Most hemiptera insects are phytophagous, which use a sucking mouthpart into the plant to suck the sap of the plant. These hemipters include cicadas, leafhoppers, horned cicadas, cicadas, waxhoppers, planthoppers, whiteflies, aphids, mesozoans, and a number of other taxa. Some hemiptera insects are monophages, they only eat plants of one or one family; some species have a slightly wider choice of host plants, they can eat several types of plants, oligophages; and some species can eat multiple types of plants, they are not much selective about host plants, they are polyphages. Some hemiptera insects can fix the change of host plants of different types or different taxa at different stages of their life history. The relationship between hemiptera insects and plants is formed very early, dating back to the Lower Devonian era (also known as the early Devonian period) about 400 million years ago.
Twig wilting bugs (coreidae) of the family Lycaenidae suck the sap of plants
The sap in the phloem of plants is the sap that flows under positive pressure. The juice contains sugars, proteins, amino acids, inorganic salts and hormones. Among them, sucrose is the mainstay, and the general content is 10 to 20%. In contrast, the sap in xylem is under negative pressure, which contains only a small amount of nutrients. Most species in the sternorrhyncha, many species in the heteroptera, and some species in the auchenorrhyncha, are dominated by sap from the phloem. Leafhopper insects (typhlocybine cicadellids) specifically suck sap from mesophyll tissue without a catheter system, and sap in mesophyll tissue is richer in nutrients than in the epidermis of leaves. Many species in the order Heteroptera also specifically suck sap from the mesophyll tissue. The juices in the mesophyll tissue and phloem are rich in nutrients, but they also contain a variety of secondary metabolic compounds, many of which are plant-defense chemicals. Therefore, these insects must first develop a set of physical or chemical detoxification mechanisms to eat this sap. This is also the main reason for the evolution of the specialization of such insect hosts, which are mostly mono-eating insects. Cicadoidea, cercopoidea, and cicadelline cicadellids of the head-beaked suborder suck sap from the xylem, mostly oligositivity or polyphagous insects. Some species that suck phloem juice can also suck xylem juice. Especially in the case of dehydration or dehydration of the phloem, in order to survive, they must obtain water from the xylem. To draw sap from the xylem, insects had to overcome the problem of negative pressure on the sap, so such insects evolved to form specialized sinus pumps (cibarial pumps) and associated developed muscular systems. Hemiptera insects that suck the juice of the phloem often have symbiotic micro-organisms in their intestines that aid in the conversion of amino acids. These insects tend to secrete honeydew from their anus. A variety of organisms feed on this honeydew, and many of them have established symbiotic associations with hemiptera insects that suck the juice of the phloem, such as ants and aphids.
A species of plant lice (psyllidae) in the family Pyllidae that causes the leaves of plants to form galls
Some species of the pectoral beak suborder, such as psyllids and some aphids, while sucking sap, will also inject some plant hormones into the plant, stimulating the proliferation of the phase group of pallet cells and forming galls. They live and feed in the gall, which also protects them from predators and adverse environmental factors, such as changes in external temperature and humidity, precipitation, wind, etc.
Spined soldier bug (podisus maculiventris)
Many species of hemiptera are also predatory , and they can prey on other insects , and even some small vertebrates. Most of them are aquatic and specialize in sucking the body fluids of larvae or adults. These insects contain proteases, phospholipase, and some species also contain amylase in the saliva they inject into their prey. Their mouthparts, in order to adapt to predation, have tooth-like spines at the ends of the needles, which are specially designed to scratch or tear the epidermis and tissue cells of their prey. Among the predatory hemiptera, some species are used for biological control of pests, such as podisus maculiventris. The English name of the spotted thorn bug is spined soldier bug, which means "a stinging soldier-like bug". They suck the fluids of potato beetle (colorado beetle) and mexican bean beetle larvae.
Cimex lectularius
There are a few hemiptera insects that can suck the blood of large mammals , including humans , and they are considered blood-sucking "parasites". Such as bedbugs (cimex spp.), triatomine kissing bugs of the family Triatomine kissing bugs. In addition to sucking blood, they also transmit chagas disease (chagas, which is caused by Cruise trypanosomiasis, the main vector of transmission is the vampire bug, discovered by dr. chagas in 1908). The formation of the blood-sucking habits of these hemiptera insects dates back 20 million years.