Flies and other insects routinely land upside down on a ceiling. The underlying complex processes that lead to such remarkable aerobatic feats remain largely unexplored.
Researchers have now gained new insights into such processes by studying blue bottle flies that land upside down on ceilings using a more complex series of behaviors than previously thought1.
They say that these insights will be useful for designing small robotic fliers and shedding light on how insect brains function.
An international research team, including a scientist from the National Centre for Biological Sciences at the Tata Institute of Fundamental Research in Bangalore, India, studied the flies’ landing behaviours in a flight chamber using high-speed videography.
They found that the flies, while landing, exhibited a sequence of four behavioural modules. Their movement starts with an upward acceleration, followed by a rapid body rotational manoeuvre and leg extension. It ends with a leg-assisted body swing, with forelegs firmly planted on the ceiling, thereby orienting the fly’s body ventral side up.
The rotational manoeuvres, occurring immediately before the touchdown, are triggered by retinal expansion.
The process, from the start of the body rotation to the ventral side up landing, involves four to eight wing beats in all the successful landings. Despite the size and physiological differences, the flies’ wing motion changes during the inverted landing closely resemble those of hummingbirds’ escape manoeuvres.
The results of this study could be utilised to develop small-animal or robotic systems that can generate fast and complex behaviours with limited computational resources.
References
1. Liu, P. et al. Flies land upside down on a ceiling using rapid visually mediated rotational maneuvers. Sci. Adv. 5 (2019) doi: 10.1126/sciadv.aax1877
