''Colophina clematis'' is a species of

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 ...

in the woolly aphid 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 ...

, native to Japan. This woolly aphid has the distinction of being the first species of aphid to have been identified as having a "soldier" caste. First

instar An instar (, from the Latin '' īnstar'', "form", "likeness") is a developmental stage of arthropods, such as insects, between each moult (''ecdysis''), until sexual maturity is reached. Arthropods must shed the exoskeleton in order to grow or ...

nymphs of this type are able to protect the aphid colony, killing the larvae of predatory

ladybirds Coccinellidae () is a widespread family of small beetles ranging in size from . They are commonly known as ladybugs in North America and ladybirds in Great Britain. Some entomologists prefer the names ladybird beetles or lady beetles as they ...

hoverflies Hover flies, also called flower flies or syrphid flies, make up the insect family Syrphidae. As their common name suggests, they are often seen hovering or nectaring at flowers; the adults of many species feed mainly on nectar and pollen, while ...

and the flower bug ''

Anthocoris nemoralis ''Anthocoris nemoralis'' is a true bug in the family Anthocoridae. The species is native to Europe and is introduced in North America. It is a predator of aphids, spider mites and jumping plant lice, and is therefore used as a biological pest ...

''.

Description

The aphids and nymphs are grey in colour with tufts of white extruded wax. There are two forms of first instar nymphs. The primary-type nymphs have long

rostra The rostra ( it, Rostri, links=no) was a large platform built in the city of Rome that stood during the republican and imperial periods. Speakers would stand on the rostra and face the north side of the comitium towards the senate house and de ...

and legs of approximately equal length; they feed and continue to grow and develop into adults. The secondary-type nymphs have short rostra and the front two pairs of legs are enlarged; they have never been known to grow beyond the first instar stage.

Ecology

The deciduous, three-leaf clematis ''

Clematis ''Clematis'' is a genus of about 300 species within the buttercup family, Ranunculaceae. Their garden hybrids have been popular among gardeners, beginning with ''Clematis'' × ''jackmanii'', a garden standby since 1862; more hybrid cultivars ...

apiifolia'' is used during the summer by ''C. clematis'' as its secondary host species. The aphids form a cluster in a shady area near the base of the climbing plant. During the summer, wingless females produce primary-type nymphs by

parthenogenesis Parthenogenesis (; from the Greek grc, παρθένος, translit=parthénos, lit=virgin, label=none + grc, γένεσις, translit=génesis, lit=creation, label=none) is a natural form of asexual reproduction in which growth and developmen ...

(live birth). These also reproduce parthenogenetically, but some of the offspring develop into secondary-type nymphs. These neither grow nor develop further and guard the colony, killing predatory larvae of

and the flower bug ''

''. To do this, the secondary-type nymphs climb onto the intruder and some insert their stylets into it. The intruder wriggles and falls to the ground where it is further attacked by walking secondary-type nymphs and dies within a few hours. In the autumn some winged adult aphids are produced which migrate to an unknown primary host plant. In late autumn only primary-type first instar nymphs are produced and these overwinter in cracks in the bark or among moss. It is not known whether these are the source of the following year's colonies, or whether the migratory insects are. Further research has disclosed that the primary host for this social aphid is a plant in the family

Ulmaceae The Ulmaceae () are a family of flowering plants that includes the elms (genus ''Ulmus''), and the zelkovas (genus ''Zelkova''). Members of the family are widely distributed throughout the north temperate zone, and have a scattered distribution ...

, often ''

Zelkova ''Zelkova'' (from Georgian ''dzelkva'', 'stone pillar') is a genus of six species of deciduous trees in the elm family Ulmaceae, native to southern Europe, and southwest and eastern Asia. They vary in size from shrubs (''Z. sicula'') to large ...

''. On this host the aphids form galls and some of the second instar nymphs form a soldier caste. The proportion of soldiers is higher in large colonies on the primary host, and the soldier nymphs differ from those on the secondary host in being capable of moulting and developing into adults.

References

{{Taxonbar, from=Q10457194 Insects of Japan Eriosomatinae Insects described in 1922