Oxycorynini
Encyclopedia
Oxycorynini are a tribe
of American
belids, primitive weevil
s of the family
Belidae
. Like in other belids, their antenna
e are straight, not elbowed as in the true weevils (Curculionidae
). In contrast to other Belidae, Oxycorynini larva
e feed on flowers or several types of fruit
.
The Oxycorynini contain 7 genera
, the bulk of the subfamily Oxycoryninae
. But while they are highly diverse, they are not particularly speciose, with nearly 20 described and a few undescribed species
compared to the more than 150 Hawaiian
species of Proterhinus of the Aglycyderini
.
The fossil
record shows that the three Oxycoryninae tribes were well distinct by the mid-Paleogene
, about 50 million years ago (mya). The belids as a whole are of Jurassic
origin, and the Oxycorynini must thus have evolve
d in the Late Cretaceous
or perhaps Paleocene
, roughly some 100-60 mya.
ally the lack of spermatheca
, with the spermathecal duct directly inserting on the common oviduct
, is conspicuous.
Adults of Parallocorynus and Rhopalotria are peculiarly soft-bodied and possess several characteristic traits: their gular
suture
s are fused to a single suture, their elytra cannot be locked in open position and have round tips between which the pygidium
can be seen. The sternite of their mesothorax
slants forward, but the part protruding between the second leg pair is not raised. Finally, their spermathecal gland and spermathecal duct form a common tube. Alloxycorynus and Hydnorobius adults have two gular sutures which form a semicircle at the head base and end in distinct tips; their elytra are ribbed lengthwise. Adults of Balanophorobius and Oxycorynus have a flattened hindside of the metathoracal
sternite.
More characteristic are the larva
e. Their labrum
has two sensilla
at the base and two more towards the center of the forward maring. They have a typical body shape with recurved hindparts; the anus
opens on the underside. Except in Oxycraspedus, the dark forehead is bordered by a ridge towards the back, where the cuticle
attaches, and the body is widest in the middle of the abdomen. And of course, Oxycorynini larvae differ from other belids in that their larvae do not feed on dead or decaying wood but on flower
s and fruit
s.
Oxycraspedina
Allocorynina
Oxycorynina
However, most of this subdivision, in particular the monophyly
of the Oxycorynina, is by no means reliably established. Oxycraspedus seems to be simply a very basal genus
. What seems probable is that Parallocorynus and Rhopalotria as well as Balanophorobius and Oxycorynus are sister genera, with the other genera are of rather uncertain position in regard to these two clade
s. But while the Allocorynina are quite surely a good clade, the biogeography
of the Oxycorynina is puzzling, because Balanophorobius does not occur anywhere near its presumed sister taxon Oxycorynus, which instead ranges adjacent to the other two members of the proposed subtribe. It is to be noted however that neither are all species of Oxycorynini discovered yet, nor is the knowledge about their distribution considered satisfactory by entomologists.
limited to Chile
between the Maule
and Araucanía Region
s and adjacent Argentina
where they have been found in Neuquén Province
.
Parallocorynus with one and Rhopalotria with three described species - several undescribed species are known in each genus - occur across Central America
and in some adjacent regions. The former only occurs in Mexico
and Honduras
, while the latter is widespread from Mexico to Panama
, also occurring on Cuba
and in Florida
, and probably in northern South America
too.
The two Alloxycorynus species are found from southern Peru
(Cusco Region
) to eastern Bolivia
and northern Argentina. Hydnorobius with three species occurs to the southeast of Alloxycorynus south to central Argentina (Mendoza
to Buenos Aires Province
s). Oxycorynus occurs with 5 known species northwards of Hydnorobius, from northern Argentina and southern Bolivia north into Brazil
(Santa Catarina state). The monotypic
Balanophorobius, described only in 2005, has not yet been found outside the Osa Peninsula
of Costa Rica
.
e feed on the parenchyma
tous tissue but not the seeds. Indeed, by the time the larvae have finished their development to pupa
tion, the host cones are typically already discarded by the plant and have shed their seeds. Very old cones that are slowly rotting on the forest floor are also taken, demonstrating the evolution
ary link between Oxycorynini and the other Belidae which also feed on decaying woody tissue, but of twigs and stems.
Parallocorynus has to date only been collected from the cycad
genus Dioon
. Similarly Rhopalotria is associated with various species of Zamia
cycads, though one of the as of yet undescribed species was collected from Dioon spinulosum
. It seems that the species of Rhopalotria are monophagous - like R. slossoni on Coontie (Z. pumila) or R. mollis on Cardboard Cycad (Z. furfuracea) - but more research in Zamia species in necessary to verify this. These two belid genera are very important pollinator
s of their host cycads; the larvae feed primarily on the sporophyll
s.
Alloxycorynus, Balanophorobius, Oxycorynus have been recorded from Balanophoraceae
. Specific beetle-plant association are A. bruchi with Ombrophytum, and O. nigripes and O. armatus with Lophophytum. B. gamezi was apparently collected from Helosis cayennensis.
Hydnorobius larvae are recorded from flowers and fruits of Prosopanche (Hydnoraceae
). P. americana is host to H. hydnorae and H. helleri; H. parvulus is found on P. bonacinae.
Balanophoraceae and Hydnoraceae are root parasitic rather primitive dicots but not closely related. Possibly, the Oxycorynini which feed on them shifted to these plants from the ones parasitized. It is likely that the initial host switch was to Balanophoraceae, but these parasitize a wide range of trees so little more can be said at present.
Tribe (biology)
In biology, a tribe is a taxonomic rank between family and genus. It is sometimes subdivided into subtribes.Some examples include the tribes: Canini, Acalypheae, Hominini, Bombini, and Antidesmeae.-See also:* Biological classification* Rank...
of American
Americas
The Americas, or America , are lands in the Western hemisphere, also known as the New World. In English, the plural form the Americas is often used to refer to the landmasses of North America and South America with their associated islands and regions, while the singular form America is primarily...
belids, primitive weevil
Weevil
A weevil is any beetle from the Curculionoidea superfamily. They are usually small, less than , and herbivorous. There are over 60,000 species in several families, mostly in the family Curculionidae...
s of the family
Family (biology)
In biological classification, family is* a taxonomic rank. Other well-known ranks are life, domain, kingdom, phylum, class, order, genus, and species, with family fitting between order and genus. As for the other well-known ranks, there is the option of an immediately lower rank, indicated by the...
Belidae
Belidae
Belidae is a family of weevils, called belids or primitive weevils because they have straight antennae, unlike the "true weevils" or Curculionidae which have elbowed antennae...
. Like in other belids, their antenna
Antenna (biology)
Antennae in biology have historically been paired appendages used for sensing in arthropods. More recently, the term has also been applied to cilium structures present in most cell types of eukaryotes....
e are straight, not elbowed as in the true weevils (Curculionidae
Curculionidae
Curculionidae is the family of the "true" weevils . It was formerly recognized in 1998 as the largest of any animal family, with over 40,000 species described worldwide at that time...
). In contrast to other Belidae, Oxycorynini 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...
e feed on flowers or several types of fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
.
The Oxycorynini contain 7 genera
Genera
Genera is a commercial operating system and development environment for Lisp machines developed by Symbolics. It is essentially a fork of an earlier operating system originating on the MIT AI Lab's Lisp machines which Symbolics had used in common with LMI and Texas Instruments...
, the bulk of the subfamily Oxycoryninae
Oxycoryninae
Oxycoryninae are subfamily of primitive weevils of the family Belidae, but sometimes treated as a distinct family Oxycorynidae. Like in other belids, their antennae are straight, not elbowed as in the true weevils , and their larvae feed on the wood of diseased or dying plants or on deadwood or...
. But while they are highly diverse, they are not particularly speciose, with nearly 20 described and a few undescribed species
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...
compared to the more than 150 Hawaiian
Hawaiian Islands
The Hawaiian Islands are an archipelago of eight major islands, several atolls, numerous smaller islets, and undersea seamounts in the North Pacific Ocean, extending some 1,500 miles from the island of Hawaii in the south to northernmost Kure Atoll...
species of Proterhinus of the Aglycyderini
Aglycyderini
Aglycyderini are a tribe of belids, primitive weevils of the family Belidae. Like in other belids, their antennae are straight, not elbowed as in the true weevils...
.
The fossil
Fossil
Fossils are the preserved remains or traces of animals , plants, and other organisms from the remote past...
record shows that the three Oxycoryninae tribes were well distinct by the mid-Paleogene
Paleogene
The Paleogene is a geologic period and system that began 65.5 ± 0.3 and ended 23.03 ± 0.05 million years ago and comprises the first part of the Cenozoic Era...
, about 50 million years ago (mya). The belids as a whole are of Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
origin, and the Oxycorynini must thus have evolve
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
d in the Late Cretaceous
Late Cretaceous
The Late Cretaceous is the younger of two epochs into which the Cretaceous period is divided in the geologic timescale. Rock strata from this epoch form the Upper Cretaceous series...
or perhaps Paleocene
Paleocene
The Paleocene or Palaeocene, the "early recent", is a geologic epoch that lasted from about . It is the first epoch of the Palaeogene Period in the modern Cenozoic Era...
, roughly some 100-60 mya.
Description
The adult Oxycorynini have a number of fairly characteristic traits, but they are not present in all members of this tribe. Many have a pronotum whose hind margin is at least as wide as the elytra bases, often wider. Except in the rather primitive Oxycraspedus, the first tarsomere is smaller than the second, and microscopicMicroscopic
The microscopic scale is the scale of size or length used to describe objects smaller than those that can easily be seen by the naked eye and which require a lens or microscope to see them clearly.-History:...
ally the lack of spermatheca
Spermatheca
The spermatheca , also called receptaculum seminis , is an organ of the female reproductive tract in insects, some molluscs, oligochaeta worms and certain other invertebrates and vertebrates...
, with the spermathecal duct directly inserting on the common oviduct
Oviduct
In non-mammalian vertebrates, the passageway from the ovaries to the outside of the body is known as the oviduct. The eggs travel along the oviduct. These eggs will either be fertilized by sperm to become a zygote, or will degenerate in the body...
, is conspicuous.
Adults of Parallocorynus and Rhopalotria are peculiarly soft-bodied and possess several characteristic traits: their gular
Gular
Gular is of or pertaining to the throat, and may more specifically refer to:* Gular scales in reptiles* Gular scute, or gular projection, in turtles and tortoises* Gular fold in lizards...
suture
Suture (anatomical)
In anatomy, a suture is a fairly rigid joint between two or more hard elements of an animal, with or without significant overlap of the elements....
s are fused to a single suture, their elytra cannot be locked in open position and have round tips between which the pygidium
Pygidium
The pygidium is the posterior body part or shield of crustaceans and some other arthropods, such as insects and the extinct trilobites. It contains the anus and, in females, the ovipositor...
can be seen. The sternite of their mesothorax
Mesothorax
The mesothorax is the middle of the three segments in the thorax of an insect, and bears the second pair of legs. Its principal sclerites are the mesonotum , the mesosternum , and the mesopleuron on each side...
slants forward, but the part protruding between the second leg pair is not raised. Finally, their spermathecal gland and spermathecal duct form a common tube. Alloxycorynus and Hydnorobius adults have two gular sutures which form a semicircle at the head base and end in distinct tips; their elytra are ribbed lengthwise. Adults of Balanophorobius and Oxycorynus have a flattened hindside of the metathoracal
Metathorax
The metathorax is the posterior of the three segments in the thorax of an insect, and bears the third pair of legs. Its principal sclerites are the metanotum , the metasternum , and the metapleuron on each side...
sternite.
More characteristic are the 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...
e. Their labrum
Labrum (arthropod mouthpart)
The labrum is a flap-like structure that lies immediately in front of the mouth in almost all extant euarthropods, the general exception being provided by the probable chelicerate-relatives the pycnogonids. It has proved to be by far the most controversial of all arthropod head structures. It is...
has two sensilla
Sensilla
A sensillum is an insect sensory organ protruding from the cuticle, or sometime lying within or beneath it. Sensilla are divided in chemical, mechanical , thermal and visual....
at the base and two more towards the center of the forward maring. They have a typical body shape with recurved hindparts; the anus
Anus
The anus is an opening at the opposite end of an animal's digestive tract from the mouth. Its function is to control the expulsion of feces, unwanted semi-solid matter produced during digestion, which, depending on the type of animal, may be one or more of: matter which the animal cannot digest,...
opens on the underside. Except in Oxycraspedus, the dark forehead is bordered by a ridge towards the back, where the cuticle
Cuticle
A cuticle , or cuticula, is a term used for any of a variety of tough but flexible, non-mineral outer coverings of an organism, or parts of an organism, that provide protection. Various types of "cuticles" are non-homologous; differing in their origin, structure, function, and chemical composition...
attaches, and the body is widest in the middle of the abdomen. And of course, Oxycorynini larvae differ from other belids in that their larvae do not feed on dead or decaying wood but on flower
Flower
A flower, sometimes known as a bloom or blossom, is the reproductive structure found in flowering plants . The biological function of a flower is to effect reproduction, usually by providing a mechanism for the union of sperm with eggs...
s and fruit
Fruit
In broad terms, a fruit is a structure of a plant that contains its seeds.The term has different meanings dependent on context. In non-technical usage, such as food preparation, fruit normally means the fleshy seed-associated structures of certain plants that are sweet and edible in the raw state,...
s.
Systematics
The Oxycorynini are tentatively divided into 3 subtribes:Oxycraspedina
- Oxycraspedus
Allocorynina
- Parallocorynus
- Rhopalotria
Oxycorynina
- Hydnorobius
- Alloxycorynus
- Oxycorynus
- Balanophorobius
However, most of this subdivision, in particular the monophyly
Monophyly
In common cladistic usage, a monophyletic group is a taxon which forms a clade, meaning that it contains all the descendants of the possibly hypothetical closest common ancestor of the members of the group. The term is synonymous with the uncommon term holophyly...
of the Oxycorynina, is by no means reliably established. Oxycraspedus seems to be simply a very basal genus
Genus
In biology, a genus is a low-level taxonomic rank used in the biological classification of living and fossil organisms, which is an example of definition by genus and differentia...
. What seems probable is that Parallocorynus and Rhopalotria as well as Balanophorobius and Oxycorynus are sister genera, with the other genera are of rather uncertain position in regard to these two clade
Clade
A clade is a group consisting of a species and all its descendants. In the terms of biological systematics, a clade is a single "branch" on the "tree of life". The idea that such a "natural group" of organisms should be grouped together and given a taxonomic name is central to biological...
s. But while the Allocorynina are quite surely a good clade, the biogeography
Biogeography
Biogeography is the study of the distribution of species , organisms, and ecosystems in space and through geological time. Organisms and biological communities vary in a highly regular fashion along geographic gradients of latitude, elevation, isolation and habitat area...
of the Oxycorynina is puzzling, because Balanophorobius does not occur anywhere near its presumed sister taxon Oxycorynus, which instead ranges adjacent to the other two members of the proposed subtribe. It is to be noted however that neither are all species of Oxycorynini discovered yet, nor is the knowledge about their distribution considered satisfactory by entomologists.
Distribution
Oxycraspedus, apparently the most ancient living genus of Oxycorynini, has three described speciesSpecies
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...
limited to Chile
Chile
Chile ,officially the Republic of Chile , is a country in South America occupying a long, narrow coastal strip between the Andes mountains to the east and the Pacific Ocean to the west. It borders Peru to the north, Bolivia to the northeast, Argentina to the east, and the Drake Passage in the far...
between the Maule
Maule Region
The VII Maule Region is one of Chile's 15 first order administrative divisions. Its capital is Talca. The region takes its name from the Maule River which, running westward from the Andes, bisects the region and spans a basin of about 20,600 km2...
and Araucanía Region
Araucanía Region
The IX Araucanía Region is one of Chile's 15 first order administrative divisions and comprises two provinces: Malleco in the north and Cautín in the south....
s and adjacent 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...
where they have been found in Neuquén Province
Neuquén Province
Neuquén is a province of Argentina, located in the west of the country, at the northern end of Patagonia. It borders Mendoza Province to the north, Rio Negro Province to the southeast, and Chile to the west...
.
Parallocorynus with one and Rhopalotria with three described species - several undescribed species are known in each genus - occur across Central America
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 in some adjacent regions. The former only occurs in 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...
and Honduras
Honduras
Honduras is a republic in Central America. It was previously known as Spanish Honduras to differentiate it from British Honduras, which became the modern-day state of Belize...
, while the latter is widespread from Mexico to Panama
Panama
Panama , officially the Republic of Panama , is the southernmost country of Central America. Situated on the isthmus connecting North and South America, it is bordered by Costa Rica to the northwest, Colombia to the southeast, the Caribbean Sea to the north and the Pacific Ocean to the south. The...
, also occurring on Cuba
Cuba
The Republic of Cuba is an island nation in the Caribbean. The nation of Cuba consists of the main island of Cuba, the Isla de la Juventud, and several archipelagos. Havana is the largest city in Cuba and the country's capital. Santiago de Cuba is the second largest city...
and in Florida
Florida
Florida is a state in the southeastern United States, located on the nation's Atlantic and Gulf coasts. It is bordered to the west by the Gulf of Mexico, to the north by Alabama and Georgia and to the east by the Atlantic Ocean. With a population of 18,801,310 as measured by the 2010 census, it...
, and probably in northern 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...
too.
The two Alloxycorynus species are found from southern 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....
(Cusco Region
Cusco Region
Cusco is a region in Peru. It is bordered by the Ucayali Region on the north; the Madre de Dios and Puno regions on the east; the Arequipa Region on the south; and the Apurímac, Ayacucho and Junín regions on the west...
) to eastern 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...
and northern Argentina. Hydnorobius with three species occurs to the southeast of Alloxycorynus south to central Argentina (Mendoza
Mendoza Province
The Province of Mendoza is a province of Argentina, located in the western central part of the country in the Cuyo region. It borders to the north with San Juan, the south with La Pampa and Neuquén, the east with San Luis, and to the west with the republic of Chile; the international limit is...
to Buenos Aires Province
Buenos Aires Province
The Province of Buenos Aires is the largest and most populous province of Argentina. It takes the name from the city of Buenos Aires, which used to be the provincial capital until it was federalized in 1880...
s). Oxycorynus occurs with 5 known species northwards of Hydnorobius, from northern Argentina and southern Bolivia north into Brazil
Brazil
Brazil , officially the Federative Republic of Brazil , is the largest country in South America. It is the world's fifth largest country, both by geographical area and by population with over 192 million people...
(Santa Catarina state). The monotypic
Monotypic
In biology, a monotypic taxon is a taxonomic group with only one biological type. The term's usage differs slightly between botany and zoology. The term monotypic has a separate use in conservation biology, monotypic habitat, regarding species habitat conversion eliminating biodiversity and...
Balanophorobius, described only in 2005, has not yet been found outside the Osa Peninsula
Osa Peninsula
The Osa Peninsula is a peninsula located in southwestern Costa Rica, in the Puntarenas Province, on the Pacific Ocean, at . The peninsula was formed geologically by a faulting system that extends north into California....
of Costa Rica
Costa Rica
Costa Rica , officially the Republic of Costa Rica is a multilingual, multiethnic and multicultural country in Central America, bordered by Nicaragua to the north, Panama to the southeast, the Pacific Ocean to the west and the Caribbean Sea to the east....
.
Ecology
Oxycraspedus utilizes the cones of the Monkey-puzzle tree (Araucaria araucana). Adults seek shelter in the cones - usually female one but occasionally male ones too - and larvaLarva
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...
e feed on the parenchyma
Parenchyma
Parenchyma is a term used to describe a bulk of a substance. It is used in different ways in animals and in plants.The term is New Latin, f. Greek παρέγχυμα - parenkhuma, "visceral flesh", f. παρεγχεῖν - parenkhein, "to pour in" f. para-, "beside" + en-, "in" + khein, "to pour"...
tous tissue but not the seeds. Indeed, by the time the larvae have finished their development to 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...
tion, the host cones are typically already discarded by the plant and have shed their seeds. Very old cones that are slowly rotting on the forest floor are also taken, demonstrating the evolution
Evolution
Evolution is any change across successive generations in the heritable characteristics of biological populations. Evolutionary processes give rise to diversity at every level of biological organisation, including species, individual organisms and molecules such as DNA and proteins.Life on Earth...
ary link between Oxycorynini and the other Belidae which also feed on decaying woody tissue, but of twigs and stems.
Parallocorynus has to date only been collected from the cycad
Cycad
Cycads are seed plants typically characterized by a stout and woody trunk with a crown of large, hard and stiff, evergreen leaves. They usually have pinnate leaves. The individual plants are either all male or all female . Cycads vary in size from having a trunk that is only a few centimeters...
genus Dioon
Dioon
Dioon is a genus of cycads in the family Zamiaceae. It contains 11 accepted species that are native to Mexico, Honduras, and Nicaragua. Their habitats include tropical forests, pine-oak forest, and dry hillsides, canyons and coastal dunes....
. Similarly Rhopalotria is associated with various species of Zamia
Zamia
Zamia is a genus of cycad of the family Zamiaceae, containing around 50 species, native to North, Central and South America. Species occur as far north as Georgia in the United States to as far south as Bolivia Zamia is a genus of cycad of the family Zamiaceae, containing around 50 species, native...
cycads, though one of the as of yet undescribed species was collected from Dioon spinulosum
Dioon spinulosum
Dioon spinulosum, giant dioon, or gum palm, is a cycad endemic to limestone cliffs and rocky hillsides in the tropical rainforests of Veracruz and Oaxaca, Mexico. It is one of the tallest cycads in the world, growing to 12m in height. The tree is found at low elevations to 300 m above sea...
. It seems that the species of Rhopalotria are monophagous - like R. slossoni on Coontie (Z. pumila) or R. mollis on Cardboard Cycad (Z. furfuracea) - but more research in Zamia species in necessary to verify this. These two belid genera are very important pollinator
Pollinator
A pollinator is the biotic agent that moves pollen from the male anthers of a flower to the female stigma of a flower to accomplish fertilization or syngamy of the female gamete in the ovule of the flower by the male gamete from the pollen grain...
s of their host cycads; the larvae feed primarily on the sporophyll
Sporophyll
A sporophyll is a leaf that bears sporangia. Both microphylls and megaphylls can be sporophylls. In heterosporous plants, sporophylls bear either megasporangia , or microsporangia...
s.
Alloxycorynus, Balanophorobius, Oxycorynus have been recorded from Balanophoraceae
Balanophoraceae
Balanophoraceae is a subtropical to tropical family of obligate parasitic flowering plants, notable for their unusual development and obscure affinities. The family consist of 17 genera and approximately 50 species...
. Specific beetle-plant association are A. bruchi with Ombrophytum, and O. nigripes and O. armatus with Lophophytum. B. gamezi was apparently collected from Helosis cayennensis.
Hydnorobius larvae are recorded from flowers and fruits of Prosopanche (Hydnoraceae
Hydnoraceae
Hydnoraceae is a family of parasitic flowering plants in the order Piperales. It contains two genera, Hydnora and Prosopanche and some seven species...
). P. americana is host to H. hydnorae and H. helleri; H. parvulus is found on P. bonacinae.
Balanophoraceae and Hydnoraceae are root parasitic rather primitive dicots but not closely related. Possibly, the Oxycorynini which feed on them shifted to these plants from the ones parasitized. It is likely that the initial host switch was to Balanophoraceae, but these parasitize a wide range of trees so little more can be said at present.