''Rhabdias bufonis'' is a species of

parasitic Parasitism is a close relationship between species, where one organism, the parasite, lives (at least some of the time) on or inside another organism, the host, causing it some harm, and is adapted structurally to this way of life. The ent ...

nematode The nematodes ( or ; ; ), roundworms or eelworms constitute the phylum Nematoda. Species in the phylum inhabit a broad range of environments. Most species are free-living, feeding on microorganisms, but many are parasitic. Parasitic worms (h ...

in the

family Family (from ) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). It forms the basis for social order. Ideally, families offer predictabili ...

Rhabdiasidae. It was first described from the lungs of the European

common toad The common toad, European toad, or in Anglophone parts of Europe, simply the toad (''Bufo bufo'', from Latin ''bufo'' "toad"), is a toad found throughout most of Europe (with the exception of Ireland, Iceland, parts of Scandinavia, and some List ...

(''Bufo bufo'') but has also been found in a number of other species of frog.

Life cycle

''Rhabdias bufonis'' has a heterogonic lifestyle in which a generation of parasitic individuals is succeeded by a free-living generation. This is advantageous to the parasite as it allows reproduction for one or more generations in the absence of the host. The free-living male and female worms mate and produce eggs which hatch inside the mother. They feed on her internal organs and moult twice before they leave her body. They are now infective larvae and can penetrate the skin of a frog. Once inside, they can migrate to the lungs and further develop there, feeding on the lung tissue. The adult parasitic worm is a

hermaphrodite A hermaphrodite () is a sexually reproducing organism that produces both male and female gametes. Animal species in which individuals are either male or female are gonochoric, which is the opposite of hermaphroditic. The individuals of many ...

and grows to be about ten times the length of the free-living form. The eggs it produces are coughed into the frog's mouth, are swallowed and develop in its intestine. They are passed in the feces and develop into free-living forms. In the soil, the worms feed on bacteria and other organic matter. The female may produce a pheromone to attract a male.

Parasitism

''Rhabdias bufonis'' is found in the parts of Europe and Asia in which its host frogs are found. Besides the common toad from which this roundworm was first described, it has been found in the common spadefoot toad (''

Pelobates fuscus ''Pelobates fuscus'' is a species of toad in the family Pelobatidae, native to an area extending from Central Europe to Western Asia. It is commonly known as the common spadefoot, garlic toad, the common spadefoot toad and the European common sp ...

''), the common frog ('' Rana temporaria''), the moor frog ('' Rana arvalis''), the agile frog ('' Rana dalmatina''), the European fire-bellied toad ('' Bombina bombina''), the yellow-bellied toad ('' Bombina variegata''), water frogs (''

Pelophylax ''Pelophylax'' is a genus of true frogs widespread in Eurasia, with a few species ranging into northern Africa. This genus was erected by Leopold Fitzinger in 1843 to accommodate the green frogs of the Old World, which he considered distinct fro ...

spp.'') and the European green toad ('' Bufo viridis''). Juvenile frogs are often infected and a heavy worm burden can seriously restrict their growth. In a study, some of the infected juveniles were only half as heavy as controls with no worms. The parasite-induced

anorexia Anorexia nervosa (AN), often referred to simply as anorexia, is an eating disorder characterized by Calorie restriction, food restriction, body image disturbance, fear of gaining weight, and an overpowering desire to be thin. Individuals wit ...

caused a decrease in food intake and some of the young host frogs died.

References

{{Taxonbar, from=Q7319958 Rhabditida Nematodes described in 1788 Parasitic nematodes of vertebrates Parasites of amphibians