@article {89658, title = {Large frugivores matter more on an island: Insights from island-mainland comparison of plant-frugivore communities.}, journal = {Ecol Evol}, volume = {11}, year = {2021}, month = {2021 Feb}, pages = {1399-1412}, abstract = {

Endozoochory, a mutualistic interaction between plants and frugivores, is one of the key processes responsible for maintenance of tropical biodiversity. Islands, which have a smaller subset of plants and frugivores when compared with mainland communities, offer an interesting setting to understand the organization of plant-frugivore communities vis-a-vis the mainland sites. We examined the relative influence of functional traits and phylogenetic relationships on the plant-seed disperser interactions on an island and a mainland site. The island site allowed us to investigate the organization of the plant-seed disperser community in the natural absence of key frugivore groups (bulbuls and barbets) of Asian tropics. The endemic Narcondam Hornbill was the most abundant frugivore on the island and played a central role in the community. Species strength of frugivores (a measure of relevance of frugivores for plants) was positively associated with their abundance. Among plants, figs had the highest species strength and played a central role in the community. Island-mainland comparison revealed that the island plant-seed disperser community was more asymmetric, connected, and nested as compared to the mainland community. Neither phylogenetic relationships nor functional traits (after controlling for phylogenetic relationships) were able to explain the patterns of interactions between plants and frugivores on the island or the mainland pointing toward the diffused nature of plant-frugivore interactions. The diffused nature is a likely consequence of plasticity in foraging behavior and trait convergence that contribute to governing the interactions between plants and frugivores. This is one of the few studies to compare the plant-seed disperser communities between a tropical island and mainland and demonstrates key role played by a point-endemic frugivore in seed dispersal on island.

}, issn = {2045-7758}, doi = {10.1002/ece3.7151}, author = {Naniwadekar, Rohit and Gopal, Abhishek and Page, Navendu and Ghuman, Sartaj and Ramachandran, Vivek and Joshi, Jahnavi} } @article {95904, title = {Seasonal drought regulates species distributions and assembly of tree communities across a tropical wet forest region}, journal = {GLOBAL ECOLOGY AND BIOGEOGRAPHY}, year = {2021}, month = {07/2021}, abstract = {

Aim How seasonal drought influences tree species distributions might shape future vegetation composition with impending changes to rainfall patterns. Theory suggests that across a seasonal drought gradient, dry-tolerant species might have wider distributions than species sensitive to seasonal drought, which will be restricted to less seasonal conditions. As wet-associated species drop out with increasing seasonality, the community will contain mainly dry-tolerant species. Time period Present. Location Western Ghats Biodiversity Hotspot in peninsular India. Major taxa studied Woody angiosperms. Methods Across a 1,200 km seasonal drought gradient, we modelled occurrences of 183 species using Gaussian logistic regression in a hierarchical Bayesian framework. We used the first-order model coefficients to attribute the association of species to seasonality (dry/wet) and second-order coefficients to assess modal responses. For 92 species, we checked for an interaction between dry/wet association and two traits: wood density and specific leaf area (SLA). Finally, we assessed the consequences of the seasonality associations of species for regional community assembly. Results Of 183 species, 38\% were significantly wet associated, 27\% dry associated and 34\% indifferent to seasonality. Nearly 80\% of species had estimated modes of occurrence within the seasonality range considered here. Species with lower SLA and lower wood density were more likely to occur in more seasonal sites where dry-associated species formed the majority of co-occurring species. The proportion of wet-associated species increased only after intermediate levels of seasonality. The community proportion of extreme wet-associated species decreased prominently from less to more seasonal sites. Main conclusions Dry-associated species persisted in less seasonal sites, but not vice versa. A shift toward more seasonal rainfall might favour dry-associated species and shrink the ranges of wet-associated species. Future work should assess how the intensity and duration of drought and interactions with other drivers of global change regulate the relative performance of species at more and less seasonal sites.

}, doi = {10.1111/geb.13350}, author = {Krishnadas, Meghna and Sankaran, Mahesh and Page, Navendu and Joshi, Jahnavi and Machado, Siddarth and Nataraj, Nandita and Chengappa, Sannuvanda K. and Kumar, Vijay and Kumar, Ajith and Krishnamani, Ramanathan and Hampe, Arndt} } @article {16566, title = {Evolutionary Assembly of Communities in Butterfly Mimicry Rings.}, journal = {Am Nat}, volume = {189}, year = {2017}, month = {2017 Apr}, pages = {E58-E76}, abstract = {

Species co-occurrence in ecological communities is thought to be influenced by multiple ecological and evolutionary processes, especially colonization and competition. However, effects of other interspecific interactions and evolutionary relationships are less explored. We examined evolutionary histories of community members and roles of mutualistic and parasitic interactions (M{\"u}llerian and Batesian mimicry, respectively) in the assembly of mimetic butterfly communities called mimicry rings in tropical forests of the Western Ghats, India. We found that M{\"u}llerian mimics were phylogenetically clustered, sharing aposematic signals due to common ancestry. On the other hand, Batesian mimics joined mimicry rings through convergent evolution and random phylogenetic assembly. Since the Western Ghats are a habitat island, we compared species diversity and composition in its mimicry rings with those of habitat mainland to test effects of biogeographic connectivity. The Western Ghats consisted of fewer mimicry rings and an overall smaller number of aposematic species and mimics compared to habitat mainland. The depauperate mimicry rings in the Western Ghats could have resulted from stochastic processes, reflecting their long temporal and spatial isolation and trickling colonization by the mimetic butterfly communities. These results highlight how evolutionary history, biogeographic isolation, and stochastic colonization influence the evolutionary assembly and diversity of ecological communities.

}, issn = {1537-5323}, doi = {10.1086/690907}, author = {Joshi, Jahnavi and Prakash, Anupama and Kunte, Krushnamegh} } @article {26655, title = {Tracking the variability of phenotypic traits on a molecular phylogeny: an example from scolopendrid centipedes in peninsular India}, journal = {Organisms Diversity \& Evolution}, volume = {17}, year = {2017}, month = {07/2017}, pages = {393{\textendash}408}, abstract = {

Taxonomic studies on scolopendrid centipedes have often documented variability at the individual and population levels and applied those data to questions of species delimitation, but these investigations have mostly lacked an explicit phylogenetic framework. A molecular phylogeny and recent taxonomic revision for Indian species of the scolopendrid Digitipes Attems, 1930, permit variability of traditional taxonomic characters for Scolopendridae to be mapped onto a phylogeny. Based on their fit to the tree using maximum likelihood, reliable species-level characters include the number of glabrous antennal articles, presence of a median ridge on the tergites, and presence or absence of a tarsal spur on leg 20. Characters that are conserved within and diagnostic for particular species but labile within others (typically with geographic structure) include the first tergite with paramedian sutures, presence or absence of a lateral spine on the coxopleuron, and the number of spines in a ventromedial row on the ultimate leg prefemur. Comparisons with published accounts of variability in species of other scolopendrid genera, particularly Scolopendra and Otostigmus, show that Indian Digitipes has conserved morphology in some characters that are taxonomically useful elsewhere in the family, and most of its taxonomically informative characters have analogous patterns of variability in other genera. The approach used in this study to evaluate morphological variation in a phylogenetic framework can be applied to other taxa in which morphologically cryptic species have been reported and where species diagnosis requires a combination of characters.

}, author = {Joshi, Jahnavi and Edgecombe, GD} }