insects
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body (head, thorax and abdomen), three pairs of j ...
of the
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of d ...
Orthoptera
Orthoptera () is an order of insects that comprises the grasshoppers, locusts, and crickets, including closely related insects, such as the bush crickets or katydids and wētā. The order is subdivided into two suborders: Caelifera – grassho ...
. These
crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
are in the
subfamily
In biological classification, a subfamily (Latin: ', plural ') is an auxiliary (intermediate) taxonomic rank, next below family but more inclusive than genus. Standard nomenclature rules end subfamily botanical names with "-oideae", and zoologi ...
Oecanthinae of the
family
Family (from la, familia) is a Social group, group of people related either by consanguinity (by recognized birth) or Affinity (law), affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its ...
Gryllidae
The family ''Gryllidae'' contains the subfamilies and genera which entomologists now term true crickets. Having long, whip-like antennae, they belong to the Orthopteran suborder Ensifera, which has been greatly reduced in the last 100 years (''e ...
.
Description
Tree crickets as well as most other
crickets
Crickets are orthopteran insects which are related to bush crickets, and, more distantly, to grasshoppers. In older literature, such as Imms,Imms AD, rev. Richards OW & Davies RG (1970) ''A General Textbook of Entomology'' 9th Ed. Methuen 8 ...
have two pairs of wings. The fore wings are located closer to the head and are hard and leathery in appearance. The hind wings are located aft of the fore wings and are the wings it uses for flight. When the cricket is not in flight the fore wings fold back to cover the hind wings. The bodies of tree crickets are long and skinny with a coloration that matches their
habitat
In ecology, the term habitat summarises the array of resources, physical and biotic factors that are present in an area, such as to support the survival and reproduction of a particular species. A species habitat can be seen as the physical ...
. They have large powerful legs used for jumping. Their heads contain two antennae which can sense both touch and odor and
compound eye
A compound eye is a visual organ found in arthropods such as insects and crustaceans. It may consist of thousands of ommatidia, which are tiny independent photoreception units that consist of a cornea, lens, and photoreceptor cells which disti ...
s which are inherent in all Orthoptera.
Distribution and habitat
They live in trees and
shrub
A shrub (often also called a bush) is a small-to-medium-sized perennial woody plant. Unlike herbaceous plants, shrubs have persistent woody stems above the ground. Shrubs can be either deciduous or evergreen. They are distinguished from trees ...
s, for which they are well
camouflage
Camouflage is the use of any combination of materials, coloration, or illumination for concealment, either by making animals or objects hard to see, or by disguising them as something else. Examples include the leopard's spotted coat, the ...
d. These crickets are
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 ...
and can be found on every continent except
Antarctica
Antarctica () is Earth's southernmost and least-populated continent. Situated almost entirely south of the Antarctic Circle and surrounded by the Southern Ocean, it contains the geographic South Pole. Antarctica is the fifth-largest contine ...
.
In Europe, tree crickets have been expanding northwards and had reached the island of Jersey in the Channel Islands by 2010. In August 2015, the first population was found in mainland England at Dungeness in Kent, where hundreds of males were present.
Tribes and genera
Three
tribes
The term tribe is used in many different contexts to refer to a category of human social group. The predominant worldwide usage of the term in English is in the discipline of anthropology. This definition is contested, in part due to conflic ...
, containing about 25 genera, have been identified in the subfamily Oecanthinae:
Oecanthus
''Oecanthus'' is a genus of cricket in subfamily Oecanthinae, the tree crickets.
Species
The ''Orthoptera Species File'' lists:
*'' Oecanthus adyeri''
*'' Oecanthus allardi''
*'' Oecanthus angustus''
*'' Oecanthus antennalis''
*'' Oecanthus ar ...
Tafalisca
''Tafalisca'' is a genus of silent bush crickets in the family Gryllidae. Records for described species in ''Tafalisca'' are mostly from Central and South America.
Species
These 24 species belong to the genus ''Tafalisca'':
* ''Tafalisca bahama ...
Leptogryllus
''Leptogryllus'' is a genus of Hawaiian crickets. Species include:
References
Leptogryllus,
Ensifera genera
Insects of Hawaii
Taxonomy articles created by Polbot
{{gryllidae-stub ...
Thaumatogryllus
''Thaumatogryllus'' is a genus of crickets in the family Gryllidae. It currently consists of four species, all of which are endemic to Hawaii. Though very little is known about any of these species, it can be confirmed that ''T. conantae'' sho ...
Neoxabea
''Neoxabea'' is a genus of smooth-legged tree crickets in the family Gryllidae. There are about 14 described species in ''Neoxabea''.
Species
These 14 species belong to the genus ''Neoxabea'':
* ''Neoxabea astales'' Walker, 1967
* ''Neoxabea bi ...
incertae sedis
' () or ''problematica'' is a term used for a taxonomic group where its broader relationships are unknown or undefined. Alternatively, such groups are frequently referred to as "enigmatic taxa". In the system of open nomenclature, uncertainty ...
Like other species of cricket they produce their calling song by rubbing the ridges of their wings together. The chirp (or trill) of a tree cricket is long and continuous and can sometimes be mistaken for the call of a
cicada
The cicadas () are a superfamily, the Cicadoidea, of insects in the order Hemiptera (true bugs). They are in the suborder Auchenorrhyncha, along with smaller jumping bugs such as leafhoppers and froghoppers. The superfamily is divided into two ...
or certain species of frogs. While male tree crickets have the ability to call, females lack the ability. This call is then received by other tree crickets in the area through a system called sender-receiver matching. For example, a male tree cricket will produce a
mating call
A mating call is the auditory signal used by animals to attract mates. It can occur in males or females, but literature is abundantly favored toward researching mating calls in females. In addition, mating calls are often the subject of mate choic ...
at a specific range of frequencies. This allows females to be able to pick out the males mating call without becoming distracted or confused by other calls from other species of insects. This range of frequencies is called a carrier frequency. Tree crickets are unique in the way they use carrier frequencies because the range of frequencies changes according to the temperature. Due to this, female tree crickets have tympanum (hearing organs) that can receive a much wider range of frequencies than most other insects. Female tree crickets seem to prefer calls at the lower range of frequencies indicating the presence of a large male. This preference for larger males could be because larger males produce a greater amount of sperm thus increasing the females chances of offspring. Some male tree crickets produce a sound that is too quiet to be audible; they amplify their mating call by making a "megaphone" type structure from tree leaves.
Diet
Tree crickets are omnivorous, and are known to feed on plant parts, other insects such as
Sternorrhyncha
The Sternorrhyncha suborder of the Hemiptera contains the aphids, whiteflies, and scale insects, groups which were traditionally included in the now-obsolete order "Homoptera". "Sternorrhyncha" refers to the rearward position of the mouthparts re ...
, and even
fungi
A fungus ( : fungi or funguses) is any member of the group of eukaryotic organisms that includes microorganisms such as yeasts and molds, as well as the more familiar mushrooms. These organisms are classified as a kingdom, separately from ...
.
Mating
Tree crickets exhibit a behavior called
courtship feeding
A nuptial gift is a nutritional gift given by one partner in some animals' sexual reproduction practices.
Formally, a nuptial gift is a material presentation to a recipient by a donor during or in relation to sexual intercourse that is not simp ...
. Shortly after copulation the male tree cricket secretes a fluid from the metanotal gland located between its wings in the thoracic cavity. This fluid provides the female with nutrients that help to increase the chances of reproduction. Female tree crickets have even been known to steal this fluid from a mating pair during copulation or finish consuming the fluid if the first female dismounts and leaves. After mating a male cannot mate again until after 30 to 60 min allowing the production of another spermatophere. Eggs are laid in the fall, in a series of small holes drilled into the bark. After remaining dormant for the winter, the eggs hatch in the spring and the young tree crickets begin feeding on aphids. They may go through as many as twelve molts before reaching maturity around mid summer.
Cultural associations
The snowy tree cricket (''
Oecanthus fultoni
''Oecanthus fultoni'', also known as the snowy tree cricket, or thermometer cricket, is a species of tree cricket from North America. It feeds on leaves but also damages fruit. The chirp of this species is often dubbed onto sound tracks of fil ...
'' is known for having a chirping rate highly correlated with ambient temperature. This relationship is known as
Dolbear's Law
Dolbear's law states the relationship between the air temperature and the rate at which crickets chirp. It was formulated by Amos Dolbear and published in 1897 in an article called "The Cricket as a Thermometer". Dolbear's observations on the rela ...