Nature in France: discover the fascinating world of insects

Springtime is, for me at least, the time of year when all the wonders of the natural world burst and sparkle before our eyes so actually it is hard to notice what is coming next. Spring this year was cool and wet, so it was almost as if we were living in a British spring, with the brilliance of the greenery and the wild flowers lasting longer than normal.

The glories of nature come in all shapes and forms; some obviously beautiful to the human eye, some less so, but nevertheless extraordinary to witness. Thus, it was that we were amazed to see, rolling across our terrace one fine afternoon, a series of nearly perfect spheres of… dog poo, deposited the evening before by one of my dogs, Panda, on the gravel about four metres away. 

They were being pushed and pulled by pairs of dung beetles (bousier), working together, one behind and one in front. Dung beetles are actually rather extraordinary animals.

Usually, it is the male that rolls the ball, while the females hitchhike or simply follow behind. However, there are cases where both work together, and this seemed to be the case on our terrace, as the one in front pulled downwards with its front legs, while the one behind pushed upwards with its front legs.

The first thing that I found amazing was the fact that they were able to manufacture perfect spheres which were several times bigger than themselves. There is a Mediterranean dung beetle, Onthophagus taurus (the taurus scarab), that is capable of pulling 1,141 times its own body weight, the equivalent of an average person pulling six double-decker buses full of people. They do exist here in France, but they prefer cattle dung – so was not the species I was watching. There are many thousands of species of dung beetles.

Obviously, this ability is the result of millions of years of evolution. The spheres were about fifteen millimetres in diameter, and I could count three different pairs making what was, for them, the long and arduous journey to slightly different destinations. They are known for travelling in a straight line. The reason why they needed to remove the ball from the original site, which was pretty similar terrain to where they were heading, is that they can steal from each other, so having made the ball there was an urgency to get it away. 

They certainly moved fast. When they arrived at their destination, the ball was pulled underground, to serve either as food storage or as a brooding ball. Having buried the ball, the pair mate, and then prepare it so that the female can lay eggs in it, which in time metamorphosize into larvae which feed on the dung.

The benefits of these amazing little beasts are many. Not only do they remove waste matter that might attract flies, but ultimately the balls decompose and so fertilise the ground. They have been deliberately introduced into Australia and the U.S. on livestock pasture, and it has led to improved soil quality; and even a reduction of nitrous oxide, a greenhouse gas. 

There are many other amazing facts about them, one of which I cannot resist telling. A nocturnal African species is one of the few invertebrates that navigates and orients itself using the Milky Way, or by the polarised patterns of moonlight. How amazing is that?

On a walk we came across an insect (a little easier on the eye, perhaps) in its pupa (or chrysalis) stage, commonly called a Gazé in French (black-veined white in English). Fairly common in southern Europe, it goes through complete metamorphosis; egg; larvae (caterpillar); pupa; butterfly (rather than a moth). It flies in daylight, holding its wings vertical when at rest, and has thin antennae with clubbed ends; all these are indicators of butterflies as opposed to moths. It can hatch into the flying form any time from April to July, when it is white on the upper sides of both wings, with distinctive black veining.

This pupal stage will last about three weeks, as does the egg stage, whilst the caterpillars will overwinter communally in a webbing tent with entwined leaves. They then feed close together on the food plant (plante hôte) – the hawthorn (Aubépine), before dispersing for the other development stages.

Sitting on my terrace eating at midday with friends, a fluttering butterfly caught my eye. It came to the trunk of an oak tree, and then disappeared. Only when I went over to search for it, did I see that it had aligned itself with the vertical grains of the bark, even positioning itself so that the rear curves of the wings followed the forms of the bark (seen in the photo below). It was so deliberate, and purposeful, that I can only believe that it was a deliberate strategy to camouflage itself against potential predators.