''Arenivaga'' is a

genus Genus (; : genera ) is a taxonomic rank above species and below family (taxonomy), family as used in the biological classification of extant taxon, living and fossil organisms as well as Virus classification#ICTV classification, viruses. In bino ...

of sand cockroaches, of the subfamily

Corydiinae Corydiinae is a subfamily of the order Blattodea (cockroaches). Many are known as sand cockroaches. The subfamily, comprising about 20 genera, contains half the genera in Corydiidae. One prominent species is the desert cockroach, ''Arenivaga inve ...

, in the family

Corydiidae Corydiidae, previously known as Polyphagidae, is a family of the order Blattodea (cockroaches). Many are known as sand cockroaches. The family is divided into five subfamilies, comprising some 40 genera. One prominent species is the desert cockroa ...

. These cockroaches live in sandy soils and dunes in the southwestern United States, Florida and Mexico. ''Arenivaga'' comes from the

Latin Latin ( or ) is a classical language belonging to the Italic languages, Italic branch of the Indo-European languages. Latin was originally spoken by the Latins (Italic tribe), Latins in Latium (now known as Lazio), the lower Tiber area aroun ...

''arena'' meaning ''sand'' and ''vagus'' meaning ''wandering''.

Characteristics

This genus is

sexually dimorphic Sexual dimorphism is the condition where sexes of the same species exhibit different Morphology (biology), morphological characteristics, including characteristics not directly involved in reproduction. The condition occurs in most dioecy, di ...

, with males and females differing in

morphology Morphology, from the Greek and meaning "study of shape", may refer to: Disciplines *Morphology (archaeology), study of the shapes or forms of artifacts *Morphology (astronomy), study of the shape of astronomical objects such as nebulae, galaxies, ...

. The insects are dorso-ventrally flattened and males have wings that are generally longer than the abdomen. The colour cannot be relied on to distinguish between species because the insects sequester pigments from their food and therefore their colour depends on their diet; they accumulate

uric acid Uric acid is a heterocyclic compound of carbon, nitrogen, oxygen, and hydrogen with the Chemical formula, formula C5H4N4O3. It forms ions and salts known as urates and acid urates, such as ammonium acid urate. Uric acid is a product of the meta ...

in varying amounts, and this also affects their appearance. The head has a pair of long, slender antennae, two large compound eyes and two protuberant

ocelli A simple eye or ocellus (sometimes called a pigment pit) is a form of eye or an optical arrangement which has a single lens without the sort of elaborate retina that occurs in most vertebrates. These eyes are called "simple" to distinguish the ...

. The labrum is broad, and the

frons Insect morphology is the study and description of the physical form of insects. The terminology used to describe insects is similar to that used for other arthropods due to their shared evolutionary history. Three physical features separate insec ...

and the hinder part of the

clypeus The clypeus is one of the sclerites that make up the face of an arthropod. In insects, the clypeus delimits the lower margin of the face, with the labrum articulated along the ventral margin of the clypeus. The mandibles bracket the labrum, but ...

are fused and form a bulge in a manner unusual for cockroaches. The

pronotum The prothorax is the foremost of the three segments in the thorax of an insect, and bears the first pair of legs. Its principal sclerites (exoskeletal plates) are the pronotum (dorsal), the prosternum (ventral), and the propleuron (lateral) on e ...

is large and covers the head and extends sideways to about the width of the body. There are

seta In biology, setae (; seta ; ) are any of a number of different bristle- or hair-like structures on living organisms. Animal setae Protostomes Depending partly on their form and function, protostome setae may be called macrotrichia, chaetae, ...

e on the dorsal surface of the pronotum and different species have different patterning, which may be impressed into the surface. The patterning may be surrounded by an aura which radiates out from the pattern, and at the side of the pronotum, uric acid may be stored in white or pale pink patches. The smallest species is '' A. pumila'' at a length of , and the largest '' A. bolliana'' at . Some species are broader and more robust than others. The legs bear many spines, including spines around the joint between the meso and meta-tibia, and the tarsi have two claws, except in '' A. darwini'' where there is only one. The main means of distinguishing between the different species is close examination of the male genitalia.

Ecology

Females and nymphs live underground, "swimming" through the sandy

substrate Substrate may refer to: Physical layers *Substrate (biology), the natural environment in which an organism lives, or the surface or medium on which an organism grows or is attached ** Substrate (aquatic environment), the earthy material that exi ...

and residing in the burrows of small mammals with which they cohabit. They feed on

mycorrhizal fungi A mycorrhiza (; , mycorrhiza, or mycorrhizas) is a symbiotic association between a fungus and a plant. The term mycorrhiza refers to the role of the fungus in the plant's rhizosphere, the plant root system and its surroundings. Mycorrhizae play ...

, plant detritus, and the seeds gathered by the mammals. Males have brief lives and live mostly on the surface. The breeding habits of sand cockroaches have been little studied but it seems that females emerge onto the surface at night, attract the winged males, perhaps by the use of

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

s, mate and rebury themselves in the sand. The desert cockroach (''A. investigata'') has been shown to be able to absorb water from the atmosphere.

References

{{Taxonbar, from=Q4668230 Cockroach genera Fauna of the Southwestern United States Insects of Mexico