🪲 Order Hemiptera and Pentatomidae

Hemiptera includes many of the most familiar sap-feeding and pestiferous insects in agriculture, from stink bugs and seed bugs to leaf hoppers, aphids, whiteflies, and scales. The order is especially recognized by its piercing-sucking mouthparts and its large number of economically important crop pests and disease vectors.

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Meaning and General Characters of Hemiptera

Hemiptera has also been called Rhynchota in older classification.

• hemi means half
• ptera means wings
• common name: true bugs

Important characters:

• head usually opisthognathous
• mouthparts piercing-sucking
• mandibles and maxillae modified into stylets resting inside a grooved labium or rostrum
• labial and maxillary palps absent or highly reduced
• mesothorax dorsally represented by a scutellum
• forewings may be uniformly textured or partly coriaceous and partly membranous
• cerci absent
• metamorphosis usually gradual
• alimentary canal often modified for liquid food, sometimes with filter chamber
• salivary glands well developed
• extra-oral digestion common
• abdominal ganglia often fused with thoracic ganglia

Piercing-sucking mouthparts with stylets inside a rostrum are the most diagnostic order-level feature of Hemiptera.

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Heteroptera and Homoptera Compared

The lesson divides Hemiptera into two major groups:

1. Heteroptera
2. Homoptera

Character	Heteroptera	Homoptera
Head position	Porrect or horizontal	Deflexed
Foreleg base	Does not touch head	Touches head
Beak origin	From anterior part of head	From posterior part of head
Gular region	Well defined	Not clearly defined
Pronotum	Usually enlarged	Usually small and collar-like
Scutellum	Well developed	Not well developed
Forewings	Basally coriaceous and apically membranous (hemelytra)	Uniform in texture
Resting position of wings	Flat over back, overlapping	Roof-like, usually non-overlapping
Honeydew secretion	Uncommon	Common
Special glands	Repugnatorial or scent glands present	Wax glands common
Habit	Terrestrial and aquatic forms occur	Mostly terrestrial
Feeding habit	Herbivorous, predaceous, or blood-sucking	Mostly herbivorous

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Important Families of Heteroptera

Gerridae

• water striders or pond skaters
• forelegs short and used in prey capture
• middle legs used in pushing
• hind legs used in steering

Reduviidae

• assassin bugs or kissing bugs
• head narrow and constricted behind eyes
• beak short and three-segmented
• many are predatory, some blood-feeding

Cimicidae

• bed bugs
• body dorsoventrally flattened
• adapted for hiding in cracks and crevices
• blood-sucking habit

Tingidae

• lace bugs
• pronotum with lateral lace-like expansions
• forewings with reticulate lace-like pattern
• many species are sap-sucking leaf pests

Miridae

• plant bugs or leaf bugs
• beak and antennae four-segmented
• hemelytra with corium, clavus, and cuneus

Lygaeidae

• seed bugs or chinch bugs
• cuneus absent
• membrane with a few irregular veins
• includes pests such as dusky cotton bug

Pyrrhocoridae

• red bugs or stainers
• conspicuous red and black warning colouration
• several are cotton pests

Coreidae

• squash bugs or leaf-footed bugs
• membrane with many branching veins
• stink glands open between middle and hind coxae

Pentatomidae

• stink bugs or shield bugs
• antennae five-segmented
• scutellum large and shield-like
• adults and nymphs produce disagreeable odour from metathoracic stink glands
• many are important crop pests

Nepidae

• water scorpions
• forelegs raptorial
• middle and hind legs used for walking
• long caudal breathing tube present

Belostomatidae

• giant water bugs or electric light bugs
• large-bodied aquatic bugs
• antennae concealed in pockets
• predatory aquatic forms

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Important Families of Homoptera

Cicadidae

• cicadas
• males possess sound-producing organs near abdominal base

Membracidae

• tree hoppers or cowbugs
• pronotum enlarged and extended backward
• body often resembles thorns or plant parts

Cicadellidae

• leaf hoppers or jassids
• elongate wedge-shaped body
• hind tibiae with double row of spines
• many suck sap and transmit plant diseases such as rice tungro

Cercopidae

• spittle bugs or froghoppers
• adults resemble tiny frogs
• nymphs live in frothy spittle masses

Delphacidae

• plant hoppers
• large flattened spur at apex of hind tibia
• includes brown plant hopper, a major rice pest and virus vector

Lophopidae

• head produced into a snout
• includes sugarcane leaf hopper Pyrilla perpusilla

Psyllidae

• jumping plant lice
• small active insects that leap well
• hind legs suited for jumping
• forewing with prominent basal vein

Aleyrodidae

• whiteflies
• minute moth-like insects
• wings coated with white powdery wax
• wing venation much reduced

Aphididae

• aphids or plant lice
• body pear-shaped
• both winged and wingless forms occur
• cornicles or siphunculi present
• many are important sap-sucking pests and vectors

Coccidae

• soft scales
• strong sexual dimorphism
• male gnat-like; female more degenerate and wax-covered

Diaspididae

• armoured scales
• adult female lacks antennae, legs, and wings
• body protected by hard waxy cover

Kerridae

• lac insects
• females highly degenerate
• body enclosed in thick resinous cell

Pseudococcidae

• mealy bugs
• body elongate oval with distinct segmentation
• body covered with mealy wax secretion
• legs functional in all instars

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Summary Cheat Sheet

• Hemiptera is characterized mainly by piercing-sucking mouthparts and includes many major sap-feeding pests.
• The lesson divides the order into Heteroptera and Homoptera.
• In Heteroptera, forewings are typically hemelytra, and many families have scent glands.
• Important heteropteran families include Gerridae, Reduviidae, Cimicidae, Tingidae, Miridae, Lygaeidae, Pyrrhocoridae, Coreidae, Pentatomidae, Nepidae, and Belostomatidae.
• Pentatomidae are shield bugs or stink bugs with large scutellum and strong odour.
• Important homopteran families include Cicadidae, Membracidae, Cicadellidae, Cercopidae, Delphacidae, Lophopidae, Psyllidae, Aleyrodidae, Aphididae, Coccidae, Diaspididae, Kerridae, and Pseudococcidae.
• Several homopterans are important because they suck plant sap, produce honeydew, and transmit plant diseases.
• Major crop-pest examples include brown plant hopper, aphids, whiteflies, mealy bugs, cotton stainers, and stink bugs.

References

2 sources • [1] [2]

[1]

Fundamentals of Entomology

[2]

Insect Morphology and Systematics