Dear Readers, as far as many invertebrates are concerned, our homes are just big warm caves. Lots of species will hibernate with us: butterflies such as peacocks will often sleep the winter away in our lofts and garden sheds, and ladybirds, especially the newly arrived harlequin species, will occupy cracks and crevices in enormous numbers. But until I saw this one I had forgotten that some species of lacewing also spend the cold months tucked up in our houses. This one attracted the attention of my cat, and she chattered and jumped about until I realised that there was something to get excited about. I managed to get a few photographs while the poor insect waved its long antennae and gave every appearance of being nervous.
Lacewings are members of the Neuroptera, or ‘nerve-wing’ family, which also contains predators such as antlions and mantidflies. The ‘nerve-wing’ refers to the tracery of veins in those elegant wings.
I have always been partial to lacewings: I love their red-gold eyes, which are super-tuned to the colour green, enabling them to find just the right fresh growth on which to lay their delicate eggs. These eggs are laid over a period of nights, with 2 to 5 eggs being deposited at a time, until her entire cache of several hundred eggs has been distributed.The eggs soon hatch into one of the most ferocious-looking larvae in the insect world. A single larva can eat up to 10,000 aphids during its lifetime, and it has been used for biological control in glasshouses, as it will eat mealybug and white fly with equal enthusiasm. It can consume entire colonies of aphids, but is not immune to a spot of cannibalism if the greenfly run out. Although the larva has poor sight and hearing, they are very sensitive to touch: they walk up and down the stems of plants swaying their head from side to side until they encounter an unsuspecting aphid, which is seized in those impressive jaws. The larva then injects the unfortunate prey with a digestive chemical so strong that the internal organs of the bug are liquidised within 90 seconds. A lacewing larva is the kind of creature that makes me glad that I am nearly six feet tall and that it is only the size of my little finger nail.
Adult lacewings flitter about, eating nectar and honeydew, and attempting to attract a mate. They have excellent hearing, and have been found to use this to detect the hunting calls of bats and to drop out of the sky to avoid being eaten. In Bugs Britannica by Peter Marren and Richard Mabey, it mentions that one way to catch a lacewing that you want to remove is to put your hand a few inches underneath the insect and to then wave your hand close to the lacewing. The insect should just fall into your hand and remain quiet for a few moments so that it can be released.
To find a suitable partner, they use a technique called ‘tremulation’ – they vibrate their abdomens, and these tremors pass through the ground and alert any available single lacewings in need of a mate. Both male and female will take part in a duet, which is described by the Royal Entomological Society as ‘an essential prerequisite to mating’.
Although lacewings look so elegant, they have the alternative name of ‘stinkflies’, because of their habit of excreting if handled (and who can blame them). At least adult lacewings are able to excrete: larvae, for some evolutionary reason, are lacking a functioning anus, and so they save up all their excreta until they moult for the last time, and then produce a single gigantic poo. Who knew? Apparently Neuroptera experts can identify the species from this pile of excrement, and good luck to them.
There are 43 species of lacewings in the UK, and, whilst the green lacewing is the one that we’re all most familiar with, there is a giant lacewing (Osymlus fulvicephalus) that loves damp, neglected corners of the garden, of which I have a superabundance at the moment. It is also very fond of willowherb, which I also have. I shall be keeping an eye open to see if I can spot this floppy-winged critter and will report back if I have any luck.
What a splendid creature the lacewing is! From those elegant eggs through the ferocious larva to the golden-eyed adult, it is fascinating at every stage. It is very welcome to share my house during the winter, and to deposit lots of little larvae all over the plants in the garden in spring.
And I am obviously not the only one. Consider this poem by Australian poet Diane Fahey. It is a fine and fitting tribute to this most fascinating of invertebrates.
Photo One by Karz09 [CC BY-SA 4.0 (https://creativecommons.org/licenses/by-sa/4.0)]
Photo Two by By Luis Miguel Bugallo Sánchez – Own work, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=11350127
Photo Three by Pierre Bornand at https://www.flickr.com/photos/kahhihou/39305300850
I’m very fond of lacewings too. They are such wonderful, fairy like insects as adults. But believe me,I shall use that fabulous fact ‘the lacewing larva has no anus’ to shut up bores for years to come! Thank you for that gem. 🙂
:-0 🙂 Me too Rayna, me too….
Those who manage vineyards sometimes plant odd plants at the ends of the trellises to attract beneficial insects, including lacewings. It is old technology that still works.
It does, Tony, it does! Provided the people nearby are not too heavy with the pesticides of course….
Pesticides are not nearly as commonly used as they were only a few decades ago. People are realizing that it is just better . . . and easier . . . to grow what does well here without chemicals. That is how it was done long before pesticides became so common. It is partly what I dislike about all these new cultivars of horticultural commodities that are designed to impress buyers, but are genetically weak, and therefore more susceptible than their ancestors are to pathogens.
Exactly, Tony. A plant that is happy in its environment is much more likely to withstand the onslaught of pests and diseases than one that is already struggling.
One of my favourite insects. I only ever see them indoors, usually on the window of my landing, they stay for a couple of days then disappear.
I treasure the information about the larvae!
I think that the anus-free lacewing larva factoid is the most popular thing that I’ve posted this year 🙂
So no ‘frass’! A most comprehensive profile, Thank you.
Nope, no frass!