The complete DNA sequence of the mtDNA cytochrome oxidase II gene from house fly, Musca domestica, face fly, Musca autumnalis, stable fly, Stomoxys calcitrans, horn fly, Haematobia irritans, and black garbage fly, Hydrotaea aenescens, are reported. The nucleotide sequence codes for a 229 amino acid peptide. The COII sequence is A + T rich (74.1%), with up to 12.3% nucleotide and 8.4% amino acid...

The feeding response of juvenile amphipod Gammarus pulex (L.) was investigated following exposure to freshwater pollutants. The method employed is nondestructive, provides a rapid indication of the status of groups of individuals, and is based on a time-response analysis of the consumption of the eggs of Artemia salina and the determination of median feeding times or FT50s. The feeding activity...

Unusual behavior before earthquakes has been reported for millennia but no plausible mechanism has been identified. One possible way in which animals could be affected by pre-earthquake processes is via stress activated positive holes leading to the formation of hydrogen peroxide at the rock water interface. Aquatic and fossorial animals could be irritated by H₂O₂ and move down the concentratio...

Phytoplankton-grazer dynamics are often characterized by long transients relative to the length of the growing season. Using a phytoplankton-grazer model parameterized for Daphnia pulex with either flexible or fixed algal carbon:nutrient stoichiometry, we explored how nutrient and light supply (the latter by varying depth of the mixed water column) affect the transient dynamics of the system st...

Taylor et al. (1993) described a pollutant bioassay based upon a change in the rate at which Gammarus pulex (L.) consumes a novel food source (eggs of the brine shrimp Anemia salina) when the animals are stressed by exposure to a pollutant. The bioassay is rapid and non-destructive, and produces results with less variation than reported using conventional leaf-feeding bioassays. However, it is ...

La mosca de los cuernos Haematobia irritans es un ectoparásito hematófago cosmopolita gran importancia en la ganadería. En México, H. se distribuye por todo el país y encuentra durante año. fluctuación población está relacionada con las condiciones climáticas. A pesar su amplia distribución, efectos sobre salud animal impacto negativo producción carne leche, existen pocos datos infestación epid...

The anthelmintic activity of the eugenol against the fish parasite Gyrodactylus sp. was evaluated. After 1-h exposure to 5 and 10 mg/L eugenol, mortality of the parasites was near 80 and 90%, respectively. The concentrations used in the antiparasitic test were not toxic to Daphnia pulex (LC50 42.5 mg/L).

Asexual reproduction avoids the costs associated with sex, predicting that invading asexual clones can quickly replace sexual populations. Daphnia pulex populations in the Great Lakes area are predominately asexual, but the elimination of sexual populations by invading clones is poorly understood. Asexual clones were detected at low frequency in one rare sexual population in 1995, with some inc...