How protein quality drives incorporation rates and trophic discrimination of carbon and nitrogen stable isotope ratios in a freshwater first-feeding fish

1. Using stable isotope ratios to explore the trophic ecology of freshwater animals requires knowledge about effects of food quality on isotopic incorporation dynamics. The aim of this experimental study was to: (1) estimate carbon and nitrogen isotopic incorporation rates and trophic discrimination factors (TDFs) of a freshwater first-feeding fish (i.e. salmonid fry) fed three diets that differed only in protein quality (animal or plant or a blend of both); (2) investigate effects of fasting and; (3) evaluate the proportion of each source assimilated when fry were fed a 50:50 animal:plant-based diet.
2. For each diet, incorporation rates of δ¹³C and δ¹⁵N values were estimated using a time or growth-dependent isotopic incorporation model. Effects of fasting on isotope ratio values were measured regularly until the death of fry. Bayesian stable-isotope mixing models were used to estimate the contribution of animal and plant material to fish fed a blend of both food types.
3. Our results show that incorporation rates were lower for fry fed a plant-based diet than for those fed an animal-based diet as growth rate decreased. Time- and growth-dependent models indicated that growth was solely responsible for isotopic incorporation in fry fed an animal-based diet, whereas catabolism increased in fry fed a plant-based diet. After lipid extraction, carbon TDFs were similar regardless of the diet, whereas nitrogen TDFs increased for fry fed a plant-based diet. Long-term fasting induced an increase of 0.63‰ in δ¹³C values of fry in 23 days, whereas δ¹⁵N values did not vary significantly. Proportions of food sources assimilated by fry fed an animal:plant-based diet were similar to those consumed when using a mixing model with the estimated TDFs, while proportions were unrealistic when using mean TDFs extrapolated from the literature.
4. The results of our study indicate that the quality of food must be considered to use an appropriate timescale to detect changes in fry diets in the field. Moreover, we recommend using different carbon and nitrogen TDFs, one for animal-derived sources and one for plant-derived sources, to increase the accuracy of mixing models.

     

Isolation and characterization of polymorphic microsatellite markers in the grasshopper <Emphasis Type="Italic">Mioscirtus wagneri</Emphasis> (Orthoptera: Acrididae)

Eight polymorphic microsatellite markers were developed for the grasshopper Mioscirtus wagneri. Polymorphism at these loci was evaluated in 25 individuals from Central Spain. The number of alleles per locus ranged from 3 to 9 and their observed and expected heterozygosities ranged from 0.28 to 0.80 and 0.25 to 0.84, respectively. All genotypic frequencies conformed to Hardy–Weinberg equilibrium expectations, with no evidence of genotypic linkage disequilibrium between any pair of loci. These loci will be highly useful for the study of the population genetic structure and diversity of this grasshopper species forming highly fragmented populations of great conservation concern.     

Red cell glyoxalase I polymorphism in Basque and Castilian populations

In samples of Arratia and Gernika populations, who are indigenous Basque ethnic groups, the frequency of the GLOI1 allele was respectively 0.457 +/- 0.042 and 0.459 +/- 0.041. Four samples belonging to Castilian populations were also studied. The results of this work suggested homogeneity between the Spanish and other populations.     

Screening known Cerambycidae pheromones for activity with the Peruvian fauna

1. Semiochemicals are powerful tools for the surveillance and suppression of forest insects. Although the literature on the chemical ecology of and use of semiochemicals to manage the Cerambycidae is growing, little is known about the chemical ecology of Cerambycidae fauna in Peru.
2. Trapping studies that screen known attractants in off-shore mitigation programs can provide valuable baseline knowledge to inform management of species introduced outside their native range.
3. Known Cerambycidae pheromones were screened for activity in a year-long field study in Peru to look for activity in the local Cerambycidae fauna.
4. The most frequently captured species were Megacyllene andesiana (Casey), Oreodera bituberculata Bates, Aegomorphus longitarsis (Bates) and Discopus eques Bates.
5. The activity period of A. longitarsis, O. bituberculata and D. eques occurred in mid-September 2020 and for M. andesiana occurred in early October 2020.
6. Responses to anti-2,3-hexanediol, fuscumol and fuscumol acetate by M. andesiana, O. bituberculata and D. eques were observed.
7. We observed antagonism of the responses of M. andesiana, O. bituberculata and D. eques when anti-2,3-hexanediol, fuscumol and fuscumol acetate were tested in blends.

     

Lessons from the Ebola Outbreak: Action Items for Emerging Infectious Disease Preparedness and Response

EcoHealth - As the Ebola outbreak in West Africa wanes, it is time for the international scientific community to reflect on how to improve the detection of and coordinated response to future...     

Globicatella sanguis gen.nov., sp.nov., a new Gram-positive catalase-negative bacterium from human sources

Phylogenetic studies were performed on some Gram-positive catalase-negative cocci from human clinical sources of uncertain taxonomic position. 16S rRNA sequence analysis demonstrated that the isolates represent a hitherto unknown line of descent within the low G + C Gram-positive bacteria for which the name Globicatella sanguis gen.nov., sp.nov. is proposed.     

Poor fossil record and major changes around 1 MaBP

The abundance of early fossil humans in African sites ceases at dates around 1.3MaBP; there is almost none until nearly 0.8MaBP. Again these are scarce until less than 0.5 Ma. Most of Homo erectus fossils in Java are dated between c.1.3 and 0.70Ma; just a few fossil humans are known in Eurasia for this time span. Questions arise on eventual environmental constraints, that may have influenced evolutionary crises of human populations, but also on geographic conditions adverse to fossilization processes and/or site formation. Records on climate variables, vegetation, sea level, sedimentary conditions and tectonic behavior in regions of the Old World are collected, and correlation traced back in time slices. Continental accretion is related to end of sedimentation in African basins; repeated compressive tectonic activity negatively affected preservation of both fossils and occupation sites widely, before and immediately after the M/B reversal. Lithic artefact assemblages, although derived, are understood as evidence of human occupation in the studied interval. Human populations are exspected to be affected by environmental changes, small, and scattered. Origin of Homo sapeins and divergence of preneandertalians are driven back to those times. Ancestorship to the latter is found probably in African fossils of that time span. Modern traits found in the Atapuerca-TD6 sample and the preceeding considerations urge research on humans and their movements intra- and intercontinental around 1 MaBP.