abstract in order to identify the plant parasitic nematodes of rapeseed fields in north khorasan provice, during years 2007-2008, 50 soil and root samples were collected. nematodes were extracted by centrifugal flotation technique and transferred to glycerin according to the modified de grisse method (1969). the permanent slides were prepared from the extracted nematodes. the nematodes were ide...

The discontinuous gas exchange cycle of the pseudoscorpion Garypus californicus, mean mass 5.9 mg, is rudimentary and is characterized by bursts of CO(2) at frequencies ranging from 3.6 mHz at 15 degrees C to 13.3 mHz at 35 degrees C. The mean volume of CO(2) emitted per burst is 3.6 micro l g(-1) at 25 degrees C, about a tenth of the amount emitted by tracheate arthropods with a well developed...

10 Red carotenoid-based coloration is widely distributed across marine and terrestrial animals and 11 has taken a prominent role in studies of how phenotypic traits evolve in response to natural and 12 sexual selection. Key to these studies is an understanding of the physiological mechanisms that 13 give rise to red coloration, yet an ideal model system for such work has not been identified. Th...

10 Astaxanthin is the dominant carotenoid pigment found in the marine copepod, Tigriopus 11 californicus (Baker), giving these animals orange-red coloration. Like all metazoans, T. 12 californicus must convert carotene or hydroxy-carotenoids present in their algal diet to 13 astaxanthin. Other astaxanthin-pigmented crustaceans have been shown to use a precursor14 specific bioconversion pathway ...

Pleometrosis, or colony founding via multiple queens, occurs in a localized population of the seedharvester ant Pogonomyrmex californicus. In an apparently unusual secondary modification, queens of P. californicus are also obligate foragers; that is, queens must forage to garner the resources necessary to rear their first brood. Laboratory experiments measured the costs and benefits of pleometr...

Most knowledge of parent-offspring relations in mammals is derived from studies of mother-infant interactions. Male parental care has been less well studied. We explored maternal and paternal behavior of the California mouse, Peromyscus californicus. Six pairs of parents and their young were videotaped continuously for 12 hours/day, on alternate days from Days 1 to 31 postpartum. Males exhibit ...

BACKGROUND: Chemical control of spider mites and thrips in everbearer strawberry is difficult as few efficient chemicals are available and residues represent a risk. In the north the success of biocontrol of mites and thrips in open fields compared with tunnels needs to be evaluated. OBJECTIVES: To investigate the need for control of spider mites and thrips and evaluate the effectiveness of bio...

1. Individuals can show positive correlations in performance (e.g. growth and reproduction) through time beyond the effects of size or age. This ‘performance autocorrelation’ has been attributed previously to traits that differ among individuals or to extrinsic generators of environmental heterogeneity. 2. A model of mobile consumers on a dynamic resource showed that consumer foraging gave rise...

Chalarostylis is a deep-sea genus close to Hemilamprops but easily distinguished from the latter mainly by its robust first pereopod. However, this appendage is frequently broken off at the anterior margin of the basis, making the identification of the species of the genus difficult. Regarding Hemilamprops brenkei, both the adult male holotype and the additional specimens herein reported from t...