The strawberry poison frog, strawberry poison-dart frog or blue jeans poison frog (''Oophaga pumilio'', formerly ''Dendrobates pumilio'') is a species of small
poison dart frog
Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are ...
found in
Central America
Central America ( es, América Central or ) is a subregion of the Americas. Its boundaries are defined as bordering the United States to the north, Colombia to the south, the Caribbean Sea to the east, and the Pacific Ocean to the west. ...
. It is common throughout its range, which extends from eastern central
Nicaragua
Nicaragua (; ), officially the Republic of Nicaragua (), is the largest country in Central America, bordered by Honduras to the north, the Caribbean to the east, Costa Rica to the south, and the Pacific Ocean to the west. Managua is the cou ...
through
Costa Rica
Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
and northwestern
Panama
Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...
. The species is often found in humid lowlands and premontane forest, but large populations are also found in disturbed areas such as plantations.Savage, J. M. 2002. The Amphibians and Reptiles of Costa Rica. University of Chicago Press, Chicago and London. The strawberry poison frog is perhaps most famous for its widespread variation in coloration, comprising approximately 15–30 color morphs, most of which are presumed to be true-breeding. ''O. pumilio'', while not the most poisonous of the dendrobatids, is the most toxic member of its genus.
Diet
The diet of ''O. pumilio'' causes the skin of the amphibian to become toxic in nature when certain subspecies of mites and ants are ingested very similar to many other
poison dart frogs
Poison dart frog (also known as dart-poison frog, poison frog or formerly known as poison arrow frog) is the common name of a group of frogs in the family Dendrobatidae which are native to tropical Central and South America. These species are ...
.
Alkaloid
Alkaloids are a class of basic, naturally occurring organic compounds that contain at least one nitrogen atom. This group also includes some related compounds with neutral and even weakly acidic properties. Some synthetic compounds of similar ...
toxins are organic in nature and contain nitrogenous bases that react with carbon and hydrogen groups.Pumiliotoxin 251D is the specialized toxin that is sequestered by this species of frog. This toxin has a negative stimulating effect on cardiac function and is a severe disruptor of the sodium potassium ion channels within cells. Upon ingestion of Pumiliotoxin 251D, organisms preying on ''O. pumilio'' experience convulsions, paralysis, and death.
It has been found that once ''O.pumilio'' reaches sexual maturity, their granular glands significantly increase in size and their diet shifts. In females, it is common to find about 53% more alkaloids than adult males.
Oribatida
Oribatida (formerly Cryptostigmata), also known as oribatid mites, moss mites or beetle mites, are an order (biology), order of mites, in the "chewing Acariformes" clade Sarcoptiformes. They range in size from . There are currently 12,000 species ...
. Toxins appear to be biosynthesized in adult mites, as nymph and larval stages of the arachnid do not carry the toxins. Experimental analysis of this species of mite show alkaloid toxins are found almost exclusively in the opisthonotal glands of mites of the
Scheloribatidae
Scheloribatidae is a family of mites and ticks in the order Sarcoptiformes. There are at least 20 genera and 320 described species in Scheloribatidae.
Genera
References
Further reading
*
*
*
*
Acariformes
Acari families
{{s ...
. Oil glands of the mite contain the toxins and are then released internally as the amphibian digests 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 ...
.
''O. pumilio'' can also attribute its cutaneous toxicity to its rich diet of
formicinae
The Formicinae are a subfamily within the Formicidae containing ants of moderate evolutionary development.
Formicines retain some primitive features, such as the presence of cocoons around pupae, the presence of ocelli in workers, and little ...
ants. Species of the formicine genus '' Brachymyrmex'' contain pumiliotoxins which the frogs incorporate and accumulate poison from. There is a variability of alkaloid profiles among populations and individuals of ''O. pumilio'', which is indicative of varying levels of available prey within their infraspecific habitats. Research and physical analysis reveal that maternally derived alkaloids exist in young tadpoles. The increase in alkaloids in tadpoles suggests that the females are providing more chemical defenses to their more vulnerable young. This being one of the first found examples of provisioning that occurs after hatching. During tadpole-rearing, mother frogs feed their young an unfertilized egg from their ovaries after dropping each individual tadpole into a repository of water usually found in a
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, ...
. Tadpoles lacking the obligate nutritive egg diet do not contain the alkaloid. This step is crucial for the tadpoles to sequester the alkaloid from their mother; without such, young tadpoles become susceptible to predation by arthropods and other frogs.
terrestrial
Terrestrial refers to things related to land or the planet Earth.
Terrestrial may also refer to:
* Terrestrial animal, an animal that lives on land opposed to living in water, or sometimes an animal that lives on or near the ground, as opposed to ...
, and can often be found in leaf litter in both forested and disturbed areas. Studies have shown that the optimal habitat is determined by the male, considering the resource benefits and defense costs. Males tend to expend more energy defending smaller but higher quality areas. There has also been evidence that the better competitors and fighters are the males guarding smaller sites with higher female density. In most Anura the louder the vocalization when competing usually means they are larger in size and in better health. However, in the O. pumilio species researchers have determined that these frogs call out at a lower rate to limit their energetic expenditures. Females, on the other hand, simply distribute themselves according to tadpole rearing sites.
Though brightly colored and toxic, these frogs are relatively small, growing to approximately in standard length.
Reproduction and parental care
''Oophaga pumilio'' is an external breeder, and other species of the genus ''Oophaga'' are notable in the
amphibian
Amphibians are tetrapod, four-limbed and ectothermic vertebrates of the Class (biology), class Amphibia. All living amphibians belong to the group Lissamphibia. They inhabit a wide variety of habitats, with most species living within terres ...
world for exhibiting a high degree of parental care. The strawberry poison frog has dual parental care. The males defend and water the nests, and the females feed the oophagous tadpoles their unfertilized eggs. Although both male and female contribute to parental care, females invest more heavily in terms of energy expenditure, time investment, and loss of potential reproduction. When choosing a partner for mating, females will choose the closest calling male rather than the highest quality male. Females provide energetically costly eggs to the tadpoles for 6–8 weeks (until metamorphosis), remain sexually inactive during tadpole rearing, and care for only one clutch of four to six tadpoles at a time. The males contribute via the relatively "cheap" (in terms of energy) act of watering and protecting the eggs for a relatively short period (10–12 days), and can care for multiple nests at one time. The extreme maternal investment in their offspring is believed to be the result of high egg mortality. Only 5–12% of the clutch develops into tadpoles, so the female's fitness may be best increased by making sure those few eggs that form tadpoles survive.
After mating, the female lays three to five eggs on a leaf or bromeliad axil. The male then ensures the eggs are kept hydrated by transporting water in his
cloaca
In animal anatomy, a cloaca ( ), plural cloacae ( or ), is the posterior orifice that serves as the only opening for the digestive, reproductive, and urinary tracts (if present) of many vertebrate animals. All amphibians, reptiles and birds, a ...
. After about 10 days, the eggs hatch and the female transports the tadpoles on her back to some water-filled location. In captivity, on rare occasions, the male is observed transporting the tadpoles, though whether this is intentional, or the tadpoles simply hitch a ride, is unknown.
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, ...
axils are frequently used tadpole deposition sites, but anything suitable can be used, such as knots in trees, small puddles, or human trash such as aluminum cans.
Tadpoles are deposited singly at each location. Once this has been done, the female will come to each tadpole every few days and deposit several unfertilized food eggs. In captivity, tadpoles have been raised on a variety of diets, ranging from algae to the eggs of other dart frogs, but with minimal success. ''O. pumilio'' tadpoles are considered obligate egg feeders, as they are unable to accept any other form of nutrition.
After about a month, the tadpole will metamorphose into a small froglet. Generally, it stays near its water source for a few days for protection as it absorbs the rest of its tail.
Taxonomy
''Oophaga pumilio'' belongs to the genus ''
Oophaga
''Oophaga'' is a genus of poison-dart frogs containing twelve species, many of which were formerly placed in the genus ''Dendrobates''. The frogs are distributed in Central and South America, from Nicaragua through the Colombian El Choco to nor ...
'', although the name ''Dendrobates pumilio'' is still sometimes used. There is evidence that the species of ''Oophaga'' (previously classified as the "female parental care group" of ''Dendrobates'') are a
monophyletic
In cladistics for a group of organisms, monophyly is the condition of being a clade—that is, a group of taxa composed only of a common ancestor (or more precisely an ancestral population) and all of its lineal descendants. Monophyletic gro ...
evolutionary group. Due to the low level of genetic divergence between the species analyzed in this genus, it is estimated that they speciated relatively recently, after the formation of the current Panamanian land bridge in the
Pliocene
The Pliocene ( ; also Pleiocene) is the epoch in the geologic time scale that extends from 5.333 million to 2.58Oophaga arborea'' and ''
Oophaga sylvatica
''Oophaga sylvatica'', sometimes known as its Spanish name diablito, is a species of frog in the family Dendrobatidae found in Southwestern Colombia and Northwestern Ecuador. Its natural habitat is lowland and submontane rainforest; it can, howev ...
.''
Evolution
Strawberry poison frog, ''Oophaga pumilio'', shows extreme variation in color and pattern between populations that have been geographically isolated for more than 10,000 years. When populations are separated by geographic distances and landscape barriers, they frequently experience restricted gene flow, which can enable phenotypic divergence between populations through selection or drift. Their variety in warning coloration is used for their visibility, toxicity and resistance to predators. When divergent phenotypes are mostly restricted to separate islands, the biogeography of color polymorphism suggests a major role for neutral process. However, Summers et al. (1997) provide evidences that neutral divergence alone is unlikely to have caused the variation in color patterns. As shown by Lande, rapid evolution in sexually selecting species is led by the interaction of random
genetic drift
Genetic drift, also known as allelic drift or the Wright effect, is the change in the frequency of an existing gene variant (allele) in a population due to random chance.
Genetic drift may cause gene variants to disappear completely and there ...
with natural and sexual selection such as random genetic drift in female mating preferences. Color is known to play a role in male–female signaling, mate attraction, and male–male signaling in anurans. Based on Tazzyman and Iwasa's study that involved collections of samples from main islands in the Bocas del Toro archipelago, its results proved that female preference on male calls led to call divergence and therefore divergence was driven by sexual selection. Mate choice plays a critical role in generating and maintaining biodiversity. Furthermore, spatial variation in predators or habitat features could exert divergent natural selection on coloration in response to its subjection to predator selection. It is still unclear to what extent sexual selection has driven the evolution of color morphs rather than reinforcing the reproductive isolation of morphs. In an
aposematic
Aposematism is the advertising by an animal to potential predators that it is not worth attacking or eating. This unprofitability may consist of any defences which make the prey difficult to kill and eat, such as toxicity, venom, foul taste or ...
organism such as ''Oophaga pumilio'', we cannot attribute a
phylogenetic signal
Phylogenetic signal is an evolutionary and ecological term, that describes the tendency or the pattern of related biological species to resemble each other more than any other species that is randomly picked from the same phylogenetic tree.
Chara ...
of selection to female mate choice alone but is quite possible that genetic drift would interact with female color preferences to trigger divergence Researchers Maan and Cummings had also found that in some cases female ''Oophaga Pumilio'' preferred male mates that had very different coloration than their own phenotype. In nature the equality of color through evolution is very unlikely considering the various sensory biases of predators and the different background colors of the environments these frogs habitat. Due to this variability in color evolution, it is unlikely to say there is superiority of aposematic purpose of color selection in the ''Oopha''Species such as Oophaga Pumilio have been known to thrive and compete very well on disturbed and converted land. With temperatures rising in many different biomes, the success of many species is going to be determined by its ability to acclimate and adapt. In the study done by Rivera and Nowakowski, they discovered that in many cases O.pumilio is experiencing greater temperature stress in converted habitats than forests''ga Pumilio'' species.
Habitat Niche
These frog species utilize scattered structures throughout these disturbed lands to relieve some of the thermal stress, yet it was found that O. pumilio is still warmer than any other species in the forested areas, being exposed to temperatures up to 27 degrees Celsius. These findings suggest that this species of dart frog acts as an ecological buffer and is predicted to be more successful than other species as land use changes and temperatures rise.
Captivity
''Oophaga pumilio'' is a popular frog in captivity, due to its striking colors and unique life cycle. They have been imported in vast quantities to the United States and Europe since the early 1990s, when they would typically be available for around US$75 each. However, these shipments have since stopped, and ''O. pumilio'' is much less common and available in reduced diversity. In Europe, ''O. pumilio'' is much more diverse due to an increased frequency of smuggling and the resulting offspring of smuggled animals. Smuggling of dart frogs is less common elsewhere, but is still a large problem as it kills large numbers of animals and often degrades or destroys viable habitat.
Recently, ''O. pumilio'' has been exported from Central America again in small numbers from frog farms. Because of this, they have seen a huge increase in numbers in the dart frog community and are regularly available.
Common color morphs in captivity
One example of a color morph is the blue jeans morph. It is most common throughout the species range, but is relatively rare in the United States pet trade. Most of these animals came from imports during the 1990s, or are their descendants. As of 2003, it was observed that this morph could be found throughout
Costa Rica
Costa Rica (, ; ; literally "Rich Coast"), officially the Republic of Costa Rica ( es, República de Costa Rica), is a country in the Central American region of North America, bordered by Nicaragua to the north, the Caribbean Sea to the no ...
, as well as in mainland
Panama
Panama ( , ; es, link=no, Panamá ), officially the Republic of Panama ( es, República de Panamá), is a transcontinental country spanning the southern part of North America and the northern part of South America. It is bordered by Cos ...