''Hyla'' is a
genus
Genus ( plural genera ) is a taxonomic rank used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In the hierarchy of biological classification, genus com ...
of
frog
A frog is any member of a diverse and largely Carnivore, carnivorous group of short-bodied, tailless amphibians composing the order (biology), order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-f ...
s in the tree frog family
Hylidae
Hylidae is a wide-ranging family of frogs commonly referred to as "tree frogs and their allies". However, the hylids include a diversity of frog species, many of which do not live in trees, but are terrestrial or semiaquatic.
Taxonomy and s ...
. As traditionally defined, it was a
wastebasket genus
Wastebasket taxon (also called a wastebin taxon, dustbin taxon or catch-all taxon) is a term used by some taxonomists to refer to a taxon that has the sole purpose of classifying organisms that do not fit anywhere else. They are typically defined ...
with more than 300 species found in Europe, Asia, Africa, and across the Americas. After a major revision of the family most of these have been moved to other genera so that ''Hyla'' now only contains 17 extant (living) species from Europe, northern Africa and Asia. The earliest known fossil member of this genus is †''
Hyla swanstoni
''Hyla'' is a genus of frogs in the tree frog family Hylidae. As traditionally defined, it was a wastebasket genus with more than 300 species found in Europe, Asia, Africa, and across the Americas. After a major revision of the family most of th ...
'' from the
Eocene
The Eocene ( ) Epoch is a geological epoch (geology), epoch that lasted from about 56 to 33.9 million years ago (mya). It is the second epoch of the Paleogene Period (geology), Period in the modern Cenozoic Era (geology), Era. The name ''Eocene' ...
of
Saskatchewan
Saskatchewan ( ; ) is a Provinces and territories of Canada, province in Western Canada, western Canada, bordered on the west by Alberta, on the north by the Northwest Territories, on the east by Manitoba, to the northeast by Nunavut, and on t ...
, Canada, but its designation to ''Hyla'' happened before the major revision, meaning that its position needs confirmation.
The genus was established by
Josephus Nicolaus Laurenti
Josephus Nicolaus Laurenti (4 December 1735, Vienna – 17 February 1805, Vienna) was an Austrian naturalist and zoologist of Italian origin.
Laurenti is considered the auctor of the class Reptilia (reptiles) through his authorship of ' (1768) ...
in 1768. It was named after
Hylas
In classical mythology, Hylas () was a youth who served as Heracles's (Roman Hercules) companion and servant. His abduction by water nymphs was a theme of ancient art, and has been an enduring subject for Western art in the classical tradition. ...
in
Greek mythology
A major branch of classical mythology, Greek mythology is the body of myths originally told by the Ancient Greece, ancient Greeks, and a genre of Ancient Greek folklore. These stories concern the Cosmogony, origin and Cosmology#Metaphysical co ...
, the companion of
Hercules
Hercules (, ) is the Roman equivalent of the Greek divine hero Heracles, son of Jupiter and the mortal Alcmena. In classical mythology, Hercules is famous for his strength and for his numerous far-ranging adventures.
The Romans adapted the Gr ...
. The name is unusual in that – though Laurenti knew that Hylas was male – the name is unambiguously treated in the
feminine grammatical gender for reasons unknown.
The
etymology
Etymology ()The New Oxford Dictionary of English (1998) – p. 633 "Etymology /ˌɛtɪˈmɒlədʒi/ the study of the class in words and the way their meanings have changed throughout time". is the study of the history of the Phonological chan ...
of the name is also often incorrectly given as being derived from the Greek word (', "forest" or "wood").
Living species
Mating systems
Female choice based on male calling
The mating systems across most species of ''Hyla'' largely feature female choice based on male calling effort.
The specific parameter of calling effort that is selected for can vary from species to species, however. In ''
H. versicolor'', for example, females show preference for calls of longer duration.
The selection of males which have calls of longer duration has shown to only be advantageous at low densities. This suggests that preference plasticity, based on environmental context, is beneficial.
Comparatively, males of ''
H. arborea'' achieve a higher rate of mating success with increased chorus attendance, that is the number of nights spent calling at a given breeding site.
Moreover, increased chorus attendance carries with it a higher energy expenditure and risk of predation. Therefore, it may seem intuitive that males with higher chorus attendance are less likely to survive to the next breeding season. Conversely, these males are more likely to survive. This suggests that the fitness of these males is high enough to overcome the costs associated with chorus attendance.
This provides evidence for chorus attendance as an indicator of mate quality in ''H. arborea''.
Male-male contests
Although it is studied less frequently than female choice, sexual selection influenced by male-male
intrasexual competition Male-male intrasexual competition occurs when two males of the same species compete for the opportunity to mate with a female. Sexually dimorphic traits, size, sex ratio, and the social situation may all play a role in the effects male-male competit ...
does exist in certain species of ''Hyla''. Males of ''H. versicolor'' produce conspicuous advertisement calls in large groups at territories known to females.
This behavior, known as
lekking
A lek is an aggregation of male animals gathered to engage in competitive displays and courtship rituals, known as lekking, to entice visiting females which are surveying prospective partners with which to mate. A lek can also indicate an avail ...
, is common in many species of ''Hyla''. In order to broadcast a clear acoustic communication to a female, males require distinct calling spaces within their respective leks.
When males infringe upon the calling space of one another, aggressive interactions may occur. Males of ''H. versicolor'' may choose to lower costs of aggressive encounters by first assessing one another's
resource holding potential In biology, resource holding potential (RHP) is the ability of an animal to win an all-out fight if one were to take place. The term was coined by Geoff Parker to disambiguate physical fighting ability from the motivation to persevere in a fight (Pa ...
.
In simple terms, the resource holding potential (RHP) of an individual is its ability to win a fight. RHP can be based on a number of factors, including mass, size, weaponry, etc. In ''H. versicolor'', the question of what determines an individual's RHP still stands. Aggressive interactions of this species are hard to observe within natural environments, because they occur briefly and infrequently.
Research has suggested that RHP in this species is not based on body size, however these findings were not based on in situ observations, but instead on the findings of a manipulated experiment.
Indirect selection
![HylaArborea-CallingMale](https://upload.wikimedia.org/wikipedia/commons/6/6f/HylaArborea-CallingMale.jpg)
In terms of sexual selection, indirect selection refers to the selection of a specific trait based on its genetic correlation to overall
fitness. ''H. arborea'' is a
nocturnal
Nocturnality is an animal behavior characterized by being active during the night and sleeping during the day. The common adjective is "nocturnal", versus diurnal meaning the opposite.
Nocturnal creatures generally have highly developed sens ...
species which depends on calling by males for female
mate choice
Mate choice is one of the primary mechanisms under which evolution can occur. It is characterized by a "selective response by animals to particular stimuli" which can be observed as behavior.Bateson, Paul Patrick Gordon. "Mate Choice." Mate Choic ...
.
In addition to its ability to detect acoustic communications, ''H. arborea'', as well as most other
Anuran
A frog is any member of a diverse and largely carnivorous group of short-bodied, tailless amphibians composing the order Anura (ανοὐρά, literally ''without tail'' in Ancient Greek). The oldest fossil "proto-frog" ''Triadobatrachus'' ...
species, possess specialized visual systems that function particularly well in low light.
This visual system allows for detection of observable male traits that could factor into female mate choice. Research has shown that ''H. arborea'' females have a preference for males with more conspicuous vocal sac coloration.
It is postulated that this preference may assist in localization and detection of males by searching females. However, vocal sac pigmentation is dictated by
carotenoid
Carotenoids (), also called tetraterpenoids, are yellow, orange, and red organic compound, organic pigments that are produced by plants and algae, as well as several bacteria, and Fungus, fungi. Carotenoids give the characteristic color to pumpki ...
levels, which must be ingested through food intake.
Thus, the presence of conspicuous vocal sac coloration could in turn signal higher male foraging ability and fitness.
References
External links
* . 2007. Amphibian Species of the World: an Online Reference. Version 5.1 (10 October 2007)
''Hyla'' Electronic Database accessible at https://web.archive.org/web/20071024033938/http://research.amnh.org/herpetology/amphibia/index.php. American Museum of Natural History, New York, USA. (Accessed: Apr 21, 2008).
*
eb application 2008. Berkeley, California
''Hyla'' AmphibiaWeb, available at http://amphibiaweb.org/. (Accessed: Apr 21, 2008).
* taxo
''Hyla''at http://www.eol.org.
{{Taxonbar, from=Q826861
Hylinae
Amphibian genera
Taxa named by Josephus Nicolaus Laurenti