Annual precipitation predicts the phylogenetic signal in bat-fruit interaction networks across the Neotropics.

Closely related species tend to be more similar than randomly selected species from the same phylogenetic tree. This pattern, known as a phylogenetic signal, has been extensively studied for intrinsic (e.g. morphology), as well as extrinsic (e.g. climatic preferences), properties but less so for ecological interactions. Phylogenetic signals of species interactions (i.e. resource use) can vary across time and space, but the causes behind such variations across broader spatial extents remain elusive. Here, we evaluated how current and historical climates influence phylogenetic signals of bat-fruit interaction networks across the Neotropics. We performed a model selection relating the phylogenetic signals of each trophic level (bats and plants) with a set of current and historical climatic factors deemed ecologically important in shaping biotic interactions. Bat and plant phylogenetic signals in bat-fruit interaction networks varied little with climatic factors, although bat phylogenetic signals positively covaried with annual precipitation. These findings indicated that water availability could increase resource availability, favouring higher niche partitioning of trophic resources among bat species and hence bat phylogenetic signals across bat-fruit interaction networks. Overall, our study advances our understanding of the spatial dynamics of bat-fruit interactions by highlighting the association of current climatic factors with phylogenetic patterns of biotic interactions.

The risk of use small matrices to measure specialization in host-parasite interaction networks: a comment to Rivera-García et al. (2016).

In the last years, there were a growing number of studies using the metric H 2' to calculate complementary specialization in host-parasite interaction networks. However, only a few studies have explored the sensitivity of H 2' to network dimensions (i.e. species richness and number of interactions), which consequently could generate studies that are not comparable among them or lead to biased conclusions. In this study, we used the recent published study conducted by Rivera-García et al. in 2016 involving host-bat fly networks as an example to call attention to the risk of using H 2' to calculate specialization for small matrices. After conducting analyses based on both empirical and simulated data, we show that H 2' values are strongly affected by randomly allocation of species interactions to another cell in the matrix for small networks and that therefore the results and conclusions presented in Rivera-García et al. in 2016 are only an artefact of the dataset used. Therefore, we fully recommended taking into account the careful use of small networks to measuring specialization in host-parasite interactions.