Chrysina, or jewel scarabs (not to be confused with
jewel beetles, which are a different family), is a
genus of brightly colored, often metallic
iridescent species of
ruteline beetles. They range from the southwestern edge of the
United States, through
Mexico and
Central America, and as far south as
Colombia and
Ecuador.[1]Chrysina contains more than 120 species, includes all those formerly in the genus Plusiotis.[1][2] The genus name is from Greek χρύσινος (chrysinos), "gold-coloured".
Distribution and habitat
Although the genus is wide-ranging, each species tends to be quite restricted in both habitat and distribution, with the vast majority only found in a single or two countries.[1]
Most species are from Mexico and Central America. The highest diversity is in Mexico and
Panama, each being home to more than sixty species;
Costa Rica,
Guatemala and
Honduras also have many species, whereas
Belize,
El Salvador and
Nicaragua each only are known to house one or two species.[1] There are only three species in South America where restricted to western Colombia and western Ecuador, and four species in the United States where restricted to highlands of
Arizona,
New Mexico and western
Texas.[1][3][4]
They tend to be found in
pine,
juniper or pine-
oak forests, or in
cloud forests, most commonly between 1,000–3,000 m (3,300–9,800 ft) elevation, but there are also species found up to 3,800 m (12,500 ft) or in lowlands.[1][5]
Behavior
The immature stages of most species are unknown,[1] but where known the larvae live in and feed on rotting wood, while the adult beetles feed on foliage.[5] They are harmless to humans and not regarded as
pests.[4] The adult beetles are attracted to light during the night.[1][5]
Appearance
These beetles are typically between 15–35 mm (0.6–1.4 in) in length. The majority of species have bright shiny green upperparts, but metallic silver and gold are also common colors (species with all-silver or all-golden upperparts only occur in Central and South America), and a few can be metallic reddish.[1][6] Some species combine the colors, like the green-and-silver striped C. gloriosa.[6]
They are very popular among collectors; many species are
polymorphic. While their value often is quite low, only a few US$, particularly attractive specimens were reported to sell for as much as US$500 in 2007.[7]
Metallic color mechanism
Research has shown that the
elytra of Chrysina are composed of about 70
chitinous layers of
exoskeleton. The different reflective indices and spacing of the layers cause light of different wavelengths to be selectively refracted through them and by them in different phases, leading to a metallic appearance, and also leads to different specimens having different colors.[8]
Species
C. aurigans typically is golden, but can also be metallic red
^
abcdefghiBarria, M.D. (2023). A Monographic Revision of The Jewel Scarabs Genus Chrysina from Panama, Colombia, and Ecuador (Coleoptera: Scarabaeidae: Rutelinae: Rutelini). Zea Books, University of Nebraska-Lincoln Libraries.
doi:
10.32873/unl.dc.zea.1345.
ISBN978-1-60962-286-2.
S2CID257918078.
^Hawks, D.C. 2001. Taxonomic and nomenclatural changes in Chrysina and a synonymic checklist of species (Scarabaeidae: Rutelinae). Occ. Papers Consort. Coleopt. 4: 1-8
^
abMaddox, T.G. (2017), Population analysis of Chrysina woodii (Coleoptera: Scarabaeidae) in the Davis Mountains of West Texas, Angelo State University
^
ab"Chrysina gallery". Generic Guide to New World Scarab Beetles. University of Nebraska-Lincoln State Museum - Division of Entomology. Retrieved 17 July 2023.
^"Jewel Scarabs". National Geographic. 2007-02-07. Archived from
the original on 2007-02-07. Retrieved 2018-08-19.