Orientation of the snail Biomphalaria straminea (Dunker, 1848) in response to light in a situation of selection

Abstract

The behavioral response of Biomphalaria straminea to light was evaluated in terms of location of the snail in a Y-shaped aquarium in a situation of selection and of the rate (cm/hour) and direction of locomotion under homogeneous (vertical) or differential (horizontal) lighting upon only one arm of the aquarium. The light source consisted of daylight fluorescent lamps with a spectrum close to that of natural light, with illumination varying from 2.8 to 350 lux. Analysis of the data showed that all animals, whether in groups or isolated, were attracted to light, although the time needed to approach the light source was 50% shorter for the former than for the latter. The rate of locomotion of B. straminea was 35% higher than that observed in B. glabrata and 51% higher than that observed in B. tenagophila studied under similar conditions. The results are discussed in terms of social factors and geographical distribution of the three species.

Use of a colorimetric (DELI) test for the evaluation of chemoresistance of Plasmodium falciparum and Plasmodium vivax to commonly used anti-plasmodial drugs in the Brazilian Amazon

“…In fact, even before the official introduction of mefloquine in Brazilian endemic areas in 1987, P. falciparum isolates with profile of resistance to mefloquine had already been reported [24]. …”

“…Some isolates showed IC50s very close to the threshold. In any case, this scenario is worrisome because a continuous decreasing in parasite sensitivity has been noted in the Brazilian Amazon [17,21,24-27] and quinine plus doxycycline is actually recommended as P. falciparum second-line treatment by the Brazilian Malaria Control Programme.…”

Tópicos em Malacologia Médica

“…As observações de Guyard & Pointier (1982), sobre a substituição de B. glabrata por B. straminea, em Martinica, e as de Woodruff et al (1985), sobre a introdução e expansão desta última espécie na China e na Austrália, confirmam a capacidade deste molusco em ocupar os mais diversos ambientes. Essa capacidade invasora estaria associada às características específicas, tais como: vagilidade e agressividade (Michelson & Dubois, 1979;; resistência à dessecação (Oliver & Barbosa, 1956;Barbosa et al, 1985); alta taxa de locomoção e poder de exploração do ambiente (Schall et al, 1986). Acrescenta-se a estes atributos a maior capacidade de sustentação (Carrying capacity) de B. straminea em comparação a B. glabrata (Barbosa et al, 1992).…”

“…Outros exemplos sobre quantificação da velocidade em caramujos, em diferentes situações experimentais, poderão ser encontrados em Pimentel & White (1959); Simpson et al (1973); Sodeman (1973); Pieri et al (1980a); Schall et al (1985;1986a;1986b).…”

“…rígido. O braço central, onde eram colocados os caramujos, tinha 50cm de extensão e os braços laterais, onde podia se colocar alternadamente a fonte luminosa, 70cm de extensão (Figura 4) (Schall et al, 1985(Schall et al, , 1986a(Schall et al, , 1986b. Outros experimentos foram feitos por Sodeman (1973) em uma caixa de atividade, de maneira a estudar a velocidade de B. glabrata em relação à intensidade luminosa.…”