Fishers' knowledge and seahorse conservation in Brazil

From a conservationist perspective, seahorses are threatened fishes. Concomitantly, from a socioeconomic perspective, they represent a source of income to many fishing communities in developing countries. An integration between these two views requires, among other things, the recognition that seahorse fishers have knowledge and abilities that can assist the implementation of conservation strategies and of management plans for seahorses and their habitats. This paper documents the knowledge held by Brazilian fishers on the biology and ecology of the longsnout seahorse Hippocampus reidi. Its aims were to explore collaborative approaches to seahorse conservation and management in Brazil; to assess fishers' perception of seahorse biology and ecology, in the context evaluating potential management options; to increase fishers' involvement with seahorse conservation in Brazil. Data were obtained through questionnaires and interviews made during field surveys conducted in fishing villages located in the States of Piauí, Ceará, Paraíba, Maranhão, Pernambuco and Pará. We consider the following aspects as positive for the conservation of seahorses and their habitats in Brazil: fishers were willing to dialogue with researchers; although captures and/or trade of brooding seahorses occurred, most interviewees recognized the importance of reproduction to the maintenance of seahorses in the wild (and therefore of their source of income), and expressed concern over population declines; fishers associated the presence of a ventral pouch with reproduction in seahorses (regardless of them knowing which sex bears the pouch), and this may facilitate the construction of collaborative management options designed to eliminate captures of brooding specimens; fishers recognized microhabitats of importance to the maintenance of seahorse wild populations; fishers who kept seahorses in captivity tended to recognize the condtions as poor, and as being a cause of seahorse mortality.     

Genetic structure of two Plusiinae species suggests recent expansion of Chrysodeixis includens in the American continent

1. The Plusiinae subfamily has many polyphagous species, many of which occur in South America. Chrysodeixis includens and Rachiplusia nu are two representatives that mainly occurs in soybeans, cotton, common beans, sunflower and alfalfa.
2. A population genetic study of C. includens and R. nu collected in the Southern Cone of America was performed using a partial COI gene sequencing data and compared with specimens from other American countries.
3. Six haplotypes were identified in C. includens populations of Brazil, Argentina, Paraguay and Uruguay, organized within a star-like haplotype network, with the most common haplotype identified as Chin_MC.
4. R. nu populations are more diverse and stable in comparison to C. includens. Populations from Argentina and Uruguay had the highest haplotype diversity, sharing five haplotypes and putatively indicating haplotype exchange.
5. Demographic change analysis suggested a recent population expansion of C. includens over the American continent.
6. Some C. includens haplotypes were country-specific, suggesting population expansion in the countries where specimens were collected.

     

Leaf nutrient content and host plant selection by leaf-cutter ants, Atta laevigata, in a Neotropical savanna

The selection of nutrient-rich leaves by leaf-cutter ants ( Atta spp.) is thought to be of indirect benefit to these ants by promoting the growth of their symbiotic fungus. However, relatively few studies have analyzed the influence of leaf nutrient content on host plant selection by leaf-cutter ants, and conflicting results have been found. We compared the content of eight nutritional elements plus the non-nutrient aluminum between leaves harvested by colonies of Atta laevigata (Smith) (Hymenoptera: Formicidae: Attini) and leaves collected randomly within their foraging areas. In addition, we evaluated whether leaf nutrient content explained the frequency with which these ants attacked and defoliated some of the tree species found in the study area. For 2 years, we monitored 17–26 trees from 15 species and determined the number of times each plant was attacked and the amount and type of foliage removed. Leaves harvested by A. laevigata presented significantly higher concentrations of N, P, K, Zn, and Cu than those collected randomly. This result is likely to reflect the foraging pattern presented by these ants, which were selective both in terms of the plant species and age of leaves most commonly attacked. Young leaves were the only or the main leaf type exploited in many species, and in comparison to mature leaves these presented significantly higher concentrations of P and K. Large differences in the mean number of ant attacks on the tree species studied were also observed, and those presenting more leaf N tended to be the most frequently attacked.     

Isolation of intact spinach chloroplasts in the CF-6 continuous-flow zonal rotor; implications for membrane-bound organelles

Intact chloroplasts were separated from large volumes of spinach brei by continuous-flow zonal centrifugation in the CF-6 rotor in gradients of colloidal silica. Tests with the Z-15/Mark 10 rotor showed that the external membranes of chloroplasts were sensitive to high rotor speeds and especially to the bore of the fluid seal. Enlargement of the CF-6 seal channel diameter to 4 mm resulted in almost complete recovery of the intact chloroplasts.     

Euploidy in Ricinus. I. Euploidy and gene dosage effects on cellular proteins

Investigation of an euploid series of castor bean, Ricinus communis L., consisting of haploid, diploid, and tetraploid individuals, was performed to determine the value of such a series in studying the biochemical consequences of genome multiplication. The effects of euploidization of the nuclear genome on the biosynthesis of cellular proteins were examined. Extracts of total soluble proteins from 10-day-old leaves of all three ploidy levels examined by electrophoresis on polyacrylamide gels revealed no difference in the complement of proteins present; however, differences in intensity of several protein bands were detected. Analysis of esterase isozyme activity by isoelectric focusing revealed both increases and decreases in the activity levels of individual isozyme variants in response to changes in ploidy levels. Results from this analysis are discussed in terms of possible regulatory mechanisms active in the regulation of duplicated genes.