this paper deals with a delayed ratio-dependent functional response predator-prey model with a threshold harvesting policy. we study the equilibria of the system before and after the threshold. we show that the threshold harvesting can improve the undesirable behavior such as nonexistence of interior equilibria. the global analysis of the model as well as boundedness and permanence properties a...

In this paper, we study dynamic commensalism model with nonmonotic functional response, density dependent birth rates on time scales and derive sufficient conditions for the permanence. We also establish the existence and uniform asymptotic stability of unique almost periodic positive solution of the model by using Lyapunov functional method.

the functional response of a predator is the base of prey-predator dynamics. functional response of serangium montazerii fã¼rsch at different egg densities (50, 100, 150, 200 and 250) of dialeurodes citri (ashmead) was studied in an open-patch experiment, in a growth chamber (25 â± 1â°c, 65 â± 5% rh and a photoperiod of 16: 8 l: d h) on ‘thompson’ navel orange (citrus sinensis cv. thompson)...

This paper deals with a ratio-dependent functional response predator-prey model with a fractional order derivative. The ratio-dependent models are very interesting, since they expose neither the paradox of enrichment nor the biological control paradox. We study the local stability of equilibria of the original system and its discretized counterpart. We show that the discretized system, which is...

This paper deals with a delayed ratio-dependent functional response predator-prey model with a threshold harvesting policy. We study the equilibria of the system before and after the threshold. We show that the threshold harvesting can improve the undesirable behavior such as nonexistence of interior equilibria. The global analysis of the model as well as boundedness and permanence properties a...

the functional response of aphidius ervi to different sitobion avenae densities on two wheat cultivars (sardary and alvand) was examined in laboratory conditions. experiments were carried out in test tubes on an f2 lab generation without wheat clusters and also on f2 and f5 generations in pots using wheat clusters. in the tubes, female wasps were exposed to aphid densities of 2, 4, 7, 14, 28, 3...

the stage specific functional response of the acarophagous ladybird beetle stethorus gilvifrons mulsant to varying densities of citrus brown mite eutetranychus orientalis (klein) eggs was examined in a simplified castor bean leaf arena under laboratory conditions. all stages of s. gilvifrons were individually isolated for 24 hours with different prey densities at 30âºc and a photoperiod of 14: ...

searching efficiency is a key parameter of functional response which is in turn the major components in the selection of predators and parasitoids for biological control. searching efficiency of scymnus syriacus mulsant feeding on aphis craccivora koch was determined at five different experimental arenas (i.e. 195, 247, 304, 385 and 650 cm2) on broad bean (vicia fabae l.). to do this, functiona...

the cotton aphid, aphis gossypii glover is a major pest of greenhouse cucumber in the world. in this study, age specific functional response of aphidius matricariae haliday and praon volucre (haliday) were investigated on a. gossypii at 25±1°c, 60±5% rh and a photoperiod of 14 l: 10 d h. the results showed that the functional response of a. matricariae was type iii during 1st, 2nd, 3rd, 4th and...