If the demographic parameters in a matrix model for the dynamics of a structured population are dependent on a parameter u, then the population growth rate r = r(u) and the net reproductive number R0 = R0(u) are functions of u. For a general matrix model, we show that r and R0 share critical values and extrema at values u = u∗ for which r(u∗) = R0(u∗) = 1. This allows us to re-interpret, in ter...

The stinkbug Supputius cincticeps (Stål) (Heteroptera: Pentatomidae) can be found in agricultural and forest ecosystems feeding primarily on larvae of Coleoptera and Lepidoptera, where it can be exposed to insecticide applications. This study therefore aimed to evaluate the reproductive potential of S. cincticeps after exposition to sublethal doses of permethrin (5.74 x 10(-3), 5.74 x 10(-2), 5...

Temperature effects on organisms are of multiple scientific interests, such as for their life history performance and for the study of evolutionary strategies. We have cultured two sympatric branchiopod species from an ephemeral pond in northern Taiwan, Branchinella kugenumaensis and Eulimnadia braueriana, and compared their hatching rate, maturation time, sex ratio, growth of body length, surv...

The reproductive performance of the parasitoid Habrobracon hebetor (Say) (Hymenoptera: Braconidae) against the moths Anagasta kuehniella Zeller and Plodia interpunctella (Hübner) (Lepidoptera: Pyralidae) was studied in the laboratory. The analysis was based on the comparison of parasitoid's life table parameters related to those of its hosts at various conditions of host density (daily supply o...

DemographyofHabrobraconhebetor(Say)(Hymenoptera:Braconidae)on twopyralid host species [Galleria mellonella (L.) and Ephestia kuehniella Zeller] (Lepidoptera: Pyralidae) was studied at 28 C in the laboratory. Data were analyzed based on an age-stage, two-sex life table, to take both sexes and variable development into consideration. The intrinsic rate of increase (r), Þnite rate of increase ( ),...

spodoptera exigua (hübner) was studied in laboratory (25±1ºc, 60±5% rh, and 16:8 l:d h) exploring the antibiotic effects of 10 canola cultivars (sarigol, slm046, hayula420, rgs003, opera, okapi, licord, modena, zarfam and talaye) on its demographic parameters. the age-stage, two-sex and the traditional female age-specific life tables were constructed by using the demographic data. the larval pe...

-the cowpea aphid, aphis craccivora koch, is an important pest of robinia pseudoacacia frisia. life table parameters of a. craccivora were determined under natural (16- 33ºc and 32-89% rh, respectively) and laboratory (25 ± 1ºc, rh of 70 ± 5% and a photoperiod of 16:8 h (l: d) conditions. the data were analyzed using the age-stage, two-sex life table theory. each experiment was replicated 45 ti...