Hemiptera

it explains about hemipteran insect characters and its families which includes homoptera and heteroptera

1. Prepared by: Vidya K. C Suresh R. Jambagi M.Sc. (Agri) Agril. Entomology University of Agricultural Sciences Dharwad, Karnataka-580005 Email: [email protected] GENERAL ENTOMOLOGY Presentation: 12 Topics : Insect order Hemiptera

2. General characters- Head is opisthognathous Mouthparts are piercing and sucking type. Two pairs of bristle like stylets which are the modified mandibles and maxillae are present Stylets rest in the grooved labium or rostrum Both labial palps and maxillary palps are atrophied. Mesothorax is represented dorsally by scutellum Forewings are either uniformly thickened throughout or basally coriaceous and distally membranous Cerci are always absent.Metamorphosis usually gradual; rarely complete Alimentary canal is suitably modified to handle liquid food. (filter chamber) Salivary glands are universally present Extra-oral digestion is apparently widespread. Abdominal ganglia fused with thoracic ganglia. Synonym : Rhynchota Etymology : Hemi - half; ptera - wing Common name : True bugs ORDER-HEMIPTERA Suresh Jambagi, M.Sc (Agri) UAS Dharwad

3. Heteroptera ( Hetero-different;ptera-wing ) Homoptera (Homo-uniform; ptera -wing) 1. Head is porrect or horizontal Head is deflexed 2. Bases of the forelegs do not touch the head Bases of the forelegs touch the head 3. Beak arises from the anterior part of the head Beak arises from the posterior part of the head 4. Gular region of the head ( midventral sclerotised part between labium and foramen magnum) well defined. Gular region not clearly defined 5. Pronotum usually greatly enlarged. Pronotum is almost always small and collar-like. 6. Scutellum (triangular plate found between the wing bases) well developed Scutellum not well developed. 7. Forewings heavily sclerotized at the base and the apical half is membranous (Hemelytra) Forewings are of uniform texture. They are frequently harder than hind pair. 8. Wings are held flat over the the back at rest and the left and right side overlap on the abdomen. Wings are held roof-like over the back and wings do not over lap. 9. Honey dew secretion uncommon Honey dew secretion common 10 Repungnatorial or odori- ferous or scent glands present. Wax glands usually present. 11. Both terrestrial and aquatic Terrestrial. 12. Herbivorous, predaceous or blood sucking. Herbivorous. Classification: There are two sub orders 1 Heteroptera 2 Homoptera . Suresh Jambagi, M.Sc (Agri) UAS Dharwad

4. Suborder: Heteroptera includes true bugs ( (Hetero-different; ptera -wing) CHARACTERS Small to large mostly terrestrial, some are aquatic Head is horizontal Antennae fairly long, 4 or 5 segmented compound eyes well developed. Ocelli when present are two in number Mouthparts piercing and sucking type and with slender segmented beak (modified labium) that arises from the front part of the head and usually extends back along the ventral side, some times as far as the bases of hind coxae . The beak and rostrum serves as a sheath for the four piercing stylets , two outer mandibular and two inner maxillary stylets . The inner maxillary stylets fit very close together with central ridge in the groove and form dorsal food channel and ventral salivary channel. There are no palpi . Pronotum large, the mesonotum exhibits five fold divisions, among which scutellum is very prominent Winged and wingless. When winged, the fore wings are basally thickened and membranous apically and are known as Hemelytra Suresh Jambagi, M.Sc (Agri) UAS Dharwad

5. The hemelytron is composed mainly of regions (corium, clavus and membrane). In some insects, a narrow strip of corium along the costal margin is set off from the reminder of corium by a suture and is called embolium In a few hemiptera , a cuneus is set off by a suture from the apical part of corium. Hind wings are entirely membranous and are slightly shorter than forewings. At rest the wings are held flat on the body. Alary polymorphism is seen Odoriferous glands or repugnatorial glands or scent glands or stink glands are present which open near hind coxae on the sides by ventral pores giving out unpleasant odour Ovipositor small with two pairs of valves or well developed for inserting their eggs in plant tissues Anal cerci absent Metamorphosis simple Honey dew secretion uncommon Herbivorous, predaceous or blood sucking Suresh Jambagi, M.Sc (Agri) UAS Dharwad

6. IMPORTANT FAMILIES OF HETEROPTERA PENTATOMIDAE (Stink bugs or Shield bugs) Medium to large insects, most common and abundant of bugs that produce disagreeable odour. Broad shield like. Head with lateral margins concealing bases of antennae Antennae usually 5 – segmented. Ocelli almost always present. Rostrum is 4 segmented. The pronotum broad and shield shaped. Scutellum large triangular some times extends posteriorly to the extent of covering the wings entirely. In hemelytron, corium large extending to anal margin. Membrane with many longitudinal veins, arising from a vein which is nearly paralelled to the apical margin of corium. Four pairs of odoriferous glands are present on dorsum of abdomen of the nymphs The eggs are usually barrel shaped with spines on the upper end. Ex: Green (stink) bug – Nezara viridula , Red pumpkin bug - Aspongopus janus Cabbage painted bug – Bagrada cruciferarum Suresh Jambagi, M.Sc (Agri) UAS Dharwad

7. 2. COREIDAE (Squash bugs or leaf footed bugs) Antennae 4 segmented sitiuated well upon the sides of the head above a line drawn from the eyes to the base of the beak. Ocelli present Head narrower, shorter than pronoutm , scutellum smaller. In hemelytra, richly branched veins are present. The edge of the abdomen is raised and wings lie in a distinct depression Stink glands are found inside the metathorax and glands openings are found on the sides of the thorax between middle and hind coxae . They emit a bad odour . In most of the species, either or both the hind femora and tibiae may have conspicuous enlargements or leaf like dilations and hence the name leaf footedbugs . Tarsi – 3 segmented pulvilli present. Ex: Rice gundhi bug- Leptocorisa acuta- paddy gundybug od bugs- Clavigralla gibbosa on pulses Suresh Jambagi, M.Sc (Agri) UAS Dharwad

8. 3. REDUVIIADE: (Assassin bugs, Kissing bugs or cone nose bugs) Head is narrow and elongate, constricted behind the eye forming a neck. Beak is short, three segmented and fits into a groove in the pro-sternum. Abdomen is widened in the middle. Lateral margins of the abdominal segments are exposed beyond the wing Many are predaceous on other insects. Ex: Platymeris leavicollis is a predator on coconut rhinoceros beetle. Triatoma sp and Rhodnius prolixus are the vectors of chagas disease caused by Trypanasoma cruzi which causes human trypanaso­miasis . 4. PYRRHOCORIDAE: (Red bugs or Stainers ) They exhibit red and black colourations, elongate oval bugsOcelli absent More branched veins present in hemelytra Coxa is rotatory and tarsi 3 segmented with pulvilli Ex: Dysdercus cingulatus – red cotton bug Feeding injury caused by these bugs leads to the contamination by the fungus Nematospora resulting in yellowish brown discoloura­tion of the lint. Suresh Jambagi, M.Sc (Agri) UAS Dharwad

9. 5. LYGAEIDAE: (Seed bugs or Chinch bugs) Antennae 4 segmented inserted down on the sides of the head, apical segment is larger Compound eyes and ocelli are well developed 4 to 5 un branched simple veins in the membrane of hemelytra. Cuneus is lacking, clavus is elongate Metathoracic gland openings are present. In some, the front femora moderately swollen with 2 rows of teeth beneath Coxa rotator, tarsi 3 segmented, pulvulli present Ex: Dusky cotton bug – Oxycarenu shyalinipennis Nymphs and adults suck the sap from seeds of injured or already opened bolls and reduce the seed quality. Suresh Jambagi, M.Sc (Agri) UAS Dharwad

10. 6. MIRIDAE: (Plant bugs or Leaf bugs). Medium or small, usually delicate insects Ocelli absent Antennae and Rostrum is are 4 segmented Hemelytra with distinct corium , clavus and cuneus (a triangular apical piece of the basal part of forewing). Forewings are tilted at the distinct angle posterior to abdomen. Loop veins are found in membrane. Wings are tilted downwards. Empodium is indistinct. Tarsi almost invariably 3 segmented Majority live on plant juices, some prey on small arthropods Ex. Tea mosquito bug - Helopeltis antonii ( causes cankerous wart like growth on guava fruits) Suresh Jambagi, M.Sc (Agri) UAS Dharwad

11. This order contains a large and diversified group of insects and is closely related to the hemiptera . These are minute to small insects and are distributed widely Head is deflexed and not generally constricted behind to form a neck. Compound eyes well developed, ocelli absent in apterous form but 2 to 3 in winged forms Antennae well developed and usually 3 to 10 segmented Mouth parts piercing and sucking type, stylets often exceedingly long, retractile, rostrum arising from the back of the head, in some cases appearing to arise between anterior coxae . In some adults like male coccids the mouth parts are vestigial or absent Thoracic segments generally fused together and not distinguishable from abdomen in wingless forms. Pronotum small and collar like. Winged or wingless when winged the four wings are uniform in consistency and the wings are held roof like over the body at rest. Alary polymorphism is prevalent. In male coccids only one pair i.e. forewings are present. Wax glands or honey tubes usually well developd in most of the members of this order. In most of the species, the life history is very complex involving sexual and parthenogenetic generations winged and wingless individuals. Usually undergo simple metamorphosis. In some species, the last nymphal instar Is quiescent and pupa like. HOMOPTERA Suresh Jambagi, M.Sc (Agri) UAS Dharwad

12. CICADELLIDAE (Leaf hoppers or Jassids ) Elongate insects with a wedge shaped body. Attractively coloured . Hind tibia is angular with one or two rows of spines which is most important feature. Forewings are somewhat thickened and often brightly coloured Anal veins 1A and 2A do not unite to form ‘Y’ shaped vein Ovipositor is well suited for lacerating the plant tissue. Nymphs and adults have the habit of running sidewise. They suck the plant sap and transmit diseases (vectors). Many excrete honeydew through anus Ex: Green leaf hopper- Nephotettix virescens transmits tungro disease in rice. Cotton leafhopper - Amrasca biguttula biguttula Mango hoppers - Amritodes atkinsoni,Ideoscopus clypealis s IMPORTANT FAMILIES OF HOMOPTERA Suresh Jambagi, M.Sc (Agri) UAS Dharwad

13. 2. DELPHACIDE (Plant hoppers) This is the largest family among the plant hoppers Most of the species are small with reduced wings The characteristic feature of this family is the presence of large mobile apical spur on hind tibiae. Antennae bears terminal arista . Costal cell is absent in the winged forms Alary polymorphism is very common winged, wingless and brachypterous forms occur in the some species. Ex: Brown plant hopper of paddy (BPH)- Nilaparvata lugens White backed plant hopper on rice (WBPH) - Sogatella furcifera Suresh Jambagi, M.Sc (Agri) UAS Dharwad

14. 3. APHIDIDAE (Aphids or Plant lice or Greenflies) Body is pear shaped Both apterous and alate forms are found. A pair of cornicles or siphonculi or wax tubes is present in the dorsum of fifth or sixth abdominal segments which secretes wax like substance. They excrete copious amount of honey dew on which ants feed and sooty mould fungus grows. Aphids are known for their extraordinary fecundity, short life cycle and parthenogenitic reproduction. Life cycle is highly complex and it involve alternation of gener­ation. They feed on plant sap and disseminate plant diseases. Ex: Cotton aphid - Aphis gossypii . Suresh Jambagi, M.Sc (Agri) UAS Dharwad

15. 4. COCCIDAE (Scale insects or Soft scales) Sexual dimorphism is present. Male : They are gnat like, with long antennae, lateral eye and vestigeal mouth parts. Mesothorax is enlarged bearing one pair of wings with on or two veins. Hind wings are reduced to halteres . A quiescent stage is present in the life history. Female : Body segmentation is indistinct. Body wall naked and covered with a waxy coating. They are wingless, legless and suck the plant sap. The first instar nymph is active and is known as crawler which moults and becomes legless. Ex: Coffee green scale- Coccus viridis . Suresh Jambagi, M.Sc (Agri) UAS Dharwad

16. 5. ALEYRODIDAE (Whiteflies) Minute insects which superficially resemble tiny moths. Wings are opaque and dusted with mealy white powdery wax. Wing venation is much reduced. Vasiform orifice is present in the last abdominal tergite . It is a conspicuous opening provided with an operculum. Beneath the operculum there is a tongue-like organ termed lingula . The anus opens at the base of the lingula through which honey dew is excreted in large amount. Immature instars are sessile, scale like, with waxy covering. Metamorphosis approaches the homometabolus type due to the presence of a quiescent stage prior to the emergence of adults. Ex: Cotton whitefly- Bemisia tabaci (transmits vein clearing disease in bhendi ). Suresh Jambagi, M.Sc (Agri) UAS Dharwad

17. 6. LOPHOPIDAE Head is produced into a snout. Hind trochanter is directed backward Hind basitarsus is moderately long. Ex: Sugarcane leaf hopper- Pyrilla perpusilla (nymphs and adults suck the sap and reduce the quality and quantity of cane juice). 7. PSEUDOCOCCIDAE (Mealy bugs) Body is elongate oval in shape. Body segmentation is distinct. Body is covered by long radiating thread of mealy secretion. Functional legs are present in all instars. Wings are absent. Nymphs and adults suck the sap and affect the growth of spindle leaf. Ex Maconellicoccus hirsutus , (also known as the pink, grape or hibiscus mealybug ) Coconut mealy bug- Pseudococcus longispinus Solanum mealy bug Phenacoccus   solenopsis   (Cotton etc) Papaya /cassava mealy bug Paracoccus marginatus Suresh Jambagi, M.Sc (Agri) UAS Dharwad