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Aphidomorpha : Aphididae : Hormaphidinae
 

 

Subfamily Hormaphidinae

Biology and Morphology

On this page: Biology Morphology Genera Tribe Cerataphidini Tribe Hormaphidini Tribe Nipponaphidini

Biology

The Hormaphidinae have 181 species in 44 genera and 3 tribes (Cerataphidini, Hormaphidini, Nipponaphidini). In the tropics and subtropics they have complex two year life cycles involving often elaborate galls (see picture below) on their primary hosts which are various tree genera, such as witch hazels (Distylium, Hamamelis) and snowbells (Styrax).

Hormaphis hamamelidis sp. grp. gall. Image copyright Katja Schulz under a Creative Commons Attribution 2.0 Generic license.

Host alternation of most Hormaphidinae species is by alate sexuparae in autumn. The picture below shows the alate sexuparae inside the gall before migration.

Image above copyright Nur Ritter under a Creative Commons Attribution License.

Most species are highly polymorphic, and the secondary host generations are often sedentary and coccid- or aleyrodid- like. They have short appendages concealed beneath the body and have glands that secrete various configurations of wax (see picture).

Hormaphis cornu aleurodiform stages. Image by permission, copyright James Baker, all rights reserved.

Members of this subfamily occur predominantly in East and South-East Asia, but a few species have spread to Europe and North America. There they may exist as permanently parthenogenetic populations on their secondary hosts, or cyclically parthenogenetic populations on the primary host (e.g. Hormaphis cornu in North America).

 

Morphology

Adult Hormaphidinae viviparae may be apterous or alate.Apterous individuals and young nymphs have triommatidia, but no compound eyes. The antennae have 3-5 segments, and are much shorter than the body. The terminal process is shorter than the base of the ultimate antennal segment. The border between the head and pronotum is indistinct. Spinal and marginal tubercles are absent. The tarsi have two long capitate dorsoapical hairs (a useful recognition feature for Hormaphidinae) common to all morphs and developmental stages. The siphunculi may be present as pores or are absent. The cauda is knobbed or rounded, and the anal plate is bilobed.

Some Hormaphidinae alatae hold their wings flat at rest as in the picture below.

Hormaphis hamamelidis alate. Image copyright Beatriz Moisset under a Creative Commons 4.0 License

The antennae of alatae bears narrow, annular secondary rhinaria. The terminal process is shorter than the base of antennal segment VI. Cubitus 1a and 1b of the forewing leave the main vein at the same points and sometimes form a common stalk. The sexuales are apterous and dwarfish, with a well developed rostrum.

Hormaphidinae Genera

Tribe Cerataphidini

Genera

 

Tribe Hormaphidini

Genera

Genus Hamamelistes [Hormaphidini]

Small wax-covered aphids living in a gall or pseudogall on the under or upper side of the leaf. The first picture (right) shows the aphid as it appears in life. The second picture (far right) is of a specimen in alcohol showing the very short 3- or 4-segmented antennae of apterae and the absence of siphunculi. Alates are distinguished by two oblique veins in the hind wing, and siphuncular pores.

A genus of five species in North America and east Asia. Most species host alternate between witch hazel (Hamamelis) and birch (Betula spp.), whilst others remain all year on birch. This variation may occur geographically within a species. The life cycle of host alternating species takes two years with the sexual stage on witch hazel.

Species overview

 

 

Hormaphis [Hormaphidini]

Hormaphis is a small genus of rather atypical aphids which induce conical galls on their primary host (see first picture below), but live as inconspicuous aleurodiform (=whitefly-shaped) morphs on the secondary host. Compound eyes are present in alatae, but absent in apterae. The antennae are 3- or 5- segmented in the alatae, but are reduced to small inconspicuous papillae with 1 or 2 segments in the aleurodiform stage. There are numerous annular secondary rhinaria present on segment III of alatae. Siphunculi are absent, and the cauda is knobbed.

The genus Hormaphis has 3 species, 2 nearctic and 1 palaearctic. They either host alternate from witch hazel (Hamamelis) to birch (Betula) or they are monoecious on witch hazel.

Species overview

 

Image copyright Katja Schulz, Creative Commons Attribution License.

 

Tribe Nipponaphidini

Genera

Acknowledgements

We particularly thank Colin Favret and Roger Blackman, who have provided invaluable assistance. Most of the subfamily diagnoses have been taken from Heie & Wegierek (2009b), Quednau (1999, 2003, 2010) and Blackman & Eastop (2021), with additional material from Russell (1982),Stroyan (1977), Stroyan (1984) and many others listed in the references for these pages.

We also thank James Baker, Beatriz Moisset, Nur Ritter and Katja Schulz for allowing us to reproduce their images, above. Note: Any images on pages that are not individually credited are copyright InfluentialPoints under a Creative Commons Attribution License.

Any errors in identification or information are ours alone, and we would be very grateful for any corrections. For assistance on the terms used for aphid morphology we suggest the figure provided by Blackman & Eastop (2006).

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