The season of insects, moths and fungi
by GLEN JAMESON
10th June 2019
PERHAPS MY favourite cyclic event of the naturalist calendar was the mass emergence of the rain moths.
It was usually an April phenomenon after the late summer storms had swept across the city and began to break the drought of summer.
Mists returned to the river valley and the steadier rainfall of March and April would refresh the earth and kick start the ecological processes that had laid dormant over Summer.
It was then that the rain moths would appear at an outside light that had been left on.
Hundreds of them, in a display of dazzling diversity.
There were heliotrope moths, twin emeralds, Clara’s satin moths, geometrids, white satin moths, granny’s cloak moths and many, many species, big and small that I could not put a name to.
The mass emergence of the rain moths provided a guaranteed food supply, a rich source of protein for the local birds essential for their late winter breeding cycle.
This critical food resource would give them an advantage over the spring/ summer migrating birds coming to the Yarra Valley.
Sometimes there would be the huge wattle goat moths that were as big as small birds.
Moths, whose caterpillars would chew their way through black wattle trees before entering the ground to emerge when the rains softened the earth enough for them to dig their way out.
Sometimes there would be great numbers of Bogong moths that would be blown off course on their trek to the mountains of the Great Divide where they historically were gathered and eaten by the local First Nations Peoples.
However, I haven’t experienced the rain moth emergence now since 2010, the year the Millennium drought broke.
Before that I recorded it in 1997, the year the Millennium Drought begun.
Twice in over 22 years instead of something that was an every-year event.
The drop in rainfall across the Yarra Valley has curtailed these critical ecological events.
It is not just moth numbers that are reduced, it is across the whole spectrum of insects.
The fall in insect presence gets mentioned in Field Naturalist Club newsletters.
People notice their car windows don’t get covered in insects on long summer drives.
Entomologists worry about it.
The fall in average rainfall that we are experiencing is also affecting the prevalence of fungi which — like the rain moths — would generally begin showing on mass around April in the old rainfall patterns.
Fungi are important to all life on many levels.
The majority of plants require a mycorrhizal relationship with fungi by which the fungi facilitate plant growth by breaking down nutrients in the soil and making them available to plants.
They influence the well-being of human populations on a large scale because they are part of the nutrient cycle in ecosystems.
They naturally produce antibiotics to kill or inhibit the growth of bacteria, limiting their competition in the natural environment.
Important antibiotics for human use can also be isolated from fungi.
When we talk of biodiversity, the numbers of species are dominated by insects and fungi.
Of all the known species in the world, vertebrates have 2 per cent of the species, plants 11 per cent, insects and invertebrates 43 per cent and fungi 44 per cent of the total species.
Species diversity is one of the greatest stabilizing influences on our planet.
A diverse ecosystem is a stable ecosystem.
The protection of biodiversity is one of the three core objectives of the Australian National Strategy for Ecologically Sustainable Future.
Conserving biodiversity is vital for maintaining our quality of life and our standard of living in the long term.
“So important are insects and other land-dwelling arthropods that if all were to disappear, humanity would not last more than a few months.
Most of the amphibians, reptiles, birds and mammals would crash to extinction about the same time.
Next would go the bulk of flowering plants and with them the physical structure of most forests and other terrestrial habitats of the world. The land surface would literally rot.”
—Wilson-The Diversity of Life