My PhD dissertation was on the characterisation of acoustic community (Order: Orthoptera, Suborder: Ensifera) of evergreen forests of Kudremukh National Park in the biodiversity hot spots of Western Ghats India. I compared the acoustic diversity of different forest types in Western Ghats using psychoacoustic sampling. I investigated the diversity of acoustic signals, vertical stratification and spatio-temporal patterns in the acoustically communicating ensiferan species assemblage. I also investigated efficiency of psychoacoustic sampling as a rapid and reliable method to monitor acoustic diversity in tropical forests.

  Current affiliations and designation: Associate Professor, Department of Environmental Studies, University of Delhi, Delhi-110007

Citations: Google Scholar

“A most courageous and dedicated student, Swati took on the incredibly difficult task of identifying the entire acoustic community of crickets and katydids in a tropical evergreen forest from floor to canopy. In this pursuit, she was bitten by a viper, delayed several months at a time due to tense political issues, and had to sample in the forest through all hours of day and night, often under difficult and dangerous conditions. Her persistence and endurance allowed her to succeed and produce an outstanding thesis. 'Crickets of Kudremukh' is a tribute to her dedication and tenacity and gives you a glimpse of some of the wonderful insects that she discovered.”

-Rohini

I investigated acoustic interactions in a group of closely related bushcricket species of the genus Mecopoda. I investigated acoustic synchrony in one of these species - which we call 'Chirper' - revealing the mechanisms underlying this synchrony. I went on to research how these mechanisms interacted with the structure of choruses in the field and the neurophysiology of acoustic selective attention. I integrated these results in an agent-based model of the evolution of bushcricket acoustic synchrony.

Current designation and affiliation: BBSRC David Phillips Research Fellow, Newcastle University

Website:Vivek Nityananda

Citations: Google Scholar

Current work

“When Vivek joined my lab, we were both posed with a strange problem: he was interested in so many things and good at everything, and we were unable to decide what he should do for a thesis! But for both of us, the decision was made by the incredible calls of the tropical bushcricket Mecopoda, more or less love at first chirp! Vivek went on to examine the phenomenon of acoustic synchrony in this genus at several levels: from physiology and behaviour to ecology and evolution; from the lab to the field and finally to simulating the possible evolutionary pathways that could lead to acoustic synchrony. No single study before his had examined this phenomenon at so many levels simultaneously and in such depth and his thesis is absolutely outstanding in this regard. He has also been the mainstay of this lab, helping out others, particularly with programming and, most importantly, with his ever-cheerful disposition, kept peace and good humour in the lab! He will be sorely missed by all.”

-Rohini

More about Vivek

Image from Vivek's Colloquium

I studied naturalistic acoustic orientation behaviour in crickets with Rohini. I used an experiment and simulation-based approach to predict the phonotactic paths of female crickets in naturalistic multi-male choruses. The main overarching conclusion from my work would be that the biomechanical & neural processing underlying phonotaxis accomplishes simple mate finding, and does not predict 'best mate' selection

Current designation and affiliation: Canada Research Chair in Invertebrate Neurobiology,Department of Biology,University of Western Ontario, London, Ontario, Canada

 Website

Citations

"Technically my first student, Natasha decided on an ambitious goal for her thesis: trying to predict acoustic orientation behaviour of crickets in complex, real-world conditions. To do this, she first did field studies to figure out what the acoustic environment of a cricket was and then used current knowledge on the physiology of cricket auditory systems together with her own investigation of walking behaviour to build virtual crickets in virtual auditory environments that mimicked real ones. She then asked whether this simulation model could successfully predict the details of acoustic orientation behaviour in complex, multi-source conditions of real crickets in the field. It was a long, meandering marathon that often brought her back to where she started, with many loops and circles, but her level-headed approach, the long hours of thinking and programming and her determination to solve this finally gave her success and a spectacular thesis that was described by her external reviewer from Cornell University, one of the leading international authorities in insect bioacoustics, as "among the top 10 theses I've ever read in my career, which has involved my reading over 300 theses...". Natasha has been a solid pillar of my lab and it is hoped that the innumerable students that she taught and to whom she has given so freely of her time will be inspired to do as well as she has."

-Rohini

Image from Natasha's Colloquium

My work in Rohini's lab centered around examining the role of two major drivers of signal evolution: habitat structure (acoustic adaptation) and masking avoidance (cocktail party problem). On the side I also worked on projects examining the reliability and usefulness of acoustic monitoring for biodiversity assessment of crickets and bats. In doing so, we also developed the first echolocation call library of bats in India. Post PhD I worked briefly on a UKIERI project with Rohini and Daniel Robert (Univ. of Bristol) examining mechanics of signal perception in a katydid.

Current affiliation and designation: Associate Professor, Dept of Biological Sciences, IISER Mohali

Website: https://manjarijain.net/

Citations

"When Manjari and I decided on examining habitat acoustics in the context of calling site selection and vertical stratification of crickets in a tropical evergreen forest for her Ph. D thesis, we were both blissfully unaware of the enormous logistical and technical challenges that lay ahead. Undeterred by the piles of equipment that had to be carried into the forest every day and set up, often at uncomfortably difficult heights, Manjari used her typical ingenuity and drive to come up with all kinds of interesting mechanical devices to solve the problem of acquiring data at different heights in a rainforest. Her willingness to keep trying and refusal to give up allowed us to obtain recordings and images from the floor to the canopy of the rainforest without canopy walkways or towers! Having got the data, the analysis of degraded sound signals posed special problems and she found herself mired deep in signal processing for a long time. But her willingness to learn new things, even in the last year of her thesis, her determination and exceptional commitment to rigorous analysis and her patience resulted in a thesis that can certainly be described as one of the most detailed and comprehensive examinations of the acoustic adaptation hypothesis at the microhabitat level. Her sense of responsibility and her willingness to help others in the lab in matters both technical and conceptual have been invaluable and her strong and vibrant personality has enlivened the lab over the past few years."

Rohini

Image from Manjari's Colloquium

Smita Nair has spent the last few years pursuing the elusive and temperamental forest elephants of Mudumalai Wildlife Sanctuary in Southern India in an effort to record their vocalizations and behaviour in the wild. This is a challenging, difficult and dangerous enterprise with low levels of return on the effort invested, and it says much for Smita’s courage, commitment, hard work and tenacity that she has built up a library of over 200 calls with their associated behaviours. A few examples of elephant calls are given below.

#add link to elephant gallery

I studied the diversity of bats of Kudremukh National Park and recorded the echolocation calls of bats to make a call library of Indian bats. I have investigated the diet of lesser false vampire bat, Megaderma spasma and confirmed that the main prey items are katydids.  A combination of diet analysis and behavioural experiments revealed that ‘silent’ katydid females are at higher risk than acoustically signaling males on bat predation. Conclusively, movement also poses severe risk during mate attraction in katydids.

Current designation and affiliation: Assistant Professor, Department of Zoology, The American College, Madurai, Tamil Nadu, India

My PhD research work dealt with understanding different processes of species identification and understanding evolution of acoustic signal pattern in crickets in a phylogenetic framework. Field crickets were of primary interest because of their high species diversity, wide acoustic modalities and morphological ambiguity. I used morphology, acoustics and molecular data, either independently or in combination to delimit species boundaries between Indian Field crickets.

Current designation and affiliation: Dr. Ranjana Jaiswara, DST-INSPIRE Faculty, Department of Zoology, Panjab University, Chandigarh, India.

Website

“Ranjana Jaiswara worked for her Ph. D on the systematics, acoustics and phylogenetics of field crickets. In the course of her Ph. D, she reconstructed, for the first time, the phylogenetic relationships between Indian field cricket genera and tested the validity of current taxonomic classification based on this phylogeny. Using the field cricket genus Itaropsis as a model system, she then examined the problem of species delineation by examining concordance between the species boundaries implied by acoustic, morphological and molecular datasets. She also used the phylogeny of Itaropsis to examine patterns of song evolution within this genus. Finally, she tested the efficacy of different multivariate statistical techniques in correctly identifying field cricket species based only on their songs, a first step towards acoustic identification and monitoring of field crickets. Ranjana worked closely with Dr. Laure Desutter-Grandcolas, a leading cricket taxonomist and phylogeneticist, at the Museum national d’Histoire naturelle in Paris, where she received training in systematics and phylogenetics. She had thus to navigate her way between acoustics, systematics and phylogenetics, field and lab work, Bangalore and Paris, as well as two mentors who sometimes had different points of view! That she has accomplished so much through all this reveals her motivation and determination.”

Rohini

My work in this laboratory primarily investigated the sensory ecological context of mate sampling strategies based on acoustic communication in crickets. More specifically I studied the effects, of the ecology of male signalers and the sensory physiology of the female receivers, on female mate choice and mate search tactics. Using an interdisciplinary approach to address these objectives, I built individual based simulations and statistical models based on behavioural and ecological data collected in wild populations as well as in the laboratory. 

Current Designation and affiliation: National Post-Doctorate Fellow (SERB), National Institute of Biomedical Genomics  

Citations: Google Scholar

Current work: I am currently studying the role of natural selection in shaping human genetic variation, specifically to understand the adaptive histories of various South Asian populations. Using whole genome sequence data, I estimate standard population genetic parameters as well as develop machine learning based classifiers to detect genomic signatures of selective sweeps and polygenic adaptation.

My work dealt with signal recognition and localization in the acoustically communicating tree cricket Oecanthus henryi. Being a poikilotherm O.henryi generates unique problems in signal recognition, which is further compounded by the presence of heterospecifics with similar call patterns. I thus examined pattern recognition both in the spectral and temporal domains. Being found in bushes makes the task of localizing the male call an exercise in 3-D space for O.henryi, exploration of which formed the latter part of my study.

Current designation and affiliation: Technology Education Team Lead, Artificial Intelligence Lab, Learning and Knowledge Management, Accenture

Citations: Google Scholar

I studied vocal communication in Greater Racket-tailed drongos in the Biligirirangan Hills in southern Karnataka (2007-2015). Mine was the first research project in India to focus on this bird species. My research investigated the functions of this mimicry, and provided new insights into the potential evolutionary drivers of these intriguing vocal displays. I continued to follow racket-tailed drongos as a SERB National Post-Doctoral Fellow at NIAS with Prof Anindya Sinha (2016-2018).

Current designation and affiliation: Senior Editorial Assistant, Office of Communications at IISc. Member of the Punarchith collective (www.punarchith.org).

Website: https://jlrexplore.com/explore/interviews/decoding-birdsong

Citations:

·        Agnihotri, S., & Si, A. (2012). Solega ethno-ornithology. Journal of Ethnobiology, 32(2), 185–211.  

·        Agnihotri, S., Sundeep, P., Seelamantula, C. S., & Balakrishnan, R. (2014). Quantifying vocal mimicry in the greater racket-tailed drongo: a comparison of automated methods and human assessment. PloS One, 9(3), e89540.    

·        Si, A., & Agnihotri, S. (2014). Solega Place Names and Their Ecological Significance. Anthropological Linguistics, 56(3/4), 389–414.  

·        Buxton, R. T., Agnihotri, S., Robin, V. V., Goel, A., & 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

Popular media

·        What’s that racket? Of drongos and acoustic landscapes (2015) (http://jlrexplore.com/explore/from-the-field/racket-tailed-drongo  

·        “Enu sahebre!” (2017) http://jlrexplore.com/explore/from-the-field/enu-sahebre     

·        A (re)discovery in the BR Hills (2018) http://jlrexplore.com/explore/from-the-field/a-rediscovery-in-the-biligiri-rangan-hills  

·        The darkness of the evergreen forest (2019) http://jlrexplore.com/explore/from-the-field/the-darkness-of-the-evergreen-forest  

·        Radio interview with Documenta 14 and Savvy Funk, Germany: https://www.mixcloud.com/Islands_Songs/ynk-6-_-june-22nd-_-field-study-1-_-listening-session-with-samira-agnihotri/  

·        Radio show on bird calls and their functions with Air Bengaluru, All India Radio, 22nd March 2019  

·        Dr Joseph George Memorial Talk at the Bengaluru Bird Day 2019 (https://birdday.in/)

During my PhD, I investigated how signal evolution is influenced by sexual selection using tree crickets. I further examined a unique tool-making behaviour in these crickets that allows poorer condition males to deceive the female preference. I used natural history, laboratory and field behaviour experiments, acoustics, computational and statistical modelling for my study. I have also collaborated in projects examining a) bat predation in katydids and b) acoustic interactions in nocturnal insect community, at Kudremukh National Park.

Webpage: https://www.researchgate.net/profile/Rittik_Deb

Current designation and affiliation: Assistant Professor, NISER Bhubaneshwar

Website:  https://www.niser.ac.in/users/debrittik

Citations: Google Scholar

I studied a potential cryptic species complex of the bushcricket Mecopoda elongata that could only be differentiated based on temporal features of the male calls (females don’t call). My study shows that the divergence in potential male contact pheromones and external genitalia follows the song type divergence. Although these songtypes co-occur in various sympatric combinations, their isolation is most likely maintained through female preference for conspecific call. Mecopoda call divergence also appears to be linked to exploitation by an acoustically locating Tachinid parasitoid.

Current designation and affiliation: DBT-Research Associate, Indian Institute of Science Education and Research Mohali

Citations: Google Scholar

During my PhD, I attempted to understand patch and prey-level decisions of the insectivorous bat, Megaderma spasma (lesser false vampire bat), in a human-dominated heterogeneous landscape. My dissertation investigated how the bat makes foraging decisions at different spatial scales from landscape to patch level using ecological field techniques and behavioural experiments. 

Current designation and affiliation: Research Associate, CES, IISc 

Citations : Google scholar

During my PhD, I studied the condition-dependent signalling and mating behaviour in the acoustically communicating tree cricket species, Oecanthus henryi. I examined condition dependence of a) male mating effort in terms of lifetime signalling, remating propensity, and nuptial feeding and b) baffling, an alternative signalling strategy. Additionally, I aimed to understand the effect of female dietary condition and mating status on female mate search and mating behaviour which could in turn impact male reproductive success.

Current affiliation: Program Analyst for One Health Bengaluru City Program, National Centre for Biological Sciences

Publications:

Sambita Modak, William D. Brown, Rohini Balakrishnan. (2021) “Decoupling of female phonotaxis and mating propensity in a tree cricket.” Behavioral Ecology and Sociobiology, 75(10), 1-13. https://doi.org/10.1007/s00265-021-03084-3

Rittik Deb, Sambita Modak, Rohini Balakrishnan. (2020) “Baffling – a condition-dependent alternative mate attraction strategy using self-made tools in tree crickets”. Proc. R. Soc. B 287(1941) 20202229. https://doi.org/10.1098/rspb.2020.2229

During my PhD, I examined the ecology of predator-prey interactions in the context of mate searching communication, using the tree cricket Oecanthus henryi as a model system. I first estimated the relative predation risk experienced by communicating and non-communicating, male and female crickets from their primary predators, green lynx spiders, at multiple spatial scales. Next, I manipulated predation risk in enclosure experiments and observed how it affects alternative reproductive tactics and survival, to compare their relative fitness consequences. Finally, I examined how crickets behaviourally manage predation risk while searching for mates, by altering their space use patterns at two different spatial scales.

Current affiliations and designation: Postdoctoral fellow, Risk-Management Ecology Lab, Department of Ecology, Evolution, and Behavior, The Hebrew University of Jerusalem, Israel

  Citations: Google Scholar

I worked on the pair-formation strategies of a canopy inhabiting, false-leaf katydid species, Onomarchus uninotatus which has a unique multimodal duetting system, wherein the long-range acoustic signals produced by males are replied to by females using short-range vibratory signals, used by males to localize responding females. I studied the pair-formation strategies at two possible spatial scales, across-tree and within-tree and also examined the reproductive investment of the sexes, to understand how mate-finding effort is related to reproductive investment.

  Current affiliation and designation: Post Doctoral Associate, National University of Singapore

Publications: Rajaraman, K., Nair, A., Dey, A., & Balakrishnan, R. (2018). Response Mode Choice in a Multimodally Duetting Paleotropical Pseudophylline Bushcricket. Frontiers in Ecology and Evolution, 6, 172.  

Nair, A. & Balakrishnan, R. (2022). Ecological constraints on sexual selection in a human-modified landscape. Frontiers in Ecology and Evolution 9, https://doi.org/10.3389/fevo.2021.802078.

For my BSc final year thesis project, I worked under the supervision of Prof. Rohini Balakrishnan and Sambita Modak on the dependence of calling effort and baffling probability of the tree cricket Oecanthus henryi on diet and age.

Current designation and affiliation: PhD student, Frederickson lab, University of Toronto St. George

I worked under Dr. Diptarup Nandi, to look at field cricket remating experiments. I conducted experiments to see how many times, field cricket virgin females, show phonotaxis, and re-mate within a night and across nights.

Current designation and affiliation: Ph.D. Candidate, Department of Quantitative and Systems Biology, University of California, Merced. My website

I worked with Dr. Harish Prakash on the Variation of diet pattern of the insectivorous bat Megaderma spasma. My work consisted of identifying culled insect remains found at bat roosts and trying to decipher the factors that affect the diet of the insectivorous bats based on these remains.

Current designation and affiliation: Masters student, Vellore Institute of Technology, Vellore.