The green lacewing (Chrysopa sp.)

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The elegant curves, a malachite colour that can draw slightly towards the azure, wings with artistic frames, and copper eyes which are golden-dyed: that’s how you could describe the green lacewings! Under their frail aspect is hidden (as often) an incredible complexity as well as amazing characteristics and behaviours!

First, let’s talk about identification! Green lacewings are not dragonflies, flies or butterflies, but belong to the order Neuroptera. Specifically, the term “green lacewing” refers to Neuroptera species belonging to the family Chrysopidae. Many people reduce green lacewings to just two species: Chrysopa perla and Chrysoperla carnea (I’ll let you appreciate the Chrysopa perla which is a species, and the Chrysoperla which is a genus, sometimes I don’t know what’s going on in the head of taxonomists), often referred to as “common green lacewing”. With that being said, the family Chrysopidae contains many more species, divided into many genera (Chrysopa, Chrysoperla, Dichochrysa, Nineta, etc.). Thus identifying green lacewing is much harder and complex than most people believe. Often you can just exclude certain species or genera! Here, the presence of an inter-antenna black spot, the vertex (top of the head) with at least one black spot, the absence of black rings on the antennae and the a priori green wing ribs at the costal field (some part of the wing) indicates we’re in the Chrysopa genus. More details should be considered to get the species.

Then let’s look into their life cycle, pretty interesting. Not interesting in respect to the stages of evolution, they are holometaboles like many other insects, but interesting in the strategies put in place at each stage of growth. As often, it all starts with an egg. But already this egg is unique: it’s hung to a substrate via a stalk, to put it out of reach of possible predators! Some species spacing their stalked eggs while others make real clusters of stalked eggs! The larva (which reminds me a bit of Stargate’s Goa’Uld) that emerges from the egg is carnivorous, extremely voracious and loves aphids, making it a precious pest control auxiliary. That’s why they are commonly called the “aphid lions” Some larvae may even wear a debris envelope on their back, whose role is still subject to debate. Then the larva weaves a silk cocoon into which she will transform herself into a pupa, a pupa that keeps her motor skills! After a while, depending on the species and temperature, from the pupa will emerge an adult. Depending on the species, the adult may be carnivorous, or feed on pollen and nectar, and can live between weeks and months!

Finally, green lacewings also have the surprising ability to sing. Actually, it is not songs as we can imagine it, and it is inaudible for a human ear. Males and females green lacewing during courting can hit the substrate with their abdomen, which produces the vibrations. These songs can also be used between males and each species seems to have their own repertoire! In fact, like grasshopers, the study of these songs can help to separate the different species. Green lacewings also have an ear on each of their front wings! Specifically, in a bulge located at the base of the sub-costal rib. It’s not really an ear, just an eardrum, but it serves them, among other things (or exclusively), to detect the ultrasound that bats emit to track down their prey, and thus avoid being eaten by them! These eardrums are among the smallest in insects.

 


Last update : January 10, 2021

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