''Callococcus'' is a genus of Australian

scale insect Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than th ...

that feeds on species of ''

Leptospermum ''Leptospermum'' is a genus of shrubs and small trees in the myrtle family Myrtaceae commonly known as tea trees, although this name is sometimes also used for some species of ''Melaleuca''. Most species are endemic to Australia, with the great ...

'', ''

Hypocalymma ''Hypocalymma'' is a genus of evergreen shrubs in the myrtle family Myrtaceae described as a genus in 1840. The entire genus is endemic to southern Western Australia. Species list The following is a list of formally described ''Hypocalymma'' sp ...

'', ''

Kunzea ''Kunzea'' is a genus of plants in the family Myrtaceae and is endemic to Australasia. They are shrubs, sometimes small trees and usually have small, crowded, rather aromatic leaves. The flowers are similar to those of plants in the genus ''Lepto ...

'' and some other members of the tribes

Chamelaucieae Chamelaucieae is a tribe of flowering plants within the family Myrtaceae, mostly from Australia, with a few species in New Caledonia and south-east Asia. Genera include: *''Actinodium'' Schauer (Australia) *'' Aluta'' Rye & Trudgen (Australia ...

and

Leptospermeae Leptospermeae is a tribe in the plant family MyrtaceaeWilson, P. G. (2011) Myrtaceae. In The Families and Genera of Vascular Plants. Volume X. Sapindales, Cucurbitales, Myrtaceae, edited by K. Kubitzki, X:212–71. Heidelberg: Springer-Verlag, 20 ...

Gullan P.J., Miller D.R. & Cook L.G. (2005). Gall-inducing scale insects (Hemiptera: Sternorrhyncha: Coccoidea). In: Biology, Ecology, and Evolution of Gall-Inducing Arthropods (eds. Raman A, Schaefer CW & Withers TM). Science Publishers New Hampshire, pp. 159-229. in the myrtle family

Myrtaceae Myrtaceae, the myrtle family, is a family of dicotyledonous plants placed within the order Myrtales. Myrtle, pōhutukawa, bay rum tree, clove, guava, acca (feijoa), allspice, and eucalyptus are some notable members of this group. All spe ...

. ''Callococcus leptospermi'' induces stem-swelling galls on some species of ''Leptospermum'', and it is considered to be a potential biological control agent of ''

Leptospermum laevigatum ''Leptospermum laevigatum'', commonly known as the coast tea tree, is a species of shrub or small tree that is endemic to south-eastern Australia, but has been widely introduced in other places where it is often considered to be a weed. It has th ...

'' in South Africa. The other described species of ''Callococcus'' do not induce galls.

Morphology

As for most

scale insects Scale insects are small insects of the order Hemiptera, suborder Sternorrhyncha. Of dramatically variable appearance and extreme sexual dimorphism, they comprise the infraorder Coccomorpha which is considered a more convenient grouping than th ...

, the

taxonomy Taxonomy is the practice and science of categorization or classification. A taxonomy (or taxonomical classification) is a scheme of classification, especially a hierarchical classification, in which things are organized into groups or types. ...

of ''Callococcus'' is based on the morphology of the adult female. Like adult females of other scale insects, those of ''Callococcus'' have no wings. They also have no legs and their antennae are reduced to tiny stubs. Adult females are sack-like and range in colour from burgundy to yellowish or brown. Adult females of ''Callococcus acaciae'' are globular and a red-burgundy colour. They feed on species of ''

'' and are covered in a curly, stretchy wax that is exuded from glands on their dorsum. Adult females of ''Callococcus newmanni'' and ''C. pulchellus'' are similar to each other, and females of both species produce a waxy covering that looks like a small clam or shell-fish. Adult females of ''C. leptospermi'' are sausage-shaped and brownish in colour.Coles R.B., Verberne F. & Brookes H.M. (1988). The immature and adult stages of ''Callococcus leptospermi'' (Maskell) (Homoptera: Coccoidea: Asterolecaniidae), with observations on life history. ''J. Aust. Entomol. Soc.'', 27, 15-25. Once a female initiates a gall as a nymph she never leaves, and she mates, reproduces and dies inside the gall. ''C. leptospermi'' is ovoviviparous, meaning that the embryos develop inside the female, nourished by special cells (not a placenta), and are born fully developed. First-instar

nymphs A nymph ( grc, νύμφη, nýmphē, el, script=Latn, nímfi, label=Modern Greek; , ) in ancient Greek folklore is a minor female nature deity. Different from Greek goddesses, nymphs are generally regarded as personifications of nature, are ty ...

(crawlers) of ''C. leptospermi'' are generally a pinkish colour and have well developed legs and antennae. They have numerous 8-shaped pores on their dorsum (back). Unusually among scale insects, male and female crawlers of ''C. leptospermi'' exhibit

sexual dimorphism Sexual dimorphism is the condition where the sexes of the same animal and/or plant species exhibit different morphological characteristics, particularly characteristics not directly involved in reproduction. The condition occurs in most an ...

. Adult males of ''C. leptospermi'' are winged (single pair, as in other winged male scale insects), pinkish in colour, and have a long slender abdomen.

Systematics

The type species, ''C. pulchellus'', was described by Maskell in 1897 (as ''Sphaerococcus pulchellus'') and the genus ''Callococcus'' was erected in 1918 by Ferris because it was recognised that the species did not belong in the

mealybug Mealybugs are insects in the family Pseudococcidae, unarmored scale insects found in moist, warm habitats. Many species are considered pests as they feed on plant juices of greenhouse plants, house plants and subtropical trees and also act as a ...

genus ''Sphaerococcus''. ''Callococcus'' had been placed in the family

Asterolecaniidae Asterolecaniidae is a family of scale insects commonly known as pit scales or asterolecaniids. They typically cause a depression in the host plant's tissues and often cause distortion of the shoots. They are found on a range of hosts but are espe ...

(the pit scales) based on the presence of 8-shaped pores on the dorsum of nymphs, because this character was interpreted as being diagnostic for this family. Recent DNA-based

phylogenies A phylogenetic tree (also phylogeny or evolutionary tree Felsenstein J. (2004). ''Inferring Phylogenies'' Sinauer Associates: Sunderland, MA.) is a branching diagram or a tree showing the evolutionary relationships among various biological spec ...

indicate that the genus is closely related to some Australian gall-inducing eriococcid scale insects.Cook L.G. & Gullan P.J. (2004). The gall-inducing habit has evolved multiple times among the eriococcid scale insects (Sternorrhyncha: Coccoidea: Eriococcidae). ''Biol. J. Linn. Soc. Lond.'', 83, 441-452
DOI: 10.1111/j 1095-8312.2004.00396.x
/ref> Subsequently, ''Callococcus'' was transferred to the family

Eriococcidae Eriococcidae is a family of scale insects in the order Hemiptera. They are commonly known as felt scales or eriococcids. Each species is usually specific to a different plant host, or closely related group of hosts. Recent research using riboso ...

(the felt scales).

References

External links

ScaleNet: a database of the scale insects
{{Taxonbar, from=Q16975374 Hemiptera of Australia Eriococcidae