sex-determining mechanism in Poeciliid fishes of the genus Xiphophorus ' F : been studied for more than forty years (BELLAMY 1928; GORDON 1927), yet many problems remain unsolved. In the southern platyfish, Xiphophorus maculatus, native to Mexico and adjacent parts of Central America, there are three types of females (XX, WX, WY) and two types of males (XY and YY) (GORDON 1947, 1954; KALLMAN 19...

BACKGROUND The suburban transmission of malaria in Selangor, Malaysia's most developed and populous state still remains a concern for public health in this region. Despite much successful control efforts directed at its reduction, sporadic cases, mostly brought in by foreigners have continued to occur. In addition, cases of simian malaria caused by Plasmodium knowlesi, some with fatal outcome h...

BACKGROUND Several teleost species have evolved anterior extensions of the swim bladder which come close to or directly contact the inner ears. A few comparative studies have shown that these morphological specializations may enhance hearing abilities. This study investigates the diversity of swim bladder morphology in four Asian and African cichlid species and analyzes how this diversity affec...

Registramos por primera vez al Rascón Pinto (Pardirallus maculatus) en el Estado de Sinaloa, México. Observamos un individuo canal agrícola adyacente a la Laguna Chiricahueto. Este hallazgo incrementa intervalo distribución previo aproximadamente 400 km hacia norte. Probablemente observado fue visitante accidental.

New data on the records of synanthropic slug species Limacus maculatus and Arion vulgaris in Belarus are analyzed. It is assumed that penetration these into territory occurred from other parts their modern range together with imported goods.

La produccion de peces ornamentales es una actividad importante dentro la acuicultura peruana generando impactos socioeconomicos positivos en toda cadena valor. El pez ornamental Platy (Xiphophorus maculatus) uno los mas coloridos utilizados ampliamente como un sistema modelo animal para comprender base genetica del polimorfismo patron color. coloracion X. maculatus esta relacionada con sintesi...

Information about spatial and temporal variability in the distribution and abundance of shark-populations are required for their conservation, management and to update measures designed to mitigate human-shark interactions. However, because some species of sharks are mobile, migratory and occur in relatively small numbers, estimating their patterns of distribution and abundance can be very diff...

We investigated effects of temperature, at 70% RH, on the reproductive parameters of the parthenogenetic psocid Lepinotus reticulatus Enderlein (Psocoptera: Trogiidae). The lowest fecundity (21) was at 35 C and the highest (41) at 27.5 C. At 22.5, 25, and 27.5 C, peak oviposition rates (eggs/female/week) occurred in week 3 and were 4.7, 6.6, and 7.8, respectively; also 51, 57, and 62%, respecti...

Con el fin de profundizar en conocimiento sobre los efectos determinados insectos registro óseo la Depresión del río Salado, se desarrolló un experimento actualístico con especie Dermestes maculatus (Coleoptera: Dermestidae) y restos actuales cuatro especies fauna diferentes tamaños (Myocastor coypus, Dasypus hybridus, Ovis aries, Oryctolagus cuniculus). D. es coleóptero cosmopolita que coloniz...

Sexual size dimorphism (SSD) is a common phenomenon and is a central topic in evolutionary biology. Recently, the importance of pursuing an ontogenetic perspective of SSD has been emphasized, to elucidate the proximate physiological mechanisms leading to its evolution. However, such research has seldom focused on the critical periods when males and females diverge. Using mark-recapture data, we...