Mantids are generalist predators and are known to feed mostly on other insects, especially on fly-like insects. There aren’t enough records of mantids feeding on vertebrates in a natural environment, however there are few records of ‘induced’ encounters between mantids and small birds, lizards, snakes, mice and turtles. In March 2017 I had the opportunity to observe and document a Praying Mantis feeding on guppy fish from the water lily pond kept in the balcony of my house.
When I saw this Asian Praying Mantis again the next evening, eating another guppy fish, my curiosity rose, and I started observing its behaviour, often spending hours sitting and watching the motionless mantid. This mantid would be seen on the water lily leaves every day between 6:30 PM to 12:30 AM, early in the morning. On most days the mantid would leave the pond after consuming two guppies. The mantid came to the pond for five consecutive days and caught only guppies from this pond, which was home to over 40 individual fish such as guppies, Zebra Danios, mollies and a Suckermouth Catfish.
It is still not known why the mantid caught only the guppy fish and not Zebra Danios as they were also observed to be very close to the surface of the water. Some of the questions this behaviour raised were:
- Was the slow movement of the guppies an advantage over the swift Zebra Danios?
- Did the long and colourful fins of guppies aid the selection process, as against the small and colourless fins of Zebra Danios?
- Did the mantid end up catching fish as a chanced opportunity and learn from the experience?
- How good are the mantid’s brain power and visual capabilities to be able to assess the speed and positioning to catch a fish from water without impacting refraction?
- Is this behaviour a new adaptive strategy of mantids or was this just never observed and documented in the natural environment before?
These are still unanswered and probably will remain so for some time unless we carry out more experimental studies and document more behaviours in nature.