Here you can find the R scripts and data for our manuscript on diel foraging activity of tropical ants.

Here you can find the R scripts and data for our manuscript on diel foraging activity of tropical ants.

Deciphering cryptic diversity can have substantial implications for our understanding of evolutionary processes and species conservation. Birds are arguably among the best studied organismal groups, but even in avian clades there are some genera that have not been thoroughly surveyed. This is particularly true for taxa that occur in hyperdiverse biogeographic regions. In this study, we focus on an endemic group of New Guinean birds, the jewel-babblers (genus: Ptilorrhoa), and study the diversification history of all known taxa. We assemble a de novo genome using linked-read sequencing and genomic data for 40 historical specimens. Both phylogenomic and population-genomic analyses strongly support the recovery of a cryptic species and shed new light on the diversification history of this group. The blue jewel-babbler (Ptilorrhoa caerulescens) is a paraphyletic species complex and P. c. nigricrissus is more closely related to the phenotypically distinct and sexually dimorphic P. geislerorum, than to other P. caerulescens subspecies. These findings demonstrate that even in well-studied groups such as birds, cryptic diversity can still be a prevalent reality. Moreover, by deciphering cryptic diversity, we shed new light on the processes driving speciation within Ptilorrhoa and the need to potentially revise the taxonomic status of all subspecies.

Complex signalling behaviors, such as avian song and courtship displays, have been associated with increases in both absolute and relative brain size, presumably mediated by relationships between brain size and motor coordination and learning abilities. Nonetheless, reliably establishing these relationships is challenging due to the difficulty of quantifying behavioral complexity. Birds of paradise perform some of the most elaborate avian courtship displays, involving a striking degree of complexity and motor coordination, which makes them interesting models for investigating the evolution of complex motor learning abilities in birds. Here, we compiled a μCT-based brain size dataset of more than half of the known species of birds of paradise and used multiple metrics of display complexity to test the hypothesis that larger brains are associated with more elaborate repertoires of motor and vocal displays. We found no clear evidence that the complexity of courtship display behaviors co-evolved with brain size among the birds of paradise: this conclusion held across three kinds of behavioral and two kinds of vocal complexity scores.

Insectivorous predators, including birds and bats, play crucial roles in trophic cascades. However, previous research on these cascades has often relied on permanent predator exclosures, which prevent the isolation of specific effects of birds and bats, given their different activity patterns throughout the day. Moreover, limited knowledge exists regarding the variations in individual effects of these predators under different biotic and abiotic conditions, such as changes in elevation. To address these uncertainties, our study aimed to investigate the distinct effects of bats and birds on arthropod densities in foliage and herbivory damage in lowland and highland rainforests of Papua New Guinea (PNG). Predator exclosures were established for one month to exclude diurnal or nocturnal predators across 120 saplings (ca. 2.5-4 m tall) selected from two lowland and two highland forests (i.e., 30 saplings per study site) along the Mt. Wilhelm transect in PNG. Arthropods were collected and measured, and herbivory damage was analysed at the end of the experiment. Birds significantly reduced arthropod densities by 30 %, particularly in arthropods longer than 10 mm, regardless of elevation. Additionally, both birds and bats appeared to mitigate herbivory damage in highland forests, with protected saplings displaying up to 189 % more herbivory. Our results support previous studies that have demonstrated the ability of insectivorous predators to reduce leaf damage through the control of arthropods. Furthermore, our approach highlights the importance and necessity of further research on the role of seasons and elevations in trophic cascades.

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The fig (Moraceae) and pollinating fig wasp (Agaonidae) mutualism is best known as a model system for the study of coevolution in plant-pollinator interactions and its central role in shaping vertebrate communities in tropical forests. Figs also host myriad antagonistic parasitic fig wasps which impose costs on both partners threatening mutualism stability. Spatio-temporal variation in parasitic wasp abundance is a key factor in mitigating these effects. Because fig wasps are temperature sensitive and likely vary in their ability to traverse environmental gradients, we expect community assemblages and abundance of both pollinating and non-pollinating fig wasps to respond to changes along an elevational gradient. In the present study, we compare the fig wasp communities and the abundance of three fig species growing along the slopes of the Mount Wilhelm altitudinal gradient in Papua New Guinea. We quantified wasps from over 100 male fig trees and calculated seed sets for 55 female trees along each of the species’ distribution on the transect. Our results show that the abundance of both pollinating and non-pollinating fig wasps follow a mid-elevation peak, consistent with fig species richness found in the same transect. The patterns, however, are different according to the host’s species distribution. The seed set remained relatively constant along the gradient for all species with some decrease along higher elevations, potentially affecting connectivity along the gradient. As suggested for insects in general, temperature and habitat diversity appear to play a fundamental role in the species richness and abundance of fig wasps.

Rainforests on high tropical mountains are globally important species diversity hotspots. We studied amphibians along an extensive rainforest elevation gradient on Mt. Wilhelm (4,509 m) in Papua New Guinea. We established eight sites at 500 m elevation increments between 200 and 3,700 m a.s.l. and related their community composition to the known species pool of New Guinea island. We recorded 3,390 frogs from 55 species, which is three times more species than at any local community along the elevation gradient. Species diversity peaked at 1,700 m a.s.l. for Mt. Wilhelm communities, and at 500–1,100 m a.s.l. in the broader New Guinea fauna, probably reflecting increasing speciation and decreasing dispersal rates with increasing elevation. The beta diversity between frog communities was high and increased with increasing elevation. The change in frog community composition across 500 m elevation corresponded to the change over 200 km distance within lowland forests. A majority of frog species were distributed over narrow <500 m elevational ranges, at Mt Wilhelm and the New Guinea fauna more broadly. We did not detect Rapoport’s pattern of wider elevation range for species at higher elevations than for lowland species, for Mt. Wilhelm communities or the New Guinea fauna. The high beta diversity patterns along elevation gradients generated by rapid species turnover with narrow elevation ranges make frog communities vulnerable to change in the environment, including climate change.