Bendigo for Butterflies on Sunday taught families of nature lovers all about the fantastic ties between the Eltham Copper butterfly, and its caterpillar young, and Notoncus ants.
The event also highlighted how people can help protect the endangered butterfly.
Move over Christmas trees, in the silly season this endangered butterfly lays its eggs on or at the base of Sweet Bursaria plants - but only those that also host an ant colony.
Nature lovers heard how the female butterfly had spurs on its feet that could detect the nutritional value of a plant, the presence of ants in the area and whether the soil conditions were ideal.
These 'footy' skills are the not the only abilities the Eltham Copper butterfly possesses.
Ants and butterflies are friends forever in Bendigo bushland
The 50-strong crowd heard how, on nights of more than 12 degrees, ants shepherded their caterpillar friends from an underground nest to enjoy the Sweet Bursaria leaves and defended them from predators such as wasps.
After a winter hibernation or diapause, caterpillars pupate in or near the ants' nest before emerging transformed in October to March.
Bendigo for Butterflies guide Aldo Penbrook called the abilities of the caterpillars a Halloween-esque "trick or treat".
The caterpillars can give off chemicals and make noises to pacify ant aggression, mimic ant brood hormones and attract and alert ants if the larvae become "alarmed".
The treat part comes when the caterpillars expel sugary secretions for the ants guarding them.
So why were the nature lovers learning about this quirky friendship?
Environmentalists are concerned about the impact of development on the endangered insect, and Mr Penbrook said there is a 100-house subdivision set to be built near the Bendigo kaleidoscope in Solomon Gully Reserve.
Conservationists worried about development impact
"We're worried about the impact of extra cars and more people on the butterflies," Mr Penbrook said.
"The situation is already so tenuous as it is - and Bendigo's population is the northern-most in the state."
Threats to the Eltham Copper butterfly include land clearing, frequent burning and feral honey bees competing for Bursaria nectar.
Rabbits, sheep and wallabies can also threaten the butterfly habitat through grazing young plants.
Solomon Gully Reserve has four hectares of habitat suitable for the butterfly - but the current numbers in the area are unknown.
The species was previously found in dry open forests from Melbourne to Western Victoria, but is now only found near Eltham, Bendigo, Castlemaine and Horsham.
Event highlights 'crisis' in natural world
The Bendigo for Butterflies event was designed to draw attention to what environments called a "crisis facing our natural world", and how people can do more to protect nature.
Australian Conservation Foundation community groups across Australia planned events as part of the ACF Communities for Creatures Campaign.
"Nature is in crisis," ACF spokesperson Marie Bonne said.
"If we don't take strong action now, more and more creatures will be at risk, and our survival is bound up with theirs."
"The ACF is calling upon the government to strengthen the provisions of the Environment Protection and Biodiversity Conservation (EPBC) Act."
Ms Bonne said the day combined education and fun, with activities for young and old.