Two species of Indomalayan cockroach newly discovered on the island are rearing their ugly heads in two Maltese localities – and they may be spreading.
The Indian cockroach (locally referred to as wirdiena tan-Naxxar) and the Greenhouse cockroach (locally referred to as wirdiena ta’ Paris) were first found back in 2017 when a local pest controller and biologist was working with glue carpets.
“These cockroaches were found lurking and it took over a year to discover their true identity and beginning to understand their local distribution,” Arnold Sciberras told Lovin Malta. “They are a species of burrowing cockroach, and are a common plant pest endemic to the Indomalayan region that has spread to temperate climates.”
It’s believed these species were inadvertently shipped over in the soil of plants – and now, they are spreading in several localities.
So far, these pests have been found in at least 43 homes and properties in the Ta’ Paris area of Birkirkara, and another 40 homes and properties in Naxxar.
However, while you may come across them in your home, you probably will not as they are not a common household pest.
“It is more of a plantation and garden pest problematic in heated greenhouses, where large numbers can hide by day and emerge at night, gnawing at the softer parts of plants,” Sciberras said. “They’ll probably be transferred into homes and businesses in potted plants.”
Interestingly, Greenhouse cockroaches are almost exclusively female, and they reproduce through parthenogenesis. Adults are around 18–25 mm in length and have dark brown to black bodies with shiny paler brown wings. The front edge of the pronotum (head shield) has a pale white-yellowish band. While males are rarely produced, male adults have longer wings than females, completely covering the abdomen.
Sciberras has urged people who come across these species to report it at email@example.com. Special thanks go to Jeffrey Sciberras and Carmel Camilleri for the images.