“Chrysina Limbata” Researchers discover optical secrets of ‘metallic’ beetles
Chrysina limbata is a species of scarab beetle found in Costa Rica and in the tropical rainforests of Mexico and South America.
They are in the Genus Chrysina and they are in a subfamily of scarabs known as Rutelinae (shining leaf chafers).
It is notable for its metallic reflective silver color.
C. limbata measures between 25 and 35 mm in length.
They have a reflective silver metallic appearance which is achieved with layers of chitin.
In addition, the layers of chitin coating are also chirped.
It is considered a complex multilayer as each layer decreases in depth, as the thickness changes, so too does the optical path-length.
Each chirped layer is tuned to a different wavelength of light. The multilayer found on the limbata reflects close to 97% of light across the visible wavelength range.
Physicist William E. Vargas believes that the metallic appearance may act like water, appearing only as a bright spot to predators.
The rain forest of Costa Rica where C. limbata lives has water suspended from leaves at ground level.
Light is refracted in different directions, and it allows metallic beetles to fool predators.
– Taxonomy –
Chrysina limbata was described in 1894 by zoologists Walter Rothschild and Karl Jordan, initially as Plusiotis limbata.
The genus Chrysina was formerly known as Plusiotis.
The C. limbata is in the superfamily of Scarabaeoidea, the family of Scarabaeidae, the subfamily of Rutelinae and the tribe Rutelini.
– Life history –
Like all beetles, scarabs go through a metamorphosis.
The life cycle begins when the female lays an egg, which becomes a larva, then a c-shaped pupa, which becomes an adult.
The scarab beetles lay their eggs in the ground or in decomposing materials.
When the scarab is in the larval stage they feed on plant roots or rotting matter.
As adults they are omnivores: they eat plants and are considered an agricultural pest.
They are known to eat fruit, carrion, and other insects.
– Distribution –
Chrysina limbata is found in tropical forests of Costa Rica, Central America and Southeast Mexico, especially in the mountain ranges 600 meters above sea level.
Collectors search out variants of the Chrysina. In 2007 National Geographic Magazine reported that certain varieties of the scarab could be sold for as much as $500.
Loss of habitat is a greater threat to the population of Chrysina variants than collectors.