ArticlePDF Available

SOME ECOLOGICAL ASPECTS OF THE FRESHWATER MOLLUSCAN FAUNA OF PANTANOS DE VILLA, LIMA, PERU

Authors:
Ronald Vivar
Ronald Vivar
Ronald Vivar
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Hemani Larrea
Hemani Larrea
Hemani Larrea
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Pedro Huaman
Pedro Huaman
Pedro Huaman
  • This person is not on ResearchGate, or hasn't claimed this research yet.
Mary Yong Cong at Florida Department of Agriculture and Consumer Services
Mary Yong Cong
Show all 5 authorsHide
Download full-text PDF
Read full-text
Download citation

Abstract and Figures

Some ecological aspects such as water quality, aquatic vegetation and associated fauna present at different areas of Pantanos de Villa in Peru were recorded and analyzed in order to assess their influence on the mollusks present in this locality. It was observed that the greatest diversity of snails occurred in the main drainage canal where the chloride concentration attained its lowest value. In the main pond, as well as on the different areas studied, the only snail present was Heleobia cumingii and empty shells of Physa venustula. All the variables (biotic and abiotic) considered were analyzed by means of a principal components analysis. It was found that the densities of mollusks were strongly afflicted by chloride. Only Heleobia cumingii was able to inhabit the areas with a high concentration of this ion. The depth also exerts a negative influence over the snail abundance and in a lesser extent the total hardness and the distance from the shore.
Figures - uploaded by Mary Yong Cong
Author content
All figure content in this area was uploaded by Mary Yong Cong
Content may be subject to copyright.
Content uploaded by Mary Yong Cong
Author content
All content in this area was uploaded by Mary Yong Cong on Feb 16, 2016
Content may be subject to copyright.
(65)
Malacological Review, 1996, 29: 65-68
SOME ECOLOGICAL ASPECTS OF THE FRESHWATER MOLLUSCAN FAUNA OF
PANTANOS DE VILLA, LIMA, PERU
Ronald Vivar, Hemani Larrea, Pedro Huaman, Mary Yong and Gloria Perera
ABSTRACT
Some ecological aspects such as water quality, aquatic vegetation and associated fauna present at
different areas of Pantanos de Villa in Peru were recorded and analyzed in order to assess their influence on the
mollusks present in this locality. It was observed that the greatest diversity of snails occurred in the main
drainage canal where the chloride concentration attained its lowest value. In the main pond, as well as on the
different areas studied, the only snail present was Heleobia cumingii and empty shells of Physa venustula. All
the variables (biotic and abiotic) considered were analyzed by means of a principal components analysis. It was
found that the densities of mollusks were strongly afflicted by chloride. Only Heleobia cumingii was able to
inhabit the areas with a high concentration of this ion. The depth also exerts a negative influence over the snail
abundance and in a lesser extent the total hardness and the distance from the shore.
Key Words: ecology, freshwater snails, Pantanos de Villa, Peru.
INTRODUCTION
The ecology of freshwater snails in Peru has not received the attention it deserves, although most snails act
as intermediate hosts of parasitic diseases that afflict man and wild and domestic animals. There are not many
ecological studies of medically important snail hosts under natural conditions, even though such studies are very
important in order to design the appropriate control programs for the snails.
Pantanos de Villa, located to the south of Lima, the capital of Peru, is considered a natural park and has
become a protected area since it harbours a great number of aquatic birds that find refuge in this locality. Little by
little this area is becoming a tourist attraction, and among the snails present in the area there are some that can act as
intermediate hosts of parasites.
Previous studies on the molluscan fauna of Pantanos de Villa (Arrarte, 1953), recorded eight species of
snails: Physa venustula (Gould), Aplexa peruviana (Cnay), Littoridina cumingii (Orbigny) [= Heleobia cumingiil,
Lymnaea cubensis (Pfeiffer), Ancylus concentricus (Orbigny), Drepanotrema kermatoides (Orbigny), Helisoma
peruvianum, (Broderip) and Helisoma trivolvis (Say). Later, Larrea et al. (1990) added two species to the list:
Helisoma duryi (Wetherby) and Melanoides tuberculata (Muller).
The present study is the first attempt to describe the ecological aspects of the aquatic molluscan fauna of this
area.
HABITAT, MATERIALS AND METHODS
Five stations were selected for the survey of this swampy area and they cover all the biotopes present in it.
Two drainage canals limit the study area (Paradero 11 and Cruce canal), which also include the main pond (Antena)
and several temporary ones (Juncal and Totoral). The aquatic vegetation vanes in each micro-habitat and is mainly
composed of Lemna sp., Pithophora sp. and Miriophyllum sp. in the canals, while the ponds harbour a dense
concentration of Typha dominguensis (Persoon) Kunth and Sporobolum virginicus (Linnaeus) Kunth. The main pond
is characterized by the presence of gramineans on its border as well as in patches in the shallow areas. The associated
fauna present in the drainage canals include several members of the families Chironomidae, Bellostomatidae [with a
high density of Bellostoma boscii (Lepeletier & Servile)J, ostracods and the fishes Xyphophorus maculatus Gunther
and Poecilia reticulata (Peters). The insect and fish fauna of the rest of the stations was very scarce and the
composition was similar. Six ecological features were recorded in the five microhabitats studied: pH, total hardness,
carbonates and chloride concentration, depth, and distance from the shore where the mollusks were collected. The
snails were sampled with a sieve in a 15-minute unit of time using the same methodology as described by Pointier
(1982). All the biotic and abiotic variables were analyzed by means of a principal components analysis (PCA) in
order to determine their relationship and the influence on the snails.
(66)
FIG. 1. Fluctuations of the most variable abiotic factors in the stations
sampled and variation of the abundance of Heleobia cumingii, between the stations.
Total hardness (t.h.), chlorides, depth and distance from the shore (d.shore), are
referred to the left Y axis. The values of chlorides in stations 2, 3, 4 and 5 are
divided by 9. (1 = Paradero 11, 2 = Antena, 3 = Cruce canal, 4 = Juncal and 5 =
Totoral).
RESULTS
The species found in the five stations sampled were Heleobia cumingii, Melanoides tubereulata, Physa
venustula, Helisoma peruvianum and Drepanotrema kermatoides.
The fluctuation of the most variable abiotic factors in the different stations studied is shown in Fig. 1. The
variation of the abundance of Heleobia cumingii between the stations is also shown. From all the factors measured,
those that experienced the most striking changes were the total hardness and the chloride concentration. It can be
seen that the high chloride concentration affects all the species and in most cases is a limiting factor for their
distribution. Among the snail species present at Pantanos de Villa, the only one that presents a homogeneous distribu-
FIG. 2. Correlation circle of the first two components of the PCA (81.9% of the total variance).
(67)
FIG. 3. Dispersion diagram of the five stations sampled on the first two
components of the PCA. The X axis represents the first component, while the Y axis
represents the second.
tion is Heleobia cumingii, being present in ah the stations sampled.
The results of the PCA performed can be seen in Fig. 2. It shows the correlation circle between the first two
components that explain 81.99% of the total variance. It can be observed that both the chloride concentration and the
depth exert a strong and negative effect over the abundance of all the snails present. The dispersion diagram of the
stations on the first two components of the PCA performed can be seen in Fig. 3. The stations occur in well defined
groups. DISCUSSION
Several authors have dealt with the influence of abiotic factors on freshwater snails. Temperature is one of
the factors that has been more thoroughly studied than others. It has been found exerting influence on different
aspects of the freshwater snails, such as distribution, abundance, growth and reproduction, etc. (Appleton, 1976,
1978; Perera & Yong, 1981, 1984, 1991; Leveque & Pointier, 1976; Sturrock, 1966; Sturrock & Sturrock, 1972; van
der Schalie & Berry, 1973).
The pH has been also found to influence the distribution of mollusks. Okland (1983) reported that
acidification limits the distribution of the freshwater snails in Norway, while Perera & Yong (1984) found that at low
pH values (<6), the only species present in the freshwater bodies of the Isle of Youth (Cuba) was Pomacea paludosa
(Say). In our study, the factors that have been found influencing the distribution of freshwater snails at Pantanos de
Villa are chlorides and depth, and in a lesser extent, the total hardness and the distance from the shore. The chlorides
affect more strongly the distribution of Melanoides tuberculata, Physa venustula, Helisoma peruvianum and
Drepanotrema kermatoides. Heleobia cumingii is also affected by this factor, but instead of limiting its distribution
chlorides diminish its abundance. The high concentration of chloride ions in most of the stations may be due to the
nature of the substrate and the proximity to the Pacific Ocean. The effect of this ion on the distribution of freshwater
snails was previously reported by Perera & Yong (1984), when they found that this factor is a limiting one in the
distribution of pulmonates, but not for Pomacea paludosa. The distance from shore and the total hardness have some
influence on the snails, although it is not as strong as the factors previously analyzed. As it can be observed in the
graph, the pH does not have any effect on the snails because it has little variation and remains between the optimal
ranges. From Fig. 3 it can be seen that the groups of the stations are formed according to their ecological
characteristics. Juncal, Totoral and Antena have the same characteristics of water quality and aquatic vegetation.
Paradero 11 and Cruce Canal form two independent groups, with the first one being the one with the largest
(68)
separation. These are the drainage canals, but the first one is the only station that has a layer of aquatic vegetation
and algae that favors the development of the snail populations. This is the station where the highest diversity was
attained. Knowledge about the ecology of freshwater snails is very important in understanding the dynamics of snail
populations, specially when dealing with intermediate hosts as is the case of Pantanos de Villa, where there are snail
species that transmit parasites to man and domestic animals.
ACKNOWLEDGEMENTS
We would like lo thank the FEDU (Fondo Especial de Desarrollo Universitario) and students from the
Malacological Group of the Universidad Nacional Mayor de San Marcos for their enthusiastic help in the field work.
We are also indebted to Lic. Alfredo Gutiérrez for his valuable advice on statistical analysis.
LITERATURE CITED
APPLETON, C.C. 1976. Observations on a thermal regime of a stream in the eastern Trasvaal, with reference to
certain aquatic Pulmonata. South African Journal of Science, 72: 20-23.
APPLETON, C.C. 1978. Review of literature on abiotic factors influencing the distribution and life cycles of
bilharziasis intermediate hosts snails. Malacological Review, 11: 1-25.
ARRARTE, J. 1953. Monografía sistemática de los moluscos de tierra y agua dulce de Lima y sus alrededores. Tesis
de Bachiller en Ciencias Biológicas, Universidad Nacional Mayor de San Marcos, Lima. 57 pp.
LARREA, H., OV1EDO, M.L., HUAMAN, P., VIVAR, R. & PACHAS, L. 1990. Gasteropodos dulceacuícolas del
departamento de Lima y su importancia médica. Boletin de Lima, 69: 39-42.
LEVEQUE, C. & POINTIER, J.P. 1976. Study of the growth of Biomphalaria glabrata (Say) and other Planorbidae
in Guadeloupe (West Indies). Annals of Tropical Medicine and Parasitology, 70(2): 199-204.
OKLAND, J. 1983. Factors regulating the distribution of freshwater snails (Gastropoda) in Norway. Malacologia,
24: 277-288.
PERERA, G. & YONG, M. 1981. Observaciones sobre el efeceto de la temperatura en los cultivos de Biomphalaria
glabrata en el laboratorio. Revista Cubana de Medicina Tropical, 33(1): 51-57.
PERERA, G. & YONG, M. 1984. The influence of some abiotic factors on the distribution of freshwater mollusks in
the Isle of Youth (Isle of Pines), Cuba. Walkerana, 2(7): 131-139.
PERERA, G. & YONG, M. 1991. Seasonal studies on Pomacea paludosa in Cuba. Walkerana, 5(13): 19-23.
POINTIER, J.P. 1982. Etude de la croissance de Biomphalaria glabrata, mollusque hôte intermédiaire de la
schistosomose intestinale dans les forets marécageuses a Pterocarpus de Guadeloupe (Antilles Françaises).
Malacologia, 22: 395-398.
STURROCK, R.F. 1966. The influence of temperature on the biology of Biomphalaria pfeifferi, an intermediate host
of Schistosoma mansoni. Annals of Tropical Medicine and Parasitology, 60: 100- 105.
STURROCK, RE & STURROCK, B.M. 1972. The influence of temperature on the biology of Biomphalaria
glabrata (Say), intermediate host of Schistosoma mansoni on St. Lucia, West Indies. Annals of Tropical
Medicine and Parasitology, 66: 385-390.
VAN DER SCHALIE, H. & BERRY, E.G. 1973. The effects of temperature on growth and reproduction of aquatic
snails. Sterkiana, 50: 1-92.
Ronald VIVAR, Hernani LARREA Mary YONG and Gloria PERERA
and Pedro HUAMAN
Instituto Pedro Kourí
Laboratorio de Fauna Dulceacuicola (ICBAR) Autopista Novia del Mediodis, km. 8
Facultad de Ciencias Biologicas Ciudad de La Habana 11500, Cuba
Universidad Nacional Mayor de San Marcos
PO. Box 14.0434, Lima, Peru
... El phyllum Mollusca incluye aproximadamente 5600 especies dulceacuícolas (Lydeard & Cummings, 2019), de las cuales, el Perú cuenta con 129 especies, 36 son especies endémicas (Ramírez et al., 2003) (Larrea et al., 1990(Larrea et al., , 1994aVivar et al., 1996Vivar et al., , 1998MolluscaBase, 2020). Las especies del género Helisoma Swainson, 1840 y M. tuberculata son especies exóticas invasoras (Vivar et al., 1998). ...
... La metodología de recolección de los moluscos se efectuó mediante el tubo de Penchaszadeh, el cual tiene una longitud de 1 m con un diámetro de 15 cm, la profundidad de incorporación en el sustrato fue hasta los 20 cm (0,32 m 2 ), obteniendo un volumen de 0,003 m³ (Penchaszadeh, 1971;Bijoy, 2016), posteriormente la muestra fue tamizada en una malla de 1000 um (Iannacone et al., 2003). El esfuerzo de muestreo fue uniforme, representado por tres réplicas en cada estación (Lindenmayer & Likens, 2010;Silva et al., 2010;Vizcardo & Gil-Kodaka, 2015), procurando abarcar diversos microhábitats (Vivar et al., 1996;Maltchik et al., 2010) y zonas establecidas para el humedal (Pulido & Bermudez, 2018). ...
... Más adelante Larrea et al. (1990) suman a Galba viator y M. tuberculata; G. cubensis no fue registrada. Para la década del 90 Vivar et al. (1996Vivar et al. ( , 1998 Por consiguiente, se observa a través del tiempo una pérdida gradual de la diversidad de gasterópodos nativos configurando las ocho especies nativas (Arrarte, 1953) en tres especies nativas y dos introducidas al año 2010. Sin embargo, es de necesidad considerar la heterogeneidad de microhábitats del humedal para la comparación con estudios previos (Paredes et al., 2007;Maltchik et al., 2010). ...
Drástica disminución de la comunidad de gasterópodos en el Refugio de Vida Silvestre Los Pantanos de Villa, Lima, Perú
Preprint
Full-text available
  • Oct 2020
Más de la mitad de gasterópodos dulceacuícolas se encuentran en alguna categoría de conservación a nivel mundial. El objetivo del presente estudio fue evaluar la drástica disminución de la comunidad de gasterópodos del Refugio de Vida Silvestre Los Pantanos de Villa (RVSPV), Lima, Perú entre los años 2005 al 2010. Se recolectaron 8640 gasterópodos procedentes de ocho estaciones de muestreo próximas a la laguna “Marvilla” del RVSPV. Se obtuvieron las abundancias relativas por especie, familias y año de estudio. La densidad poblacional de gasterópodos (ind·m-²) entre años de estudio por familias fue analizada, además se agrupó entre especies nativas y exóticas. Se evaluó el efecto de la calidad del agua, establecida por factores fisicoquímicos, en la densidad de gasterópodos según familia y año de estudio. La diversidad alfa para la comunidad de gasterópodos abarcó los índices de diversidad alfa: S (Riqueza), H' (Shannon-Wiener), D (Simpson), DMn (Menhinick) por año de estudio. La fauna malacológica registró ocho especies de gasterópodos entre los años 2005-2010: Heleobia cumingii (d'Orbigny, 1835), Melanoides tuberculata (O. F. Müller, 1774), Pectinidens diaphanus (King, 1832), Physella venustula (Gould, 1847), Mexinauta peruvianus (Gray, 1828), Drepanotrema kermatoides (d'Orbigny, 1835), Helisoma peruvianum Broderip, 1832) y Planorbella trivolvis (Say, 1817). H. cumingii (2005: 73%; 2010: 57%) y M. tuberculata (2005: 19%; 2010: 37%) presentaron las mayores abundancias relativas, sus densidades iniciaron en 845,8 y 217,2 ind·m-2 finalizando en 9,22 y 6,06 ind·m-2 al año 2010. Las densidades por familia y especie fueron diferentes entre los años de estudio, con una fuerte tendencia a la reducción. No se hallaron especímenes vivos de P. diaphanus, P. venustula y H. peruvianum para el año 2010. La reducción de la comunidad de gasterópodos en el periodo estudiado implica que los gasterópodos dulceacuícolas representan uno de los grupos taxonómicos más amenazados y vulnerables del RVSPV.
View
... En el presente estudio se colectaron 67 taxones de macroinvertebrados, siendo 44 de estos nuevos registros para el humedal Huacho-Hualmay-Carquín; ya que, previamente se registraron 24 dípteros acuáticos y dos parasitoides (Castillo et al. 2021), lo cual incrementa su inventario total a 70 registros. Con la presente publicación se ubica como uno de los humedales costeros más ricos del país, en términos de riqueza de taxones de macroinvertebrados acuáticos en comparación con otros humedales (Iannacone et al. 2003, Vizcardo y Gil-Kodaka 2015, Castillo-Velásquez y Huamantinco-Araujo 2022); superado apenas por los inventarios de humedales como Santa Rosa, que a su favor cuentan con un esfuerzo de muestreo mayor (Castillo-Velásquez y Huamantinco-Araujo 2020) o como Pantanos de Villa, que ha sido objeto de diversas investigaciones sobre su fauna acuática (Blancas 1978, Vivar et al. 1996, Peralta-Argomeda y Huamantinco-Araujo 2014, Córdova-Tello y Huamantinco-Araujo 2023, entre otros). Tabla 1. Lista de los géneros de macroinvertebrados acuáticos registrados en el humedal costero Huacho-Hualmay-Carquín (Lima, Perú). ...
Biodiversity and spatial composition of the aquatic macroinvertebrate community of the Huacho-Hualmay-Carquín wetland, Lima, Peru
Article
Full-text available
  • Jun 2024
In the last decades, the loss and reduction of wetlands have become evident worldwide due to various pressures related to the increase in human population and their activities. This situation is also present in the coastal wetlands of Peru, especially in small bodies, which makes it necessary to investigate their biodiversity and ecology in order to provide useful information for management and conservation plans for these environments. The objective of this study was to describe the biodiversity and spatial composition of the aquatic macroinvertebrate community of the Huacho-Hualmay-Carquín coastal wetland. Collection was carried out in August 2018 at fifteen sites, divided into five sectors, recording the pH, electrical conductivity, salinity, total dissolved solids, and dissolved oxygen of each station. A total of 3 550 macroinvertebrates were collected, distributed in 67 genera, with a predominance of the orders Diptera, Coleoptera, and Hemiptera, which are widely cited as dominant groups in coastal lentic environments. This small wetland showed lower water electrical conductivity values compared to values reported in other Peruvian coastal wetlands; furthermore, it exhibited greater genus richness, especially in less impacted areas with considerable depth and high dissolved oxygen values, making it a diverse and important ecosystem within the large Peruvian coastal corridor.
View
... Además, tiene un alto poder competitivo, al igual que Physa venustula (Gould) (Iannacone & Alvariño, 1999). Esta alta capacidad de adecuación y dispersión en diferentes tipos de ambientes para M. tuberculata ha permitido que se le haya encontrado en todas las estaciones y en los siete muestreos (Tabla 2) (Vivar et al., 1996). ...
Macroinvertebrados en las lagunas de Puerto Viejo, Lima – Perú
Article
Full-text available
  • Jan 2003
Se realizó un estudio para evaluar la biodiversidad y similaridad de los macroinvertebrados del bentos de las lagunas de Puerto Viejo del 15 de Julio al 15 de Octubre del 2001. Se realizaron siete muestreos (M) temporales en ocho estaciones (E) espaciales en sus lagunas naturales y artificiales. Se calculó la diversidad alfa usando el Indice de Diversidad de Shannon-Wienner (H´), el de Equidad de Pielou (J´) y el Indice de Dominancia de Simpson (C). Para la determinación de la diversidad beta se empleó los Indices cuantitativos de Sörensen y Morisita-Horn. Un total de 5519 especímenes, tres filas, seis órdenes, nueve familias y 10 especies fueron colectadas en el macrozoobentos durante todo este estudio. Las taxas más dominantes durante este estudio fueron: Melanoides tuberculata (Müller) (Mesogastropoda: Thiaridae) con 3276 individuos (59,36 %), Chironomus sp. (Diptera: Chironomidae) con 1281 individuos (23,21 %) y Heleobia cumingi (Orbigny) (Mesogastropoda: Hydrobiidae) con 891 individuos (16,14 %). Estas tres especies presentaron una distribución espacial amontonada a lo largo de todos los muestreos realizados. Los valores de diversidad alfa mediante los Indices de diversidad de Shannon-Wiener, de Equidad de Pielou y de Simpson no variaron significativamente entre los siete muestreos realizados y entre las ocho estaciones censadas.
View
... En el Perú se le encuentra en los departamentos de Lambayeque, La Libertad, Lima e Ica, en diversos ambientes lénticos y lóticos. En los Pantanos de Villa sólo se encuentra a este prosobranchia en las acequias laterales que llegan a la laguna principal (Vivar et al., 1996). Esta especie es capaz de soportar pH variable de 6,4 a 8,9. ...
Efecto del detergente doméstico alquil aril sulfonato de sodio lineal (LAS) sobre la mortalidad de tres caracoles dulceacuícolas en el Perú
Article
Full-text available
  • Jan 2002
Se realizó una evaluación ecotoxicológica estandarizada del surfactante aniónico alquil aril sulfonato de sodio lineal (LAS), en la Universidad Federico Villarreal, Lima, Perú, empleando a tres caracoles dulceacuícolas Melanoides tuberculata (Müller, 1774) (Thiaridae), Physa venustula (Gould, 1847) (Physidae) y Heleobia cumingii (Orbigny, 1835) (Hydrobiidae) como herramientas para la evaluación de riesgos ambientales. La colecta de las tres especies de caracoles se realizó en diversos humedales naturales y artificiales del departamento de Lima, Perú. M. tuberculata fue colectada de la Laguna de la Molina (15°5´ LS, 75°57´ LO), P. venustula de las lagunas de Villa (12° 13´ LS, 77°01´ LO) y H. cumingii de las lagunas de Puerto Viejo (12°35,2´ LS, 76°42,2´ LO). Los tres moluscos fueron individualizados y criados en acuarios de vidrio de 30 cm x 20 cm 20 cm y se aclimataron en condiciones estandarizadas de laboratorio por una semana previa a los bioensayos, empleando agua filtrada a 0,54 µ de abertura procedentes de las lagunas de colecta y agua de grifo hervida fría (1:1 v/v). Los gasterópodos fueron alimentados adlibitum empleando el alga verde filamentosa Cladophora glomerata y la microalga Chlorella vulgaris Beij. Los valores determinados de la concentración letal media (CL50) para el efecto letal fueron a 48 h de exposición respectivamente: M. tuberculata 201,07 mg L-1; P. venustula 71,41 mg L-1 y H. cumingii 82,93 mg L-1. Además no existieron diferencias en la toxicidad sobre los caracoles de tres formulaciones comerciales de estos detergentes domésticos. Se proponen a estas tres especies de moluscos como herramientas para la evaluación de riesgos ambientales por detergentes domésticos.
View
View
Distribution and abundance of macroinvertebrates within two temporary ponds
Article
  • May 2003
We investigated the distributions of macroinvertebrates within two temporary ponds (Spring Peeper Pond and Taylor-Ochs Pond) in central Ohio and examined what environmental factors may be driving those distributions. We sampled macroinvertebrates in Spring Peeper Pond three times from May to July 2001, and Taylor-Ochs Pond two times from May to June 2001. Macroinvertebrate distributions were significantly aggregated on all sampling dates in both ponds. Bivalve abundance in Spring Peeper Pond was higher in shallower water. The distribution of bivalves in Taylor-Ochs Pond was not correlated with any variable we measured. Dragonfly nymph abundance in Taylor-Ochs Pond decreased between the first and second sampling dates, whereas in Spring Peeper Pond no factor examined was correlated with dragonfly nymph density. Snail densities in Spring Peeper Pond were negatively related to dissolved oxygen and depth. In Taylor-Ochs Pond, snail abundance was positively related to temperature. The densities of damselfly nymphs in Spring Peeper Pond were positively related to dissolved oxygen and depth and declined across the study. In Spring Peeper Pond, hemipteran densities were negatively related to depth and increased across the study. Damselfly nymphs and hemipterans were not common enough in Taylor-Ochs to analyze. In general, the abiotic and biotic factors we examined explained relatively little (
View
View
Study of growth of Biomphalaria-Glabrata (Say) and other Planorbidae in Guadeloupe (West-Indies)
Article
Full-text available
  • Jul 1976
The growth of Biomphalaria glabrata, B. schrammi, Drepanotrema lucidum and D. kermatoides was studied in three habitatis on Guadeloupe. Theortical growth curves were calculated for each species by applying the Walford method and the von Bertalanffy equation. On Guadeloupe, the growth of B. glabrata was faster in the ponds of Grand Terre than in the small high altitude streams of Basse Terre. There is good correlation between the observations made in Guadeloupe and previous data obtained on Pureto Rico and St Lucia.
View
View
View
View
View
The influence of temperature on the biology of Biomphalaria glabrata (Say), intermediate host of Schistosoma mansoni on St. Lucia, West Indies
Article
  • Oct 1972
Life tables were obtained over 16 fortnights for three cohorts of Biomphalaria glabrata at 20oC, 25oC and 30oC respectively. At 35oC no eggs hatched. The intrinsic rate of natural increase r was greater at 25oC(0.8834) but the mean generation time T was similar to that at 30oC(8-9 fortnights). Egg production and survival were reduced at 30oC but r(0.6866) was higher than at 20oC(0.4725). T was greatest at 20oC(12 fortnights) due to the delay in the onset of egg laying. The growth rate at 30oC was only a little faster than that at 25oC, but both were greater than that at 20oC. Comparison of these results with those of similar studies elsewhere suggests that the St. Lucians strain of B. glabrata is adapted to living in unstable, temporary habitats. B. glabrata, unlike its African relatives, is capable of surviving prolonged exposure to temperatures of 30oC so that, despite reduced fecundity, it can colonize the hot, low lying coastal plains of northeastern South America. (AU)
View
View
Observaciones sobre el efeceto de la temperatura en los cultivos de Biomphalaria glabrata en el laboratorio
  • Jan 1981
  • Rev Cubana Med Trop
  • 51-57
  • G Perera
  • M Yong
PERERA, G. & YONG, M. 1981. Observaciones sobre el efeceto de la temperatura en los cultivos de Biomphalaria glabrata en el laboratorio. Revista Cubana de Medicina Tropical, 33(1): 51-57.
The influence of some abiotic factors on the distribution of freshwater mollusks in the Isle of Youth (Isle of Pines)
  • Jan 1984
  • 131-139
  • G Perera
  • M Yong
PERERA, G. & YONG, M. 1984. The influence of some abiotic factors on the distribution of freshwater mollusks in the Isle of Youth (Isle of Pines), Cuba. Walkerana, 2(7): 131-139.