Adaptive changes in sexual signalling in response to urbanization

Urbanization can cause species to adjust their sexual displays, because the effectiveness of mating signals is influenced by environmental conditions. Despite many examples that show that mating signals in urban conditions differ from those in rural conditions, we do not know whether these differences provide a combined reproductive and survival benefit to the urban phenotype. Here we show that male túngara frogs have increased the conspicuousness of their calls, which is under strong sexual and natural selection by signal receivers, as an adaptive response to city life. The urban phenotype consequently attracts more females than the forest phenotype, while avoiding the costs that are imposed by eavesdropping bats and midges, which we show are rare in urban areas. Finally, we show in a translocation experiment that urban frogs can reduce risk of predation and parasitism when moved to the forest, but that forest frogs do not increase their sexual attractiveness when moved to the city. Our findings thus reveal that urbanization can rapidly drive adaptive signal change via changes in both natural and sexual selection pressures

Anarchic centromeres:deciphering order from apparent chaos

Specialised chromatin in which canonical histone H3 is replaced by CENP-A, an H3 related protein, is a signature of active centromeres and provides the foundation for kinetochore assembly. The location of centromeres is not fixed since centromeres can be inactivated and new centromeres can arise at novel locations independently of specific DNA sequence elements. Therefore, the establishment and maintenance of CENP-A chromatin and kinetochores provide an exquisite example of genuine epigenetic regulation. The composition of CENP-A nucleosomes is contentious but several studies suggest that, like regular H3 particles, they are octamers. Recent analyses have provided insight into how CENP-A is recognised and propagated, identified roles for post-translational modifications and dissected how CENP-A recruits other centromere proteins to mediate kinetochore assembly

Environmental Correlates Of Species Richness And Composition Of Riparian Anuran Communities In Rainforests Of North-western Borneo: A Metacommunity Perspective

The diversity of stream anurans in Southeast Asia is highly endangered by habitat loss and fragmentation. To optimise conservation planning, their distribution patterns and habitat requirements need to be better understood. In this study, we investigated the distribution and habitat requirements of stream-associated anurans across four sites in north-western Borneo. The sites showed differences in species richness and composition. At a local scale, only microhabitat parameters and stream dynamics had a significant explanatory power on species composition. At a regional scale, environmental variables and geographical distances were both correlated with species composition, with adjacent locations having more similar species assemblages than distant locations. In order to protect the diversity of riparian anurans of north-western Borneo, protected areas need to include distant sites within the same region in addition to a diversity of habitats.2712532Universiti Brunei DarussalamBrunei Darussalam National Development Plan [UBD/GSR/ST/13

A new species of puddle frog from an unexplored mountain in southwestern Ethiopia (Anura, Phrynobatrachidae, Phrynobatrachus)

A new species of Phrynobatrachus is described from the unexplored and isolated Bibita Mountain, southwestern Ethiopia, based on morphological characters and sequences of the mitochondrial rRNA16s. The new species can be distinguished from all its congeners by a small size (SVL = 16.8 ± 0.1 mm for males, 20.3 ± 0.9 mm for females), a slender body with long legs and elongated fingers and toes, a golden coloration, a completely hidden tympanum, and a marked canthus rostralis. The phylogenetic hypothesis based on 16s sequences places the new species as sister to the species group that includes P. natalensis, although it is morphologically more similar to other dwarf Phrynobatrachus species, such as the Ethiopian P. minutus

Mitogenomics of historical type specimens clarifies the taxonomy of Ethiopian Ptychadena Boulenger, 1917 (Anura, Ptychadenidae)

The taxonomy of the Ptychadena neumanni species complex, a radiation of grass frogs inhabiting the Ethiopian highlands, has puzzled scientists for decades because of the morphological resemblance among its members. Whilst molecular phylogenetic methods allowed the discovery of several species in recent years, assigning pre-existing and new names to clades was challenged by the unavailability of molecular data for century-old type specimens. We used Illumina short reads to sequence the mitochondrial DNA of type specimens in this group, as well as ddRAD-seq analyses to resolve taxonomic uncertainties surrounding the P. neumanni species complex. The phylogenetic reconstruction revealed recurrent confusion between Ptychadena erlangeri (Ahl, 1924) and P. neumanni (Ahl, 1924) in the literature. The phylogeny also established that P. largeni Perret, 1994 represents a junior synonym of P. erlangeri (Ahl, 1924) and distinguished between two small species, P. nana Perret, 1994, restricted to the Arussi Plateau, and P. robeensis Goutte, Reyes-Velasco, Freilich, Kassie & Boissinot, 2021, which inhabits the Bale Mountains. The phylogenetic analyses of mitochondrial DNA from type specimens also corroborate the validity of seven recently described species within the group. Our study shows how modern molecular tools applied to historical type specimens can help resolve long-standing taxonomic issues in cryptic species complexes

The Importance of Ambient Sound Level to Characterise Anuran Habitat

<div><p>Habitat characterisation is a pivotal step of any animal ecology study. The choice of variables used to describe habitats is crucial and need to be relevant to the ecology and behaviour of the species, in order to reflect biologically meaningful distribution patterns. In many species, acoustic communication is critical to individuals’ interactions, and it is expected that ambient acoustic conditions impact their local distribution. Yet, classic animal ecology rarely integrates an acoustic dimension in habitat descriptions. Here we show that ambient sound pressure level (SPL) is a strong predictor of calling site selection in acoustically active frog species. In comparison to six other habitat-related variables (i.e. air and water temperature, depth, width and slope of the stream, substrate), SPL had the most important explanatory power in microhabitat selection for the 34 sampled species. Ambient noise was particularly useful in differentiating two stream-associated guilds: torrents and calmer streams dwelling species. Guild definitions were strongly supported by SPL, whereas slope, which is commonly used in stream-associated habitat, had a weak explanatory power. Moreover, slope measures are non-standardized across studies and are difficult to assess at small scale. We argue that including an acoustic descriptor will improve habitat-species analyses for many acoustically active taxa. SPL integrates habitat topology and temporal information (such as weather and hour of the day, for example) and is a simple and precise measure. We suggest that habitat description in animal ecology should include an acoustic measure such as noise level because it may explain previously misunderstood distribution patterns.</p> </div

Environmental and morphological constraints interact to drive the evolution of communication signals in frogs

Animals show a rich diversity of signals and displays. Among the many selective forces driving the evolution of communication signals, one widely recognized factor is the structure of the environment where animals communicate. In particular, animals communicating by sounds often emit acoustic signals from specific locations, such as high up in the air, from the ground or in the water. The properties of these different display sites may impose different constraints on sound production, and therefore drive signal evolution. Here, we used comparative phylogenetic analyses to assess the relationship between calling site (aquatic versus nonaquatic), body size and call dominant frequency of 160 frog species from the families Ranidae, Leptodactylidae and Hylidae. We found that the frequency of frogs calling from the water was lower than that of species calling outside of the water, a trend that was consistent across the three families studied. Furthermore, phylogenetic path analysis revealed that call site had both direct and indirect effects on call frequency. Indirect effects were mediated by call site influencing male body size, which in turn was negatively associated with call frequency. Our results suggest that properties of display sites can drive signal evolution, most likely not only through morphological constraints imposed on the sound production mechanism, but also through changes in body size, highlighting the relevance of the interplay between morphological adaptation and signal evolution. Changes in display site may therefore have important evolutionary consequences, as it may influence sexual selection processes and ultimately may even promote speciation

Reflections on the growing use of sounds in systematics and synecology: why an acoustic signal cannot become an onomatophore

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