Depopulation of cockroaches in post-Soviet states

Since the beginning of the 21st century, the rapid disappearance of several types of cockroaches has been observed in Russia and other post-Soviet states. Various factors have been suggested as causes of their depopulation.

Background

A mass depopulation of cockroaches has been observed since the beginning of the 21st century in Russia and other countries of the former USSR. Observers^[who?] have noted a rapid disappearance of various types of cockroaches from cities and towns in Russia, Azerbaijan, Kazakhstan, Ukraine, Moldova, and Belarus.^{[citation needed]} However, no such depopulation has been observed in larger Russian megalopolises such as Moscow, Saint Petersburg, and Nizhny Novgorod.^[1]

Scientists from Chelyabinsk and Yekaterinburg have suggested that the oriental cockroach should be added to the IUCN Red List of Threatened Species.^[2][3]

Suggested explanations

The depopulation of cockroaches may be exaggerated, or this phenomenon may be temporary or cyclic.^[1][4] A number of explanations of the phenomenon are discussed in the media, of varying degree of credibility.

• Usage of plastic bags to store domestic waste and the discontinuation of rubbish chute usage.^[5]
• Cockroaches may have migrated out of homes to other, more suitable places.^[6][7]
• Transitioning from antiquated roach-management methods such as egg yolk and boric acid to newer poisons and methods may have led to more effective depopulation.^{[8][9][10][1]}
• Usage of modern construction materials may also contribute to the phenomenon; the population of cockroaches might have been reduced due to their purported ingestion of unsafe substances.^[11][12][13] However, cockroaches were noticed to disappear even in the houses where such construction materials were not used.^[14]
• The emergence of Pharaoh ants, who compete with the cockroaches for food, and may even feed on them. The ants will feed on dead cockroaches. ^[15]
• Ozone holes may also lead to abnormal chronobiology in cockroaches.^[12][13]
• Internal competitions between cockroaches may decrease the number of cockroaches.^[5]

See also

• Colony collapse disorder, bees