Higher investment in flight morphology does not trade off with fecundity estimates in a poleward range‐expanding damselfly

1. Evolutionary increases in dispersal‐related traits are frequently documented during range expansions. Investment in flight‐related traits is energetically costly and a trade‐off with fecundity may be expected during range expansion. 2. However, in contrast to wing‐dimorphic species, this trade‐off is not general in wing‐monomorphic species. In the absence of a dispersal‐‐fecundity trade‐off, an increased investment in clutch size at the expansion front is expected possibly at a cost of reduced offspring size. 3. The study evaluated investment in female flight morphology and fecundity‐related traits (clutch size, hatchling size) and potential trade‐offs among these traits in replicated populations of the poleward range‐expanding damselfly Coenagrion scitulum. 4. Females at the expansion front had a higher relative thorax length, indicating an increased investment in flight; this can be explained by spatial sorting of dispersal ability or in situ natural selection at the expansion front. Edge females produced larger hatchlings, however, this pattern was totally driven by the population‐specific thermal larval regimes and could not be attributed to the range expansion per se. By contrast, clutch sizes did not differ between core and edge populations. There was no signal of a dispersal–fecundity trade‐off either for a trade‐off between clutch size and hatchling size. 5. These results indicate that evolution of a higher dispersal ability at the expansion front of C. scitulum does not trade off with investment in fecundity, hence a dispersal–fecundity trade‐off is unlikely to slow down range expansion of this species.     

Meligethes aeneus oviposition preferences,larval parasitism rate and species composition of parasitoids on Brassica nigra,Raphanus sativus and Eruca sativa compared with on Brassica napus

The trap crop strategy is based on host plant discrimination by pests and their parasitoids, which may respond differently to various host plant cues, thus affecting their respective population distributions. We conducted a three-year study to compare the responses of the most damaging pest of oilseed rape (Brassica napus L.), the pollen beetle (Meligethes aeneus Fab.), and its hymenopteran parasitoids to various potential trap crops: Brassica nigra L., Raphanus sativus var. olifera Pers. and Eruca sativa Mill. with that to B. napus. We recorded their abundance, oviposition preferences and the species composition of the parasitoids.Our results show that oviposition rates of the pollen beetle and its parasitoids as well the species composition of the parasitoids varies with plant species. We discuss the potential of these plant species, especially B. nigra, to enhance the natural control of the beetle by fostering several parasitoid species. The species composition of the parasitoids on different host plants compared with on B. napus is presented for the first time. In addition to trapping pests, the trap crops could also act as parasitoid banks, enhancing natural control of the pest through providing suitable hosts for natural enemies, without increasing the population growth of the next generation of pests.     

Confronting the challenges of discovery of novel antibacterial agents

Bacterial resistance is inevitable and is a growing concern. It can be addressed only by discovery and development of new agents. However the discovery and development of new antibacterial agents are at an all time low. This article broadly examines the historical as well as current status of antibacterial discovery and provides some perspective as how to address some of the challenges.     

Female reproductive biology of the sand smelt in brackish lagoons of southern France

The breeding season of Atherina boyeri living in the brackish lagoons of Mauguio, Pérols and Méjean (Hérault, southern France) was very protracted (February-September). The peak of the reproductive effort occurred in April, May and June. Larger fishes started spawning earlier, and stopped later, than smaller ones. Batch fecundity varied from 4 to 447 oocytes and was positively related to female length and weight. Monthly mean fecundity increased at the beginning of the breeding season and decreased between June and July. Individual mean oocyte diameter ranged from 1.34 to 1.94 mm and was not related to fish length. Monthly mean oocyte size declined throughout the breeding season as water temperature rose. There was no trade-off between number and egg size. The strategy of these sand smelts seemed well adapted to ensure spawning success without endangering their survival. The highest reproductive effort period occurred in such a way that environmental conditions were suitable to the best survival and growth of hatched larvae. When breeding ceased, fishes, particularly the youngest ones, had enough time to improve their condition before overwintering.     

Biogeographical network analysis of plant species distribution in the Mediterranean region

The delimitation of bioregions helps to understand historical and ecological drivers of species distribution. In this work, we performed a network analysis of the spatial distribution patterns of plants in south of France (Languedoc‐Roussillon and Provence‐Alpes‐Côte d'Azur) to analyze the biogeographical structure of the French Mediterranean flora at different scales. We used a network approach to identify and characterize biogeographical regions, based on a large database containing 2.5 million of geolocalized plant records corresponding to more than 3,500 plant species. This methodology is performed following five steps, from the biogeographical bipartite network construction to the identification of biogeographical regions under the form of spatial network communities, the analysis of their interactions, and the identification of clusters of plant species based on the species contribution to the biogeographical regions. First, we identified two sub‐networks that distinguish Mediterranean and temperate biota. Then, we separated eight statistically significant bioregions that present a complex spatial structure. Some of them are spatially well delimited and match with particular geological entities. On the other hand, fuzzy transitions arise between adjacent bioregions that share a common geological setting, but are spread along a climatic gradient. The proposed network approach illustrates the biogeographical structure of the flora in southern France and provides precise insights into the relationships between bioregions. This approach sheds light on ecological drivers shaping the distribution of Mediterranean biota: The interplay between a climatic gradient and geological substrate shapes biodiversity patterns. Finally, this work exemplifies why fragmented distributions are common in the Mediterranean region, isolating groups of species that share a similar eco‐evolutionary history.