Invasive species – Mosquitoes are crossing the map! Time to lay a trap?
2017 has arrived – time to leave the bad luck of 2016 behind, right? I’m afraid not – well, not if you live in Florida. In the ‘Sunshine State’, there are already some Mosquito species (Aedes aegypti) that are plaguing the mainland, spreading Zika virus and Dengue virus. If this wasn’t bad enough, two new visitors were recently found to be making a new home for themselves in a new insect trap, created by Dr. Matthew DeGennaro of Florida International University.
These gatecrashers (or, should we say, trapcrashers) have travelled far from their native areas in Central and South America. Both Culex panocossa (from Latin America) and Aedeomyia squamipennis (a native of the Caribbean), have been found in Homestead and Florida city, places which are around 300 miles (or more) north of their native homeland.
Figure 1. Map showing path from ‘Greater Antilles (Black dot) to Florida City, FL (Red marker) 
The arrival of these new Mosquito species, spells trouble for Florida in 2017, as they have just recently had to deal with a torrent of Zika virus cases over the summer and autumn months of 2016. These new, unwelcome guests, both carry viruses which are detrimental to human health and will spread within populated areas, given the chance.
So how do these mosquitoes survive? – the ‘double-trouble invasive (species) bubble’. These newcomers utilise another invasive species (as if they weren’t enough to deal with) called water lettuce , Pistia stratiotes, on which to lay their eggs. Both species can do this; however, the viruses which they spread and the hosts which they infect, are quite different.
Figure 2. Water lettuce (Pistia stratiotes) – AKA Tropical duckweed, found in Florida.
The first, Aedeomyia mosquito, spreads the West Nile virus and Eastern Equine encephalitis to birds . On first hearing this , you may think “that’s ok, as its primary host isn’t a human”; however, if enough of these birds become infected, the viruses can be passed along to humans and various other animals. This mosquito has been responsible for spreading avian malaria, caused by the protozoan, Plasmodium relictum.
The second, Culex mosquito, is more of an urgent threat, as it is known to be a vector for Venezuelan equine encephalitis which has been shown to be lethal to both children and the elderly population. Another worry, is that this mosquito could carry the local Everglades virus, causing a febrile (showing symptoms of fever) illness, coupled with headaches and muscle pain.
Despite these mosquitoes being able to transmit these viruses, they have been kept at bay in the local Everglades as they do not survive as well outside of this undisturbed habitat. However, it is becoming an increasing worry that the Aedeomyia species (tropical) could start to transmit the virus; and if that starts to happen, we may have another Zikaesque panic on our hands – DON’T PANIC! DON’T PANIC…at least not yet, anyway.
When we add these two most recent invasive species into the mix, it brings the total number of invasive mosquitoes to nine (of those discovered in Florida).
Is this a sign that global warming is allowing these tropical species to venture into more northerly territories; bringing with them, a plethora of disease-causing viruses?