Fish Migration, Dams, and Loss of Ecosystem Services in the Mekong Basin

The past decade has seen increased international recognition of the importance of the services provided by natural ecosystems. It is unclear however whether such international awareness will lead to improved environmental management in many regions. We explore this issue by examining the specific case of fish migration and dams on the Mekong river. We determine that dams on the Mekong mainstem and major tributaries will have a major impact on the basin's fisheries and the people who depend upon them for food and income. We find no evidence that current moves towards dam construction will stop, and consider two scenarios for the future of the fisheries and other ecosystems of the basin. We conclude that major investment is required in innovative technology to reduce the loss of ecosystem services, and alternative livelihood strategies to cope with the losses that do occur.

Positioning and localization of two-wavelength interferograms for wavefront reconstruction with volume holographic media

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Ultramorphology and histology of dorsal vessel - Gastral portion - Of Camponotus rufipes

The dorsal diaphragm of Camponotus rufipes (Hymenoptera: Formicidae) is a thin membrane structure, with free edges between the points of attachment to the body wall that almost cover the whole extension of the dorsal vessel at its abdominal portion. A layer of fat body cells covers the region of the cuticle above the dorsal vessel and the incurrent ostia can be a vertical or horizontal slit in the wall of the heart. One organized structure as a network ofalary muscles was observed holding the heart at its middorsal position and supporting the pericardial cells too. A great number of pericardial cells were found laterally associated with the heart and cellular projections from those cells insert directly into the heart wall.

Chemical analysis of different larval instars and tissues of Pachycondyla (=Neoponera) villosa (Hymenoptera: Formicidae, Ponerinae)

Chemical analyses of complete larvae of the first to third instar and cuticle, fat body and salivary glands extracts of fourth instar larvae using gas chromatography and gas chromatography-mass spectrometry, were performed upon Pachycondyla villosa. The results revealed that P. villosa larvae do not produce a pheromone, as only fatty acids and n-alkanes were detected. After quantifying the identified compounds, it was determined that the fat body is the main place of storage and/or production of the cuticular hydrocarbons. It was also observed that the absolute quantity of cuticular hydrocarbons increases progressively during larval development. Inferences about the transport behavior of matured larvae to the pupation place and the colony odor are discussed.

Enzymatic activity of the hypopharyngeal gland extract from workers and males of Scaptotrigona postica Lat. (Hymenoptera, Apidae, Meliponini)

The objective of this research was to contribute to elucidation of the function of the hypopharyngeal glands of S. postica in enzyme production, using the Api Zym kit (Bio Mérieux). Dealing with a comparative analysis between the enzymatic content of the hypopharyngeal gland extracts from newly emerged, nurse and forager workers, as well as, newly emerged males and males mature for mating of S. postica. The hypopharyngeal glands from nurse workers of Apis mellifera, that produce part of the royal jelly, were used for comparison. While in A. mellifera, the hypopharyngeal glands are present only in workers, in S. postica, the hypopharyngeal glands are present and functioning in all adult individuals of the colony. The higher enzymatic activity was observed in the hypopharyngeal gland extracts from nurse workers and may be related to a larger demand for energy, compared to other individuals. The occurrence of large quantities of leucine arylamidase in all individuals may mean that protein processing is happening.

Estimates of Foraging Population and Territory of Heterotermes tenuis Colonies using Mark-Release-Recapture (Isoptera: Rhinotermitidae)

Heterotermes tenuis is an important economic pest in São Paulo state. Foraging populations of three field colonies of H. tenuis located on a University campus (UNESP, Rio Claro, SP, Brazil) were characterized. Foraging populations of H. tenuis colonies were calculated using four cycles of a mark-release-recapture program with a weighted mean method. The foraging population sizes of three colonies: A, B and C were 389,313±14,907; 265,589 ±12,635; and 641,600∓12,127; respectively. Foraging biomasses were 0.77 kg in the colony A, 0.51 kg in the colony B and 1.17 kg in colony C. Mean worker biomass was approximately 1.9 mg. Foraging territories occupied an area ranging from 70 m2 to 131 m2 per colony. The maximum linear foraging distance traveled by H. tenuis was 28m.

Non-Specific Interaction between Ants (Hymenoptera; Formicidae) and Fruits of Syagrus romanzoffiana (Arecaceae) in an Area of the Brazilian Atlantic Forest

On the forest floor of a fragment of the Atlantic Forest which is considered to be in a stage of recuperation, located in southeastern Brazil, we recorded 54 species of ants interacting with the fruits of Syagrus romanzoffiana (Arecaceae). Myrmicinae was the subfamily which was the richest in species, followed by Ponerinae, Formicinae, Ecitoninae, Dolichoderinae, Pseudomyrmecinae and Cerapachyinae. The fruits of S. romanzoffiana can be classified according to whether or not they are preyed by the squirrel Sciurus ingrami, and the ant fauna that visits the fruits has an average similarity. Regarding diversity, the data suggest that there is no significant difference between ant assemblages at preyed and non-preyed-upon fruit falls. The results also indicate that there is no specific interaction between the ant fauna that visits the fruits of S. romanzoffiana, as it consists largely of species with omnivorous feeding habits.

Temporal polyethism and survivorship of workers of Agelaia pallipes (Hymenoptera, Vespidae, Epiponini)

In this study, known-age workers of Agelaia pallipes (Olivier) were introduced into a colony maintained in the laboratory and the effects of age polyethism on the worker life span were observed. As in other Neotropical swarm-founding wasps, the results showed that younger workers remained on different places inside the nest performing activities related to the brood and nest maintenance, while risky tasks such as foraging were performed by older workers. Furthermore, the start of foraging activities had a significant effect on worker mortality.

Interference of epicuticular wax from leaves of grasses in selection and preparation of substrate for cultivation of symbiont fungus by Atta capiguara (Hym. Formicidae)

The selection of plants is one of the stages of foraging behavior, executed by leaf-cutting ants for the cultivation of symbiont fungus. Anatomical, biochemical and physiological characteristics of vegetal species are some of the factors that influence selection of substrate; however, most studies described in the literature refer to leaf-cutting ants. Due to the scarcity of studies on the role of epicuticular waxes of grasses in relation to foraging behavior of monocotyledonous leaf-cutters, we completed three experiments with the ant species Atta capiguara in which we analyzed: the attractiveness or selectivity of leaves of Saccharum officinarum (sugarcane) and/or Hypharrenia rufa (capim jaraguá), with and without epicuticular wax in relation to the worker of this ant species, their processing and elimination in the form of pellets of epicuticular wax from the referred fragments removed by the workers for cultivation of symbiont fungus. We observed that vegetal fragments without wax were those most transported by workers to the inside of the nests; that they processed the fragments equally with as much as without wax, and eliminated, in the form of pellets, wax removed from the same into garbage chambers of the colonies, leading us to conclude that for monocotyledonous leaf-cutters, epicuticular wax from vegetal leaves has great importance in vegetal integrity by being used as substrate, representing a physical barrier to the growth of symbiont fungus.

Ultramorphology and histology of the venom gland of workers of Apis mellifera (Hymenoptera, Apidae) before and after an electrical shock treatment

This paper describes the ultramorphology and histology of the venom reservoir in 14-day old workers of Apis mellifera, immediately before and after the application of electrical shocks with the object of causing venom elimination and reservoir collapse. The external epithelial surface of the reservoir was differentiated according to its morphological aspects into posterior, median, and proximal or duct regions at the ventral surface and into anterior and posterior regions at the dorsal surface. While the epithelium of the proximal region forms a ventral infolding, a dorsal salience is formed at this region. These structures and the epithelial regions persist both in full and empty reservoirs. The reservoir appeared full and distended before the electrical shocks were applied and became empty and withered afterwards due to the elimination of the secretion, without any reductions in length. Nevertheless, some secretion was kept inside the lumen, thus suggesting a possible role for the reservoir in the modification of the secretion.

Bionomics and identification of Acromyrmex (Hymenoptera: Formicidae) through an illustrated key

This study is based on sampled data obtained in 60 equally distant municipalities of São Paulo State. In this study, we proposed a tool to identify Acromyrmex species in a practical and agile manner through the use of an illustrated key that demonstrates the morphological attributes of workers, associated with the type of cut plant material, external and internal appearance of nests and nidification sites. Through sampling, eleven species and six subspecies of Acromyrmex occurring in the State were identified, including the first registers of A. diasi and A. subterraneus molestans.

Description and morphometry of the sting apparatus in the three worker casts of Acromyrmex subterraneus brunneus (Formicidae, Attini)

We studied the morphometry of the sting apparatus of Acromyrmex subterraneus brunneus workers by dissection and mounting of the structures on slides, and present here a brief description and illustrations. Sting apparatus examinations showed differences in size, but without morphological differences. The seven morphometric variables studied permitted grouping of the Ac. subterraneus brunneus workers into the following three groups: cluster 1 - consisting of 85, 39 large, 45 medium and 1 small workers; cluster 2 - consisting of 44 small workers, and cluster 3 - consisting of 6 large workers. This study demonstrated that all worker castes follow the same morphological pattern, although functional characteristics of the sting apparatus should be highlighted.

Isolation and growth of the symbiotic fungus of Atta capiguara (Hymenoptera: Formicidae)

This work's objectives were to isolate and evaluate the growth of the symbiotic fungus of Atta capiguara Gonçalves on artificial medium, under different pH and temperature conditions. Isolation was accomplished using the following media: Sabouraud, oat-agar, PDA, and PDA with the addition of extracts from the grasses Paspalum sp. Flügge and Hyparrhenia rufa (Nees) Stapf.. The medium used in the growth study was PDA with the addition of a Paspalum sp. (0.22%, w/v) extract at initial pH values of 4.5, 6.0, and 7.5. Mycelium disks were transferred to plates containing the culture medium. The plates were maintained at temperatures of 20, 23, and 26 ± 1°C. Mycelial radial growth evaluations were performed at 7, 14, 21, 28, and 35 days of incubation. Fungus isolation was obtained in all media studied. The highest radial means were obtained at initial pH values of 6.0 and 7.5 and temperatures of 23 and 26± 1°C. Greater plot losses occurred at the initial pH condition of 7.5. In general, A. capiguara fungi can be grown in the medium studied, at an initial pH of 6.0 and temperatures of 23 or 26± 1°C. Radial growth evaluations at 14 and 28 days of incubation can be recommended for substrate studies involving the symbiotic fungus.