Biological invasions result in novel species interactions, which can have significant evolutionary impacts on both native and invading taxa. One evolutionary concern with invasions is hybridization among lineages that were previously isolated, but make secondary contact in their invaded range(s). Black rats, consisting of several morphologically very similar but genetically distinct taxa that c...

In this study we examine the size of primary sensory areas in the neocortex and the cellular composition of area 17/V1 in three rodent groups: laboratory nocturnal Norway rats (Long-Evans; Rattus norvegicus), wild-caught nocturnal Norway rats (R. norvegicus), and laboratory diurnal Nile grass rats (Arvicanthis niloticus). Specifically, we used areal measures of myeloarchitecture of the primary ...

Fifteen experimental treatments with rodenticidal baits containing 0.1, 0.15 or 0.2% flupropadine were conducted on farmsteads against Rattus norvegicus infestations. Eight treatments were completely successful and the others gave kills ranging from 36 to 72% in 28 days. Treatments with 0.1 and 0.15% flupropadine were less successful against large infestations than against small ones. Flupropad...

Norway rats were eradicated on bush-covered Hawea Island (9 ha) in Breaksea Sound, using the anticoagulant rodenticide "Talon 50 WB" (brodifacoum). The work was done as a conservation measure and to evaluate the feasibility and costs of eradicating rodents quickly from islands. The 50-100 rats present were eradicated in about two weeks by applying a simple strategy that took full account of the...

In 1926, Crozier and Pincus first reported that 2-week-old rats placed head-down on an inclined plane orient in a head-up direction; this response is called negative geotaxis. In Experiment 1, we replicated this finding by testing 12- to 14-day-old rats on an inclined plane covered with wire mesh. Pups oriented in a head-up direction and avoided the head-down direction at inclines of 45 degrees...

Weanling Sprague Dawley rat pups (Rattus norvegicus) selected between 2 safe palatable diets in concordance with the preferences of either an adult or a juvenile conspecific model (Experiment 1). Nevertheless, weanlings chose to feed more in the vicinity of an adult than in the vicinity of a juvenile, thus fulfilling the prediction of an adaptive feeding strategy (Experiment 2). The weanlings' ...

Country Reservoirs Vectors Bolivia Akodon sp Xenopsylla cheopis Rattus rattus Pulex irritans Brazil Akodon sp X. cheopis Oryzomys sp Callomys sp Bolomy sp Monodelphis deomestica Ecuador R rattus P. irritans R. norvegicus R. alexandrinus Akodon mollis Oryzomys sp Phyllotis sp Scirurus stramineus United States Marmot (Cynomys sp) Orchopeas sexdentatus Rabbits Oropsylla montana Rats (Dipodomys sp)...

During February 2004 and September 2005, Xenopsylla cheopis were collected from small mammal hosts during rodent-bone disease surveys in Jakarta and Bandung, Indonesia. During 4 trap nights in Jakarta, 4 rodent species (Rattus exulans, Rattus norvegicus, Rattus tanezumi and Mus musculus) and one shrew species (Suncus murinus) were collected. Rattus tanezumi had the highest X. cheopis load (128 ...

The authors used laboratory rats (Rattus norvegicus) of known relatedness and contrasting familiarity to assess the potential effect of preexperimental social experience on subsequent social recognition. The authors used the habituation-discrimination technique, which assumes that multiple exposures to a social stimulus (e.g., soiled bedding) ensure a subject discriminates between the habituati...

We have identified and determined the sequence and organization of a new rat satellite DNA in Rattus rattus, the roof rat. This satellite DNA, which we call R. rattus satellite I', consists of tandem arrays of a 185 base pair (bp) repeat unit that we call a'. a' is 86% homologous to a 185 bp portion of the 370 bp repeat unit of the previously described rat satellite [Pech et al. (1979) Nucleic ...