nutritional incides have important role in economical efficiency of silkworm rearing. in order to estimate nutritional indices six silkworm hybrids including 103×104, 31×32, 107×110, 104×103, 32×31 and 110×107 which were commercially used in iran for cocoon production were tested. these hybrids were reared in spring 2003, spring 2004 and autumn 2004. the studied parameters were amount of ingest...

The pistachio psylla, Agonoscena pistaciae Burckhardt and Lauterer (Hemiptera: Psyllidae) is a major pest of pistachio trees, Pistacia vera L. (Sapindalis: Anacardiaceae) throughout pistachio-producing regions in Iran. Different density levels of A. pistaciae nymphs were maintained on pistachio trees by different insecticide dosages to evaluate the relationship between nymph density and yield l...

Ecological character displacement describes a pattern where morphological differences between sympatric species are enhanced through interspecific competition. Although widely considered a pervasive force in evolutionary ecology, few clear-cut examples have been documented. Here we report a case of ecological character displacement between two salamander species, Plethodon cinereus and Plethodo...

Colorado potato beetle, Leptinotarsa decemlineata (Say), feeding, development, and survival to adulthood were examined after continuously exposing large larvae to Bacillus thuringiensis subsp. tenebrionis-treated potato foliage from the field. In laboratory assays, the overall consumption and the length of period to become prepupae were determined for larvae, which began as 3rd and 4th instars,...

Lygus hesperus Knight (Hemiptera: Miridae) is a key pest of fruit and vegetable crops, forages, and cotton (Gossypium spp.) in the western United States. Accurate models describing relationships between temperature and L. hesperus development are critical to the study of seasonal L. hesperus population dynamics. Development of L. hesperus nymphs was assessed at nine constant temperatures from 1...

Studies of interactions between invasive and native species often focus on impacts on natives. We report potential impacts of a native predator, the Lake Erie Watersnake (Nerodia sipdeon insularum) on an invasive fish, the Round Goby (Apollonia melanostomus). Round Gobies have increased exponentially in the Great Lakes and now constitute >90% of prey consumed by Lake Erie Watersnakes. We invest...