Sensitivity of North American sturgeons and paddlefish to fishing mortality

Sturgeons and paddlefish exhibit unusual combinations of morphology, habits, and life history characteristics, which make them highly vulnerable to impacts from human activities, particularly fisheries. Five North American sturgeons (shortnose, Gulf, pallid, Alabama, and green sturgeon) are listed as endangered or threatened by management authorities. Managers have instituted fishery closures for the three other species of North American sturgeons (Atlantic, white, and shovelnose) and paddlefish because of low stock abundance at some point in this century. Reproductive potential in four species I examined (Atlantic, white, and shortnose sturgeon, and paddlefish) is more sensitive to fishing mortality than it is for three other intensively-fished coastal species in North America: striped bass, winter flounder, and bluefish. The sturgeons and paddlefish are generally longer-lived than the three other coastal species, and also have an older age at full maturity, lower maximum fecundity values, and older ages at which 50% of the lifetime egg production is realized with no fishing mortality.     

Mass Spectrometry–Driven Discovery of Neuropeptides Mediating Nictation Behavior of Nematodes

Neuropeptides regulate animal physiology and behavior, making them widely studied targets of functional genetics research. While the field often relies on differential -omics approaches to build hypotheses, no such method exists for neuropeptidomics. It would nonetheless be valuable for studying behaviors suspected to be regulated by neuropeptides, especially when little information is otherwise available. This includes nictation, a phoretic strategy of Caenorhabditis elegans dauers that parallels host-finding strategies of infective juveniles of many pathogenic nematodes. We here developed a targeted peptidomics method for the model organism C. elegans and show that 161 quantified neuropeptides are more abundant in its dauer stage compared with L3 juveniles. Many of these have orthologs in the commercially relevant pathogenic nematode Steinernema carpocapsae, in whose infective juveniles, we identified 126 neuropeptides in total. Through further behavioral genetics experiments, we identify flp-7 and flp-11 as novel regulators of nictation. Our work advances knowledge on the genetics of nictation behavior and adds comparative neuropeptidomics as a tool to functional genetics workflows.     

Leaf economics and hydraulic traits are decoupled in five species‐rich tropical‐subtropical forests

Leaf economics and hydraulic traits are critical to leaf photosynthesis, yet it is debated whether these two sets of traits vary in a fully coordinated manner or there is room for independent variation. Here, we tested the relationship between leaf economics traits, including leaf nitrogen concentration and leaf dry mass per area, and leaf hydraulic traits including stomatal density and vein density in five tropical‐subtropical forests. Surprisingly, these two suites of traits were statistically decoupled. This decoupling suggests that independent trait dimensions exist within a leaf, with leaf economics dimension corresponding to light capture and tissue longevity, and the hydraulic dimension to water‐use and leaf temperature maintenance. Clearly, leaf economics and hydraulic traits can vary independently, thus allowing for more possible plant trait combinations. Compared with a single trait dimension, multiple trait dimensions may better enable species adaptations to multifarious niche dimensions, promote diverse plant strategies and facilitate species coexistence.     

Polymorphisme biochimique chez le faisan commun (Phasianus colchicus)

Egg white proteins, hemoglobin, serum proteins and enzymes from Phasianus colchicus have been examined by starch gel electrophoresis. All three genetic parameters, mean proportion of loci polymorphic per population (P), mean numbers of alleles per locus (A), and mean proportion of loci heterozygous per individual (H), are given. Comparison were made between the proteins of the related species Coturnix coturnix japonica, and the variation of pheasant proteins is discussed in connexion with the genetic structure of the population studied.