Feral Animals of the Northern Territory

Exotic Invertebrates

Impacts

Exotic invertebrates (animals without a backbone) may have a considerable impact on the natural environment. These exotic pests may cause significant threats to biodiversity because they:

prey on native fauna,
compete with native invertebrates for resources (food, nest sites),
are often highly aggressive towards other native invertebrates and vertebrates,
promote the abundance and / or distribution of other pest invertebrates, leading to the establishment or increased population growth of other pest species.

Another negative impact of several exotic invertebrates is that they may bite or sting people. This may be fatal in people with specific allergies to the venom carried by these invertebrates. Other exotic invertebrates, such as mosquitoes, may carry diseases, while others, such as cockroaches, may become a nuisance in houses.

Of particular concern are bees, ants and wasps, although there are a number of other invertebrates that may also cause significant environmental damage.

There are a number of exotic invertebrates in the Northern Territory. Some of the most environmentally-damaging species are listed in the table below.

Name	Impacts
European honey bee (Apis mellifera)	The European honey bee competes with native pollinators, such as native bees and birds, for nectar and hollows in trees where they roost. For this reason, in many areas where the honey bee is present there have been declines in the abundances of native animals. In some cases, European honey bees have promoted the invasion of weeds because they often favour the nectar of weeds over native plants. This species also has a nasty sting, which may be fatal to people with allergies.
Yellow crazy ant (Anoplolepis gracilipes)	See the Exotic Ants Project
Big-headed ant (Pheidole megacephala)	See the Exotic Ants Project
Ginger ant (Solenopsis geminata )	See the Exotic Ants Project
Pharaoh's ant (Monomorium pharaonis)	The pharaoh’s ant competes with native ants for food and shelter. This species also acts as a vector for human pathogens. Its presence in hospitals is of great concern because it may increase infection rates.
Singapore ant (Monomorium destructor)	The Singapore ant competes with and preys on native invertebrates, leading to decreased native ant species diversity. In addition, this species causes extensive economic damage within urban environments by gnawing through rubber and fabric, removing rubber insulation from electric wiring and phone lines, and damaging polyethylene cable.
Ghost ant (Tapinoma melanocephala)	The Ghost ant competes with native pollinators and robs the nectar from native plants. It has a nasty sting, which can be fatal to people with allergies.
Electric ant (Wasmannia auropunctata)	See the Exotic Ants Project
Red Imported Fire Ant (Solenopsis invicta)	See the Exotic Ants Project
European bumblebee (Bombus terrestris)	This species has not been recorded in the Northern Territory. The main threats posed by this species include robbing the nectar of native plants, disrupting native pollination, promoting weeds because it favours the nectar of weeds over native plants. This species has a nasty sting. The venom can cause severe reactions in some people, including swelling, nausea, vomiting and breathing difficulties.
The Giant African Land Snail (Achantina fulica)	This species has been eradicated from the Northern Territory. This species has been linked to declines in both invertebrates and plants, primarily as a result of competition for resources.
Common malaria mosquito (Anopheles quadrimaculatus)	This species is known to spread malaria.
Asian tiger mosquito (Aedes albopictus)	This species has not been recorded in the Northern Territory. Social threat because of capacity to transmit disease. Not yet present in Australia, but suited to tropical climates.