Aphididae - WikiHQ

The Aphididae are a very large insect family in the aphid superfamily (Aphidoidea), of the order Hemiptera. These insects suck the sap from plant leaves. Several thousand species are placed in this family, 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.

thumb|Eggs of [[Cinara strobi on white pine]]

thumb |[[Aphis nerii|Milkweed aphids giving live birth on narrow leaf milkweed. Sped up twenty times.]]

Evolution

Aphids originated in the late Cretaceous 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.

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

thumb|thumbtime=56|[[Aphis nerii|Milkweed aphids on narrow-leaf milkweed eliminating honeydew. Unlike some aphids, these kick the drop away with their leg.]]

thumb|thumbtime=3|A [[Aphis nerii|milkweed aphid on narrow-leaf milkweed is attacked by a hoverfly larvae. It thrashes and releases pheromones and sticky wax from its cornicles. Nearby aphids flee. Video played at 4X speed.]]

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 cornicles, projecting dorsally from the posterior of their abdomens. 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 when the insects are attacked by predators.

alt=Aphid (Aphididae)|thumb|[[Hyadaphis winged and wingless adults]]

thumb|thumbtime=51|[[Hoverfly larva on narrow-leaf milkweed with milkweed aphids, ladybird eggs, and larva. After first minute, shown at four times speed. Larva recorded in early morning prior to sunrise.]]

When wings are present they occur only on particular morphs called "alates", and wingless morphs are said to be "apterous". 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 margin of the forewing. The rear (metathoracic) wings have a similar scheme, but simpler in structure, with no stigma.

Subfamilies

The Aphid Species File currently (2021) lists:

Aiceoninae [Eastop & van Emden. 1972?] - monotypic
Anoeciinae Tullgren, 1909
Aphidinae Latreille, 1802
Baltichaitophorinae Heie, 1980
Calaphidinae Oestlund, 1919
Chaitophorinae Börner. 1949
Drepanosiphinae Herrich-Schaeffer, 1857
Eriosomatinae [Baker, 1920?]
Greenideinae Baker, 1920
Hormaphidinae [Baker 1920?]
Israelaphidinae Ilharco, 1961 - monotypic
Lachninae 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

References

External links

On the UF / IFAS Featured Creatures Web site:

Aphis gossypii, melon or cotton aphid
Aphis nerii, oleander aphid
Cerataphis brasiliensis, palm aphid
Hyadaphis coriandri, corianderaphid
Longistigma caryae, giant bark aphid
Myzus persicae, green peach aphid
Sarucallis kahawaluokalani, crapemyrtle aphid
Schizaphis graminum, greenbug
Shivaphis celti, an Asian woolly hackberry aphid
Sipha flava, yellow sugarcane aphid
Toxoptera citricida, brown citrus aphid