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The big wet

Posted by: dry027

March 27, 2018

The Ovi trap (L) invites female Aedes aegypti mosquitoes to lay her eggs; the BG trap (R) has contrasting colours which attracts females, therefore also attracting the males)

Innisfail and its surrounding areas have copped a deluge in recent weeks where some suburbs were flooded and people suffered quite a disturbance to their homes and businesses, whilst others were lucky enough to remain high and dry. Time will tell exactly how the wet has affected our study, but already we are seeing some impacts.

Firstly, some interesting mosquito specimens have entered our traps.

Our BG and Ovi traps are designed specifically to attract the Aedes aegypti mosquito due to its low lying position in homes/sheds, and its contrasting colours. Female Aedes aegypti love low dark places to hide and lay eggs.

We have however had some interesting mosquitoes come through our identification lab. Soon after the rain event, we found six Toxorhynchites speciosus in our BG samples. This is one of the biggest mosquitoes in the world and its larvae are predatory and feed on other mosquito larvae including Aedes aegypti and Aedes notoscriptus.

Another interesting mosquito that came with the wet was Mimomyia elegans. This mosquito has an elegant bulbous ended proboscis and is known to feed on the blood of dogs, pigs and even amphibians.

These are not commonly found in our traps, but constitute some of the 30+ species of mosquito found in the area.

Toxorhynchites speciosus (L) and Mimomyia elegans (R)

In fact, we are hearing from a number of residents that they are experiencing a huge number of mosquitoes around their homes and workplaces. Most however seem to be in the backyard or downstairs hanging the washing. These are likely to be marsh mosquitoes which are aggressive biters and are capitalising on the conditions.

The Aedes aegypti is a shy/timid biter which generally only hangs around inside the house.

Aside from interesting finds, our network of traps have generally survived well, although some in the East Innisfail area have obviously been subject to a bit of a drowning. Nothing a good clean out won’t fix – our field team are checking that they are still in good working order as they do their rounds.

A BG trap (now undergoing a clean) sitting low in East Innisfail – One of our Field Technicians is pointing to the level where the flood waters rose to a couple of weeks ago.

If you have one of our traps at your home/business, please let us know if you have any concerns about it. We particularly appreciate your contact if our traps are missing or damaged which can happen in severe weather events. Call 1800 40 30 83 or email innisfail_project@csiro.au to get in touch.

Releases were cancelled on Friday 9th March for access and safety reasons due to the major floods, but were back underway on the following Monday.

With more rain early this week and access to Cairns JCU proving difficult, we have decided to hold off on releases on Monday 26th March.

Thank you to the trap hosts who continue to house our traps, and to the communities supporting our releases! We hope all affected by the wet have a swift recovery and continue to stay safe!