Even though insects have a brain that weighs less than a milligram, with fewer than one million neurons, they possess complex sensory information that is necessary for achieving stable flight with extraordinary accuracy. Insects employ a range of computationally simple techniques to overcome the limitations of their small brain techniques to aid flight control and navigation.
Bees have always offered an attractive study system to the neuroscientist Emily Baird, lead a researcher at Lund University in Sweden. Emily Baird who has her passion for animals, behavior, flying and robots, investigates the strategies of flight mechanisms, that are extracted by the insect’s from their visual scène to control and navigate the flight in complex environments.
Unlike honeybees and bumble bees that fly through open habitats, deaccelerating to land on attractive blooming flowers; Orchid bees (Euglossa imperialis), race through tangled and gloomy tropical rainforests. The researchers said that “I was interested in understanding how a bee that lives in the rainforest manages to detect and avoid obstacles while flying at really high speeds,” Baird’s research narrows down to the question, “How do they really use vision?”
The results published explains that, in addition to the two large compound eyes, bees and other flying insects have three simple eyes also called as ocelli. These are located on the top of their heads. Previously, these structures were thought as flight stabilizers, that allows insects to position their bodies to the range of vision.
More information can be gathered on the ocelli from the traditional microscopy, a technique that involves slicing up samples. Baird says, “You lose resolution in one direction, so you can’t really make good three-dimensional models of the eyes. And you also don’t know how they’re sitting in the head.”
To have better understanding of the visual inputs an orchid bee uses during the flight, the lead scientist Braid and her colleagues tried the technique, X-ray micro-computed tomography, so that they could model light reception by the ocelli in three dimensions. Surprisingly, they discovered that each simple eye has not one, but two visual fields. Baird enlightens, ““These eyes essentially have at least two different areas in them that are looking at different parts of the world,”
One area of the ocelli aimed at the horizon and receives focused light that helps flight stabilization, and the other area receives fuzzy light from above. The discovery found that photoreceptors in this area of each ocellus are sensitive to the orientation of polarized light, a potential navigational cue. The researcher added, “As long as you can see the sky and are sensitive to polarized light, as many insects are, then you can actually use this as a compass reference and We predict that these eyes are acting like polarized-light analyzers.”
Holger Krapp, also a neuroscientist at Imperial college London commented on the published data, “The function of the ocelli was not entirely understood in many different insects. He says the findings suggest really that there are two different aspects of visual information that can be used in different contexts.” He also added that behavioral experiments could provide supporting evidence that orchid bees really use light polarization to navigate during flight.