Argulus foliaceus

Ge­o­graphic Range

Ar­gu­lus fo­li­aceus is a fresh­wa­ter fish ec­topar­a­site that has been re­ported through­out tem­per­ate re­gions of Eu­rope, Cen­tral Asia, and North Amer­ica. It has been well stud­ied in Eu­rope, es­pe­cially the British Isles, where is has had major im­pacts on UK sport fish­eries through fish stress and mor­tal­ity. (Har­ri­son, et al., 2006; Ok­tener, et al., 2007; Paster­nak, et al., 2004)

Habi­tat

Ar­gu­lus fo­li­aceus is found in warm, eu­trophic, still lakes of both fresh and brack­ish water. Eggs are laid in shady areas, rather than in di­rect sun­light. Typ­i­cally con­sid­ered a shal­low water species, this louse is often ob­served lay­ing eggs within the top 1 m of the water col­umn (al­though it will lay eggs in deeper water at the end of the re­pro­duc­tive sea­son). Ar­gu­lus fo­li­aceus is an ob­lig­ate par­a­site, re­quir­ing host avail­abil­ity. This louse has a low host speci­ficity, so it can in­fect a va­ri­ety of fish within its habi­tat. (Har­ri­son, et al., 2006; Paster­nak, et al., 2000; Tay­lor, et al., 2006)

Phys­i­cal De­scrip­tion

On av­er­age, Ar­gu­lus fo­li­aceus mea­sures a total length of 3-7 mm and a width of 2.5-5 mm. Ar­gulid fe­males are gen­er­ally larger than males, and the growth of the par­a­site may be in­flu­enced by the size of the host. A dis­tin­guish­ing char­ac­ter­is­tic of A. fo­li­aceus is the uro­some, con­sist­ing of rounded lobes that are cov­ered mar­gin­ally with small spines. The pos­te­rior in­cisures of the uro­some do not reach to the cen­ter. An­other char­ac­ter­is­tic is the an­te­rior por­tion of the cephalotho­rax that forms a broad pro­tru­sion with shal­low grooves. Adults use suc­tion discs for host at­tach­ment, whereas lar­vae uti­lize lar­val hooks. (Moller, et al., 2008; Ok­tener, et al., 2007; Paster­nak, et al., 2004)

  • Sexual Dimorphism
  • female larger
  • Range length
    3 to 7 mm
    0.12 to 0.28 in

De­vel­op­ment

Ar­gu­lus fo­li­aceus lar­vae are free-swim­ming. The length of the lar­val phase is highly vari­able, most likely in­flu­enced by tem­per­a­ture. In gen­eral, lar­vae are typ­i­cally first ob­served in the late spring and morph into adults in the fall. Ar­gu­lus fo­li­aceus is ex­ceed­ingly rare in the win­ter. Lar­val de­vel­op­ment is di­vided into two dis­tinct mor­pho­log­i­cal phases: stage I as a metanau­plius and stage two as a ju­ve­nile. While mor­pho­log­i­cal adap­ta­tions do ap­pear in stage I lar­vae, there is cur­rently no con­clu­sive ev­i­dence that the stage I lar­vae are ei­ther par­a­sitic or pelagic, so they are typ­i­cally con­sid­ered “semi-pelagic." (Moller, et al., 2007; Paster­nak, et al., 2000)

Re­pro­duc­tion

Ar­gu­lus fo­li­aceus usu­ally cop­u­lates on the sur­face of a host fish, but cop­u­la­tion has also been ob­served on other types of solid sur­faces such as leaves and stones. (Paster­nak, et al., 2000)

A fe­male A. fo­li­aceus leaves the host fish to lay its eggs, but as an ob­lig­ate par­a­site, it must re­turn to a host fish oc­ca­sion­ally through­out the process. There is vari­abil­ity in the fre­quency and length of time that the fe­male leaves and re­turns to the host. Be­cause fe­males are de­pen­dent on the host fish while lay­ing eggs, the in­di­vid­ual vul­ner­a­bil­ity and pop­u­la­tion den­sity of fish can in­flu­ence this louse's re­pro­duc­tive suc­cess and sur­vivor­ship. While A. fo­li­aceus is com­monly be­lieved to be a shal­low water species be­cause it is most often ob­served to lay eggs in the top 1 m of the water col­umn, some stud­ies have in­di­cated that, if avail­able, they pre­fer deeper water (8.5 m) at the end of the egg-lay­ing sea­son. The sug­ges­tion that they lay eggs in shal­low water may be a bias due to study sites. Tem­per­a­ture and dis­solved oxy­gen con­tent may in­flu­ence egg lay­ing depths, but there is cur­rently no con­clu­sive ev­i­dence for these trends. Eggs are laid in strings or clutches that con­tain an av­er­age of 100-150 eggs, but there can be as few as four or as many as 250 eggs. The fe­male lays her eggs in the win­ter, but there is a wide vari­abil­ity in hatch­ing time, pos­si­bly due to fish avail­abil­ity. (Har­ri­son, et al., 2006; Paster­nak, et al., 2000)

  • Key Reproductive Features
  • gonochoric/gonochoristic/dioecious (sexes separate)
  • sexual
  • oviparous
  • Breeding season
    Eggs laid in the winter
  • Range number of offspring
    4 to 250
  • Average number of offspring
    100-150

There is no in­for­ma­tion about parental in­vest­ment in Ar­gu­lus fo­li­aceus re­ported in the lit­er­a­ture.

  • Parental Investment
  • no parental involvement

Lifes­pan/Longevity

Ar­gu­lus fo­li­aceus is rare in the win­ter and has been de­scribed as hav­ing a short lifes­pan. There is no in­for­ma­tion re­ported in the lit­er­a­ture, how­ever, on the ac­tual length of its lifes­pan. (Dzika, 2002; Paster­nak, et al., 2000)

Be­hav­ior

Ar­gu­lus fo­li­aceus most com­monly at­taches to the host on the skin ep­ithe­lium of the body and fins, but has been ob­served to also at­tach to the gills. This louse feeds by pierc­ing the host skin, in­ject­ing a toxin, and draw­ing blood. In­fec­tion of A. fo­li­aceus often re­sults in host tis­sue dam­age and some­times mor­tal­ity. Ar­gu­lus fo­li­aceus in­fects ir­re­spec­tive of the health of the host. The length of res­i­dence time on the host be­tween at­tach­ment to de­tach­ment is quite vari­able. In gen­eral, ec­topar­a­sites ag­gre­gate on the host so that few in­di­vid­u­als within the host pop­u­la­tion are ac­tu­ally in­fected. The ag­gre­ga­tion is likely due to host be­hav­ior; when stressed, the host’s move­ment is re­duced, al­low­ing more par­a­sites to at­tach. (Bandilla, et al., 2005; Nolan, et al., 2000; Ok­tener, et al., 2006; Paster­nak, et al., 2004)

Home Range

There is no in­for­ma­tion on the home range of Ar­gu­lus fo­li­aceus re­ported in the lit­er­a­ture.

Com­mu­ni­ca­tion and Per­cep­tion

Adult ar­gulids can re­spond to some chem­i­cal cues. They have higher sen­sory abil­i­ties, swim­ming abil­i­ties, and me­tab­o­lism than ju­ve­niles, so the adults are less de­pen­dent on host at­tach­ment, al­low­ing them to leave one host in search for an­other of higher pref­er­ence. At the in­di­vid­ual level, the search­ing abil­i­ties of Ar­gu­lus fo­li­aceus are lim­ited, so changes at the pop­u­la­tion level, such as host pref­er­ence and ag­gre­ga­tion, are nec­es­sary to in­crease re­pro­duc­tive suc­cess and sur­vivor­ship, in light of un­pre­dictable host avail­abil­ity. (Bandilla, et al., 2005; Paster­nak, et al., 2000)

Food Habits

Ar­gu­lus fo­li­aceus is an ob­lig­ate blood­sucker, and it can­not sur­vive more than few days with­out a host. Hav­ing lit­tle speci­ficity for hosts, it in­fects a wide range of species. (Paster­nak, et al., 2000)

  • Animal Foods
  • amphibians
  • fish

Pre­da­tion

Di­rect pre­da­tion of free-swim­ming Ar­gu­lus fo­li­aceus by trout and some other fish species has been ob­served. (Tay­lor, et al., 2006)

  • Known Predators
    • Trout

Ecosys­tem Roles

Ar­gu­lus fo­li­aceus is often noted for its role in ecosys­tems as an ec­topar­a­site. With a low host speci­ficity, it has been found on al­most every type of fresh­wa­ter fish within its nat­ural habi­tat, yet some fish are more sus­cep­ti­ble than oth­ers. Ar­gu­lus fo­li­aceus has been re­ported on fish in the fam­i­lies Cyprinidae, Salmonidae, Go­b­i­idae, Gas­terostei­dae, and Acipenseri­dae, as well as am­phib­ians, in­clud­ing frogs and toads (Anura). In fish farms of Cen­tral Fin­land, it was found to co­ex­ist with Ar­gu­lus core­goni, a closely re­lated ec­topar­a­site. In ad­di­tion to its func­tion in ecosys­tems as a par­a­site, A. fo­li­aceus can also be a vec­tor for bac­te­ria and fla­gel­lates, and it serves as an in­ter­me­di­ate host of ne­ma­todes in the fam­ily Skr­ja­bil­lanidae. (Ok­tener, et al., 2006; Paster­nak, et al., 2004; Walker, et al., 2007)

Com­men­sal/Par­a­sitic Species
  • Skr­ja­bil­lanidae

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

There are no known pos­i­tive ef­fects of Ar­gu­lus fo­li­aceus on hu­mans.

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

While Ar­gu­lus fo­li­aceus is fre­quently found in small num­bers with lit­tle dam­age to the hosts, epi­zootics may occur. When in­fected by A. fo­li­aceus, host fish dis­play an in­crease in jump­ing be­hav­ior and a de­crease in feed­ing, fol­lowed by sec­ondary bac­te­r­ial and fun­gal in­fec­tions, shoal­ing be­hav­ior, and fi­nally, pos­si­ble large-scale mor­tal­ity. Ar­gu­lus fo­li­aceus in­fec­tions have been re­ported to wipe out trout stock pop­u­la­tions and cause prob­lems in carp farm­ing. In sport fish­eries, a com­mon issue is not mor­tal­ity but rather re­duced catch and low­ered aes­thetic ap­peal, re­sult­ing in eco­nomic losses. (Cross and Stott, 1974; Nolan, et al., 2000; Tay­lor, et al., 2006)

Con­ser­va­tion Sta­tus

Other Com­ments

Ar­gu­lus fo­li­aceus is a me­chan­i­cal vec­tor of the spring vi­raemia of carp (SVC), an acute viral dis­ease in Cypri­nus car­pio, trans­fer­ring the virus from in­fected to non-in­fected in­di­vid­u­als. (Ahne, 1985)

Con­trib­u­tors

Jes­sica Kafer (au­thor), The Col­lege of New Jer­sey, Keith Pecor (ed­i­tor), The Col­lege of New Jer­sey, Renee Mul­crone (ed­i­tor), Spe­cial Pro­jects.

Glossary

Nearctic

living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.

World Map

Palearctic

living in the northern part of the Old World. In otherwords, Europe and Asia and northern Africa.

World Map

bilateral symmetry

having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.

brackish water

areas with salty water, usually in coastal marshes and estuaries.

carnivore

an animal that mainly eats meat

chemical

uses smells or other chemicals to communicate

ectothermic

animals which must use heat acquired from the environment and behavioral adaptations to regulate body temperature

freshwater

mainly lives in water that is not salty.

heterothermic

having a body temperature that fluctuates with that of the immediate environment; having no mechanism or a poorly developed mechanism for regulating internal body temperature.

metamorphosis

A large change in the shape or structure of an animal that happens as the animal grows. In insects, "incomplete metamorphosis" is when young animals are similar to adults and change gradually into the adult form, and "complete metamorphosis" is when there is a profound change between larval and adult forms. Butterflies have complete metamorphosis, grasshoppers have incomplete metamorphosis.

motile

having the capacity to move from one place to another.

natatorial

specialized for swimming

oviparous

reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.

parasite

an organism that obtains nutrients from other organisms in a harmful way that doesn't cause immediate death

sanguivore

an animal that mainly eats blood

sexual

reproduction that includes combining the genetic contribution of two individuals, a male and a female

temperate

that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).

Ref­er­ences

Ahne, W. 1985. Ar­gu­lus fo­li­aceus L. and Pis­ci­cola geome­tra L. as me­chan­i­cal vec­tors of spring vi­raemia of carp virus (SVCV). Jour­nal of Fish Dis­eases, 8: 241-242.

Bandilla, M., T. Hakalahti, P. Hud­son, E. Val­to­nen. 2005. Ag­gre­ga­tion of Ar­gu­lus core­goni (Crus­tacea: Branchiura) on rain­bow trout (On­corhynchus mykiss): a con­se­quence of host sus­cep­ti­bil­ity or ex­po­sure?. Par­a­sitol­ogy, 130: 1-8. Ac­cessed March 02, 2011 at http://​www.​personal.​psu.​edu/​users/​p/​j/​pjh18/​downloads/​168_​Bandilla_​%20et_​al_​2004_​Argulus_​aggregation_​%20Parasitology.​pdf.

Cross, D., R. Stott. 1974. The ef­fect of Ar­gu­lus fo­li­aceus L. on the growth and mor­tal­ity of a grass carp pop­u­la­tion. Fish­eries Man­age­ment, 5: 39-42.

Dzika, E. 2002. The par­a­sites of bream Abramis brama (L.) from Lake Ko­r­towskie. Archives of Pol­ish Fish­eries, 10: 85-96. Ac­cessed March 02, 2011 at http://​www.​infish.​com.​pl/​wydawnictwo/​Archives/​Fasc/​work_​pdf/​Vol10Fasc1/​Vol10fasc1-w08.​pdf.

Har­ri­son, A., N. Gault, J. Dick. 2006. Sea­sonal and ver­ti­cal pat­terns of egg-lay­ing by the fresh­wa­ter fish louse Ar­gu­lus fo­li­aceus (Crus­tacea: Branchiura). Dis­eases of Aquatic Or­gan­isms, 68: 167-173. Ac­cessed March 02, 2011 at http://​www.​int-res.​com/​articles/​dao2005/​68/​d068p167.​pdf.

Moller, O., J. Ole­sen, A. Avenant-Old­ewage, P. Thom­sen, H. Glen­ner. 2008. First max­il­lae suc­tion discs in Branchiura (Crus­tacea): de­vel­op­ment and evo­lu­tion in light of the first mol­e­c­u­lar phy­logeny of Branchiura, Pen­tas­to­mida, and other "Max­il­lopoda". Arthro­pod Struc­ture & De­vel­op­ment, 37: 333-346. Ac­cessed March 02, 2011 at http://​www.​sciencedirect.​com/​science?_​ob=ArticleURL&_​udi=B6W66-4RM1KW9-1&_​user=1086025&_​coverDate=07%2F31%2F2008&_​rdoc=1&_​fmt=high&_​orig=search&_​sort=d&_​docanchor=&​view=c&_​acct=C000051441&_​version=1&_​urlVersion=0&_​userid=1086025&​md5=0ec40d9e631e8cd68a0b82e610455f6f.

Moller, O., J. Ole­sen, D. Waloszek. 2007. Swim­ming and clean­ing in the free-swim­ming phase of Ar­gu­lus lar­vae (Crus­tacea, Branchiura) - ap­pendage adap­ta­tion and func­tional mor­phol­ogy. Jour­nal of Mor­phol­ogy, 268: 1-11. Ac­cessed March 02, 2011 at http://​www.​zmuc.​ku.​dk/​InverWeb/​staff/​PDF/​M%C3%B8ller,%20Ole­sen,%20Waloszek%202007.​pdf.

Nolan, D., A. van der Salm, S. Wen­de­laar Bonga. 2000. The host-par­a­site re­la­tion­ship be­tween the rain­bow trout (On­corhynchus mykiss) and the ec­topar­a­site Ar­gu­lus fo­li­aceus (Crus­tacea: Branchiura): ep­ithe­lial mu­cous cell re­sponse, cor­ti­sol and fac­tors which may in­flu­ence par­a­site es­tal­ish­ment. Con­tri­bu­tions to Zo­ol­ogy, 69: 57-63. Ac­cessed March 02, 2011 at http://​dpc.​uba.​uva.​nl/​ctz/​vol69/​nr01/​art06.

Ok­tener, A., A. Ali, A. Gustinelli, M. Fio­ra­vanti. 2006. New host records for fish louse Ar­gu­lus fo­li­aceus L., 1758 (Crus­tacea, Branchiura) in Turkey. It­tiopa­tolo­gia, 3: 161-167.

Ok­tener, A., J. Trilles, I. Leonar­dos. 2007. Five ec­topar­a­sites from Turk­ish fish. Turkiye Paraz­i­tologi Der­gisi, 31: 154-157. Ac­cessed March 02, 2011 at http://​www.​tparazitolderg.​org/​pdf/​pdf_​TPD_​260.​pdf.

Paster­nak, A., V. Mikheev, E. Val­to­nen. 2004. Growth and de­vel­op­ment of Ar­gu­lus core­goni (Crus­tacea: Branchiura) on salmonid and cyprinid hosts. Dis­eases of Aquatic Or­gan­isms, 58: 203-207. Ac­cessed March 02, 2011 at http://​www.​int-res.​com/​articles/​dao2004/​58/​d058p203.​pdf.

Paster­nak, A., V. Mikheev, E. Val­to­nen. 2000. Life his­tory char­ac­ter­is­tics of Ar­gu­lus fo­li­aceus L. (Crus­tacea: Branchiura) pop­u­la­tions in Cen­tral Fin­land. An­nales Zo­o­logici Fen­nici, 37: 25-35. Ac­cessed March 02, 2011 at http://​www.​sekj.​org/​PDF/​anzf37/​anzf37-025p.​pdf.

Tay­lor, N., C. Som­merville, R. Woot­ten. 2006. The epi­demi­ol­ogy of Ar­gu­lus spp. (Crus­tacea: Branchiura) in­fec­tions in still­wa­ter trout fish­eries. Jour­nal of Fish Dis­eases, 29: 193-200.

Walker, P., J. Har­ris, G. van der Velde, S. Bonga. 2007. Size mat­ters: stick­le­back size and in­fec­tion with Ar­gu­lus fo­li­aceus (L., 1758) (Branchiura, Ar­gu­loida). Crus­taceana, 80: 1397-1401.