Animal Diversity Web

Ge­o­graphic Range

Hy­per­olius virid­i­flavus, or African reed frogs, are a wide­spread species that oc­cupy most suit­able habi­tats (ponds and lakes) through­out north­west­ern Ethiopia, through South­ern Sudan to west­ern Kenya, Rwanda, Uganda, Bu­rundi, north­west­ern Tan­za­nia, north­east­ern De­mo­c­ra­tic Re­pub­lic of Congo, and most likely east­ern Cen­tral African Re­pub­lic. (Schiøtz, et al., 2004)

• Biogeographic Regions
• ethiopian
  • native

Habi­tat

Hy­per­olius virid­i­flavus lives in the trop­i­cal African sa­vanna. It is as­so­ci­ated with emerg­ing veg­e­ta­tion in sa­vanna, grass­lands, and at the mar­gins of forests, lakes, rivers, and swamps, where these frogs may live in high den­si­ties. Hy­per­olius virid­i­flavus also lives in areas as­so­ci­ated with hu­mans, like cul­ti­vated land and gar­dens. This species breeds in a va­ri­ety of aquatic habi­tats from very small to large ponds that may be per­ma­nent but are usu­ally tem­po­rary. It ranges from low al­ti­tudes to 2,400 m in Ethiopia. (Schiøtz, et al., 2004; Schiøtz, 1999)

• Habitat Regions
• tropical
• terrestrial
• freshwater

• Terrestrial Biomes
• savanna or grassland
• rainforest

• Aquatic Biomes
• lakes and ponds
• rivers and streams
• temporary pools

• Wetlands
• marsh
• swamp

• Other Habitat Features
• agricultural
• riparian

• Range elevation

  2,400 (high) m

  ft

Phys­i­cal De­scrip­tion

Hy­per­olius virid­i­flavus is a highly vari­able species that ex­hibits con­sid­er­able poly­mor­phism in color pat­tern. Some pop­u­la­tions con­tain dis­tinct morphs while in oth­ers there is gra­da­tion among ex­tremes. It is widely re­garded as a su­per­species with more than fifty sub­species rec­og­nized. The sub­species are di­vided into two sub­groups, par­al­lelus and virid­i­flavus, based on vari­a­tion in ge­o­graphic range and col­oration. There is some con­tro­versy about the tax­on­omy of H. virid­i­flavus that is dis­cussed fur­ther in the other com­ments sec­tion.

Hy­per­olius virid­i­flavus is a small to medium sized frog species with an av­er­age mass of 2 g and body length of 15 to 30 mm, de­pend­ing on the sub­species.

This species ex­hibits sex­ual di­mor­phism with males slightly smaller than fe­males. Fe­males are more col­or­ful than males; their adult pat­tern is re­ferred to as Phase F which is highly vari­able and con­tains sev­eral dis­tinct morphs. Ma­ture males fre­quently re­main in the ju­ve­nile phase (Phase J), which ranges from brown­ish to green with paired light dor­so­lat­eral lines.

Mem­bers of this species have hor­i­zon­tal pupils, ex­ten­sive web­bing of the feet, a brief snout, and a very large, sha­greened, gular flap. They lack an ex­ter­nal metatarsal tu­ber­cle. Males have a large di­lat­able vocal sac. Fe­males have a tran­verse gular flap All sub­species have a sub­der­mal dark bluish lat­eral streak caused by black pig­men­ta­tion of the mus­cu­lus obliquus ab­dom­i­nal mus­cle. This band is some­times dif­fi­cult to see if the sides of the frog are heav­ily pig­mented. The band dif­fers in place­ment be­tween the sexes.

The sub­species have dif­fer­ent col­oration rang­ing from solid light green in the H. virid­i­flavus mwan­zae to light brown in H. virid­i­flavus pan­ther­i­nus to very brightly spot­ted and striped in H. virid­i­flavus tau­nia­tus. The feet are fre­quently brightly col­ored. (Grafe, et al., 1992; Schiøtz, et al., 2004; Schiøtz, 1999)

• Other Physical Features
• ectothermic
• heterothermic
• bilateral symmetry
• polymorphic

• Sexual Dimorphism
• female larger
• sexes colored or patterned differently
• female more colorful

• Average mass

  2 g

  0.07 oz

• Range length

  14 to 33 mm

  0.55 to 1.30 in

De­vel­op­ment

Hy­per­olius virid­i­flavus eggs hatch into tad­poles two to five days after lay­ing, de­pend­ing on the tem­per­a­ture of the water. Tad­poles take eight weeks to meta­mor­phose into ju­ve­niles. Ju­ve­niles ma­ture sex­u­ally in three to twelve months de­pend­ing on the cli­mate. Ju­ve­nile H. virid­i­flavus have a dif­fer­ent col­oration than adults, re­ferred to as Phase J, which is light brown to green in color. Sex­u­ally ma­ture males fre­quently main­tain the ju­ve­nile col­oration through­out adult­hood. Phase F, the adult phase, is a highly vari­able color pat­tern with dis­tinct morphs. (Bubac, 2009; Grafe and Lisen­mair, 1989; Schiøtz, 1999)

• Development - Life Cycle
• metamorphosis

Re­pro­duc­tion

Hy­per­olius virid­i­flavus breeds dur­ing the wet sea­son. The length of the breed­ing ac­tiv­ity varies among sub­species but typ­i­cally lasts sev­eral months. This species is polyg­y­nan­drous. At the be­gin­ning of the breed­ing sea­son, males mi­grate to bod­ies of water such as shal­low ponds and form call­ing cho­ruses to at­tract mates. Males main­tain an in­di­vid­ual call­ing space through com­bat. Males typ­i­cally call at dusk and ex­pend con­sid­er­able en­ergy try­ing to at­tract a mate. Fe­males H. virid­i­flavus may se­lect larger males as mates. Fe­males ap­proach males and ini­ti­ate am­plexus. Am­plexus is ax­il­lary (the male holds the fe­male around the armpits). The eggs are laid on veg­e­ta­tion under the water in ponds, lakes, and slow-mov­ing streams. Fe­male H. virid­i­flavus pro­duce mul­ti­ple clutches dur­ing the breed­ing sea­son. (Bubac, 2009; Grafe and Lisen­mair, 1989; Grafe, et al., 1992)

• Mating System
• polygynandrous (promiscuous)

Hy­per­olius virid­i­flavus breeds dur­ing the wet sea­son. The length of the breed­ing ac­tiv­ity varies among sub­species but typ­i­cally lasts sev­eral months. Fe­males have mul­ti­ple clutches over the course of the breed­ing sea­son. The av­er­age size of a clutch is 330 eggs. Eggs hatch after 2 to 5 days, and have meta­mor­phosed into ju­ve­niles by 8 weeks of age. Ju­ve­niles of both sexes be­come sex­u­ally ma­ture at 4 to 12 months old.

Hy­per­olius virid­i­flavus has been shown to ex­pe­ri­ence pro­tog­yny, or fe­male to male sex change, in the lab­o­ra­tory. The new males were able to fer­til­ize the eggs of fe­males. This likely oc­curs when the sex ratio within a pop­u­la­tion is heav­ily weighted to­wards males.

Hy­per­olius virid­i­flavus is semel­parous, but may breed mul­ti­ple times in its one breed­ing sea­son. This re­pro­duc­tive strat­egy is largely due to cli­matic fac­tors, as no adults have been doc­u­mented sur­viv­ing the an­nual, harsh dry sea­son. Even in lab­o­ra­tory set­tings, in­di­vid­u­als will senesce shortly after the breed­ing sea­son. (Grafe and Lisen­mair, 1989)

• Key Reproductive Features
• semelparous
• seasonal breeding
• gonochoric/gonochoristic/dioecious (sexes separate)
• sexual
• fertilization
  • external
• oviparous

• Breeding interval

  Female Hyperolius viridiflavus produce a new clutch every 10 to 20 days during the breeding season.

• Breeding season

  Hyperolius viridiflavus breed during the wet season which typically lasts several months.

• Range number of offspring

  94 to 800

• Range time to hatching

  2 to 5 days

• Range age at sexual or reproductive maturity (female)

  4 to 12 months

• Range age at sexual or reproductive maturity (male)

  4 to 12 months

Hy­per­olius virid­i­flavus pro­vides no parental in­vest­ment other than yolk and sperm for the eggs. (Bubac, 2009)

• Parental Investment
• no parental involvement
• pre-fertilization
  • provisioning
  • protecting
    • female

Lifes­pan/Longevity

Hy­per­olius virid­i­flavus lives in an en­vi­ron­ment with widely fluc­tu­at­ing weather con­di­tions. Shortly after the breed­ing sea­son, these frogs face a se­vere dry sea­son when they must rely on stored water. Adults do not han­dle this water short­age as well as ju­ve­niles. Adults do not gen­er­ally sur­vive the dry sea­son, and in areas with pro­longed dry sea­sons adults are prob­a­bly an­nual. Lin­sen­mair has never found an adult H. virid­i­flavus ni­tidu­lus that has sur­vived the dry sea­son in West Africa. Even under lab­o­ra­tory con­di­tions, adult H. virid­i­flavus senesce quickly after the end of breed­ing ac­tiv­ity. Males also ex­pe­ri­ence high mor­tal­ity be­cause they are highly vocal and are there­fore more sus­cep­ti­ble to pre­da­tion by acousti­cally-hunt­ing preda­tors. (Geise and Lin­sen­mair, 1988; Grafe and Lisen­mair, 1989)

• Typical lifespan
  Status: wild

  1 (high) years

Be­hav­ior

These frogs uti­lize ex­posed call­ing sites and males ex­hibit ter­ri­to­r­ial be­hav­ior dur­ing the breed­ing sea­son at these sites. In order to main­tain an in­di­vid­ual call­ing site, males en­gage in in­tense and pro­longed com­bat. Dur­ing the dry sea­son, H. virid­i­flavus aes­ti­vates. Ju­ve­niles es­ti­vate on dry veg­e­ta­tion in ex­posed po­si­tions, in­stead of bur­row­ing in the ground. This be­hav­ior is unique among frogs. Only ju­ve­niles are able to sur­vive the dry sea­son; they do so by re­duc­ing me­tab­o­lism and ad­just­ing water econ­omy. Adults are not able to make these changes and gen­er­ally do not sur­vive the dry sea­son. Ju­ve­niles do not move, eat, uri­nate, or defe­cate dur­ing the dry sea­son. Ju­ve­niles must rely on stored water for sev­eral months dur­ing the dry sea­son so they must min­i­mize evap­o­ra­tive water loss. The dor­sal and ven­tral skin of H. virid­i­flavus is dif­fer­en­ti­ated in order to max­i­mize water con­ser­va­tion and up­take. Dur­ing the dry sea­son the skin turns white be­cause of built-up purine crys­tals in the skin. (Geise and Lin­sen­mair, 1988; Grafe and Lisen­mair, 1989)

• Key Behaviors
• saltatorial
• natatorial
• diurnal
• motile
• sedentary
• aestivation
• territorial

Home Range

There is no in­for­ma­tion on home range for this species.

Com­mu­ni­ca­tion and Per­cep­tion

Hy­per­olius virid­i­flavus has a melodic call like a xy­lo­phone that is more tonal than that of other species in this genus. Their calls are a char­ac­ter­is­tic part of the African night sounds. Males have an ex­posed call­ing site and form cho­ruses in order to at­tract mates.

Hy­per­olius virid­i­flavus ni­tidu­lus males have two dis­tinct calls, a mat­ing call and a ter­ri­to­r­ial call. The ter­ri­to­r­ial call is longer and deeper than the mat­ing call, and lasts from 0.28 to 0.36 sec­onds and has a fre­quency of 0.98 to 2.6 kHz. The mat­ing call is a short metal­lic click that lasts be­tween 0.10 to 0.24 s and has a fre­quency of 2.04 to 3.43 kHz, de­pend­ing on the size of the frog. Fe­male H. virid­i­flavus can­not make sounds.

Mem­bers of this species use keen vi­sual per­cep­tion in order to cap­ture in­sects. They have bulging eyes and hor­i­zon­tal pupils. (Bubac, 2009; Grafe and Lisen­mair, 1989; Schiøtz, et al., 2004; Schiøtz, 1999)

• Communication Channels
• acoustic

• Other Communication Modes
• choruses

• Perception Channels
• visual
• acoustic

Food Habits

Hy­per­olius virid­i­flavus are in­sec­ti­vores that feed on many dif­fer­ent types of in­sects in­clud­ing flies in the gen­era Drosophila, Musca, Phormia, Lu­cilia, and Cal­liphora. The free-liv­ing tad­poles of Hy­per­olius virid­i­flavus ni­tidu­lus eat algae. (Bubac, 2009)

• Primary Diet
• carnivore
  • insectivore

• Animal Foods
• insects

• Plant Foods
• algae

Pre­da­tion

Hy­per­olius virid­i­flavus has a bright warn­ing col­oration that wards off preda­tors. Drag­on­fly lar­vae, bee­tle lar­vae, tur­tles, ray-finned fish and water snakes eat the tad­poles of H. virid­i­flavus. (Bubac, 2009)

• Anti-predator Adaptations
• aposematic

• Known Predators

  • Dragonfly larvae (Order Odonata)
  • Beetle larvae (Order Coleoptera)
  • Turtles (Order Testudines)
  • Fish (Class Actinopterygii)
  • Water snakes (Lycodonomorphus refutus)

Ecosys­tem Roles

Hy­per­olius virid­i­flavus is a preda­tor of in­sects in the African sa­vanna. It is also the prey of sev­eral species of an­i­mals. (Grafe and Lisen­mair, 1989)

Eco­nomic Im­por­tance for Hu­mans: Pos­i­tive

This species is a part of the in­ter­na­tional pet trade al­though not at high lev­els. (Schiøtz, et al., 2004)

• Positive Impacts
• pet trade

Eco­nomic Im­por­tance for Hu­mans: Neg­a­tive

There are no known ad­verse ef­fects of Hy­per­olius virid­i­flavus on hu­mans. How­ever, the Masai of East Africa have a su­per­sti­tion that their cat­tle will die if they eat these frogs be­cause of their bright warn­ing col­oration. (Schiøtz, 1999)

Con­ser­va­tion Sta­tus

Hy­per­olius virid­i­flavus is listed as least con­cern by the In­ter­na­tional Union for Con­ser­va­tion of Na­ture be­cause of its very wide dis­tri­b­u­tion and tol­er­ance of a broad range of habi­tats. It also likely has a large pop­u­la­tion size with no sig­nif­i­cant threats. This species is oc­ca­sion­ally found in the in­ter­na­tional pet trade, but not at a high enough level to pose a threat to it. (Schiøtz, et al., 2004)

• IUCN Red List

  Least Concern
  More information

• IUCN Red List

  Least Concern
  More information

• CITES

  No special status

Other Com­ments

The tax­on­omy of Hy­per­olius virid­i­flavus is com­plex and has been the sub­ject of much de­bate. Much of the dif­fi­culty has come from the de­pen­dence on dor­sal color pat­terns as tax­o­nomic char­ac­ters. Schiøtz ar­gues that H. virid­i­flavus is a su­per­species with many sub­species that can be di­vided into two sub­groups, par­al­lelus and virid­i­flavus based on col­oration and ge­o­graphic range. Wiec­zorek has bro­ken up the var­i­ous sub­species of H. virid­i­flavus into ten full species based on mi­to­chon­dr­ial DNA. Adult H. virid­i­flavus are unique be­cause they can re­gen­er­ate fully func­tional dig­its after am­pu­ta­tion. (Richards, et al., 1975; Schiøtz, 1975; Wiec­zorek, et al., 2001)

Con­trib­u­tors

Jen­nifer Brady (au­thor), Uni­ver­sity of Michi­gan-Ann Arbor, Phil Myers (ed­i­tor), Uni­ver­sity of Michi­gan-Ann Arbor, Rachelle Ster­ling (ed­i­tor), Spe­cial Pro­jects.

Ref­er­ences

Bubac, C. 2009. "Hy­per­olius ni­tidu­lus" (On-line). Am­phib­i­aWeb. Ac­cessed April 05, 2010 at http://​amphibiaweb.​org/​cgi/​amphib_​query?​where-genus=Hyperolius&​where-species=nitidulus.

Drewes, R. 1984. A phy­lo­ge­netic analy­sis of the Hy­per­oli­idae (Anura) : treefrogs of Africa, Mada­gas­car, and the Sey­chelles Is­lands. San Fran­cisco: Cal­i­for­nia Acad­emy of Sci­ences.

Geise, W., K. Lin­sen­mair. 1988. Adap­ta­tions of the Reed Frog Hy­per­olius virid­i­flavis (Am­phibia, Anura, Hy­per­oli­idae) to Its Arid En­vi­ron­ment. IV. Eco­log­i­cal sig­nif­i­cance of Water Econ­omy with Com­ments on Ther­moreg­u­la­tion and En­ergy Al­lo­ca­tion. Oe­colo­gia, 77, No. 3: 327-338. Ac­cessed April 05, 2010 at http://​www.​jstor.​org/​stable/​4218784.

Grafe, T., R. Schmuckt, K. Lisen­mair. 1992. Re­pro­duc­tive En­er­get­ics of the African Reed Frogs, Hy­per­olius virid­i­flavus and Hy­per­olius mar­mora­tus. Phys­i­o­log­i­cal Zo­ol­ogy, 65: 153-171. Ac­cessed Feb­ru­ary 20, 2010 at http://​www.​opus-bayern.​de/​uni-wuerzburg/​volltexte/​2009/​3118/​pdf/​Linsenmair_​Reproductive.​pdf.

Grafe, T., K. Lisen­mair. 1989. Pro­tog­y­nous Sex Change in the Reed Frog Hy­per­olius virid­i­flavus. Copeia, 4: 1024-1029. Ac­cessed Feb­ru­ary 20, 2010 at http://​www.​jstor.​org/​pss/​1445989.

Richards, C., B. Carl­son, S. Rogers. 1975. Re­gen­er­a­tion of dig­its and fore­limbs in the Kenyan reed frog Hy­per­olius virid­i­flavus fer­niquei Con­tri­bu­tion num­ber 52 from the Am­phib­ian Fa­cil­ity. Sup­ported in part by grants from the Mus­cu­lar Dy­s­tro­phy As­so­ci­a­tions of Amer­ica and NIH Grant No. 1 PO6 RR 00572 to George W. Nace.. Jour­nal of Mor­phol­ogy, 146: 431-445. Ac­cessed Feb­ru­ary 21, 2010 at <http://​hdl.​handle.​net/​2027.​42/​50260>.

Schiøtz, A. 1975. The Treefrogs of East­ern Africa. Copen­hagen: Steen­stru­pia.

Schiøtz, A. 1999. Treefrogs of Africa. Frank­furt am Main: Edi­tion Chi­maira.

Schiøtz, A. 2008. "Hy­per­olius virid­i­flavus" (On-line). Am­phib­i­aWeb. Ac­cessed Feb­ru­ary 20, 2010 at http://​amphibiaweb.​org/​cgi/​amphib_​query?​query_​src=aw_​lists_​soundInclude_&​where-genus=Hyperolius&​where-species=viridiflavus.

Schiøtz, A., A. Chan­ning, J. Poyn­ton, M. Largen. 2004. "Hy­per­olius virid­i­flavus" (On-line). IUCN Red List of Threat­ened Species. Ac­cessed Feb­ru­ary 20, 2010 at http://​www.​iucnredlist.​org/​apps/​redlist/​details/​56219/​0.

Schmuckt, R., K. Lisen­mair. 1988. Adap­ta­tions of the reed frog Hy­per­olius virid­i­flavus (Am­phibia, Anura, Hy­per­oli­idae) to its arid en­vi­ron­ment. Oe­colo­gia, 75: 354-361. Ac­cessed Feb­ru­ary 21, 2010 at http://​www.​jstor.​org/​pss/​4218582.

Wiec­zorek, A., R. Drewes, A. Chan­ning. 2001. Phy­lo­ge­netic re­la­tion­ships within the Hy­per­olius virid­i­flavus com­plex (Anura: Hy­per­oli­idae), and com­ments on tax­o­nomic sta­tus. Am­phibia-Rep­tilia, 22: 155-166. Ac­cessed Feb­ru­ary 19, 2010 at http://​www.​ingentaconnect.​com/​content/​brill/​amre/​2001/​00000022/​00000002/​art00002.