Naturalist David Attenborough has said, “I was totally struck by how complex and amazing slug mating is.” And indeed is the prolonged and acrobatic reproductive life of Limus maximus.
Literally, this means ‘biggest slug,’ which it is not. But the great grey slug, also known as the leopard slugs thanks to its dark spots, may reach a respectable eight inches. However mighty is its male reproductive organ. As the BBC observed the slugs “huge blue-tinted penises and upside-down acrobatics make for a colourful sex life.” So big indeed is that the slug has to rely on the law of gravity to unfurl it. But more of this pornographic performance later.
Native to Europe and parts of western Africa, it has been accidentally introduced into Asia, Africa, the Americas, and Australia. In Canada it is known from south-central Ontario, New Brunswick, Nova Scotia, western Newfoundland and, since 2014, south Okanagan in British Columbia. Wherever it goes, it enrages by feasting on crops and hence is often declared a pest.
However, it also feasts on dead and rotting leaves, flowers and fruit, while also dining on weeds. It is also a carnivore actively pursuing other, smaller slugs. Around human dwellings, its favoured habitat, it will also dine on pet food. An English woman even advised she found them useful in cleaning otherwise baked-on food of ovenware if these were left outside overnight for the slugs’ attention.
Even for a hermaphrodite – having both male and female organs –
L. maximus enjoys what can only be described as a very unusual and distinctive mating method. Possibly spurred by a shower of rain, a pair spends hours courting each other, circling and licking with their teeth-coated tongues. Eventually, the happy couple climb into a tree or other tall place, and then lower themselves entwined on a slimy mucous cord. They unfold their impressive penises from openings on the right side of their head, entwine these organs and exchange sperm. Separating they each go their own way, later to lay several hundred translucent eggs.
Enjoying as it does hermaphrodite habits, as do other gastropods, appalled author Lawrence Durrell. Informed of this biological fact of life by his younger sibling, the zoologist Gerald Durrell, he lamented that such lowly creatures should experience the joys of both sexes. What would Lawrence have said if his brother had added that a parasitic nematode lives in its rectum? He would have been even more appalled to learn that for real enthusiasts a website exists: petcaretips.net/leopard-slugs.html.
