![Pseudogarypus_synchrotron_Henderickx_et_al_2012](https://upload.wikimedia.org/wikipedia/commons/d/d5/Pseudogarypus_synchrotron_Henderickx_et_al_2012.jpg)
Phoresis or phoresy is a non-permanent,
commensalistic interaction in which one organism (a phoront or phoretic) attaches itself to another (the host) solely for the purpose of travel.
Phoresis has been observed directly in
ticks and mites since the 18th century,
and indirectly in fossils 320 million years old.
It is not restricted to
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s or
animal
Animals are multicellular, eukaryotic organisms in the Kingdom (biology), biological kingdom Animalia. With few exceptions, animals Heterotroph, consume organic material, Cellular respiration#Aerobic respiration, breathe oxygen, are Motilit ...
s;
plant
Plants are predominantly photosynthetic eukaryotes of the kingdom Plantae. Historically, the plant kingdom encompassed all living things that were not animals, and included algae and fungi; however, all current definitions of Plantae exclud ...
s with seeds that disperse by attaching themselves to animals are also considered to be phoretic.
''Phoresis'' is rooted in the Greek words ''phoras'' (bearing) and ''phor'' (thief).
The term, originally defined in 1896 as a relationship in which the host acts as a vehicle for its passenger, clashed with other terminology being developed at the time, so constraints on the length of time, feeding and ontogeny are now considered.
Phoresis is used as a strategy for
dispersal,
seasonal migration
Animal migration is the relatively long-distance movement of individual animals, usually on a seasonal basis. It is the most common form of Migration (ecology), migration in ecology. It is found in all major animal groups, including Bird migrat ...
,
transport to new host/habitat
escaping
ephemeral habitats
Ephemerality (from the Greek word , meaning 'lasting only one day') is the concept of things being transitory, existing only briefly. Academically, the term ephemeral constitutionally describes a diverse assortment of things and experiences, fr ...
,
and reducing
inbreeding depression
Inbreeding depression is the reduced biological fitness which has the potential to result from inbreeding (the breeding of related individuals). Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. In ...
.
In addition to the benefits afforded to individuals and species, its presence can add to the
ecological diversity
Ecosystem diversity deals with the variations in ecosystems within a geographical location and its overall impact on human existence and the environment.
Ecosystem diversity addresses the combined characteristics of biotic properties (biodiver ...
and complexity of an ecosystem.
Mutualism, parasitism and predation
The strict definition of phoresis excludes cases in which the relationship is permanent (e.g. that of a
barnacle
A barnacle is a type of arthropod constituting the subclass Cirripedia in the subphylum Crustacea, and is hence related to crabs and lobsters. Barnacles are exclusively marine, and tend to live in shallow and tidal waters, typically in eros ...
surviving on a
whale
Whales are a widely distributed and diverse group of fully aquatic placental marine mammals. As an informal and colloquial grouping, they correspond to large members of the infraorder Cetacea, i.e. all cetaceans apart from dolphins and ...
) or those in which the phoront gains any kind of advantage from the host organism (e.g.
remora
The remora (), sometimes called suckerfish, is any of a family (Echeneidae) of ray-finned fish in the order Carangiformes. Depending on species, they grow to long. Their distinctive first dorsal fins take the form of a modified oval, sucker-li ...
s attaching to sharks for transportation and food).
Phoresis is a
commensal
Commensalism is a long-term biological interaction (symbiosis) in which members of one species gain benefits while those of the other species neither benefit nor are harmed. This is in contrast with mutualism, in which both organisms benefit fro ...
relationship and deviations result in
mutualistic or
parasitic
Parasitism is a close relationship between species, where one organism, the parasite, lives on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The entomologist E. O. Wilson has c ...
relationships. Phoretic relationships can become parasitic if a cost is inflicted upon the host, such as if the number of mites on a host begins impeding its movement. Parasitic relationships could also be selected for from phoretic ones if the phoront gains a
fitness advantage from the death of a host (e.g. nutrition). Mutualistic relationships could also develop if the phoront began to confer a benefit to the host (e.g. predator defense).
The evolutionary plasticity of phoretic relationships allow them to potentially add to the complexity and diversity of ecosystems.
Cases in which the phoront
parasitizes or preys upon the host organism after travel are still considered phoresis, as long as the travel behaviour and the feeding or parasitizing behaviour are separate.
Similarly, some
pseudoscorpion
Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida.
Pseudoscorpions are generally beneficial to humans sin ...
s prey upon the same species that act as their phoretic host. The behaviours are completely separate however, since the pseudoscorpion uses anatomical features used specifically for
predation
Predation is a biological interaction where one organism, the predator, kills and eats another organism, its prey. It is one of a family of common feeding behaviours that includes parasitism and micropredation (which usually do not kill the ...
when treating the host as prey, but employs anatomical features used for phoresis when travelling.
Examples of phoretic relationships
Examples may be found in the
arthropod
Arthropods (, (gen. ποδός)) are invertebrate animals with an exoskeleton, a Segmentation (biology), segmented body, and paired jointed appendages. Arthropods form the phylum Arthropoda. They are distinguished by their jointed limbs and Arth ...
s associated with
sloth
Sloths are a group of Neotropical xenarthran mammals constituting the suborder Folivora, including the extant arboreal tree sloths and extinct terrestrial ground sloths. Noted for their slowness of movement, tree sloths spend most of their li ...
s.
Coprophagous
Coprophagia () or coprophagy () is the consumption of feces. The word is derived from the grc, κόπρος , "feces" and , "to eat". Coprophagy refers to many kinds of feces-eating, including eating feces of other species (heterospecifics), of ...
sloth moths, such as ''
Bradipodicola hahneli
''Bradypodicola hahneli'' is a sloth moth in the family Pyralidae that lives exclusively in the fur of the pale-throated three-toed sloth (''Bradypus tridactylus''), a three-toed sloth found in South America. It is the only species of the genus ...
'' and ''
Cryptoses choloepi
''Cryptoses choloepi'' is a sloth moth in the snout moth family that as an adult lives exclusively in the fur of sloths, mammals found in South and Central America
Central America ( es, América Central or ) is a subregion of the Amer ...
'', are unusual in that they exclusively inhabit the fur of sloths, mammals found in
central
Central is an adjective usually referring to being in the center of some place or (mathematical) object.
Central may also refer to:
Directions and generalised locations
* Central Africa, a region in the centre of Africa continent, also known as ...
and
South America
South America is a continent entirely in the Western Hemisphere and mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere at the northern tip of the continent. It can also be described as the southe ...
. The sloth provides transport for the moths, the females of which
oviposit
The ovipositor is a tube-like organ used by some animals, especially insects, for the laying of eggs. In insects, an ovipositor consists of a maximum of three pairs of appendages. The details and morphology of the ovipositor vary, but typical ...
in the droppings of sloths, which the larvae feed on, and the newly hatched moths move into the forest canopy in search of a new sloth host.
Larvae of the blister beetle (''
Meloe franciscanus
''Meloe franciscanus'' is a species of blister beetle in the family Meloidae. It is found in the deserts of the southwestern United States. The larvae are parasites of bee larvae, eating them and consuming their provisions.
Distribution and habi ...
)'' need to find the nests of their host, the solitary bee (''
Habropoda pallida
''Habropoda pallida'', known generally as the pallid habropoda or white-faced bee, is a species of anthophorine bee in the family Apidae
Apidae is the largest family within the superfamily Apoidea, containing at least 5700 species of bees. The ...
'') to continue their life cycle. The larvae gather in colonies and emit chemicals that mimic the
pheromone
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...
s of the female solitary bee''.'' Larvae attach to the attracted males when they visit the false source of pheromones, and then subsequently to any female that male mates with. The blister beetle larvae then infest and parasitize the female bee's nest.
Some species of Bromeliad treefrog (''
Scinax littoreus'' and ''
Scinax perpusillus)'' carry
ostracod
Ostracods, or ostracodes, are a class of the Crustacea (class Ostracoda), sometimes known as seed shrimp. Some 70,000 species (only 13,000 of which are extant) have been identified, grouped into several orders. They are small crustaceans, typic ...
s (''
Elpidium'' sp.), which in turn carry
ciliate
The ciliates are a group of alveolates characterized by the presence of hair-like organelles called cilia, which are identical in structure to flagellum, eukaryotic flagella, but are in general shorter and present in much larger numbers, with a ...
s (''
Lagenophrys'' sp.) from one
bromeliad
The Bromeliaceae (the bromeliads) are a family of monocot flowering plants of about 80 genera and 3700 known species, native mainly to the tropical Americas, with several species found in the American subtropics and one in tropical west Africa, ...
plant to another. The plants act as
ecological island An ecological island is a term used in New Zealand, and increasingly in Australia, to refer to an area of land (not necessarily an actual island) isolated by natural or artificial means from the surrounding land, where a natural micro-habitat exists ...
s to the ostracods and phoresis allows them to disperse over a wider area than would be available to them otherwise. The term for a phoretic organism riding on another phoretic organism is
hyperphoresis.
A specialist mite (''
Parasitellus fucorum)'' that parasitizes bumble bees (''
Bombus
A bumblebee (or bumble bee, bumble-bee, or humble-bee) is any of over 250 species in the genus ''Bombus'', part of Apidae, one of the bee families. This genus is the only extant group in the tribe Bombini, though a few extinct related gener ...
'' spp.) avoids
inbreeding depression
Inbreeding depression is the reduced biological fitness which has the potential to result from inbreeding (the breeding of related individuals). Biological fitness refers to an organism's ability to survive and perpetuate its genetic material. In ...
in a single hive and remains genetically independent of any specific host lineage by travelling to a new hive. This is accomplished by travelling on a foraging bee to a flower and detaching, and waiting for and attaching to another bee which may be from another hive, and infesting the new hive. These mites can survive on flowers for up to 24 hours and show a preference for opened flowers, where they would be most likely to find a host.
![Nicrophorus humator - sexton beetle - Flickr - Nick Goodrum Photography](https://upload.wikimedia.org/wikipedia/commons/3/33/Nicrophorus_humator_-_sexton_beetle_-_Flickr_-_Nick_Goodrum_Photography.jpg)
Dung and carrion are ephemeral habitats that are frequently visited by beetles (
dung beetles
Dung beetles are beetles that feed on feces. Some species of dung beetles can bury dung 250 times their own mass in one night.
Many dung beetles, known as ''rollers'', roll dung into round balls, which are used as a food source or breeding cha ...
,
burying beetles
Burying beetles or sexton beetles, genus ''Nicrophorus'', are the best-known members of the family Silphidae (carrion beetles). Most of these beetles are black with red markings on the elytra (forewings). Burying beetles are true to their name ...
). Phoretic
nematodes
The nematodes ( or grc-gre, Νηματώδη; la, Nematoda) or roundworms constitute the phylum Nematoda (also called Nemathelminthes), with plant-parasitic nematodes also known as eelworms. They are a diverse animal phylum inhabiting a broa ...
(Rhabditoides) and
mites
Mites are small arachnids (eight-legged arthropods). Mites span two large orders of arachnids, the Acariformes and the Parasitiformes, which were historically grouped together in the subclass Acari, but genetic analysis does not show clear evid ...
(e.g. genera ''
Macrocheles
''Macrocheles'' is a genus of mites in the family Macrochelidae. There are more than 80 described species in ''Macrocheles''.
Species
These 81 species belong to the genus ''Macrocheles'':
* ''Macrocheles analis'' (Hyatt & Emberson)
* '' Macroc ...
,
Poecilochirus
''Poecilochirus'' is a Holarctic genus of mites in the family Parasitidae. They are relatively large (ca. 0.5-1mm) and often found on rotting corpses, where they are transported by beetles. Deuteronymphs are characterized by two orange dorsal sh ...
,
Uroobovella'') use the beetles to reach these rich resources, where they themselves reproduce.
The pseudoscorpion (''
Cordylochernes scorpioides'') is frequently found riding harlequin beetles (''
Acrocinus longimanus''). Initially there were a number of alternate hypothesis for why the
pseudoscorpion
Pseudoscorpions, also known as false scorpions or book scorpions, are small, scorpion-like arachnids belonging to the order Pseudoscorpiones, also known as Pseudoscorpionida or Chelonethida.
Pseudoscorpions are generally beneficial to humans sin ...
s were found on the beetles: by accident, to forage for mites inhabiting the beetle, or as an
obligate parasite
An obligate parasite or holoparasite is a parasitic organism that cannot complete its life-cycle without exploiting a suitable host. If an obligate parasite cannot obtain a host it will fail to reproduce. This is opposed to a facultative parasite, ...
. Evidence suggested, however, that the pseudoscorpions were using beetles to travel from tree to tree where they preyed upon other beetle larvae.
If their host dies, lice can opportunistically use phoresis to hitch a ride on a fly and attempt to find a new host.
The largest mammalian example of phoresis is human beings directly riding on horses or other animals or using them to pull vehicles with humans in them.
See also
*
Animal locomotion#Animal transport
References
External links
*
{{Biological_interaction-footer
Symbiosis
Animal locomotion