may have a host shift to the honeybee. This is shown because A. borealis tend to parasitize bumble bees more often than honeybees because the bumble bee’s larger size allows for greater reproductive success. However, some regions have a greater population of honeybees, which increases the chances of a successful A. borealis infection [6] Information is insufficient to explain why the parasitic fly jumped to its new host, but concern exists that this new host provides an opportunity for the fly to thrive and further threaten the decreasing honey bee population. [7] To identify this fly, DNA barcoding was used, demonstrating that the phorids that emerged from Apis and Bombus had no more than 0.2% (1 bp) divergence among samples. What variation was found was from among those phorids reared from honey bees, rather than between flies reared from honey bees versus bumble bees.[ clarification needed ] Other analyses gave similar results, including morphological criteria, sequencing of 18S rRNA genes, and cross-infection of honey bees using phorids that had emerged from both honeybees and bumblebees,[ clarification needed ] thus confirming that the phorids attacking honey bees are the same species as those attacking bumble bees. [1]

As a vector for pathogens

It has been shown that this parasite can reduce a bumble bee's lifespan by up to 70%. [6] To make matters worse for the infected hosts, microarray analyses of honey bees from infected hives reveal that these bees are often infected with deformed wing virus and Nosema ceranae . Both larvae and adult phorids have tested positive for these pathogens, implicating the fly as a potential vector or reservoir host of these honey bee pathogens. [1] A. borealis has also been suggested to be a possible vector promoting the spread of the pathogens responsible for colony collapse disorder. [1] [8]

Life cycle

Eggs are laid in the abdomen of the bee; when the larvae hatch, they feed on flight muscles in the thorax and hemolymph. Development of larvae takes an average of one week. Mature fly larvae typically emerge from the host between the head and thorax (but rarely result in decapitation), and the larvae pupate outside the host body. About 28 days are needed for the entire life cycle. [1] Infected bees can be found walking in circles, as well as losing the ability to stand. Disorientation is likely caused by mechanical interference or by pressure of the growing larvae on the internal organs and nervous system. Inactivity during the daytime, along with activity during cold or inclement weather, has been observed in infected bees.

Hive abandonment, particularly at night, has been implicated as a behavior modification of A. borealis. Reasons for abandoning the hive remain unclear. Researchers hypothesized that infected bees may be ejected by their hive mates, with chemosensory particles playing a possible role in detection of infected bees. It is also possible that infected bees altruistically remove themselves from the hive in efforts to stop the spread of disease to the bee colony. [1] [9]

A bee leaving the hive and going towards a light source at night has yet to be observed. However, many dead bees have been observed near light sources, and when collected many of these bees show evidence of being parasitized, leading to the conclusion that parasitized bees might be drawn to light sources at night. The mechanisms of this phenomenon have yet to be analyzed, but possible culprits are mechanical interference of the larvae growing within the bee or a response to chemical signals the larvae are emitting in the bee.

Effect of seasons

The rates of infection in honey bees fluctuate as A. borealis populations increase and decline over the seasons. No adults of the fly were found within hives, indicating that phorids do not survive in large numbers in the late winter when foraging bees are inactive. [1]

The initial description of the species by Charles Thomas Brues, 1924. Notes on Some New England Phoridae (Diptera).pdf
The initial description of the species by Charles Thomas Brues, 1924.

Zombee Watch

A citizen science project, "Zombee Watch", uses a social media framework for people to report sightings of potentially parasitized bees. [5] The stated goals of the project are to determine where in North America the zombie fly is parasitizing honey bees and how often honey bees leave their hives at night (even if they are not parasitized) and to engage citizen scientists in making a significant contribution to knowledge about honey bees and in becoming better observers of nature. [11]

Related Research Articles

<span class="mw-page-title-main">Bee</span> Clade of insects

Bees are winged insects closely related to wasps and ants, known for their roles in pollination and, in the case of the best-known bee species, the western honey bee, for producing honey. Bees are a monophyletic lineage within the superfamily Apoidea. They are currently considered a clade, called Anthophila. There are over 20,000 known species of bees in seven recognized biological families. Some species – including honey bees, bumblebees, and stingless bees – live socially in colonies while most species (>90%) – including mason bees, carpenter bees, leafcutter bees, and sweat bees – are solitary.

<span class="mw-page-title-main">Parasitoid</span> Organism that lives with its host and kills it

In evolutionary ecology, a parasitoid is an organism that lives in close association with its host at the host's expense, eventually resulting in the death of the host. Parasitoidism is one of six major evolutionary strategies within parasitism, distinguished by the fatal prognosis for the host, which makes the strategy close to predation.

<span class="mw-page-title-main">Apocrita</span> Suborder of insects containing wasps, bees, and ants

Apocrita is a suborder of insects in the order Hymenoptera. It includes wasps, bees, and ants, and consists of many families. It contains the most advanced hymenopterans and is distinguished from Symphyta by the narrow "waist" (petiole) formed between the first two segments of the actual abdomen; the first abdominal segment is fused to the thorax, and is called the propodeum. Therefore, it is general practice, when discussing the body of an apocritan in a technical sense, to refer to the mesosoma and metasoma rather than the "thorax" and "abdomen", respectively. The evolution of a constricted waist was an important adaption for the parasitoid lifestyle of the ancestral apocritan, allowing more maneuverability of the female's ovipositor. The ovipositor either extends freely or is retracted, and may be developed into a stinger for both defense and paralyzing prey. Larvae are legless and blind, and either feed inside a host or in a nest cell provisioned by their mothers.

Nosema apis is a microsporidian, a small, unicellular parasite recently reclassified as a fungus that mainly affects honey bees. It causes nosemosis, also called nosema, which is the most common and widespread of adult honey bee diseases. The dormant stage of N. apis is a long-lived spore which is resistant to temperature extremes and dehydration, and cannot be killed by freezing the contaminated comb. Nosemosis is a listed disease with the Office International des Epizooties (OIE).

<span class="mw-page-title-main">Hyperparasite</span> Parasite of another parasite

A hyperparasite, also known as a metaparasite, is a parasite whose host, often an insect, is also a parasite, often specifically a parasitoid. Hyperparasites are found mainly among the wasp-waisted Apocrita within the Hymenoptera, and in two other insect orders, the Diptera and Coleoptera (beetles). Seventeen families in Hymenoptera and a few species of Diptera and Coleoptera are hyperparasitic. Hyperparasitism developed from primary parasitism, which evolved in the Jurassic period in the Hymenoptera. Hyperparasitism intrigues entomologists because of its multidisciplinary relationship to evolution, ecology, behavior, biological control, taxonomy, and mathematical models.

<i>Varroa destructor</i> Species of mite

Varroa destructor, the Varroa mite, is an external parasitic mite that attacks and feeds on honey bees and is one of the most damaging honey bee pests in the world. A significant mite infestation leads to the death of a honey bee colony, usually in the late autumn through early spring. Without management for Varroa mite, honey bee colonies typically collapse within 2 to 3 years in temperate climates. These mites can infest Apis mellifera, the western honey bee, and Apis cerana, the Asian honey bee. Due to very similar physical characteristics, this species was thought to be the closely related Varroa jacobsoni prior to 2000, but they were found to be two separate species after DNA analysis.

<span class="mw-page-title-main">Phoridae</span> Family of flies

The Phoridae are a family of small, hump-backed flies resembling fruit flies. Phorid flies can often be identified by their escape habit of running rapidly across a surface rather than taking to the wing. This behaviour is a source of one of their alternate names, scuttle fly. Another vernacular name, coffin fly, refers to Conicera tibialis. About 4,000 species are known in 230 genera. The most well-known species is cosmopolitan Megaselia scalaris. At 0.4 mm in length, the world's smallest fly is the phorid Euryplatea nanaknihali.

<span class="mw-page-title-main">Parasitoid wasp</span> Group of wasps

Parasitoid wasps are a large group of hymenopteran superfamilies, with all but the wood wasps (Orussoidea) being in the wasp-waisted Apocrita. As parasitoids, they lay their eggs on or in the bodies of other arthropods, sooner or later causing the death of these hosts. Different species specialise in hosts from different insect orders, most often Lepidoptera, though some select beetles, flies, or bugs; the spider wasps (Pompilidae) exclusively attack spiders.

<i>Deformed wing virus</i> Species of virus

Deformed wing virus (DWV) is an RNA virus, one of 22 known viruses affecting honey bees. While most commonly infecting the honey bee, Apis mellifera, it has also been documented in other bee species, like Bombus terrestris, thus, indicating it may have a wider host specificity than previously anticipated. The virus was first isolated from a sample of symptomatic honeybees from Japan in the early 1980s and is currently distributed worldwide. It is found also in pollen baskets and commercially reared bumblebees. Its main vector in A. mellifera is the Varroa mite. It is named after what is usually the most obvious deformity it induces in the development of a honeybee pupa, which is shrunken and deformed wings, but other developmental deformities are often present.

Nosema ceranae is a microsporidian, a small, unicellular parasite that mainly affects Apis cerana, the Asiatic honey bee. Along with Nosema apis, it causes the disease nosemosis, the most widespread of the diseases of adult honey bees. N. ceranae can remain dormant as a long-lived spore which is resistant to temperature extremes and dehydration. This fungus has been shown to act in a synergistic fashion with diverse insecticides such as fipronil or neonicotinoids, by increasing the toxicity of pesticides for bees, leading to higher bee mortality. It may thus play an indirect role in colony collapse disorder. In addition, the interaction between fipronil and N. ceranae induces changes in male physiology leading to sterility.

Animal viruses are viruses that infect animals. Viruses infect all cellular life and although viruses infect every animal, plant, fungus and protist species, each has its own specific range of viruses that often infect only that species.

<i>Galleria mellonella</i> Species of moth

Galleria mellonella, the greater wax moth or honeycomb moth, is a moth of the family Pyralidae. G. mellonella is found throughout the world. It is one of two species of wax moths, with the other being the lesser wax moth. G. mellonella eggs are laid in the spring, and they have four life stages. Males are able to generate ultrasonic sound pulses, which, along with pheromones, are used in mating. The larvae of G. mellonella are also often used as a model organism in research.

<i>Bombus pensylvanicus</i> Species of bee

Bombus pensylvanicus, the American bumblebee, is a threatened species of bumblebee native to North America. It occurs in eastern Canada, throughout much of the Eastern United States, and much of Mexico.

Two-spotted bumble bee Species of bee

The two-spotted bumble bee is a species of social bumble bee found in the eastern half of the United States and the adjacent south-eastern part of Canada. In older literature this bee is often referred to as Bremus bimaculatus, Bremus being a synonym for Bombus. The bee's common name comes from the two yellow spots on its abdomen. Unlike many of the other species of bee in the genus Bombus,B. bimaculatus is not on the decline, but instead is very stable. They are abundant pollinators that forage at a variety of plants.

Behavior-altering parasites are parasites with two or more hosts, capable of causing changes in the behavior of one of their hosts to enhance their transmission, sometimes directly affecting the hosts' decision-making and behavior control mechanisms. They do this by making the intermediate host, where they may reproduce asexually, more likely to be eaten by a predator at a higher trophic level which becomes the definitive host where the parasite reproduces sexually; the mechanism is therefore sometimes called parasite increased trophic facilitation or parasite increased trophic transmission. Examples can be found in bacteria, protozoa, viruses, and animals. Parasites may also alter the host behaviour to increase protection of the parasites or their offspring; the term bodyguard manipulation is used for such mechanisms.

Chronic bee paralysis virus (CBPV) commonly affects adult Apis mellifera honey bees and causes a chronic paralysis that can easily spread to other members of a colony. Bees infected with CBPV begin to show symptoms after 5 days and die a few days after. Chronic bee paralysis virus infection is a factor that can contribute to or cause the sudden collapse of honeybee colonies. Since honeybees serve a vital role in ecological resilience, it is important to understand factors and diseases that threaten them.

<i>Black queen cell virus</i> Species of virus

The black queen cell virus (BQCV) is a virus that infects honey bees, specifically Apis mellifera, Apis florea, and Apis dorsata. Infection of the latter two species is more recent and can be attributed to genetic similarity and geographical closeness.

<i>Malpighamoeba mellificae</i> Species of protozoan

Malpighamoeba mellificae is a single-celled parasite which affects excretory organs of adult bees, causing the contagious disease called amoebiasis, which ultimately leads to death of the host. Worker bees are most prone to being infected. It is commonly found in collaboration with nosemosis. In order to diagnose the 3 - 15 μm size parasite, removal of the malphigian tubule is necessary. Because of there being no viable treatment against this parasite, preventional measures such as providing a clean food supply for the hive are crucial.

Mallophora ruficauda is a species of parasitic robber fly in the family Asilidae, endemic to South and Central America. Like other robber flies, M. ruficauda is known for its aggressive behavior and predation upon other insects, especially bees. M. ruficauda mimics a bumblebee to fool predators into thinking it has a painful sting and is not worth eating.

References

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  2. Kayla Figard (August 2, 2012). "Seeking Zombee Hunters". The San Francisco Examiner. p. 12.
  3. Ben Gittleson (January 30, 2014). "'Zombie' Bees Surface in the Northeast". ABC News .
  4. Sandi Doughton (September 26, 2012). "Start's first case of 'zombie bees' found in Kent". The Seattle Times.
  5. 1 2 TedTalk (October 31, 2012). "Flight of the Living Dead: Dr. John Hafernik". TedTalk.
  6. 1 2 Cohen, Hamutahl; Quistberg, Robyn D; Philpott, Stacy M (2017-10-23). "Vegetation Management and Host Density Influence Bee–Parasite Interactions in Urban Gardens". Environmental Entomology. 46 (6): 1313–1321. doi:10.1093/ee/nvx155. ISSN   0046-225X. PMID   29069309. S2CID   4523857.
  7. Anton Preston Arce, Rojelio Pedraza (2012). "Evaluation of Phorid Fly (Apocephalus borealis) Parasitism of Feral Honey Bee (Apis mellifera) Colonies in South Orange County". KSBR and the Department of Biological Sciences, Saddleback College.[ permanent dead link ]
  8. Andy Coghlan (January 3, 2012). "Parasitic fly could account for disappearing honeybees". New Scientist.
  9. Castro, Joseph. "Fly Parasite Turns Honeybees Into Zombies | LiveScience".
  10. Brues, C. T. (1924). "Notes on Some New England Phoridæ (Diptera)". Psyche: A Journal of Entomology . 31: 41–44. doi: 10.1155/1924/42175 .
  11. "Zombee Watch". Zombee Watch.