Geoff Park, ‘Natural Newstead: Observations of flora, fauna and landscape in central Victoria’, Tarrangower Times

I recently watched an excellent short video by PBS Eons on the rise of ants and the importance of flowering plants in the story. The story is of early ants, wasps that lost their wings over 95 million years ago. The video explains how few ants there were until the start of the Cenozoic era 66 million years ago when the number of species dramatically increased. This increase seems to parallel the rise of flowering plants, a rise which involved many symbiotic relationships with ants. The video is well worth a look.

These complex relationships were very apparent to me as I wandered around the bush at our place, camera in hand. On Golden Wattles, Wrinkle Ants (Rhytidoponera sp) were busy taking drops of sweet liquid from the extrafloral nectaries at the base of the leaves of the wattles. The wattles in our bush are currently supporting, I suspect to the detriment of some, quite a population of Wattle Plant Lice – psyllid bugs of the family Acizziinae.

On a nearby Spreading Wattle (Acacia genistifolia), there was a great abundance of these bugs including nymphs and eggs. A photo of some ladybugs gives a glimpse of how many there are, with clearly detrimental effects. A tiny spider can also be seen. Is this preponderance of sap-sucking bugs related to the absence of extrafloral nectaries on the Spreading Wattle?

But can a plant always trust the friendly ant? So often the symbiosis is between an ant species and an insect that will target the sap of the plant. I found some small nocturnal ants (Notoncus sp I think) nurturing some freshly hatched Scale Bugs that will themselves reward the ant with some sweet secretions to buy protection.

Elsewhere, Spiny Ants (Polyrhachis sp) were checking out Shiny Everlasting flower buds for their next meal. Ants are very important pollinators of flowering plants – another example of the mutually beneficial relationships that mean flowering plants and ants are so successful with so many species and so much biomass! 

This article appeared in the Tarrangower Times, 13 October 2023.