Reduviidae

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"Assassin bug" redirects here. For the creature in Dungeons & Dragons, see Assassin bug (Dungeons & Dragons).
Reduviidae
Assassin bug aug08 02.jpg
An adult assassin bug
Scientific classification
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Hemiptera
Suborder: Heteroptera
Infraorder: Cimicomorpha
Superfamily: Reduvioidea
Family: Reduviidae
Latreille, 1807
Subfamilies

Bactrodinae
Centrocnemidinae
Cetherinae
Chryxinae
Ectrichodiinae
Elasmodeminae
Emesinae
Hammacerinae
Harpactorinae
Holoptilinae
Manangocorinae
Peiratinae
Phimophorinae
Phymatinae
Physoderinae
Pseudocetherinae
Reduviinae
Saicinae
Salyavatinae
Sphaeridopinae
Stenopodainae
Triatominae
Tribelocephalinae
Vesciinae
Visayanocorinae

Reduviidae (from the contained genus, Reduvius, which comes from the Latin reduvia, meaning "hangnail" or "remnant") is a large, cosmopolitan family of predatory insects in the suborder Heteroptera. It includes assassin bugs (genera include Melanolestes, Platymeris, Pselliopus, Rasahus, Reduvius, Rhiginia, Sinea, Triatoma, and Zelus), ambush bugs (subfamily Phymatinae), wheel bugs (Arilus cristatus), and thread-legged bugs (the subfamily Emesinae, including the genus Emesaya). There are about 7000 species altogether, making it one of the largest families in the Hemiptera.

Morphology[edit]

A Zelus nymph from the Southeastern United States

Adult insects often range from 4 to 40 mm. They most commonly have an elongated head with a distinct narrowed neck, long legs, and a prominent, segmented tube for feeding (rostrum). Most species are dark bright in color with hues of brown, black, red, or orange. The most distinctive feature of the family is that the tip of the rostrum fits into a groove in the prosternum, where it is rasped against ridges there (a stridulitrum) to produce sound, a tactic often used to intimidate predators. If harassment continues, they can use their rostrum to deliver a painful bite, which in some species can be medically significant. The saliva of the reduviid species Rhynocoris marginatus (Fab.) and Catamirus brevipennis (Servile) have anti-bacterial activity towards the human pathogens Gram-negative bacteria (Escherichia coli, Pseudomonas aeruginosa, Proteus vulgaris, Salmonella typhimurium) and one Gram-positive (Streptococcus pyogenes).

Feeding[edit]

Orange Assassin Bug (Gminatus australis) feeding on a beetle
Reduviidae sp. camouflaged with debris, Australia.
Rhynocoris - Predacious flower assassin bug from South Africa. May bite when carelessly handled; painful after-effects often persist for months.[1]

Predatory Reduviidae use the long rostrum to inject a lethal saliva that liquefies the insides of the prey, which are then sucked out. The saliva contains enzymes that predigest the tissues they swallow. This process is generally referred to as extra-oral digestion, or EOD.[2] The saliva is commonly effective at killing prey substantially larger than the bug itself.

The legs of some Reduviidae have areas covered in tiny hairs that aid in holding onto their prey while they feed. Others, members of the subfamily Phymatinae in particular, have forelegs that resemble those of the praying mantis, and they catch and hold their prey in a similar way to mantises.

As nymphs, some species will cover and camouflage themselves with debris or the remains of dead prey insects, which forms a very effective camouflage. The nymphal instars of the species Acanthaspis pedestris present one good example of this behaviour where they occur in Tamil Nadu in India. Another well-known species is Reduvius personatus, known as the masked hunter because of its habit of camouflaging itself with dust. Some species tend to feed on pests such as cockroaches or bedbugs and are accordingly popular in regions where people regard their hunting as beneficial. Reduvius personatus is a case in point, and some people breed them as pets and for pest control. Some assassin bug subfamilies are adapted to hunting certain types of prey. For example, feather-legged bugs eat termites, and Ectrichodiinae eat millipedes.

Some research on the nature of the venom from certain Reduviidae is under way. The saliva of Rhynocoris marginatus showed some insecticidal activity in vitro, in tests on lepidopteran pests. The effects included reduction of food consumption, assimilation and utilization. Its anti-aggregation factors also affected the aggregation and mobility of haemocytes.[3]

Some species are blood suckers rather than predators, and they are accordingly far less welcome. Triatoma species and other members of the subfamily Triatominae, such as Rhodnius species, Panstrongylus megistus and Paratriatoma hirsuta, are known as kissing bugs, because they tend to bite sleeping humans in the soft tissue around the lips and eyes. A more serious problem than their bites is the fact that several of these haematophagous Central and South American species transmit the potentially fatal trypanosomal Chagas disease, sometimes called American trypanosomiasis.

Phylogeny[edit]

Current taxonomy is based on morphological characteristics. The first cladistic analysis based on molecular data (mitochondrial and nuclear ribosomal DNA) was published in 2009 and called into question the monophyly of some current groups, such as the Emesinae.[4]

References[edit]

  1. ^ Weaving, Alan; Picker, Mike; Griffiths, Charles Llewellyn (2003). Field Guide to Insects of South Africa. New Holland Publishers, Ltd. ISBN 1-86872-713-0. 
  2. ^ Sahayaraj, Kitherin; Kanna, Ayyachamy Vinoth; Kumar, Subramanian Muthu (2010). "Gross Morphology of Feeding Canal, Salivary Apparatus and Digestive Enzymes of Salivary Gland of Catamirus brevipennis (Servile) (Hemiptera: Reduviidae)". Journal of the Entomological Research Society 12 (2): 37–50. Retrieved 14 December 2012.  open access publication - free to read
  3. ^ Kitherin, Sahayaraj; Muthukumar, S. (2011). "Zootoxic effects of reduviid Rhynocoris marginatus (Fab.) (Hemiptera: Reduviidae) venomous saliva on Spodoptera litura (Fab.)". Toxicon 58 (5): 415–425. doi:10.1016/j.toxicon.2011.06.001.  Closed access
  4. ^ Weirauch, Christiane; Munro, James B. (October 2009). "Molecular phylogeny of the assassin bugs (Hemiptera: Reduviidae), based on mitochondrial and nuclear ribosomal genes". Molecular Phylogenetics and Evolution (Elsevier) 53 (1): 287–299. doi:10.1016/j.ympev.2009.05.039. PMID 19531379.  Closed access

External links[edit]