Post-Embryonic Development of Larvae of the Weaver Ant Camponotus textor (Hymenoptera: Formicidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Seed deposition patterns and the survival of seeds and seedlings of the palm Euterpe edulis

The seed deposition pattern created by a seed disperser is one of the components of the efficiency of a species as seed disperser, and ultimately may influence the recruitment of a plant species. In this study, we used the seeds of a bird-dispersed forest palm, Euterpe edulis, to investigate the effects of two distinct seed deposition patterns created by birds that defecate (clumped pattern) and regurgitate seeds (loose-clumped pattern) on the survival of seeds experimentally set in an E. edulis-rich site, and of seedlings grown under shade-house conditions. The study was conducted in the lowland forest of Parque Estadual Intervales, SE Brazil. Clumped and loose-clumped seeds were equally preyed upon by rodents and insects. Although clumped and isolated seedlings had the same root weight after 1 year, the isolated seedlings survived better and presented more developed shoots, suggesting intraspecific competition among clumped seedlings. Our results indicate that animals that deposit E. edulis seeds in faecal clumps (e.g. cracids, tapirs) are less efficient seed dispersers than those that regurgitate seeds individually (e.g. trogons, toucans). Intraspecific competition among seedlings growing from faecal clumps is a likely process preventing the occurrence of clumps of adult palms. (C) 2001 Editions scientifiques et medicales Elsevier SAS.

Seed size variation in the palm Euterpe edulis and the effects of seed predators on germination and seedling survival

Intraspecific variation in seed size is common in wild plant populations and has important consequences for the reproductive success of individual plants. Multiple, often conflicting evolutionary forces mediated by biotic as well as abiotic agents may maintain such a variation. In this paper we assessed seed size variation in a population of the threatened, commercially important palm Euterpe edulis in southeast Brazil. We investigated (i) how this variation affects the probability of attack by vertebrate and invertebrate post-dispersal seed predators, and (ii) if seed size influences the outcome of seeds damaged by beetles in terms of seed germination and early survival of seedlings. Euterpe edulis seeds varied in diameter from 8.3 to 14.1 mm. Neither insects nor rodents selected the seeds they preyed upon based on seed size. Seed germination and total, shoot and root biomasses of one-year seedlings were significantly and positively affected by seed size. Root biomass and seedling survival were negatively affected by seed damage caused by a scolytid beetle (Coccotrypes palmarum) whose adults bore into seeds to consume part of the endosperm, but do not oviposit on them. Seed size had a marginally significant effect on seedling survival. Therefore, if any advantage is accrued by E. edulis individuals producing large seeds, this is because of greater seed germination success and seedling vigor. If this is so, even a relatively narrow range of variation in seed size as observed in the E. edulis population studied may translate into differential success of individual plants. (c) 2006 Elsevier SAS. All rights reserved.

Water content and GA(3)-induced embryonic cell expansion explain Euterpe edulis seed germination, rather than seed reserve mobilisation

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Modelling post-release survival of reintroduced Red-billed Curassows Crax blumenbachii

Modelling post-release survival probabilities of reintroduced birds can help inform 'soft-release' strategies for avian reintroductions that use captive-bred individuals. We used post-release radiotelemetry data to estimate the survival probabilities of reintroduced captive-bred Red-billed Curassow Crax blumenbachii, a globally threatened Cracid endemic to the Brazilian Atlantic Rainforest. Between August 2006 and December 2008, 46 radiotagged Curassows from the Crax Brazil breeding centre were reintroduced to the Guapiacu Ecological Reserve (REGUA), Rio de Janeiro state, Brazil, in seven different cohorts. Reintroduced birds were most vulnerable during the first 12 months post-release from natural predation, domestic dogs and hunting. Annual post-release survival probability was high (75%) compared with published estimates for other Galliform species. However, when considering survival in all birds transported to REGUA (some birds died before release or were retained in captivity) and not only post-release survival, phi in this study was closer to estimates for other species (60%). The duration of the pre-release acclimatization period within the soft-release enclosure and the size of the released cohorts both positively influenced post-release survival of reintroduced Curassows. Our results are relevant to future Cracid reintroductions and highlight the importance of utilizing post-release monitoring data for evidence-based improvements to soft-release strategies that can significantly enhance the post-release survival of captive-bred birds.

Polyembryony increases embryo and seedling mortality but also enhances seed individual survival in Handroanthus species (Bignoniaceae)

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Survival probability of large rapidity gaps in a QCD model with a dynamical infrared mass scale

We compute the survival probability {vertical bar S vertical bar(2)} of large rapidity gaps (LRG) in a QCD based eikonal model with a dynamical gluon mass, where this dynamical infrared mass scale represents the onset of nonperturbative contributions to the diffractive hadron-hadron scattering. Since rapidity gaps can occur in the case of Higgs boson production via fusion of electroweak bosons, we focus on WW -> H fusion processes and show that the resulting {vertical bar S vertical bar(2)} decreases with the increase of the energy of the incoming hadrons; in line with the available experimental data for LRG. We obtain {vertical bar S vertical bar(2)} = 27.6 +/- 7.8% (18.2 +/- 17.0%) at Tevatron (CERN-LHC) energy for a dynamical gluon mass m(g) = 400 MeV. (c) 2006 Elsevier B.V. All rights reserved.

Survival of Ucides cordatus (Decapoda: Ocypodidae) megalopae during transport under different conditions of density and duration

Target areas for Ucides cordatus (Linnaeus, 1763) restocking programs are often located far from the laboratory where larval rearing is developed. During translocation, the larvae are submitted to highly stressful conditions due to handling, packing, and transport activities. The aim of the present study was to assess the mortality rates of U. cordatus megalopae caused by different transportation procedures. Megalopae at loading densities of 50, 150, and 300 ind.L-1 were packed in double polyethylene 12 x 25 cm plastic bags with 200 ml of marine water at salinity 30. The bags were filled with oxygen at a proportion of 1:2 parts of water and sealed tightly. The trepidations during transport were simulated by the use of a shaker device (800 vibrations/minute) over periods of three and six hours inside a dark container. The survivorship rates of larvae after simulation were compared to those obtained in control groups, which consisted of plastic vials with megalopae at a loading density of 50 ind.L-1 maintained at rest. Immediately after the two transport simulations, there was no significant difference in survivorship between the treatments and the control. However, 24 hours after simulation some of the tested densities resulted in significantly lower survivorships. The results demonstrated that U. cordatus megalopae can tolerate six hours of shaking during transportation, at high densities with minimal mortality.

Effect of flooding on survival and initial growth of Ocotea pulchella (Nees) Mez. seedlings in semi-controlled light conditions

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Demographic determinants of survival of people living with HIV attending an outpatient reference unit in the city of Três Lagoas, state of Mato Grosso do Sul, Brazil, in the period 1984-2009

,,,,,,,,,, While the incidence of HIV infection and AIDS is increasing in small Brazilian cities, epidemiological studies are often conducted in large urban centers. ,,,,,,,,,,,,,,,,,, Our group conducted a retrospective analysis of survival determinants among 358 patients who attended a reference unit in a small city.,,,,,,,,,,,,,,,,,,,,,,,Death risk was lower among men that had sex with men, patients with an HIV-seropositive partner, and those admitted after highly active antiretroviral therapy (HAART) was available. ,,,,,,,,,,,,,,,,,, The study documents the striking beneficial effect of HAART. The finding of other groups with improved survival may aid in the development of programmatic strategies.,,,,

Fecundity of crab Hepatus-pudibundas (herbst, 1785) (crustacea, decapoda, calappidae) in Ubatuba (SP), Brazil

The egg number and the rate in which they are produced constitute important informations for the comprehension of the reproductive process. The egg number carried by a female crab is related to a body dimension (carapace width or length). These data are adjusted to a linear regression. The specimens of Ii. pudibundus were collected in Ubatuba region, Brazil during the period from January 1991 to July 1993. In this paper 30 females with eggs in the initial embryonic phase were used to estimate ther egg number. The mean fecundity obtained was 75,615 +/- 30,120 eggs/female/spawn. Although the H. pudibundus fecundity was not high, it can be inferred that the larval survival in nature should be large, because it is one of the most abundant crabs in the studied area.

Use of survival analysis as a tool for the genetic improvement of age at first conception in Nellore cattle

Restricted breeding seasons in beef cattle lead to censoring of reproductive data. In this paper, age at first conception (AFC) of Nellore females exposed to the sires for the first time between 11 and 16 months of age, was studied aiming to verify the possibility of genetically advance sexual precocity using a survival model. The final data set contained 6699 records of AFC in days. Records of females that did not calve in the next year following exposure to the sire were considered censored (77.5% of total). The model used was a Weibull mixed survival model including effects of contemporary groups, period (fixed) and animal (random). The effect of the contemporary groups on AFC was important (p < 0.01). Heritabilities were 0.51 and 0.76 in logarithmic and original scales respectively. Results indicate that it is possible to genetically advance sexual precocity, using the outcome of survival analysis of AFC as selection criterion. They also suggest that improvements of the environment could advance sexual precocity too, thus an adequate pregnancy rate for farmers could quickly be achieved.