Book Review

Moths of Agastya, by R. Bhanumathi. Published by Agastya International Foundation. 2025.

Reviewed by R. J. Ranjit Daniels

Moths are as fascinating as are butterflies. Yet, they are rarely taken into account in biodiversity documentation. Despite being ten times more diverse than butterflies, moths have historically aroused relatively less scientific interest, except in those who are concerned with crop and forest insect pest management. As a result, moth diversity continues to remain grey. Moths can therefore be described as ‘bats of the insect world’.

The book under review concerns an institutional campus. Throughout the world, institutional campuses are gaining greater ecological significance as ‘refuges of biodiversity’ in otherwise hostile, human-dominated landscapes. Agastya is apparently one such institutional campus with remarkable biodiversity. Despite being less than a square kilometre in extent and being located in a dry zone that receives less than 500 mm of rainfall annually, the campus is home to 550 species of plant, 155 species of bird, 21 species of reptile, 55 species of spider, 107 species of butterfly and maybe scores of not-yet-documented species of invertebrate. This richness may be because the campus is at an elevation of 733 m ASL. Or because it is a part of the Eastern Ghats landscape. Or it may have something to do with its diverse vegetation. Or it may even be its past history. All these assumptions provide more opportunities for future research.

R. Bhanumathi has made a noteworthy contribution on moths. She has meticulously documented 653 species with good-quality photographs. The photographs have been presented in a user-friendly format. This is a remarkable feat and commendable, considering the general paucity of information on Indian moths, their local diversity and how they fare in specific habitats, and the fact that the author is not a moth specialist. Further, she has taken the trouble to introduce the readers to the various aspects of moth research and the associated challenges. Challenges mainly arise in the correct identification of species, especially due to the lack of authentic field guides that focus on specific regions. And as has been evident from the book, identifying every species (including those exhibiting sexual dimorphism and only using photographs) will remain a challenge for many years to come. It is therefore understandable that 50 species have not been identified and that for a handful of others, the specific identity is missing.

The author has broadly categorized the 653 species into micro- and macromoths. She has also provided a classified checklist going down to the level of tribes under which the respective species are listed. The book includes an index to scientific names. The most useful section is, however, the detailed description of methods used in documenting the species. That moth researchers should have a lot of patience becomes evident, especially when it is said that moths arrive at the source of light in waves. Not all species come together, nor at the same time. There is a clear rhythm in moth arrival, and the researcher should be aware of the most appropriate time of the night when particular species of moth can be seen. This information is very useful and will greatly help in reducing sampling biases during serious moth research.

Six hundred and fifty-three species of moth documented in four years from a small campus is only indicative of the much greater diversity of moths in the landscape. Moths, being highly mobile, can be attracted to light from sources that are quite far away. And as some of the species listed, such as fruit-piercing moths and stem-borers, are also pests in agriculture, it would not be naive to speculate that the landscape matrix within which Agastya is located has had some cultivation. Landscape ecologists are well aware of the fact that a patch of habitat such as that in Agastya is never free of biotic influences from the larger landscape matrix. Therefore, if the author plans a second edition of the book, it would be best if she provides more details of the landscape and the type of land use outside the campus. This can be easily done using a map and GIS. It will add immense value to any future edition of the book.

Another aspect of interest for future editions would be to compare the moth diversity of Agastya with other localities. For instance, how does it compare with a place of comparable size in the Western Ghats? Moths in general being heavierwinged (more densely coated with powdery scales) than butterflies, may not tolerate very wet conditions as found in the Western Ghats. Is Agastya more suited because it is dry? It is well-known that many species of moth that are pests in agriculture pupate under leaf litter and organic debris. Wet litter such as that in rainforests may attract more predators such as ants. It can also be infested with fungi that can harm the pupae. Can this be a reason why dry habitats are more conducive to moths?

Moths of Agastya has no doubt opened a new avenue for biodiversity research in general and moth-watching in particular. It will be of great interest to young naturalists and curious nature-lovers. It will also be useful to serious moth researchers. More than anything else, this book will motivate field biologists of the future to include moths in biodiversity assessments. How can a group of terrestrial animals that is more diverse than butterflies, birds and plants be ignored? A wonderful book indeed, and it is my sincere wish that the author bring out a future edition addressing some of the concerns discussed in the foregoing. No book can be hundred per cent correct or complete. Each book makes a new beginning, and Moths of Agastya has just done that.