We are interested in understanding the evolutionary and ecological processes influencing biodiversity gradients and community assembly in space and time. Molecular phylogenies have become crucial to understanding biodiversity and community assembly because they allow us to incorporate species’ evolutionary relationships and investigate the relative role of phylogenetic inertia, biogeography, climate and biotic interactions, including both antagonistic and mutualistic interactions. 

Community phylogenetic approach

We used phylogenetic diversity measures to explore the evolutionary dynamics of butterfly mimicry rings. In particular, we examined the effects of two interspecific interactions, mutualism and parasitism, on the community assembly of mimetic butterflies in the Western Ghats. We showed that evolutionary history, biogeographic isolation, and stochastic colonisation had influenced mimetic community assembly (Joshi et al., 2017). We used to disentangle the relative roles of functional traits and phylogenetic history in the assembly of the plant-frugivore community by comparing mainland and island systems (Naniwadekar et al., 2021). We have also used spatial phylogenetic measures along with species distribution modelling to discern the role of geo-climatic and biogeographic processes in driving biodiversity gradients (Bharti et al., 2021; Gopal et al., 2023).  

Ancestral trait reconstruction and phylogenetic signal

Ancestral trait reconstruction methods allow assessing relative contributions of natural and sexual selection, phylogenetic inertia, and biogeography in shaping phenotypic diversity. We have examined alternate hypotheses for trait evolution in both centipedes and butterflies, including mimicry, sexual dimorphism, and anti-predatory defences among swallowtail butterflies (Joshi and Edgecombe, 2017; Gaitonde, Joshi et al., 2018). 

We plan to apply these methods to multiple groups for which we generate detailed species phylogenies (evolutionary data) and phenotypic traits, climate and distribution data to understand their community structure in space and time in the Indian Subcontinent. In addition, we aim to develop new methods for understanding community assembly across taxa at multiple spatial and temporal scales.

Publications:

1. Kulkarni M., Paripatyadar S., Naniwadekar N., Joshi J. 2023. Local-scale abiotic factors influence the organisation of rock pool arthropod communities in a biodiversity hotspot. Limnology and Oceanography, Early online version https://doi.org/10.1002/lno.12427

2. Gopal A., Bharti D. K., Page N., Dexter K. G., Krishnamani R., Kumar A., Joshi J. 2023. Range restricted old and young lineages show the southern Western Ghats to be both museum and cradle of diversity for woody plants. Proceedings of the Royal Society B.  290: 20222513

3. Bharti D., Edgecombe G., Karanth P.,  Joshi J. 2021. Spatial patterns of phylogenetic diversity and endemism in the Western Ghats, India: a case study using ancient predatory arthropods. Ecology and Evolution, 11, 3, 16499-16513. https://doi.org/10.1002/ece3.8119

4. Naniwadekar R., Gopal A., Page N., Ghuman S., Ramachandran V., Joshi J. 2021. Large frugivores matter more on an island: Insights from island-mainland comparison of plant–frugivore communities. Ecology and Evolution 11, 3, 1399–1412.  https://doi.org/10.1002/ece3.7151; Covered by:  Birds, Trees and the Narcondam Islands, What 1,000 hornbills contribute to the tiny Narcondam Island 

5. Gaitonde N., Joshi J., & Kunte K. 2018. Exploring evolution of defense ensembles among Papilionidae butterflies Ecology and Evolution, 32: 601-611. https://doi.org/10.1002/ece3.4426 

6. Joshi J., Prakash A., & Kunte K. 2017. Evolutionary assembly of butterfly mimetic community in the Western Ghats, India American Naturalist, 189, E58-E76.  doi/10.1086/690907  Won the ASN Presidential Award 2018. 

7. Joshi J., & Edgecombe G. 2017. Tracking the variability of phenotypic traits on a molecular phylogeny: an example from scolopendrid centipedes. Organisms, Diversity and Evolution, 7, 1-16. https://doi.org/10.1007/s13127-017-0323-9