This blog post was written by postgraduate student Davena Watkin as part of the course, Research Methods in Ecology (Ecol608). Davena revisits a Lincoln University research area that looks at a study of how possums respond to moonlight in 2011.
The moon has a face like the clock in the hall;
She shines on thieves on the garden wall,
On streets and fields and harbour quays,
And birdies asleep in the forks of the trees.
The squalling cat and the squeaking mouse,
The howling dog by the door of the house,
The bat that lies in bed at noon,
All love to be out by the light of the moon.
She shines on thieves on the garden wall,
On streets and fields and harbour quays,
And birdies asleep in the forks of the trees.
The squalling cat and the squeaking mouse,
The howling dog by the door of the house,
The bat that lies in bed at noon,
All love to be out by the light of the moon.
– excerpt from The Moon by R. L. Stevenson
For our species, the moon is a theme of many literary and cultural ideas. And it's more than just waxing lyrical; we also have a long history of attributing human behaviour to moon phases. Calling someone a ‘lunatic’ is a reference to the historic belief that prolonged exposure to moonlight caused insanity and epilepsy. In folklore, a full moon in some instances could also mean turning into a hairy, rampaging beast; lycanthropy is popular in many modern fictions.
![]() |
Morepork: a native nocturnal predator. Photo by russellstreet |
Typically, small terrestrial mammals that are preyed on by higher-order nocturnal predators exhibit lunar phobia, while the opposite is usually true of their predators. In fact, contrary to Robert Louis Stevenson’s poem, mice and some bats are both lunar phobics. Lunar phobia is thought to be a form of predator avoidance, as more light increases the ability of visual hunters to detect prey.
The Ecology Department at
Brushtailed possums are native to Australia, where they are preyed on by snakes, eagles, foxes and dingos. As such, Australian possums display anti-predator behaviour by avoiding well-lit open areas. It was expected that the possums in Jessica's study would therefore be more active during new moons.
New Zealand possum nocturnal behaviour: a dramatic re-creation of the study findings. Picture from Jeff Carter (modified) |
Possums are perfectly capable of clambering around tree tops in the dark, so possum foraging strategies must have changed since their introduction into
Caught on camera trap: possums
interacting with wax tags, which
are used to monitor possum density.
Photo from Parisi, 2011
|
This research has important implications for the timing of possum control. Poisoning and trapping during times of greatest activity will conceivably increase possum encounter rates with control measures. Control operations may therefore achieve threshold values faster if populations are targeted during peak lunar phases. Similarly, monitoring using indirect measures should achieve greater precision if standardised to particular times of the month. Focusing control on open areas may also be particularly beneficial regardless of moon phase.
More than anything, the study highlights the importance of behavioural studies for applied ecology. "Unless we fully understand pest animal behaviour, how can we effectively manage them?" asks James Ross, the supervisor of the study. Spoiler alert: we can’t. Behavioural ecology is essential for informing conservation and pest management, and helps us sort fact from fiction. As such, it is a valuable scientific pursuit. To believe otherwise is lunacy.
"AWOOOooo!" Picture by DCW |
Lennon, J. S. (1998). The Effect of Moonlight Intensity and Moon Phase on Feeding Patterns of Common Brushtail Possums. (Master's thesis, Lincoln University, 1998.) Retrieved from http://hdl.handle.net/10182/3062
Parisi, J. D. (2011). The Influence of Lunar Phase on Indirect Indices of Activity for the Common Brushtailed Possum (Trichosurus vulpecula) on Banks Peninsula, New Zealand. (Unpublished master's thesis). Lincoln University, Lincoln, New Zealand.
No comments:
Post a Comment