Autochthonous probiotic as growth promoter and immunomodulator for Astyanax bimaculatus cultured in water recirculation system

This work aimed to evaluate the probiotic Lactobacillus spp. in the microbiota of Astyanax bimaculatus reared in a water recirculation system. The experiment was randomized, using 800 postlarvae distributed into eight polyethylene containers, separated into two treatments, in quadruplicate: supplementation with Lactobacillus spp. (Probiotic) and no supplementation (Control). After 90 days of culture, 13 fish per container were anaesthetized. Three of these underwent microbiological evaluation, and haematological analyses were carried out on five. Immunological assessment was performed on another five fish. Zootechnical parameters were evaluated for all animals. In the microbiological evaluation, the probiotic group presented higher counts of lactic acid bacteria, but lower counts of Vibrio spp., Pseudomonas spp., and Staphylococcus spp., when compared with control. After haematological analysis, the supplemented group presented low haematimetric indices of Mean Corpuscular Haemoglobin Concentration and Mean Corpuscular Haemoglobin (MCHC and MCH, respectively) and higher amounts of total leucocytes, thrombocytes and circulating monocytes when compared with control. The immunological profile did not differ between treatments. In the zootechnical performance, probiotic group presented higher productivity, survival and apparent food efficiency when compared with control. Therefore, when Lactobacillus spp. was supplemented in the diet of A. bimaculatus, immunocompetence and the zootechnical performance of animals increased.     

Understanding the relationship between volunteers’ motivations and learning outcomes of Citizen Science in rice ecosystems in the Northern Philippines

This study relies on the Flying Beauties Citizen Science project conducted in the Philippines to assess personal motivations and learning outcomes of volunteers who were involved in documenting butterflies and dragonflies in rice ecosystems. While evaluation of motivations of volunteers in Citizen Science is not new, at least in affluent western countries, little is done in investigating volunteers’ motivations and learning outcomes of Citizen Science projects in low-income countries. Using surveys, we collected data from volunteers that were analysed qualitatively and quantitatively. We adopted a two stages evaluation format—before and after volunteers finished the project exercise. We compared pre-motivations to motivations attained and changes in level of knowledge before and after the project ended. We use Spearman’s Rho, Kendall’s Tau—nonparametric tests to draw correlations between variables. The results showed that key determinants that drove people to volunteer in the project were (a) learning about species and (b) being part of scientific research and the principal learning outcome was improved awareness about ecosystem functions of the species.     

Masculinization of the Native Bay Snook,Petenia splendida,Using Oral Administration of the Synthetic Steroid 17α‐methyltestosterone

The possibility of inducing sex reversal in bay snook, Petenia splendida, was evaluated to generate a protocol aimed at producing single‐sex populations (100% males) and improving farming conditions for this species. This popular staple food is a cichlid fish native to Central America, with aquaculture potential. We evaluated oral administration of the synthetic steroid 17α‐methyltestosterone (MT) to determine optimal dosage (30, 45, and 60 mg/kg of food) and days of feeding (30, 45, and 60) to attain efficient masculinization. The statistical analysis indicates a highly significant effect of both factors as well as for the interaction (P < 0.01). We registered significant differences in growth at the end of the experiment; fish fed with 60 mg of MT for 60 d reached the largest size, while fish fed with no MT were smaller. No significant differences were observed for survival (P > 0.05), ranging from 55.7 to 75.3% in the treatments. We recommend the use of 60 mg/kg of MT for 30 d for achieving successful sex reversal. This study provides valuable information supporting the inclusion of new species in aquaculture, reducing time and costs associated with sex reversal previously proposed for the species.     

Unusual Microstructure and Mechanical Properties of Egg Case of the Bolas Spider <Emphasis Type="Italic">Mastophora corpulenta</Emphasis> Banks (Araneae,Araneidae)

Bolas spiders of the genus Mastophora are very uncommon orb-weaver spiders, famous for their unusual predatory behavior. Being strictly nocturnal and very cryptic, they are extremely difficult to reveal, which explains their rarity in world arachnological collections. After a recent finding of an adult female of Mastophora corpulenta Banks (one of especially rare representatives of the genus), a few egg cases of this species became available, which seem to be very different from those of more common spiders due to their unusual hardness and coloration. We characterized some spectral, structural, and mechanical properties of this unusual silk material, by using Fourier-transform infrared spectroscopy, scanning electron microscopy (SEM), 3D profilometer imaging, and atomic force microscopy (AFM). For comparison, similar studies were performed for egg cases of the Southern black widow Latrodectus mactans Fabricius, since spiders of the genus Latrodectus are known to produce silk fibers of comparable toughness. Some similarities were observed between the silks produced by Mastophora corpulenta and Latrodectus mactans in terms of the size and chemical composition of egg cases. At the same time, SEM imaging and AFM force characterization revealed striking differences between them, due to the fact that Mastophora egg cases, unlike those produced by more common Araneae species, includes a solid (fused) wall, lacking evident porous structure, which results in their outstanding stiffness and strength.     

Interacting effects of soil degradation and precipitation on plant productivity in NE Patagonia,Argentina

Our objective was to examine the effects of inter-annual variation of precipitation on productivity of two dominant species (Chuquiraga avellanedae, an evergreen shrub, and Nassella tenuis, a perennial grass) in two communities of contrasting soil degradation: a herbaceous steppe with shrubs (HSS) and a degraded shrub steppe (SS). Data were collected during two consecutive years with different annual precipitation. Aboveground productivity was determined nondestructively using a double sampling approach. The number of inflorescences per plant was recorded too. Perennial grass productivity was lower in SS than in HSS in both years, while shrub productivity was lower in SS only during the year of below average precipitation. With rising precipitation the perennial grass increased the number of inflorescences while the evergreen shrub augmented vegetative biomass. In summary, the effects of precipitation on plant productivity are community dependent; abiotic factors, such as superficial and sub-superficial soil characteristics, and biotic factors, such as leaf area index (LAI) or tussock sizes, may interact to influence the responses of species to precipitation. Our results suggest that if precipitation increased, this would favor the dominance of shrubs over grasses.     

墨西哥锡那罗亚引种麻竹:应对气候变化的粮食安全战略

墨西哥锡那罗亚是拉丁美洲最重要的粮食生产区。2009年以来,霜冻和大风不断袭击该区,造成作物减产25%,损毁作物17万hm²,每年损失粮食折合5亿美元。在锡那罗亚州,引种麻竹作为一种主要的经济作物,可以弥补因气候变化导致的粮食损失,并可为墨西哥西北部地区增加17万hm²的竹林。麻竹鲜笋亦可销往墨西哥其他地区、美国南部和中美洲各国。文章旨在阐述当前气候变化背景下竹子资源为人类带来巨大效益的潜力,并可进行商业性生产。在中国的大力帮助下,在墨西哥设计建立了一个竹子商业性生产的试验项目,以此说明竹子在提高人们生活质量方面的潜力。总之,竹子及其相关产业的社会经济价值会极大地影响墨西哥锡那罗亚人们的生活方式。