#icerya

An Iceryine Scale Insect (Icerya sp.) in Nanping Zhen, Yunnan, China

Large Cushion Scale Insect

Unidentified, genus Icerya

What appears to be a scale insect from the Icerya genus.

Icerya

Native to Australia, but first described from New Zealand in 1878 by William Miles Maskell, Kiwi politician and entomologist. He named it after one Rev. Dr. Purchas, apparently the first person to notice the species. It was certainly noticed rather more often after that - within 10 years it was a devestating pest in Californian Citrus orchards, and it's now found in Citrus-growing regions worldwide.

Not that it limits itself to Citrus - in the photos here it's growing on Crownbeard (Verbesina encelioides, Asteraceae), and it's been reported from over 80 other families.

Happily, an early attempt at biological control was quite successful - the vedalia ladybird (Novius cardinalis) was introduced from Australia to California in 1888 and proved quite effective.

Icerya purchasi has another claim to fame, however - it's one of very very few hermaphroditic insects (and most of the others are close relatives). However, the sperm-producing cells in their ovitestes are derived from excess sperm that penetrated the egg during conception (usually self-fertilised since pure males are only derived from unfertilised eggs, and are very uncommon and sometimes absent entirely). Since that means the sperm the hermaphrodite offspring eventually make will be produced by the excess-sperm-derived male tissue, the entire cell-line is a continous culture. Essentially, Cottony Cushion Scale reproduction uses immortal incestous sex tumours.