Pheropsophus aequinoctialis
Encyclopedia
Pheropsophus aequinoctialis is a species
of ground beetle
from Central
and South America
that feeds on the eggs of mole cricket
s.
, with a distribution that stretches from Yucatán
(Mexico
) in the north to Peru
, Bolivia
, Uruguay
and Catamarca
and Jujuy
provinces in Argentina
in the south.
complex.
s.
Adults of P. aequinoctialis sometimes feed on plant matter, such as the fruit of the palm
Astrocaryum
, but are generally predators, especially of adult mole cricket
s of the genus Scapteriscus. P. aequinoctialis has therefore been considered as a potential biological control agent to control Scapteriscus species. Three species of Scapteriscus (S. abbreviatus, S. borellii & S. vicinus) are adventive species
in Florida, having arrived around 1900 from South America
. The mole cricket's burrowing and the feeding of its larvae cause significant damage to a number of grass species, including Paspalum notatum, Cynodon dactylon
, Eremochloa ophiuroides, Stenotaphrum secundatum
, Zoysia
spp. and Hemarthria altissima.
close to the burrows of mole crickets. The eggs are white and rectangular in outline, with rounded apices. The three instar
s (larva
l stages) which follow are white, with a cream head capsule, and darker colouration at the tips of the mouthparts. The first-instar larvae have long legs, and seek out the egg chambers within the mole cricket burrows. The second instar differs markedly from the first – a phenomenon known as hypermetamorphosis
; they are shorter and wider, with much shorter legs. The larva feeds on the eggs of the mole cricket, and remains in the burrow until it has moulted into the imago
(adult state). The pupa
is of the typical form in ground beetle
s.
from the Neotropic ecozone. It was first described by Carl Linnaeus in his 1763 work Centuria Insectorum
, under the name Cicindela aequinoctialis. It was also later described by Johan Christian Fabricius
in 1775 as Carabus complanatus and by Guillaume-Antoine Olivier
in 1795 as Carabus planus, both of which are junior synonyms of Pheropsophus aequinoctialis. It was later made the type species
of the genus Pheropsophus
.
Species
In biology, a species is one of the basic units of biological classification and a taxonomic rank. A species is often defined as a group of organisms capable of interbreeding and producing fertile offspring. While in many cases this definition is adequate, more precise or differing measures are...
of ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...
from Central
Central America
Central America is the central geographic region of the Americas. It is the southernmost, isthmian portion of the North American continent, which connects with South America on the southeast. When considered part of the unified continental model, it is considered a subcontinent...
and South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
that feeds on the eggs of mole cricket
Mole cricket
The mole crickets compose family Gryllotalpidae, of thick-bodied insects about long, with large beady eyes and shovel-like forelimbs highly developed for burrowing and swimming. They can also fly: the adult mole cricket may fly as far as during mating season, is active most of the year, and...
s.
Distribution
Pheropsophus aequinoctialis is the most widespread species in the genus PheropsophusPheropsophus
Pheropsophus is a genus of beetles in the family Carabidae, containing the following species:* Pheropsophus abbreviatus Arrow, 1901* Pheropsophus abyssinicus Alluaud, 1916* Pheropsophus acutecostatus Fairmaire, 1892...
, with a distribution that stretches from Yucatán
Yucatán
Yucatán officially Estado Libre y Soberano de Yucatán is one of the 31 states which, with the Federal District, comprise the 32 Federal Entities of Mexico. It is divided in 106 municipalities and its capital city is Mérida....
(Mexico
Mexico
The United Mexican States , commonly known as Mexico , is a federal constitutional republic in North America. It is bordered on the north by the United States; on the south and west by the Pacific Ocean; on the southeast by Guatemala, Belize, and the Caribbean Sea; and on the east by the Gulf of...
) in the north to Peru
Peru
Peru , officially the Republic of Peru , is a country in western South America. It is bordered on the north by Ecuador and Colombia, on the east by Brazil, on the southeast by Bolivia, on the south by Chile, and on the west by the Pacific Ocean....
, Bolivia
Bolivia
Bolivia officially known as Plurinational State of Bolivia , is a landlocked country in central South America. It is the poorest country in South America...
, Uruguay
Uruguay
Uruguay ,officially the Oriental Republic of Uruguay,sometimes the Eastern Republic of Uruguay; ) is a country in the southeastern part of South America. It is home to some 3.5 million people, of whom 1.8 million live in the capital Montevideo and its metropolitan area...
and Catamarca
Catamarca Province
Catamarca is a province of Argentina, located in the northwest of the country. The province has a population of 334,568 as per the , and covers an area of 102,602 km². Its literacy rate is 95.5%. Neighbouring provinces are : Salta, Tucumán, Santiago del Estero, Córdoba, and La Rioja...
and Jujuy
Jujuy Province
Jujuy is a province of Argentina, located in the extreme northwest of the country, at the borders with Chile and Bolivia. The only neighboring Argentine province is Salta to the east and south.-History:...
provinces in Argentina
Argentina
Argentina , officially the Argentine Republic , is the second largest country in South America by land area, after Brazil. It is constituted as a federation of 23 provinces and an autonomous city, Buenos Aires...
in the south.
Description
As well as being the most widespread, P. aequinoctialis is also the most variable species in the genus. It has a similar colour pattern to the beetles Phaeoxantha aequinoctialis, P. klugii and Trichognathus marginipennis, and all these species probably form a Müllerian mimicryMüllerian mimicry
Müllerian mimicry is a natural phenomenon when two or more harmful species, that may or may not be closely related and share one or more common predators, have come to mimic each other's warning signals...
complex.
Ecology
Pheropsophus aequinoctialis adults are nocturnal, often hiding in groups during the day under stones, logs or clumps of grass, but emerging in the night to run along sandy trails or riverine beaches. In common with other members of the tribe Brachinini, they display a crepitating behaviour, and produce quinoneQuinone
A quinone is a class of organic compounds that are formally "derived from aromatic compounds [such as benzene or naphthalene] by conversion of an even number of –CH= groups into –C– groups with any necessary rearrangement of double bonds," resulting in "a fully conjugated cyclic dione structure."...
s.
Adults of P. aequinoctialis sometimes feed on plant matter, such as the fruit of the palm
Arecaceae
Arecaceae or Palmae , are a family of flowering plants, the only family in the monocot order Arecales. There are roughly 202 currently known genera with around 2600 species, most of which are restricted to tropical, subtropical, and warm temperate climates...
Astrocaryum
Astrocaryum
Astrocaryum is a genus of about 36 to 40 species of palms native to Central and South America and Trinidad.-Description:Astrocaryum is a genus of spiny palms with pinnately compound leaves–rows of leaflets emerge on either side of the axis of the leaf in a feather-like or fern-like pattern. Some...
, but are generally predators, especially of adult mole cricket
Mole cricket
The mole crickets compose family Gryllotalpidae, of thick-bodied insects about long, with large beady eyes and shovel-like forelimbs highly developed for burrowing and swimming. They can also fly: the adult mole cricket may fly as far as during mating season, is active most of the year, and...
s of the genus Scapteriscus. P. aequinoctialis has therefore been considered as a potential biological control agent to control Scapteriscus species. Three species of Scapteriscus (S. abbreviatus, S. borellii & S. vicinus) are adventive species
Adventive species
An Adventive species is one that has arrived in the geographical area specified from somewhere else by any means , but is not self-sustaining and whose numbers are only increased through non-reproductive means, unlike a naturalised species.-See also:*Naturalisation *Introduced species*Invasive...
in Florida, having arrived around 1900 from South America
South America
South America is a continent situated in the Western Hemisphere, mostly in the Southern Hemisphere, with a relatively small portion in the Northern Hemisphere. The continent is also considered a subcontinent of the Americas. It is bordered on the west by the Pacific Ocean and on the north and east...
. The mole cricket's burrowing and the feeding of its larvae cause significant damage to a number of grass species, including Paspalum notatum, Cynodon dactylon
Cynodon dactylon
Cynodon dactylon , also known as Dūrvā Grass, Bermuda Grass, Dubo, Dog's Tooth Grass, Bahama Grass, Devil's Grass, Couch Grass, Indian Doab, Arugampul, Grama, and Scutch Grass, is a grass native to north and east Africa, Asia and Australia and southern Europe...
, Eremochloa ophiuroides, Stenotaphrum secundatum
St. Augustine grass
St. Augustine Grass or Buffalo Grass is a warm season lawn grass that is popular for use in tropical and subtropical regions. It is a medium to high maintenance grass that forms a thick, carpetlike lawn, crowding out most weeds and other grasses.-Characteristics:St...
, Zoysia
Zoysia
Zoysia is a genus of creeping grasses native to southeast and east Asia and Australasia. These species, commonly called zoysia or zoysiagrass, are found in coastal areas or grasslands. The genus is named after the Austrian botanist Karl von Zois.-Species:*Zoysia japonica Steud.*Zoysia macrantha...
spp. and Hemarthria altissima.
Life cycle
Pheropsophus aequinoctialis lays clutches of 25–60 eggsEgg (biology)
An egg is an organic vessel in which an embryo first begins to develop. In most birds, reptiles, insects, molluscs, fish, and monotremes, an egg is the zygote, resulting from fertilization of the ovum, which is expelled from the body and permitted to develop outside the body until the developing...
close to the burrows of mole crickets. The eggs are white and rectangular in outline, with rounded apices. The three instar
Instar
An instar is a developmental stage of arthropods, such as insects, between each molt , until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or assume a new form. Differences between instars can often be seen in altered body proportions, colors, patterns, or...
s (larva
Larva
A larva is a distinct juvenile form many animals undergo before metamorphosis into adults. Animals with indirect development such as insects, amphibians, or cnidarians typically have a larval phase of their life cycle...
l stages) which follow are white, with a cream head capsule, and darker colouration at the tips of the mouthparts. The first-instar larvae have long legs, and seek out the egg chambers within the mole cricket burrows. The second instar differs markedly from the first – a phenomenon known as hypermetamorphosis
Hypermetamorphosis
Hypermetamorphosis is a kind of complete insect metamorphosis in which the different larval instars represent two or more different forms of larva. As the larva molts its morphology can change from that of a campodeiform to scarabaeiform or to vermiform...
; they are shorter and wider, with much shorter legs. The larva feeds on the eggs of the mole cricket, and remains in the burrow until it has moulted into the imago
Imago
In biology, the imago is the last stage of development of an insect, after the last ecdysis of an incomplete metamorphosis, or after emergence from the pupa where the metamorphosis is complete...
(adult state). The pupa
Pupa
A pupa is the life stage of some insects undergoing transformation. The pupal stage is found only in holometabolous insects, those that undergo a complete metamorphosis, going through four life stages; embryo, larva, pupa and imago...
is of the typical form in ground beetle
Ground beetle
Ground beetles are a large, cosmopolitan family of beetles, Carabidae, with more than 40,000 species worldwide, approximately 2,000 of which are found in North America and 2,700 in Europe.-Description and ecology:...
s.
Taxonomic history
Pheropsophus aequinoctialis was one of the first ground beetles to be describedAlpha taxonomy
Alpha taxonomy is the discipline concerned with finding, describing and naming species of living or fossil organisms. This field is supported by institutions holding collections of these organisms, with relevant data, carefully curated: such institutes include natural history museums, herbaria and...
from the Neotropic ecozone. It was first described by Carl Linnaeus in his 1763 work Centuria Insectorum
Centuria Insectorum
is a 1763 taxonomic work by Carl Linnaeus, and defended as a thesis by Boas Johansson; which of the two men should be credited with its authorship has been the subject of some controversy. It includes descriptions of 102 new insect and crustacean species that had been sent to Linnaeus from...
, under the name Cicindela aequinoctialis. It was also later described by Johan Christian Fabricius
Johan Christian Fabricius
Johan Christian Fabricius was a Danish zoologist, specialising in "Insecta", which at that time included all arthropods: insects, arachnids, crustaceans and others...
in 1775 as Carabus complanatus and by Guillaume-Antoine Olivier
Guillaume-Antoine Olivier
Guillaume-Antoine Olivier was a French entomologist.He was the author of Entomologie, ou histoire naturelle des Insectes and Le Voyage dans l'Empire Othoman, l'Égypte et la Perse . He was a close friend of Johan Christian Fabricius and a patron of Pierre André Latreille.-References:...
in 1795 as Carabus planus, both of which are junior synonyms of Pheropsophus aequinoctialis. It was later made the type species
Type species
In biological nomenclature, a type species is both a concept and a practical system which is used in the classification and nomenclature of animals and plants. The value of a "type species" lies in the fact that it makes clear what is meant by a particular genus name. A type species is the species...
of the genus Pheropsophus
Pheropsophus
Pheropsophus is a genus of beetles in the family Carabidae, containing the following species:* Pheropsophus abbreviatus Arrow, 1901* Pheropsophus abyssinicus Alluaud, 1916* Pheropsophus acutecostatus Fairmaire, 1892...
.