A rapid survey of herpetofaunal diversity in Nijhum Dwip National Park, Bangladesh

The ecological effects of habitat use by herpetofaunal species vary widely and recognizing relative habitat value will help to improve conservation theory and practice in a particular landscape. To understand how different habitat uses influence diversity in riparian landscapes, we studied reptile and amphibian assemblages across major habitats (agricultural land, forest, human habitation, and waterbodies) in Nijhum Dwip National Park, Bangladesh. A total of 35 herpetofaunal species were found; among them, 17 were directly observed and 18 were reported from a questionnaire survey. Among the observed species, the Asian Common Toad Duttaphrynus melanostictus was the most commonly seen (relative abundance 0.32). We found that forest habitat contained a greater diversity of herpetofauna than other habitats followed by agricultural land, human habitation, and waterbodies. We also found 8 habitat specialist species and 9 generalist species in this study. Our results show that different habitats support different species assemblages in Nijhum Dwip National Park, signifying the importance of diversified habitats for the herpetofaunal population. Understanding this importance is crucial for identifying matrix environments that can complement the forest habitats of sensitive as well as specialist herpetofaunal species.

Repeated genetic adaptation to high altitude in two tropical butterflies

Repeated evolution can provide insight into the mechanisms that facilitate adaptation to novel or changing environments. Here we study adaptation to high altitude in two divergent tropical butterflies, H. erato and H. melpomene, which have repeatedly and independently adapted to high elevations on either side of the Andean mountains. We sequenced 518 whole genomes from elevational transects and found many regions under selection at high altitude, with repeated genetic differentiation across multiple replicates, including allopatric comparisons. In contrast, there is little ‘molecular parallelism’ between H. erato and H. melpomene. With a further 85 whole genomes of five close relatives, we find that a large proportion divergent regions have arisen from standing variation and putative adaptive introgression from high-altitude specialist species. Taken together our study supports a key role of standing genetic variation and gene flow from pre-adapted species in promoting parallel genetic local adaptation to the environment.

Protected areas are not effective for the conservation of freshwater insects in Brazil

Biodiversity conservation has faced many challenges, especially the conversion of natural areas that compete with use for agriculture, energy production and mineral extraction. This problem is further aggravated by lack of knowledge of the biodiversity that exists and the geographical distribution of different groups. The objectives of our study were to examine the distributional pattern of Gerromorpha diversity in Brazil, create a map of conservation priority areas, estimate the degree of protection that the current network of protected areas guarantees to this insect group, and identify the size thresholds in geographical distributions that would allow species to be protected. We used species occurrences from the Water Bugs Distributional Database, and we used 19 bioclimatic variables to build models of the potential distributions of species using the MaxEnt program. Using the potential model results, we calculated diversity metrics and overlapped them with the current state and federal “conservation units” (protected areas for biodiversity) in Brazil. Total beta diversity and turnover portions were separated into two faunistic groups, one in northern and the other in southern Brazil. The Amazon has higher beta diversity than what was predicted by the null models. We detected a positive relationship between species distribution area and occurrence in conservation units. Conservation units with less than 250 km2 do not protect Gerromorpha species. Our results reinforce the necessity of formulating new conservation strategies for this group, contemplating species with both restricted and ample distributions, because rare and specialist species are the most harmed by habitat reduction, given that they are more sensitive to environmental disturbance.

Effects of productive management of an agroforestry system on the associated diversity of parasitoids (Hymenoptera: Braconidae)

The overuse of pesticides, landscape fragmentation and poor environmental management practices have contributed to the drastic decline of Neotropical unique biodiversity. Parasitoid wasps are widely used as biological control agents, however little is known about the effects of land use and degradation on parasitoid species richness and abundance. This work explores how parasitoid species richness is affected by agroecosystems in which plant diversity is limited (crops; crops adjacent to secondary vegetation). It was found that there is no direct effect of plant diversity in the group of parasitoids studied; however, the number of specialist species (koinobionts) was high, which indicates that diversified agroecosystems probably function as remnants of natural habitat. Future research could help further understand the extent to which landscape fragmentation and plant diversity may alter host-plants interactions and parasitism strategies.

Habitat patches providing south–north connectivity are under-protected in a fragmented landscape

As species’ ranges shift to track climate change, conservationists increasingly recognize the need to consider connectivity when designating protected areas (PAs). In fragmented landscapes, some habitat patches are more important than others in maintaining connectivity, and methods are needed for their identification. Here, using the Condatis methodology, we model range expansion through an adaptation of circuit theory. Specifically, we map ‘flow’ through 16 conservation priority habitat networks in England, quantifying how patches contribute to functional South–North connectivity. We also explore how much additional connectivity could be protected via a connectivity-led protection procedure. We find high-flow patches are often left out of existing PAs; across 12 of 16 habitat networks, connectivity protection falls short of area protection by 13.6% on average. We conclude that the legacy of past protection decisions has left habitat-specialist species vulnerable to climate change. This situation may be mirrored in many countries which have similar habitat protection principles. Addressing this requires specific planning tools that can account for the directions species may shift. Our connectivity-led reserve selection procedure efficiently identifies additional PAs that prioritize connectivity, protecting a median of 40.9% more connectivity in these landscapes with just a 10% increase in area.

Snakes on an African plain: the radiation of Crotaphopeltis and Philothamnus into open habitat (Serpentes: Colubridae)

Background The African continent is comprised of several different biomes, although savanna is the most prevalent. The current heterogeneous landscape was formed through long-term vegetation shifts as a result of the global cooling trend since the Oligocene epoch. The overwhelming trend was a shift from primarily forest, to primarily savanna. As such, faunal groups that emerged during the Paleogene/Neogene period and have species distributed in both forest and savanna habitat should show a genetic signature of the possible evolutionary impact of these biome developments. Crotaphopeltis and Philothamnus (Colubridae) are excellent taxa to investigate the evolutionary impact of these biome developments on widespread African colubrid snakes, and whether timing and patterns of radiation are synchronous with biome reorganisation. Methods A phylogenetic framework was used to investigate timing of lineage diversification. Phylogenetic analysis included both genera as well as other Colubridae to construct a temporal framework in order to estimate radiation times for Crotaphopeltis and Philothamnus. Lineage diversification was estimated in Bayesian Evolutionary Analysis Sampling Trees (BEAST), using two mitochondrial markers (cyt–b, ND4), one nuclear marker (c–mos), and incorporating one fossil and two biogeographical calibration points. Vegetation layers were used to classify and confirm species association with broad biome types (‘closed’ = forest, ‘open’ = savanna/other), and the ancestral habitat state for each genus was estimated. Results Philothamnus showed an ancestral state of closed habitat, but the ancestral habitat type for Crotaphopeltis was equivocal. Both genera showed similar timing of lineage diversification diverging from their sister genera during the Oligocene/Miocene transition (ca. 25 Mya), with subsequent species radiation in the Mid-Miocene. Philothamnus appeared to have undergone allopatric speciation during Mid-Miocene forest fragmentation. Habitat generalist and open habitat specialist species emerged as savanna became more prevalent, while at least two forest associated lineages within Crotaphopeltis moved into Afromontane forest habitat secondarily and independently. Discussion With similar diversification times, but contrasting ancestral habitat reconstructions, we show that these genera have responded very differently to the same broad biome shifts. Differences in biogeographical patterns for the two African colubrid genera is likely an effect of distinct life-history traits, such as the arboreous habits of Philothamnus compared to the terrestrial lifestyle of Crotaphopeltis.

Are Protected Areas Effective In the Conservation of Priority Areas for Freshwater Insects In Brazil?

Biodiversity conservation has faced many challenges, especially the conversion of natural areas that compete with use for agriculture, energy production and mineral extraction. This problem is further aggravated by lack of knowledge of the biodiversity that exists and the geographical distribution of different groups. The objectives of our study were to examine the distributional pattern of Gerromorpha diversity in Brazil, create a map of conservation priority areas, measure the importance level of the current network of protected areas, and identify the size thresholds in geographical distributions that would allow species to be protected. We used species occurrences from the Water Bugs Distributional Database, and we used 19 bioclimatic variables to build models of the potential distributions of species using the MaxEnt program. Using the potential model results, we calculated diversity metrics and overlapped them with the current state and federal “conservation units” (protected areas for biodiversity) in Brazil. Total beta diversity and turnover portions were separated into two faunistic groups, one in northern and the other in southern Brazil. The Amazon has higher beta diversity than what was predicted by the null models. We detected a positive relationship between species distribution area and occurrence in conservation units. Conservation units with less than 250 km² do not protect Gerromorpha species. We reinforce the necessity of formulating new conservation strategies for this group, contemplating species with both restricted and ample distributions, because rare and specialist species are the most harmed by habitat reduction, given that they are more sensitive to environmental disturbance.

Urban Pit-Building Insects Are Attracted to Walls for Multiple Reasons

Whereas most animals find urban habitats to be inferior to natural habitats, some “urban specialist” species thrive there. Wormlions present such an example. Common in Mediterranean cities, they cluster in thin layers of loose soil below man-made shelters. Wormlions are fly larvae that dig pit-traps in loose soil and hunt small arthropods. Our first aim was to determine whether wormlion pits accumulate next to walls. Wormlion pits were indeed closer to walls than expected by chance at most of the study sites. We examined possible factors behind this apparent preference, combining field observations and experiments, laboratory work, and theoretical analysis. We examined the effect of soil depth, particle size, shade, and prey abundance. Each factor provided a partial explanation for the wormlions’ proximity to walls, but none provided an overall explanation. We developed a spatially explicit simulation model, demonstrating under which conditions wall-adjacent positions are favored. Finally, we created artificial microhabitats, and placed wormlions either in the center or next to the wall. The wormlions in the center moved over longer distances than those next to the wall and did so more in the wall’s direction. The abundance of walls may help to explain the success of wormlions in urban habitats.

Investigation of Salmonella Phage–Bacteria Infection Profiles: Network Structure Reveals a Gradient of Target-Range from Generalist to Specialist Phage Clones in Nested Subsets

Bacteriophages that lyse Salmonella enterica are potential tools to target and control Salmonella infections. Investigating the host range of Salmonella phages is a key to understand their impact on bacterial ecology, coevolution and inform their use in intervention strategies. Virus–host infection networks have been used to characterize the “predator–prey” interactions between phages and bacteria and provide insights into host range and specificity. Here, we characterize the target-range and infection profiles of 13 Salmonella phage clones against a diverse set of 141 Salmonella strains. The environmental source and taxonomy contributed to the observed infection profiles, and genetically proximal phages shared similar infection profiles. Using in vitro infection data, we analyzed the structure of the Salmonella phage–bacteria infection network. The network has a non-random nested organization and weak modularity suggesting a gradient of target-range from generalist to specialist species with nested subsets, which are also observed within and across the different phage infection profile groups. Our results have implications for our understanding of the coevolutionary mechanisms shaping the ecological interactions between Salmonella phages and their bacterial hosts and can inform strategies for targeting Salmonella enterica with specific phage preparations.