Coccus adonidum, , Linnaeus, 1767

Williams, D. J. & Z. - Q, 2007, Carl Linnaeus and his scale insects (Hemiptera: Coccoidea) *, Zootaxa 1668 (1), pp. 427-490 : 439-441

Coccus adonidum

For many years, the name Coccus adonidum was given to the long-tailed mealybug but Ledermüller’s article cited by Linnaeus (see citation under Lederm. 1762) was discussed and the illustration reproduced by De Lotto (1965), who stated that it cannot be associated with the mealybug. Replying to an application by Miller (1974) to designate Dactylopius longispinus Targioni Tozzetti as the type species of the genus Pseudococcus Westwood, Danzig & Kerzhner (1981) gave evidence that Ledermüller’s description and illustration could only be a mealybug. Nevertheless, the specific names Coccus adonidum Linnaeus, 1767 (Name Number 1117), and Pediculus coffeae Linnaeus, 1767 (Name Number 1118), were suppressed under the plenary powers and placed on the Official Index of Rejected and Invalid Specific Names in Zoology by Melville (1983).

Coccus aonidum (Family Diaspididae )

( Figures 1A, 2 )

Description

Scale covering of adult female round, reddish-brown to purple, with exuviae central, lighter in colour. Male scale smaller, elongate, similar colour to that of adult female with exuviae towards one end.

Adult female on microscope slide almost pyriform, membranous except for gently rounded pygidium. With 3 pairs of definite lobes present, a fourth pair each represented by sclerotized points. Long paraphyses present extending from inner and outer bases of median lobes, from inner base of each second lobe, between each second and third lobe, and from inner base of each third lobe. Plates fringed, normally 2 present between median lobes, 3 between each second and third lobe, and a series between each third and fourth lobe. Macroducts extending forwards in a short line between paraphyses of each median and second lobe, and in 2 rows, each 2–3 deep, extending well forwards into pygidium between second and third lobes and between third and fourth lobes. A single cluster of smaller ducts present on lateral margins of second abdominal segment. Perivulvar pores usually in 4 groups, occasionally in 5 groups. Thoracic tubercles thorn-like, present on margins of metathorax. Antennae each with 1 long seta. Spiracles without any associated pores.

Comments

This species is common outside in most tropical to temperate areas of the world and in greenhouses elsewhere. It can cause considerable damage to citrus and is common on many plants.

Under its original name, Coccus aonidum , this armoured scale insect was regarded as unrecognisable and most scale insect workers were unaware that a species named Chrysomphalus ficus Ashmead , described by Ashmead (1880), was identical to it. Cockerell (1899a) was the first to synonymise the name Chrysomphalus ficus with Coccus aonidum under the new combination Chrysomphalus aonidum (L.) and stated that the description by Linnaeus “is excellent, and can apply to nothing else” (1899a: 25).

The species was one of the few listed by Jackson (1913a) (as No. 2 under Coccus ) in the catalogue of insects still extant in Linnaeus’ collection. There are a few specimens on a piece of leaf labelled “aonidum” in Linnaeus’ handwriting ( Figure 1A), and one of these has now been prepared on a microscope slide. The specimen is in good condition despite its age and clearly shows that Cockerell was correct in his interpretation of the species. This single specimen is here designated lectotype ( LSL) .

The illustration reproduced in Figure 2 first appeared in this form in Microentomology, 1939, Volume 4: 71. For a full synonymy of this species see Ben-Dov and German (2003). A recent full description of this species and a new illustration have been presented by Miller & Davidson (2005).

Coccus betulae (Family Coccidae )

The entry in Linnaeus (1758) refers to Fauna Svecica 723 ( Linnaeus, 1746) where Linnaeus quotes De Geer without any reference. Linnaeus also gives a short description of the habit, referring to Betula 776, which in turn refers to Flora Svecica ( Linnaeus, 1755) containing a short description of Betula or birch. With the help of Carl-Axel Gertsson in Sweden, I have checked all of De Geer’s publications from 1740–1746 and can find no description of a scale insect on birch. The name Coccus betulae Linnaeus , therefore, must be a nomen nudum. It is obvious that Cockerell (1901) also doubted the validity of the name. Modeer discussed the species under the name Coccus betulae alba without reference to De Geer.

The first description under the name Coccus betulae is by Fabricius (1776) who described the insect as “corpus minutes, albidum”, which can be translated as “body very small, whitish”. The name Coccus betulae should be credited, therefore, to Fabricius. Gmelin (1790), although referring to Fabricius, gives a different description as “teres, spadiceus” or “cylindrical, deep reddish-brown”.

In Linnaeus’ lectures on the animal kingdom compiled by Lönnberg (1913), Linnaeus refers to sp. 723, the number of the entry under Coccus betulae in Fauna Svecica, 1746 as: “It is on birch where the eggs are like small red buttons on their threads” (translation from Swedish by Carl-Axel Gertsson). Whether the species first referred to by Linnaeus (1758) or the name validated by Fabricius (1776) belongs to the genus Pulvinaria first proposed by Signoret (1873) as listed by Fernald (1903) is probably not worth exploring further. It seems best to accept the synonymy of Coccus betulae Fabricius with Coccus vitis L. (= Pulvinaria vitis ) by Newstead (1903) and later confirmed by experimental studies by Malumphy (1991) and Łagowska (1996) except that the name Coccus betulae L. quoted in these publications should refer instead to Coccus betulae Fabricius syn.n.

Coccus cacti (Family Monophlebidae )

Linnaeus (1758) listed several references under this entry, all of which contain descriptions of the cochineal insect of commerce now known as Dactylopius coccus Costa. The citation of these references alone, each containing a description of the insect, would have been sufficient to validate Linnaeus’ name Coccus cacti as the cochineal insect. In the description following these references, Linnaeus described what he thought was the same insect but, as he stated, the specimens were collected by Daniel Rolander in America on cactus. Linnaeus (1759a) gave an interesting account of how he received these insects at the University of Uppsala Botanic Garden in 1756 [see the English translation by Williams & Gertsson (2005)]. The live colony was inadvertently destroyed and, apparently, Linnaeus described the species from a single surviving specimen. As discovered by Cockerell (1899a), the description does not apply to the cochineal insect. Specimens of the insect that Linnaeus described were also sent by Daniel Rolander to Carl De Geer who also thought they represented the cochineal insect of commerce and he also described the species with a good illustration ( De Geer, 1776) and stated that, although the insects had been sent from Surinam, they had been collected in Sint Eustatius, an island in the Netherlands Antiles. Cockerell (1902 a, b) was able to recognise that the description by De Geer applied to a species which Cockerell referred to as Monophlebus cacti (L.) and later ( Cockerell, 1902c) as Llaveia cacti (L.). Cockerell & Hellems (1907) gave an account of this error. Morrison (1928) transferred the species to Protortonia Townsend as P. cacti (L.) where it is currently placed. The species has been redescribed in detail and illustrated by Williams & Gullan (2007), now in press.

Figures

FIGURE 2. Coccus aonidum L. Adult female. (Now Chrysomphalus aonidum (L.)).