''Paracletus cimiciformis'' is a species of

aphid Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...

with a complex life cycle. Its primary host plant is ''

Pistacia ''Pistacia'' is a genus of flowering plants in the cashew family, Anacardiaceae. It contains 10 to 20 species that are native to Africa and Eurasia from the Canary Islands, all of Africa, and southern Europe, warm and semidesert areas across Asia ...

'' and its secondary host is a grass, where it is present on the roots. Here it is associated with an ant and part of its life cycle is spent in the ant's nest.

Hosts

The primary host for this species is the terebinth or turpentine tree (''

Pistacia terebinthus ''Pistacia terebinthus'' also called the terebinth and the turpentine tree, is a deciduous tree species of the genus ''Pistacia'', native to the Mediterranean region from the western regions of Morocco and Portugal to Greece and western and s ...

''). Its secondary hosts include the grasses and cereals bent,

wild oat ''Avena'' is a genus of Eurasian and African plants in the grass family. Collectively known as the oats, they include some species which have been cultivated for thousands of years as a food source for humans and livestock. They are widespread ...

cock's-foot ''Dactylis'' is a genus of Eurasian and North African plants in the bluegrass subfamily within the grass family. ''Dactylis'' is native to North Africa, they are found throughout the world, and are an invasive species. They are known in Englis ...

, fescue, wall barley,

barley Barley (''Hordeum vulgare''), a member of the grass family, is a major cereal grain grown in temperate climates globally. It was one of the first cultivated grains, particularly in Eurasia as early as 10,000 years ago. Globally 70% of barley p ...

rice Rice is the seed of the grass species '' Oryza sativa'' (Asian rice) or less commonly ''Oryza glaberrima'' (African rice). The name wild rice is usually used for species of the genera '' Zizania'' and '' Porteresia'', both wild and domesticat ...

, meadow-grass, '' Polypogon viridis'',

tall fescue ''Festuca arundinacea'' ( syn., ''Schedonorus arundinaceus'' and ''Lolium arundinaceum'') is a species of grass commonly known as tall fescue. It is a cool-season perennial C3 species of bunchgrass native to Europe. It is an important forage gr ...

, '' Stipa capensis'' and

wheat Wheat is a grass widely cultivated for its seed, a cereal grain that is a worldwide staple food. The many species of wheat together make up the genus ''Triticum'' ; the most widely grown is common wheat (''T. aestivum''). The archaeologi ...

Distribution

''Paracletus cimiciformis'' is native to much of Europe and has been recorded in North Africa and Asia.

Life cycle

The life cycle of ''P. cimiciformis'' is complex. For most of the year, wingless females are produced parthenogenetically, but in the late summer on their secondary hosts (grass), winged males and females are produced which fly to their primary host, the terebinth tree. Here they mate and

overwintering Overwintering is the process by which some organisms pass through or wait out the winter season, or pass through that period of the year when "winter" conditions (cold or sub-zero temperatures, ice, snow, limited food supplies) make normal activi ...

eggs are laid. In the spring these hatch and the wingless females that develop create swollen galls on the leaves; they live in these galls and reproduce asexually. In late summer some winged females develop which fly off and colonise the roots of grasses. Some of these aphids are carried into their nests by ants, where they overwinter, emerging in the spring to recolonise the roots of their secondary hosts, the whole cycle taking two years.

Ecology

Although ''Pistacia'' is the primary host plant, this aphid is present in parts of Europe where this tree does not grow, and in these localities, the insect stays on the roots of the secondary host all year round. On grasses, it is always found living in association with ants in the genus ''

Tetramorium ''Tetramorium'' is a genus of ants in the subfamily Myrmicinae that includes more than 520 species. These ants are also known as pavement ants. Taxonomy and phylogeny ''Tetramorium'' was first described by Gustav Mayr in 1855 in the same pub ...

'' such as the pavement ant, ''

Tetramorium caespitum ''Tetramorium caespitum'', also known as the pavement ant, is a species of ant in the family Formicidae. References Tetramorium Ants described in 1758 Taxa named by Carl Linnaeus {{ant-stub ...

'' and '' Tetramorium semilaeve''. On its secondary host, the aphids have two genetically identical forms. One of these has a rounded green body and sucks the sap of the host plant; it produces honeydew which is consumed by the ants, and in fact the ants herd the aphids and stimulate them to produce honeydew. The other form has a flattened brown body and produces

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 which mimic those produced by ant larvae. When approached by an ant these flattened aphids remain stationary and get carried into the ant nest and deposited among the ant

brood Brood may refer to: Nature * Brood, a collective term for offspring * Brooding, the incubation of bird eggs by their parents * Bee brood, the young of a beehive * Individual broods of North American Periodical Cicadas: ** Brood X, the largest b ...

. Here they proceed to prey on the ant larvae, piercing them with their stylets and sucking out the

hemolymph Hemolymph, or haemolymph, is a fluid, analogous to the blood in vertebrates, that circulates in the interior of the arthropod (invertebrate) body, remaining in direct contact with the animal's tissues. It is composed of a fluid plasma in which ...

. They stay in the ant nest during the winter, and in the spring are carried to near the surface of the ground with the ant's own young. Here they produce round-bodied aphids which proceed to feed on grass roots and reproduce asexually. Both round-bodied and flattened morphs can reproduce parthenogenetically, producing either form of offspring, and it is unclear what factors trigger the production of one morph in preference to another.

References

{{Taxonbar, from=Q10617188 Eriosomatinae Insects described in 1837 Hemiptera of Europe Insect pests of millets