Animal communication and Bioacoustics
A major aim of my research is to understand the causes and consequences of animal behaviour in natural environments at both proximate and ultimate levels, for which I use acoustic communication as the model. The methods employed are both reductionist (using behaviour and physiology) and synthetic (using simulations), with concurrent quantification of the natural abiotic and biotic environment, the latter providing the ecological context and thus the selection pressures under which animals must survive and reproduce. My research projects span the areas of bioacoustics, animal behaviour, community and habitat ecology, and systematics. Theoretical, experimental and observational approaches are used in an integrated manner in most of the projects, which often involve both laboratory and field studies.
A major research focus is on understanding sender and receiver strategies for communication in complex natural acoustic environments, which range in scale and scope from patches of tropical rain forest to small choruses of males of a species producing similar calls. Sender strategies being examined include signal structure, calling time and site selection and signaling behaviour. Receiver strategies include physiological and behavioural mechanisms to enhance signal detection, recognition and localization. Habitat structure and acoustics are also examined to understand signal propagation and degradation and their effects on communication. A detailed understanding of senders, signals and receivers should provide insights both into the functioning of natural communication networks and the evolutionary forces that do or do not drive them. I am also interested in developing acoustic tools for identification and monitoring of species diversity.
A second line of work examines predator-prey interactions. I am interested in how spatio-temporal patterns of availability of insect prey, together with their movement and signalling behaviour, influence foraging strategies and outcomes for predators, resulting in sex- and species-biased predation. We also examine how predation influences the signalling and mating strategies of prey.
A third line of research focuses on decision-making and orientation behaviour in the context of mate-finding and mate choice in natural environments. I am interested in understanding how the physiological processing that underlies decision-making and the ecological context together constrain or enable different mating strategies.
Modak, S., Brown, W. D., & Balakrishnan, R. (2021). Decoupling of female phonotaxis and mating propensity in a tree cricket. Behavioral Ecology and Sociobiology 75, 146. https://doi.org/10.1007/s00265-021-03084-3.
Prakash, H., Saha, K., Sahu, S., & Balakrishnan, R. (2021). Ecological drivers of selection for remnant forest habitats by an insectivorous bat in a tropical, human-modified landscape. Forest Ecology and Management 496, 119451. https://doi.org/10.1016/j.foreco.2021.119451
Prakash, H., Greif, S., Yovel, Y. and Balakrishnan, R. (2021) Acoustically eavesdropping predators take longer to capture prey signalling in aggregation. Journal of Experimental Biology 224, jeb233262. https://doi.org:10.1242/jeb.233262.
Nityananda, V. & Balakrishnan, R. (2021) Synchrony of complex signals in an acoustically communicating katydid. Journal of Experimental Biology 224 (9), jeb241877. DOI: https://doi.org/10.1242/jeb.241877. Featured as an article of special interest in 'Inside JEB'
Deb, R., Modak, S. & Balakrishnan, R. (2020) Baffling: a condition-dependent alternative mate attraction strategy using self-made tools in tree crickets. Proceedings of the Royal Society B, 20202229 (in press). https://doi.org/10.1098/rspb.2020.2229
Torsekar, V. R. & Balakrishnan, R. (2020). Sex differences in alternative reproductive tactics in response to predation risk in tree crickets. Functional Ecology 34, 2326-2337. https://doi.org/10.1111/1365-2435.13652
Torsekar, V. R., Isvaran, K. & Balakrishnan, R. (2019) Is the predation risk of mate searching different between the sexes? Evolutionary Ecology 33, 329-343. https://doi.org/10.1007/s10682-019-09982-3
Rajaraman, K., Nair, A., Dey, A. and Balakrishnan, R. (2018). Response mode choice in a multimodally duetting paleotropical pseudophylline bushcricket. Frontiers in Ecology and Evolution, 6, 172 (1-12).
Buxton, R.T., Agnihotri, S., Robin, V.V., Goel, A. and Balakrishnan, R. (2018). Acoustic indices as rapid indicators of avian diversity in different land-use types in an Indian biodiversity hotspot. Journal of Ecoacoustics, 2, GWPZVD (1-17).
Mhatre, N., Malkin, R., Deb, R., Balakrishnan, R. & Robert, D. (2017) Tree crickets optimize the acoustics of baffles to exaggerate their mate-attraction signal. eLife 6: e32763 doi: 10.7554/eLife.32763
Balakrishnan, R. (2016). Behavioral ecology of insect acoustic communication. In: Insect Hearing Eds.: Pollack, G. S., Mason, A. C., Popper, A., Fay, R. R., Springer Handbook of Auditory Research, Springer-Verlag, New York.
Raghuram, H., Deb, R., Nandi, D. and Balakrishnan R. (2015) Silent katydid females are at higher risk of bat predation than acoustically signalling katydid males. Proceedings of the Royal Society B 282: 20142319. http://dx.doi.org/10.1098/rspb.2014.2319
Rajaraman, K., Godthi, V., Pratap, R. & Balakrishnan, R. (2015) A novel acoustic-vibratory multimodal duet. Journal of Experimental Biology 218, 3042-3050.
Schmidt, A. K. D. & Balakrishnan, R. (2015) Ecology of acoustic signalling and the problem of masking interference in insects. Journal of Comparative Physiology A 201:133-142.
Jain, M., Diwakar, S., Bahuleyan, J., Deb, R. & Balakrishnan, R. (2014) A rain forest dusk chorus: Cacophony or sounds of silence? Evolutionary Ecology 28, 1-22.