I have been doing some research into some of the pictures I took last year of bugs that I didn’t recognize and yet again I am amazed by the miniature dramas that we rarely stop to see. I thought I had discovered quite an exotic bug and certainly one I didn’t recall seeing before. It turns out that this is an insect that can be found in most gardens, waiting in ambush for potential prey.
The Zelus luridus is also known as the Pale Green Assassin Bug. This one is a nymph because there are no wings yet. They come under the “helpful” insect list, but it might be good to keep our distance. They are ambush hunters that inject a toxin into their prey with their proboscis-like appendage, which dissolves the soft tissues. Their bites are fatal to their insect victims, but can cause allergic reactions in humans that can last several days. They are less than ½ inch long and take a whole year to reach maturity, when they finally get their wings. The wingless nymphs moult five times before they reach adulthood.
Some Assassin bugs specialize on certain prey groups such as ants. They have special glands in the exoskeleton of the legs that secrete a sticky substance to ensnare and hold insects. Their front legs are densely covered in short hairs and the insects smear their front legs with their glue-like secretion, which allows them to catch prey. Newly hatched nymphs use the sticky coating of the egg mass to cover the forelegs until they are older and start to produce the sticky fluid.
It looks like this one lost the battle and the ants are attacking it. Given one of the ants is behind and not obviously attached to the forelegs, it seems that my Zealous Zelus is getting overpowered by the ants. Now I know a little more I wish I had stayed longer to watch the drama unfold. At the time I was more interested in figuring out what this little insect was and missed the action that was taking place. How blinkered we can be to what goes on around us. Isn’t that the same with our daily lives? We see what we want to see and filter out unwanted information. There I was patting myself on my back for being observant and noticing such a tiny little insect, but I failed to truly see what was going on around it. I got my picture and off I went to identify it.
And what about the out of focus ants, where the action actually was?
Well I did take a slightly better photograph elsewhere and it looks to be a Field Ant. Formica is the Latin word for “ant” and the genus of ants commonly known as Wood Ants, Mound Ants and Field Ants. Some are nectar feeders and others are scavengers or predators of other insects, which I guess was what was going on in the earlier photographs.
Over 100 different field ant species live throughout North America and I don’t have enough details to figure out much about this little guy. One thing that I did read is that they are capable of pinching human skin with their mouthparts and can expel formic acid as a defence mechanism. That is why they can be an issue when mowing and humans disturb them. Field Ants are also commonly called Mound Ants or Thatching Ants. This is due to the shelters they build. Mounds can be as large as 30 cm in diameter.
The way to tell a Field Ant from a Carpenter Ant is by the thorax. The Field Ant has an uneven thorax, which has a dent in the middle. A Carpenter Ant has a smooth thorax. So whilst I need to make sure I don’t disturb these little Field Ants and avoid a bite, they don’t pose the threat of structural damage to the cottage that the Carpenter Ants pose.