''Rhynocoris longifrons'' is a species of

assassin bug The Reduviidae is a large cosmopolitan family of the suborder Heteroptera of the order Hemiptera (true bugs). Among the Hemiptera and together with the Nabidae almost all species are terrestrial ambush predators; most other predatory Hemiptera ...

in the family

Reduviidae The Reduviidae is a large Cosmopolitan distribution, cosmopolitan family of the suborder Heteroptera of the Order (biology), order Hemiptera (true bugs). Among the Hemiptera and together with the Nabidae almost all species are terrestrial ambush ...

. It is a predator of other insects and is found in Asia. Crops on which it is found feeding on

pests PESTS was an anonymous American activist group formed in 1986 to critique racism, tokenism, and exclusion in the art world. PESTS produced newsletters, posters, and other print material highlighting examples of discrimination in gallery represent ...

include

pigeon pea The pigeon pea (''Cajanus cajan'') or toor dal is a perennial legume from the family (biology), family Fabaceae native to the Eastern Hemisphere. The pigeon pea is widely cultivated in tropical and semitropical regions around the world, being com ...

cardamom Cardamom (), sometimes cardamon or cardamum, is a spice made from the seeds of several plants in the genus (biology), genera ''Elettaria'' and ''Amomum'' in the family Zingiberaceae. Both genera are native to the Indian subcontinent and Indon ...

and

peanut The peanut (''Arachis hypogaea''), also known as the groundnut, goober (US), goober pea, pindar (US) or monkey nut (UK), is a legume crop grown mainly for its edible seeds. It is widely grown in the tropics and subtropics by small and large ...

s. The insects are potentially useful in biological control because they are more resistant to pesticides than are the pests they consume.

Distribution

''Rhynocoris longifrons'' is found in various parts of India including

Tamil Nadu Tamil Nadu (; , TN) is the southernmost States and union territories of India, state of India. The List of states and union territories of India by area, tenth largest Indian state by area and the List of states and union territories of Indi ...

, and often occurs in agro-ecosystems. It is a generalist

predator Predation is a biological interaction in which one organism, the predator, kills and eats another organism, its prey. It is one of a family of common List of feeding behaviours, feeding behaviours that includes parasitism and micropredation ...

Biology

Like other

hemiptera Hemiptera (; ) is an order of insects, commonly called true bugs, comprising more than 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from ...

ns, assassin bugs are

hemimetabolous Hemimetabolism or hemimetaboly, also called partial metamorphosis and paurometabolism,McGavin, George C. ''Essential Entomology: An Order-by-Order Introduction''. Oxford: Oxford University Press, 2001. pp. 20. is the mode of development of certain ...

and do not undergo

metamorphosis Metamorphosis is a biological process by which an animal physically develops including birth transformation or hatching, involving a conspicuous and relatively abrupt change in the animal's body structure through cell growth and different ...

. Instead, the egg hatches into a miniature version of the adult form, and at each growth stage the

nymph A nymph (; ; sometimes spelled nymphe) is a minor female nature deity in ancient Greek folklore. Distinct from other Greek goddesses, nymphs are generally regarded as personifications of nature; they are typically tied to a specific place, land ...

resembles the adult more than the previous one. Predatory assassin bugs use their long rostrums to inject toxic

saliva Saliva (commonly referred as spit or drool) is an extracellular fluid produced and secreted by salivary glands in the mouth. In humans, saliva is around 99% water, plus electrolytes, mucus, white blood cells, epithelial cells (from which ...

into their prey; this liquefies the soft tissues which are then sucked out, and prey larger than the bug can be killed in this way. ''Rhynocoris longifrons'' is a

polyphagous Feeding is the process by which organisms, typically animals, obtain food. Terminology often uses either the suffixes -vore, -vory, or -vorous from Latin ''vorare'', meaning "to devour", or -phage, -phagy, or -phagous from Greek φαγε ...

predator with a wide range of prey including a number of insect pests. These include '' Exelastis atomosa'', a pest of

, ''

Nezara viridula ''Nezara viridula'', commonly known as the southern green stink bug (USA), southern green shield bug (UK) or green vegetable bug (Australia and New Zealand), is a plant-feeding stink bug. Believed to have originated in Ethiopia, it can now be f ...

'', a pest of beans, and '' Riptortus pedestris''.

Use in biological control

''Rhynocoris longifrons'' has been investigated for use in biological control of three sap-sucking

of cotton, the red cotton stainer ''

Dysdercus cingulatus ''Dysdercus cingulatus'' is a species of Hemiptera, true bug in the family Pyrrhocoridae, commonly known as the red cotton stainer. It is a serious Pest (organism), pest of cotton crops, the adults and older nymphs feeding on the emerging bolls a ...

'', the mealybug ''

Phenacoccus solenopsis ''Phenacoccus solenopsis'', the cotton mealybug or solenopsis mealybug, is a species of mealybug in the family Pseudococcidae. Having originated in North America, it has spread to other parts of the world and become a major pest of cotton crops. ...

'' and the greenfly ''

Aphis gossypii ''Aphis gossypii'' is a tiny insect, an aphid Aphids are small sap-sucking insects in the Taxonomic rank, family Aphididae. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The grou ...

''. In general, both adults and nymphs of ''R. longifrons'' selectively chose adult ''P. solenopsis'' and ''A. gossypii'' rather than nymphs on which to feed, but preferred the partially grown nymphs of ''D. cingulatus'' to the adults. This predator exhibits a type II

functional response A functional response in ecology is the intake rate of a consumer as a function of food density (the amount of food available in a given ecotope). It is associated with the numerical response, which is the reproduction rate of a consumer as a fu ...

, where the rate of prey consumption rises as the density of prey increases, but eventually reaches a plateau and rises no further. Other insect pests which the predator might control include the termite ''

Odontotermes obesus ''Odontotermes obesus'' is a species of termite in the family Termitidae. It is native to tropical southwestern Asia. This termite cultivates a symbiotic fungus in a special chamber in the nest. Workers gather vegetable detritus which they bring ...

'', the brown plant bug '' Clavigralla gibbosa'' and the cotton bollworm ''

Helicoverpa armigera ''Helicoverpa armigera'' is a species of Lepidoptera in the family Noctuidae. It is known as the cotton bollworm, corn earworm, Old World (African) bollworm, or scarce bordered straw (the lattermost in the UK, where it is a migrant). The larvae ...

''. Assassin bugs are attracted to their prey by odour. Olfactory tests have shown that ''Rhynocoris longifrons'' is more attracted to

moth Moths are a group of insects that includes all members of the order Lepidoptera that are not Butterfly, butterflies. They were previously classified as suborder Heterocera, but the group is Paraphyly, paraphyletic with respect to butterflies (s ...

larvae than to hemipteran pests. Important moth pests to which it is attracted include ''

Spodoptera litura ''Spodoptera litura'', otherwise known as the tobacco cutworm or cotton leafworm, is a nocturnal moth in the family Noctuidae. ''S. litura'' is a serious polyphagous pest in Asia, Oceania, and the Indian subcontinent that was first described by ...

'', ''

Achaea janata ''Achaea janata'', the castor semi-looper or croton caterpillar, is an erebid moth, the caterpillars of which are termed 'semi-loopers' due to their mode of locomotion. It is found from the Indo-Australian tropics and subtropics, extending south ...

'' and ''Helicoverpa armigera''. Volatile chemicals are emitted by the larvae and by the adult moths, including by their shed scales. These

kairomone A kairomone is a semiochemical released by an organism that mediates interspecific interactions in a way that benefits a different species at the expense of the emitter. Derived from the Greek καιρός, meaning "''opportune moment""kairomon ...

s can help guide predators and the application of a solution of them to crops may attract ''Rhynocoris longifrons'' to feed on other pests despite the absence of moth larvae.

References

{{Taxonbar, from=Q71410973 Reduviidae Hemiptera of Asia Insects of India Insects described in 1874 Taxa named by Carl Stål