Nature has invented many creatures to clean up waste, from weevils that roll dung to zombie worms that feast on whale bones.
But nature’s recyclers can cause problems. The moths that feed on fungus and feathers in bird nests eat our clothes. Termites that clean up dead wood eat our homes. And the insects that clean up dead plant and animal matter would love to get their mouthparts on our collections. Here’s how we stop them.
Protecting our wildlife collection from pests
Our Australian National Wildlife Collection in Canberra holds 200,000 specimens. They reveal the genetic history and diversity of Australian wildlife.
Collection Manager Tonya Haff said the best defence against pest insects is rolling pest checks. We ensure each specimen is checked for pests once per year.
“We line our specimen trays with white paper so that signs of pest insects are easy to spot. They like to hide in the tight spaces where a specimen is in contact with a tray. So to check for pests, we lift each specimen and look for frass, which means insect waste,” Tonya said.
“If we find pests, we treat the entire cabinet by freezing or fumigation. We colour code our cabinets with magnetic strips to keep track of when we last checked them for pests and whether they received the all clear.
“We also use sticky traps, which are small cardboard tents with a sticky floor to trap invertebrates that crawl through them. This alerts us to any pests that might be lurking in the collection vaults.”
Keeping insects away from our insect collection
The number one enemy of the 12 million specimens held in our Australian National Insect Collection in Canberra is carpet beetles.
Collection Manager Federica Turco said, like the wildlife collection, her team also uses a type of sticky trap to provide early warning of pests.
“We line our windowsills with long sticky strips that trap insects based on their behaviour. Female carpet beetles fly towards light and drop downwards when they meet a vertical obstacle. This means when they fly to a window, they land on the sticky trap on the sill,” Federica said.
The insect collection team also relies on regular specimen checks, which are mainly carried out by volunteers.
“Frass is dark and easy to spot on the white labels or foam under pinned specimens. If necessary, we treat the cabinet by placing the drawers of pinned insects into a quarantine freezer,” she said.
“We also use the quarantine freezers to treat new specimens before we add them to our collection.”
Traditionally, we have used naphthalene to deter pests. Naphthalene is is a chemical insecticide that is sometimes used in mothballs.
“But when we move to our new National Collections Building, we’ll be able to stop using this chemical due to the design of the building,” Federica said.
Looking after our algae cultures
There are more than 1000 living strains of microalgae and some seaweeds held at our Australian National Algae Culture Collection in Hobart. They grow in flasks of media or on plates of agar. They are used for research and supplied to industry.
Ros Watson is a research technician responsible for maintaining the cultures and keeping them free from ‘pests’ such as fungi, bacteria and even each other.
“We need to transfer each strain to new culture media every six weeks on average, because the cells run out of nutrients. We do this in laminar flow hoods or biological safety cabinets, where filters remove particles and bacteria from the air. We handle one culture at a time to prevent cross-contamination,” Ros said.
“Fewer than 10 per cent of our cultures are axenic, which means bacteria-free. Many of them need friendly bacteria, or probiotics, to grow."
Ros said there are several ways we can isolate algae strains to make axenic cultures.
“We can use tiny glass pipettes under a microscope to pick up individual algae cells. Or we can make serial dilutions of the culture until only one cell or colony is present in the media. We can then treat the cultures with antibiotics to kill bacteria,” he said.
“We can also test whether a culture is free from bacteria by growing it in the dark on an agar plate that has nutrients for bacteria and fungi. Algae won’t grow under these conditions, so if any colonies grow on the agar plate, we know we have a problem.”
The new National Collections Building is jointly funded by CSIRO and the Department of Education through the National Collaborative Research Infrastructure Strategy.