Order Hemiptera - True Bugs, Cicadas, Hoppers, Aphids and Allies
photographed at North American locations.
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Plant Bug Proboscis
Bugs' business end: the proboscis or rostrum. Plant bug M. Dislocatus
Hemiptera was first recognized by Linnaeus in the Systema Naturae of 1758. Defined as monophyletic by its possession of distinctive mouthparts in which the labium assumes the form of a sheath surrounding the elongate, slender mandibles and maxillae. The maxillae are modified into a pair of concentric tubes forming the salivary and food canals; the mandibles lie external to the maxillae, are coupled to them, and serve a cutting function when introducing the proboscis into the food source, be it flora or fauna.

The maxillary and labial palpi are completely lost in the Hemiptera. This feeding method requires liquid food. Saliva may serve a variety of functions including histolysis, paralysis, or anticoagulant passes through the salivary canal to the food source. The liquid food is then drawn into the insect gut through the action of pharyngeal and cibarial pumps (the cibarium is the primary sucking organ in mosquitoes). [1]  Bugs suck, literally.

It is by the introduction of the proboscis into the host, and the injection of the associated chemicals (and sometimes pathogens) that make the bug family so destructive to agriculture and to its animal victims. (See mosaic leaf damage and Chaga's disease.)

Hemiptera is presently divided into four suborders, after it was established that the families grouped together as "Homoptera" are not as closely related as had previously been thought.

Auchenorrhyncha contains the cicadas, leafhoppers, treehoppers, planthoppers, and froghoppers.

The suborder Sternorrhyncha contains aphids, whiteflies, scale, and mealybugs.
Heteroptera, the least primitive of the group, represents the true bugs.

Lace Bug
Lace Bug - Corythucha species hides beneath an elaborate cloaking device
Suborder Heteroptera: The True Bugs
A number of Hemipteran families, most notably the Pentatomidae (stink bugs) and the Coreidae (squash and leaf footed bugs) engage in chemical warfare with their predators and parasites by emitting strongly odorous or corrosive fluids from special glands when disturbed.

Members of the family Reduviidae are commonly called assassin bugs. They are highly successful predators of other insects and a few are ectoparasites of warm-blooded mammals, including humans. [2] Reduviids are active hinters that kill their prey by injecting them with venomous salivary fluid with their rostrum, or beak. Ambush bugs (Phymatidae) use the same weapon but wield it in a sedentary fashion.

Ambush bugs
Ambush bugs (Family Phymatidae) are some of the most fascinating hunters. They hang around flower blossoms, nearly invisible in their exquisite camouflage, waiting for a  pollinator to blunder into range. Their forelimbs are adapted for a quick snatch much like the praying mantis. Once they have latched onto a bumble bee, butterfly, or even a wasp, the ambush bug immobilizes the prey by injecting toxic saliva through their beak.

Like all true bugs, ambush bugs undergo simple metamorphosis. Clusters of eggs are laid by overwintered females when the weather warms in springtime.  After hatching, nymphs undergo from 4-7 molts, shedding their exoskeleton as they grow.

Stink Bugs - Family Pentatomidae feed on developing seed of many hosts including trees, shrubs, vines, weeds and many cultivated crops. They may also feed on the stems and foliage when seed are not present. Both nymph and adult stink bugs pierce plants with their needlelike mouthparts and suck sap from pods, buds, blossoms and seeds.

The family name, Pentatomidae, comes from the Greek "pente" (five) + "tomos" (a section); a reference to the 5-segmented antennae, or to the body which is divided into 5 sections. The scutellum is the largest section.
Stink Bug
Plant Bugs - Family Miridae
Scentless Plant Bugs - Family Rhopalidae

The family Miridae is the largest among the order Hemiptera (true bugs), with approximately 10,000 described species. Most plant bugs are phytophagous, that is, feeding on plants, others are predatory and carnivorous.

Rhopalidae, the so-called "scentless" plant bugs is a much smaller family, with only about 200 species in 18 genera worldwide. However, the perennial pest, the boxelder bug falls into this family, along with other agriculture pests (feeding as they do on seeds).

Most plant bugs are phytophagous (plant-feeding), others are predatory and carnivorous. Megaloceroea recticornis
Large Milkweed Bug - Oncopeltus fasciatus
Large Milkweed Bug
White-margined Burrower Bug - Sehirus cinctus
Sehirus cinctus
Common Water Strider
Common Water Strider
Damsel Bug
Damsel Bug
Assassin Bug - Zelus luridus
Assassin Bug
Small Milkweed Bug
Small Milkweed Bug

Leaf-Footed Bug
Broadheaded Bug
Broadheaded Bug
Bed Bugs
Treehopper Ceresa taurina
Suborder Auchenorrhyncha - Cicadas, Leafhoppers, Planthoppers, Treehoppers, and Spittlebugs
Insects in the order Hemiptera were historically placed into two orders, Homoptera and Heteroptera/Hemiptera, based on the differences in wing structure and the position of the rostrum. These two orders were then combined into the single order Hemiptera by many authorities, with Homoptera and Heteroptera classified as suborders.

The order is presently more usually divided into four or more suborders, after it was established that the families grouped together as "Homoptera" are not as closely related as had previously been thought. Auchenorrhyncha contains the cicadas, leafhoppers, treehoppers, planthoppers, and froghoppers.

The 12,500 species in the suborder Sternorrhyncha are aphids, whiteflies and scale insects. The suborder Coleorrhyncha (comprising the single family Peloridiidae), contains fewer than 30 species and is sometimes grouped with the Heteroptera (to form the suborder Prosorrhyncha). Heteroptera itself is a group of 25,000 species of relatively large bugs, including the seed bugs, assassin bugs, flower bugs and the water bugs.

ants tend an aphid farm
Suborder Sternorrhyncha - Aphids, Scales, Mealybugs
Recent research suggests
chemicals on ants' feet tranquilize and subdue colonies of aphids, keeping them close by as a ready source of food. The study sheds new light on the complex symbiotic relationship between the ants and the aphids, hugely destructive insects in the order Hemiptera.

It has long been known that certain types of aphids are herded and farmed by ants, and that the ants offer protection from other insect would-be predators (ladybugs and their larvae are perhaps the most prolific), in exchange for honeydew, a sugary secretion the ants eat. Ants have been known to bite the wings off the aphids in order to stop them from flying away with one of ants' staple foods. Chemicals produced in the glands of ants can also sabotage the growth of aphid wings. The new study shows that ants' chemical footprints also play a key role in manipulating the aphid colony, keeping it sedentary.

The research, which was carried out by a team from Imperial College London, Royal Holloway University of London, and the University of Reading and published October 10, used a digital camera and specially modified software to measure the walking speed of aphids when they were placed on filter paper that had previously been walked over by ants. The data showed that the aphids' movement was much slower when they were on paper that had been walked on by ants, than on plain paper.

Furthermore, when placed on a dead leaf, where the aphid's instinct is to walk off in search of healthy leaves for food, the scientists found that the presence of ants significantly slowed the aphids' dispersal from the leaf. Lead author of the article, Tom Oliver from Imperial's Department of Life Sciences, explains how ants could use this manipulation in a real-life scenario:

"We believe that ants could use the tranquillizing chemicals in their footprints to maintain a populous 'farm' of aphids close their colony, to provide honeydew on tap. Ants have even been known to occasionally eat some of the aphids themselves, so subduing them in this way is obviously a great way to keep renewable honeydew and prey easily available." [4]

In other words, ants treat aphids exactly how we treat our domesticated cows and steers; principle difference being, ants' fences consist of chemicals they spread with their feet.

  1. Ralph Harbach, Mosquito Taxonomic Inventory, "cibarium"
  2. Thomas Eisner, Maria Eisner, and Melody Siegler, Secret Weapons: Defenses of Insects, Spiders, Scorpions, and Other Many-Legged Creatures (Belknap Press, 2005).
  3. Gary A. Dunn, Insects of the Great Lakes Region (University of Michigan Press/Regional, 1996).
  4. Imperial College London "Herding Aphids: How 'Farmer' Ants Keep Control Of Their Food." Science Daily
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Order Hemiptera: True Bugs number almost 5,000 species in North America, and 40,000 worldwide. They have mouthparts formed into a beak, adapted for sucking plant juices or the liquefied insides of their animal prey.
Suborder Auchenorrhyncha - Cicadas & Planthoppers
Suborder Sternorrhyncha - Aphids, scales, mealybugs, jumping plant lice
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