Mighty science on minute mites: An interaction with acarologist Dr. Krishna Karmakar
My experience of learning about acarology (study of mites and ticks) during my doctoral course inspired me to write this blog. I still remember numerous hours when we looked through the microscope to identify mites during our practical classes. In this regard, I must recall Dr. C. Chinnamadegowda, Professor of Entomology at the University of Agricultural Sciences, Bangalore who used to take these classes with unmatched patience and constant dedication.
Only six of us had opted for the “Advances in Acarology” course during 2010, and Dr. Gowda divided our practical class into two slots because we had only one phase-contrast microscope. From 2 to 4 PM, the first three would attend the class and from 4 to 6 PM, another three, I was assigned the second slot, which never ended before 7 PM. It was fun to study these tiny arthropods. It appeared tiresome when we couldn’t actually see the characters which we must observe, especially when we had to refer taxonomic keys from the beginning for every single mistake. In many groups of mites, the taxonomic keys are based on the structure and arrangement of tiny setae, and observing those characters of micrometer lengths was a nightmare for us at that stage.
For the past year, I am in contact with a group of Indian researchers who are working on the taxonomy of mites during the last four decades headed by Dr. Krishna Karmakar, Professor & Head, Department of Agricultural Entomology, Bidhan Chandra Krishi Viswavidyalaya, West Bengal. I was fascinated by the recent publications from this group in many peer-reviewed journals like the International Journal of Acarology and Systematic, Applied Acarology, and Zootaxa. Dr. Karmakar was kind enough to answer a few questions related to acarology in India and his interest in the field.
Shashank: Why studying mites is important?
Dr. Karmakar: Mites are a group of small arthropodan organisms belonging to the class Arachnida, subclass Acari. They are ubiquitous, highly diversified in habit and habitat, distributed in soil, water, and terrestrial condition. Mites perform great ecological roles such as soil mites help to sequester plant nutrients and thus enrich soil fertility; water mites occur as an important component of the aquatic food web; plant inhabiting mites occur as herbivores, predators, and parasites; many others parasitize birds, reptiles, mammals including humans. From the perspective of agricultural entomology, these are highly important groups of organisms as many of the herbivorous mites cause huge economic loss by damaging the crops, the spider mites (Tetranychus spp. Oligonychus spp. Panonychus spp. Schizotetranychus spp.) are polyphagous pests of many agri-horticultural crops; tarsonemid mites, Polyphagotarsonemus latus, Steneotarsonemus spinki are serious pests of hundreds of crop cultivars and rice respectively. Eriophyoid mites cause devastating damage to coconut, mango, litchi, citrus, tea, sugarcane, pigeon pea, garlic etc. The false spider mites, Brevipalpus spp., Tenuipalpus spp., the red palm mite Raoiella indica ravages coconut, areca nut and other palm trees. Many of them are predacious to destructive mite pest species including small insect pests and thus are used for biological control of many pest species. Many of the mites are insect parasitic like Acarapis woodi, Varroa jacobsoni, V. destructor may wipe out the bee colony.
Apart from these, it has medical and veterinary importance. The human parasitic mites cause allergy and respiratory problems, bizarre scabies diseases, itching, and many other diseases. Ticks, another group related to mites are animal parasitic, bloodsuckers and are considered as dangerous pests of not only domesticated and wild animals even spread dreaded diseases to human beings. Considering these diverse and dynamic ecological relationships one can easily realize how important these tiny creatures are.
Shashank: Being such an important group, what is the status of acarology in India, and how many acarologists are available?
Dr. Karmakar: Not so many scientific studies have been done to understand diversity, bio-ecology, the destructive and beneficial role of mites in India except a very few. The scientific study of mites is called Acarology which is still confined to only 3-4 Indian universities in a vast country like India probably, due to unawareness, tininess, and tendency to overlook the appearance of mites.
The Acarological study was started in India from 1950 onwards with the significant contribution of Prof. Swaraj Ghai, Prof. Menon from IARI, New Delhi, Prof. G.P. Channabasavanna, Prof. L.K. Lakkundi from UAS, Bangalore; Dr. S.K. Bhattacharyya, Dr. A.K. Bhattacharyya, Dr. A.K. Sanyal from ZSI, Kolkata. Dr. S.K. Gupta, ZSI, Kolkata; Dr. Samiran Chakraborti, University of Kalyani; Prof. M. Mohanasundaram, Tamil Nadu Agricultural University; Prof. G. S. Sadana, Prof. Bindra, Prof. M.S. Dhooria from Punjab Agricultural University; Prof. M. A. Haq, Prof. N. Ramani of the University of Calicut contribute on different groups and different aspects of mites. Pioneering and significant taxonomic work on Indian mites has been contributed by Dr. S.K. Gupta on Phytoseiidae with the publication of series of papers and also as a consolidated work on Indian mites in the book "Handbook plant feeding mites of India, 1986". Dr. S. K. Bhattacharyya, Dr. A. K. Bhattacharyya, Dr. A. K. Sanyal from ZSI, Kolkata and Prof. M. A. Haq contributed on Indian Oribatid and soil mites. Monumental contributions on Indian eriophyoid mites have been done by Prof. M. Mohanasundaram from TNAU and Prof. Samiran Chakraborti from Kalyani University. At present we need more scientists and students from India to engage in Acarology, carry on the legacy of our predecessors in this science, and explore the huge diversity of Acarine fauna in India. There is a tremendous potential to carry out a lot of research on their taxonomy, ecology, and management aspects.
Shashank: For how many years you and your group have been working on mites?
Dr. Karmakar: Observing the importance and immense potentiality of these tiny creatures in all spheres of human life especially, in the field of agriculture, I was interested in Acarology since my masters programme during 1989-1990. I confined and continued to observe the damaging and beneficial role of plant mites. I submitted my dissertation work in my masters programme on Schizotetranychus cajani Gupta, 1976 infesting pigeon pea. Initially, I learned the basic acarology from my teachers Dr. S. K. Gupta, Prof. A. B. Mukerjee, Prof. A. K. Somchoudhry, and Dr. P. K. Sarkar at BCKV during my master's and Ph.D. programme. Later, I was very much interested to take up my thesis work in Ph. D. programme on yellow mite, Polyphagotarsonemus latus (Banks) (Acari: Tarsonemidae) in chilli observing its huge damage potentiality. This monotypic species ravages hundreds of economically important plants including chilli, jute, sesame, cowpea, green gram, gerbera, marigold, datura etc. I tried to develop techniques and strategies to mitigate the yellow mite problem in chilli. After joining in the University service in 1991, I continued research work on mites and joined as Junior Acarologist under the All-India Network Project on Acarology during 2020.
Shashank: Can we know how your international connect helped you to achieve your expertise in this group?
Dr. Karmakar: I was recognized by the international acarologist community after publication of one of my research articles on rice sheath mite, Steneotarsonemus spinki Smiley. Later, with the blessings and encouragement of Dr. Vikram Prasad, renowned Acarologist and Founder of the International Journal of Acarology, Indira Publishing House, West Bloomfield, Michigan, USA, we organized International Symposium Cum Workshop in Acarology during 8-10th April, 2010 at BCKV. Many renowned Acarologists from USA, Egypt, Iran, Turkey, France and the Indian acarologists participated, presented, and discussed various issues of Acarology to make it a grand success. Prof. J. W. Amrine from West Virginia University and Dr. Vikram Prasad delivered lectures in the workshop on mite taxonomy to train the young Acarologists. Following year, I got the opportunity to participate in Acarology training programme at Ohio State University, Colombus, Ohio and came in contact with renowned phytoseiid taxonomist Prof. Gilberto J. de Moraes from ESALQ, USP, Brazil; tarsonemid taxonomist Dr. Ronald Ochoa from USDA and eriophyoid taxonomist Prof. J. W. Amrine and learned a lot to work on mite taxonomy. Just the following year, I receive the invitation from Prof. Gilberto J. de Moraes to work with him in his University for three months when I learned the process, protocol and details to describe the new mite species under his guidance. Now, we are describing many new species of Indian predatory phytoseiid mites, eriophyoid mites, and tarsonemid mites.
Shashank: What are the difficulties in studying acarology in India?
Dr. Karmakar: There are a lot of difficulties in studying acarology in India. Few to quote her are: i) Awareness about the mite and the subject acarology is very poor. ii) Even National and state-level people are very reluctant to consider or emphasize this issue iii) Limited funding to a credentialed person to study the mites. iv) Visionary, and planned efforts are extremely lacking. v) Important works are vested on some helpless people.
In conclusion, Acarology as science still has a long way to go to achieve parity with related disciplines. The new and restructured post-graduate academic programme of ICAR for plant protection sciences included two acarology courses (General and Advanced acarology). However, there is still a need for trained faculty in acarology to teach. Perhaps if we make more of an effort to encourage students and young scientists to take acarology, collaborate with national and international experts and increase focused funding, the science of studying these tiny arthropods will flourish in the future.
Dr. P.R. Shashank is a Scientist at the Division of Entomology, ICAR-IARI, New Delhi. He is specialized in Insect Systematics (Lepidoptera) and invasive pests.
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