Most animals face the challenge of finding a place where they intend to go, technically called homing. Different animal species have evolved diverse physiological, neurological, anatomical and behavioural mechanisms to deal with this challenge. It is therefore of interest to understand the general as well as species-specific mechanisms of such a wide-spread behaviour by which animals, including humans, execute this universal task of homing.
Social insects, which include honey bees, wasps and ants, are an excellent choice for the study of homing behaviour because of their habit of central place foraging. They are also especially fascinating because they execute this complex task in spite of a rather simple nervous system. For my thesis, I have explored the homing abilities and mechanisms of Ropalidia marginata, a eusocial wasp (commonly known as paper wasp) found throughout the peninsular India.
I started my work by documenting their homing abilities by displacing them in increasing distances from their nests in four cardinal directions. I found that when released within about 500 metres, all the released wasps returned to their nest on the day of release. This might be because of their familiarity with the releasing areas, which they might have acquired by foraging there regularly. I also found that some of them returned to their nest even from about 1.5 kilometres. To find out what makes some of the wasps successful from such far distances, and what factors determine their overall homing performance, I next conducted three experiments from which I found that the age and familiarity with the surrounding play a significant role on their homing performance. I then investigated the mechanisms by which foragers acquire familiarity with their foraging grounds. I found that they initially increase the time they spend on foraging per day. But after about 2-3 weeks of foraging, their foraging duration starts decreasing although their foraging success keeps increasing. Besides, they also develop directional fidelity in their foraging paths. These results indicate that the wasps are capable of learning and memorising the features of the landscape and use them for foraging. I suggest that the foraging abilities and mechanisms of R. marginata are a reflection of their evolution in feature-rich tropical habitat.

Video abstract: https://www.youtube.com/watch?v=Yvrv7tAveLE