The line of hairy caterpillars was marching across the brickwork of the house into a dark hole in the wooden doorway. They are Ochrogaster lunifer, better known as processionary caterpillars. The name hallmarks their orderly movement, echoing a solemn religious ritual. Their European relatives are another species but, marching in the same way, they have the same common name. The southern European ones head for pine trees and the Australian ones for Acacias. From what I can see, these ones here seem to be lost.

Maybe I am presuming a lot to say the processionaries are lost. After all, they may have had enough of green leaves and our wet winter. They could be off to some dry place where they can peacefully cocoon and turn into springtime moths.

These last sentences credit the insects with motives and a sense of timing. Am I draping human qualities onto these barely conscious beings? Even as my friends and I discuss them, are we attributing sensibility where there is none? As I write, I wonder. Is all our talk and writing about nature somehow flawed in this irredeemable way?

Jean-Henri Fabre, an extraordinary French scientist (1832-1915), was quite unabashedly affected by what he saw in nature. He wrote more than seventy publications about insects, full of sharp observations about the animals and his own culture. Victor Hugo, author of Les Miserables, praised Fabre as ‘the insect’s Homer’. This comparison with the classic Greek poet is more than an old-fashioned way of speaking. Fabre made literature of the lives of insects. One of his most famous works is about processionary caterpillars.

What Fabre saw about processionary caterpillars in France is also seen here: these larvae gather together to live as a group. They weave their own home base. These silken bag nests are located either at the bases or in the canopies of their favourite trees. Their bristles are poisonous.

Processionaries are social insects, much like wasps, bees or ants. Fabre put members of several nests into one and found what Australian researchers also notice: everyone is accepted into one group. When the time comes to forage, the caterpillars all line up and march away. Upon return to the nest, all spin to strengthen the shelter. This prompted Fabre into a consideration of communism, social order and the merits of family life and work.

In our modern times, this same experiment is done again but rather differently. The storyline becomes ‘what are the benefits and costs of group living?’ One Spanish study found larger communes, up to certain numbers, maximised healthy conditions for caterpillars. The larvae were bigger and grew more rapidly. They finally became bigger moths who lay more eggs.

Fabre’s story gets faulted for his old literary style. But both versions, although a hundred years apart, base their storytelling on economic ideas. The latest one boasts of data analysis using statistics. It reads like a report from a government office.

Back in 1896, Fabre continued his experiments with the processionals. When a line traveled up to the rim of a large urn, they began to march horizontally. When the rim was full of caterpillars, he brushed away the others still coming up. The processionals on the rim marched round and round. They found no food. Still, they continued for eight days. Fabre calculated the tiny creatures traveled in total of almost half a kilometre.

Several times on the eighth day, a lone caterpillar paused, waved its head and tried heading down the vase.  But it soon returned to the rim. Finally, in groups of three or four, they all abandoned the circuit and returned to the ground where Fabre had left them fresh pine branches.

Fabre saw their collective behaviour as completely dependent on instinct and chance. He cautioned scientists against looking for the ‘origin of reason’ in the ‘dregs of the animal kingdom’. But, especially since the 1970s, scientists have done exactly that.

Scientists look at the collective behaviours of ants and bees as well as caterpillars. They include the movements of fish schools and crowds of people exiting large rooms with only two exits. In every case, individuals cannot know enough about ‘the big picture’ but still they must decide. Regardless if these choices prove to be ‘right’ or ‘wrong’, how are these made?

Over and over again, what appears to be happening is that individuals copy their immediate neighbours. This continues until everyone is doing the same thing. The story goes that nothing more complicated is happening.

Really? Isn’t the story simply leaving unnamed that undeniable ‘awareness of surroundings’? Regardless of what types of senses any living being has, whatever their size, they can coordinate with ‘out there’. Yes, there’s a chance that effort may set up a futile loop or result in disaster. More often, it works well. For all of us evolved on earth, this ability is what we got.

Fabre was asked why he refused to use guinea pigs for testing toxic chemicals from caterpillars. Why use his own arm? He wrote ‘We can take it (life) away. But we cannot give it.’

And if science will chip away at our sentimentality about life, then nature writing will replace it with renewed respect. Every story is another view of the continuing paradox: a sharper look of life’s mystery. For all us storytellers, we have our work cut out.