The Aphididae are a very large
insect
Insects (from Latin ') are pancrustacean hexapod invertebrates of the class Insecta. They are the largest group within the arthropod phylum. Insects have a chitinous exoskeleton, a three-part body ( head, thorax and abdomen), three pa ...
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
in the
aphid
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, although individuals within a species can vary widely in color. The group includes the fluffy white woolly aphids. A t ...
superfamily
SUPERFAMILY is a database and search platform of structural and functional annotation for all proteins and genomes. It classifies amino acid sequences into known structural domains, especially into SCOP superfamilies. Domains are functional, str ...
(
Aphidoidea), of the
order
Order, ORDER or Orders may refer to:
* Categorization, the process in which ideas and objects are recognized, differentiated, and understood
* Heterarchy, a system of organization wherein the elements have the potential to be ranked a number of ...
Hemiptera
Hemiptera (; ) is an order of insects, commonly called true bugs, comprising over 80,000 species within groups such as the cicadas, aphids, planthoppers, leafhoppers, assassin bugs, bed bugs, and shield bugs. They range in size from to arou ...
. These insects suck the sap from plant leaves. Several thousand
species
In biology, a species is the basic unit of classification and a taxonomic rank of an organism, as well as a unit of biodiversity. A species is often defined as the largest group of organisms in which any two individuals of the appropriat ...
are placed in this
family
Family (from la, familia) is a group of people related either by consanguinity (by recognized birth) or affinity (by marriage or other relationship). The purpose of the family is to maintain the well-being of its members and of society. Idea ...
, many of which are considered plant/crop pests. They are the family of insects containing most plant virus vectors (around 200 known) with the green peach aphid (''
Myzus persicae'') being one of the most prevalent and indiscriminate carriers.
Evolution
Aphids originated in the late
Cretaceous
The Cretaceous ( ) is a geological period that lasted from about 145 to 66 million years ago (Mya). It is the third and final period of the Mesozoic Era, as well as the longest. At around 79 million years, it is the longest geological period of ...
about (Mya), but the Aphidinae which comprises about half of the 4700 described species and genera of aphids alive today come from their most recent radiation which occurred in the late Tertiary less than 10 Mya.
[Von Dohlen CD, Moran NA (2000) Molecular data support a rapid radiation of aphids in the Cretaceous and multiple origins of host alternation. Biol J Linnean Soc 71: 689–717][Von Dohlen CD, Rowe CA, Heie OE (2006) A test of morphological hypotheses for tribal and subtribal relationships of Aphidinae (Insecta: Hemiptera: Aphididae) using DNA sequences. Mol Phylo Evol 38: 316–329]
Reproduction
Most aphid species can reproduce both asexually and sexually, with several
parthenogenetic generations between each period of sexual reproduction. This is
known as cyclical parthenogenesis and, in temperate regions, sexual reproduction
occurs in autumn and results in the production of overwintering eggs, which hatch
the following spring and initiate another cycle. Many pest aphids, however, do not
overwinter as an egg but as nymphs or adults and others as both eggs and active
stages (see Williams and Dixon 2007). For their size, the parthenogenetic individuals have very short developmental times and potentially prodigious rates of increase
(de Réaumur 1737;
Huxley 1858; Kindlmann and Dixon 1989; Dixon 1992). Thus,
aphids show very complex and rapidly changing within-year dynamics, with each
clone going through several generations during the vegetative season and being
made up of many individuals, which can be widely scattered in space. The survival
of the eggs and/or overwintering aphids determines the numbers of aphids present
the following spring.
The within-year dynamics of aphids are largely determined by seasonal changes
in host quality. Aphids do best when amino acids are actively translocated in the
phloem. In spring, the leaves grow and import amino acids via the phloem; in summer leaves are mature and export mainly sugars. In autumn, the leaves senesce and
export amino acids and other nutrients. Thus on trees the leaves are most suitable
for aphids in spring and autumn. The differences in within-year population dynamics of aphids are due to differences in the effect these seasonal fluctuations in host
plant quality have on the per capita rate of increase and intraspecific competition
in each species. This annual cycle, consisting of two short periods when the host
plant is very favourable and a long intervening period when it is less favourable, is
well documented for tree dwelling aphids. This has greatly facilitated the modelling
of their population dynamics. In general the aphid carrying capacity of annual crop
plants tends to increase with the season until the plants mature after which it tends
to decrease very rapidly. Thus, the aphid carrying capacity of trees tends to be high
in spring and autumn and low in summer, whereas that particularly of short-season
annual crops tends to be low early in a year, peaking mid year and then declining.
Characteristics
Members of the Aphididae are soft-bodied, pear-shaped insects called aphids, as are other members of the superfamily Aphidoidea. Most of them have a pair of little tubes, called
cornicle
The cornicle (or siphuncule) is one of a pair of small upright backward-pointing tubes found on the dorsal side of the 5th or 6th abdominal segments of aphids. They are sometimes mistaken for cerci. They are no more than pores in some species.
...
s, projecting
dorsally
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek roots, describe something in its standard anatomical position. This position prov ...
from the
posterior of their
abdomen
The abdomen (colloquially called the belly, tummy, midriff, tucky or stomach) is the part of the body between the thorax (chest) and pelvis, in humans and in other vertebrates. The abdomen is the front part of the abdominal segment of the to ...
s. The cornicles have been variously interpreted as organs of excretion or for the production of honeydew, but their only confirmed function to date is that they produce fatty
alarm pheromones
A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavi ...
when the insects are attacked by predators.
When wings are present they occur only on particular
morphs called "
alates", and wingless morphs are said to be "
apterous
Aptery is the anatomical condition of an animal completely lacking any kind of wings. An animal with this condition is said to be apterous.
Most animal species belong to and are phylogenetic descendants of apterous taxa. These groups are said to ...
". The forewing (
mesothoracic wing) of the alate in the Aphididae has four to six veins attached to a major vein-like structure that has been interpreted as the combined stems of all the other
major wing veins. That structure ends in a stigma, a solid spot on the
anterior
Standard anatomical terms of location are used to unambiguously describe the anatomy of animals, including humans. The terms, typically derived from Latin or Greek language, Greek roots, describe something in its standard anatomical position. Th ...
margin of the forewing. The rear (metathoracic) wings have a similar scheme, but simpler in structure, with no stigma
The rear wing however, does bear a
hamulus
A hamus or hamulus is a structure functioning as, or in the form of, hooks or hooklets.
Etymology
The terms are directly from Latin, in which ''hamus'' means "hook". The plural is ''hami''.
''Hamulus'' is the diminutive – hooklet or little ho ...
, a small hook that, when in flight, engages the
claval fold of the forewing, keeping the wing beats in
synchrony.
All aphids have very small eyes, sucking mouthparts in the form of a relatively long, segmented
rostrum, and fairly long
antenna
Antenna ( antennas or antennae) may refer to:
Science and engineering
* Antenna (radio), also known as an aerial, a transducer designed to transmit or receive electromagnetic (e.g., TV or radio) waves
* Antennae Galaxies, the name of two collid ...
e.
These insects are so small (a few millimeters in length), that winds can transport them for fairly long distances. They are often green, but might be red or brown, as well. They move quite slowly and cannot jump or hop. Aphids excrete a sugary liquid called
honeydew, because the plant sap from which they feed contains excess carbohydrates relative to its low protein content. To satisfy their protein needs, they absorb large amounts of sap and excrete the excess carbohydrates. Honeydew is used as food by
ants,
honeybee
A honey bee (also spelled honeybee) is a eusocial flying insect within the genus ''Apis'' of the bee clade, all native to Afro-Eurasia. After bees spread naturally throughout Africa and Eurasia, humans became responsible for the current cosm ...
s, and many other insects.
Classification
There is considerable controversy in the classification of aphids, with conservative classifications recognizing as many as 24 subfamilies within a single family Aphididae and others elevating various subfamilies to establish as many as 9 other families within Aphidoidea in addition to Aphididae.
Subfamilies
The ''Aphid Species File''
Aphid Species File (Version 5.0/5.0; retrieved 10 July 2021)
/ref> currently (2021) lists:
# Aiceoninae
''Aiceona''Takahashi R (1934) ''Stylops'' 3(3): 56. is the only genus in Aiceoninae: a monotypic subfamily of aphids
Aphids are small sap-sucking insects and members of the superfamily Aphidoidea. Common names include greenfly and blackfly, ...
astop & van Emden. 1972?/small> - monotypic
In biology, a monotypic taxon is a taxonomic group (taxon) that contains only one immediately subordinate taxon. A monotypic species is one that does not include subspecies or smaller, infraspecific taxa. In the case of genera, the term "unispe ...
# Anoeciinae Tullgren, 1909
# Aphidinae
Aphidinae is an aphid subfamily in the family Aphididae.
Many species of aphids spread potyviruses and most are from the subfamily Aphidinae (genera ''Macrosiphum'' and ''Myzus
''Myzus'' is a genus of true bugs belonging to the family Aphidi ...
Latreille, 1802
# Baltichaitophorinae Heie, 1980
# Calaphidinae Oestlund, 1919
# Chaitophorinae Börner. 1949
# Drepanosiphinae
Drepanosiphinae is a subfamily of aphids in the family Aphididae. There are about 13 genera, 8 of which are extinct, and more than 60 described species in Drepanosiphinae.
While a few authors have suggested treating the group as a family, this h ...
Herrich-Schaeffer, 1857
# Eriosomatinae
Woolly aphids (subfamily: Eriosomatinae) are sap-sucking insects that produce a filamentous waxy white covering which resembles cotton or wool. The adults are winged and move to new locations where they lay egg masses. The nymphs often form la ...
aker, 1920?/small>
# Greenideinae Baker, 1920
# Hormaphidinae aker 1920?/small>
# Israelaphidinae Ilharco, 1961 - monotypic
# Lachninae
Lachninae is a subfamily of the family Aphididae, containing some of the largest aphids, and they are sometimes referred to as "giant aphids". Members of this subfamily typically have greatly reduced cornicle
The cornicle (or siphuncule) is o ...
Herrich-Schaeffer, 1854
# Lizeriinae Blanchard, 1923
# Macropodaphidinae Zachvatkin & Aizenberg, 1960
# Mindarinae Tullgren, 1909 - monotypic
# Neophyllaphidinae Takahashi, 1921 - monotypic
# Phloeomyzinae Mordvilko, 1934
# Phyllaphidinae Herrich-Schaeffer, 1857
# Pterastheniinae Remaudière & Quednau, 1988
# Saltusaphidinae Baker, 1920
# Spicaphidinae Essig, 1953
# Taiwanaphidinae Quednau & Remaudière, 1994 - monotypic
# Tamaliinae Oestlund, 1923 - monotypic
# Thelaxinae Baker, 1920
* Fossil genera
Selected species
See also
*Wooly aphids - Subfamily: Eriosomatinae
Woolly aphids (subfamily: Eriosomatinae) are sap-sucking insects that produce a filamentous waxy white covering which resembles cotton or wool. The adults are winged and move to new locations where they lay egg masses. The nymphs often form la ...
References
External links
*
On the UF / IFAS Featured Creatures Web site:
''Aphis gossypii'', melon or cotton aphid
{{Eusociality
Aphids
Hemiptera families