Greenhouse orthezia Orthezia insignis, copyright JMK.

Belongs within: Coccinea.

The Ortheziidae are a group of scale insects in which females bear a dorsal anal opening surrounded by six setae and a band of pores. Female antennae have three to eight segments with a stout apical spur on the terminal segment (Carver et al. 1991).

Soft waxy scales
Published 28 April 2008
Nettle ensign scale Orthezia urticae. Photo by Pavel Krásenský.

The Hemiptera (true bugs) are one of the definite contenders for the insect order containing the most oddballs (Coleoptera and Hymenoptera are probably their competitors). Hemiptera are well marked as a group by their specialised sucking mouthparts, but within the Hemiptera a wide range of body plans have arisen. The scale insects (Coccinea) are perhaps one of the oddest groups of all, and it is one of the scale families, the Ortheziidae, that is our current Taxon of the Week.

Scale insects get their name from the adult females, which have completely abandoned the joys of mobility and live their lives on a single spot, sucking the sap from a host plant. To protect themselves they secrete a covering of sticky wax or a hardened scale. Because of their sedentary lifestyle, indulgences such as legs or eyes are unnecessary, and have become reduced or lost. Only close inspection of the adult, or of the males or nymphs, would identify these creatures as even being insects. Those scales that are significant to humans are mostly plant pests, though some species are used to produce lacquer or the red dye known as cochineal (yep, gramophone records were once made from crushed insects).

Orthezia insignis female with crawlers emerging from the ovisac. Photo from here.

Scales of both sexes first hatch out of their eggs as highly mobile nymphs called ‘crawlers’, with fully developed legs and antennae (Carver et al. 1991). This is the dispersal phase of their life cycle—not only can they crawl around, but they are also small enough to be easily blown by the wind. Once they find a suitable host plant and moult to the next instar, scale nymphs become pretty much immobile, and lose all the paraphernalia of their youth. While females pretty much remain in this state for the rest of their life, males do things quite differently. They feed for the second and third instars, then enter a non-feeding pupal stage before emerging as the winged adult (the adult males of a few species lack wings). Adult male scales also don’t feed and lack mouthparts—they will only live for a short time while they find a mate. Male scales are also one of the few groups of winged insects, in addition to Diptera (flies) and Strepsiptera, to have lost one of the pairs of wings (the first time I ever saw one, I was not yet aware of this and it confused me immensely). Because of their brief lifespan, male scales are relatively rare overall, though I get the impression that they can appear in large numbers in the right season. However, they are also of microscopic size, so are not likely to be noticed.

Male Orthezia insignis. Photo from here.

Scale insects are divided between a number of families. They are often divided into two superfamilies, the Orthezioidea (archaeococcids) and Coccoidea (neococcids) (Koteja 2000), though other authors combine them all into the Coccoidea. However, the archaeococcids are united only by primitive characters and are assumed to be paraphyletic and ancestral to neococcids. The Ortheziidae (ensign scales) is one of the most basal of the families of Coccinea, and one of the earliest families known from the fossil record, in the Lower Cretaceous (Koteja 2000)—however, the Coccinea fossil record is extremely poor and should be treated with caution (most female scales are distinguished by microscopic characters not usually preserved in fossils, and the great difference between males and females makes them impossible to identify with each other unless specimens are preserved in the process of mating). Characters giving away the basal position of ortheziids include the presence of abdominal spiracles in the female (lost in neococcids), and compound eyes in the male (in neococcids the compound eye has disintegrated into a row of separate simple eyes). Nymphs and adult females secrete symmetrical plates of wax on their backs, while the female also secretes a wax ovisac at the end of the abdomen in which she incubates her eggs. This is the ‘ensign’ referred to in the common name.

The Ortheziidae are not a particularly large family by insect standards—about 200 species are known. As with other scales, a number of species have been spread around the world along with infected host plants, and some can cause trouble as pest species.

Systematics of Ortheziidae
    |  i. s.: ‘Coccus’ termitinus Menge 1856K00
    |--Ochyrocoris Menge 1856K00
    |    `--O. electrina Menge 1856K00
    |--Protorthezia Koteja 1987K00
    |    `--P. aurea Koteja 1987K00
    |--Palaeonewsteadia Koteja 1987K00
    |    `--P. huaniae Koteja 1987K00
    |    |--N. guadalcanaliaCGW91
    |    `--N. obscuraM96
    |--Arctorthezia Cockerell 1902K00
    |    |--A. antiqua Koteja & Żak-Ogaza 1988K00
    |    `--A. occidentalisGE05
    |--Newsteadia Green 1902K00
    |    |--N. floccosaCGW91
    |    |--N. succini Koteja & Żak-Ogaza 1988K00
    |    `--N. tristaniM96
    `--Orthezia Bosc d’Antic 1784 [incl. Dorthezia]K00
         |--O. acapulcoaM96
         |--O. cacticolaM96
         |--O. cataphractaH44
         |--O. caudataM96
         |--‘Dorthesia’ characiasG20
         |--‘Dorthesia’ citrusR26
         |--O. ferrisiM96
         |--O. insignisCGW91
         |--O. lasiorumM96
         |--O. mexicanaM96
         |--O. occidentalisC01
         |--O. piniM96
         |--O. pinicolaM96
         |--O. praelongaM96
         |--O. pseudinsignisM96
         |--O. selaginellaM96
         |--O. smythiM96
         `--O. sonorensisM96

*Type species of generic name indicated


[CGW91] Carver, M., G. F. Gross & T. E. Woodward. 1991. Hemiptera (bugs, leafhoppers, cicadas, aphids, scale insects etc.) In: CSIRO. The Insects of Australia: A textbook for students and research workers vol. 1 pp. 429–509. Melbourne University Press: Carlton (Victoria).

[C01] Cockerell, T. D. A. 1901. Contributions from the New Mexico Biological Station.—XI. New and little-known insects from New Mexico. Annals and Magazine of Natural History, series 7, 7: 333–337.

[G20] Goldfuss, G. A. 1820. Handbuch der Naturgeschichte vol. 3. Handbuch der Zoologie pt 1. Johann Leonhard Schrag: Nürnberg.

[GE05] Grimaldi, D., & M. S. Engel. 2005. Evolution of the Insects. Cambridge University Press: New York.

[H44] Hammer, M. 1944. Studies on the oribatids and collemboles of Greenland. Meddelelser om Grønland 141 (3): 1–210.

[K00] Koteja, J. 2000. Advances in the study of fossil coccids (Hemiptera: Coccinea). Polskie Pismo Entomologiczne 69: 187–218.

[M96] Miller, D. R. 1996. Checklist of the scale insects (Coccoidea: Homoptera) of Mexico. Proceedings of the Entomological Society of Washington 98 (1): 68–86.

[R26] Risso, A. 1826. Histoire naturelle des principales productions de l’Europe méridionale et particulièrement de celles des environs de Nice et des Alpes maritimes vol. 5. F.-G. Levrault: Paris.

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