Behaviour 2019
Investigating break-ins: Intraspecific brood theft in a tropical ant
Bishwarup Paul1,2, Sumana Annagiri1. 1Indian Institute of Science Education and Research (IISER) Kolkata, Mohanpur, West Bengal, India; 2Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, Andhra Pradesh, India

Thievery is ubiquitous in the animal kingdom, and thieves across taxa employ different tactics to achieve success. In this study, we have explored the phenomenon of intraspecific brood theft in Diacamma indicum, a primitively eusocial ant found in the tropics, where individuals steal instead of conducting organized raids.

Thieves were found out to escape from the victim nest at a staggering speed while stealing a brood item (n = 42). Comparison of the speed during theft with two other contexts – procuring brood from an unguarded nest (n = 99) and transporting own brood during nest relocation (n = 56) showed that thieves doubled their speed during brood theft.

Further experiments revealed that the presence of foreign gestalt or incapacitated foreign adults did not account for the extent of behavioural modification, rather the potential of receiving aggression from foreign adults was the primary cause. Though thieves (n = 37) repeatedly visited the victim colony, their latency to revisit increased significantly upon facing aggression, which corroborated our previous observation. In this comprehensive study, we reveal the simple rules of engagement between thieves and their victims.