Osman, M. A. and Bayoumy, M. H. (2011). Effect of prey stages on functional response of Stethorus gilvifrons feeding on the two-spotted spider mite, Tetranychus urticae Acta Phytopathologica et Entomologica Hungarica. 46 (2), pp. 279–290 (original) (raw)
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Acta Phytopathologica et Entomologica Hungarica, 2011
The effect of prey stages of the two-spotted spider mite Tetranychus urticae on the functional response of the coccinellid predator Stethorus gilvifrons was studied at 25±1 °C, 65±10% rh, and 16:8 h (L:D photoperiod). The functional response of S. gilvifrons female, to increasing prey stage density from 10−100 preys per patch, was of the curvilinear shape depicting Roger's type II response with the highest consumption rate of larval prey stage. Results of the maximum likelihood analyses confirmed this type. By plotting a type II functional response model and polynomial logistic regression model to the numbers and proportions of consumed stages of T. urticae, respectively, the resulting regression lines fitted the data well. However, a composite waving form that appeared to be a decelerating (type II) response at low to medium prey densities and an accelerating (type III) response at high prey densities. We assume that the small size of experimental arena or predator feeding behaviour at low and high prey densities may have induced the modified type II response. A sensitivity analysis of the functional response model shows the crucial effect of prey stages on predation rates by S. gilvifrons. Theoretically, based on the lowest handling time for S. gilvifrons on larval stage of T. urticae, the maximum numbers of mites that could consume by a single female of S. gilvifrons within 24 h period were 77.42 larvae. These results improve our understanding of the interaction among S. gilvifrons and T. urtica stages and provide insights into the control of T. urticae.
The effect of prey stages of the two-spotted spider mite Tetranychus urticae on the functional response of the coccinellid predator Stethorus gilvifrons was studied at 25±1 °C, 65±10% rh, and 16:8 h (L:D photoperiod). The functional response of S. gilvifrons female, to increasing prey stage density from 10−100 preys per patch, was of the curvilinear shape depicting Roger's type II response with the highest consumption rate of larval prey stage. Results of the maximum likelihood analyses confirmed this type. By plotting a type II functional response model and polynomial logistic regression model to the numbers and proportions of consumed stages of T. urticae, respectively, the resulting regression lines fitted the data well. However, a composite waving form that appeared to be a decelerating (type II) response at low to medium prey densities and an accelerating (type III) response at high prey densities. We assume that the small size of experimental arena or predator feeding behaviour at low and high prey densities may have induced the modified type II response. A sensitivity analysis of the functional response model shows the crucial effect of prey stages on predation rates by S. gilvifrons. Theoretically, based on the lowest handling time for S. gilvifrons on larval stage of T. urticae, the maximum numbers of mites that could consume by a single female of S. gilvifrons within 24 h period were 77.42 larvae. These results improve our understanding of the interaction among S. gilvifrons and T. urtica stages and provide insights into the control of T. urticae.
The functional response of a ladybeetle, Stethorus gilvifrons Mulsant, to increasing density of two spotted spider mite, Tetranychus urticae koch, was of the curvilinear shape depicting Holling's type II response with larval stage being the most voracious stage when compared with nymphal and adult stages. Results of the maximum likelihood analyses confirmed this type. By plotting a type II functional response model and polynomial logistic regression model to the numbers and proportions of consumed stages of T. urticae, respectively, the resulting regression lines fitted the data well. A sensitivity analysis of the functional response model shows the crucial effect of prey stages on predation rates by S. gilvifrons. Theoretically, based on the lowest handling time for S. gilvifrons on larval stage of T. urticae, the maximum numbers of mites that could be consumed by a single female of S. gilvifrons within 24 h period were 77. 42 larvae. Based on the inversely density-dependent predation rate for S. gilvifrons on different prey stages, it seems to be more effective in low prey densities and this result has to be considered in future inundative biological control programs. These results might be a better strategy for developing mass rearing of S. gilvifrons and biocontrol program of T. urticae.
Experimental and Applied Acarology
Prey stage preference of female Kampimodromus aberrans (Oudemans) (Phytoseiidae) at constant densities of different stages of Tetranychus urticae Koch (Tetranychidae), functional response types and parameters of the predator females to the varying densities of eggs, larvae, protonymphs and deutonymps of T. urticae were determined in order to establish its potential for the mite biological control. Experiments were conducted at 25 ± 1°C, 65 ± 10% RH and 16:8 (L:D) photoperiod. Our results indicated that the predator consumed significantly more prey larvae than other prey stages. Functional response type of predator was determined by a logistic regression model. The predator exhibited a Type II response on all prey stages. The attack rate (a) and handling time (T h) coefficients of a Type II response were estimated by fitting a ''random-predator'' equation to the data. The lowest estimated value a and the highest value of T h (including digestion) were obtanined for the predator feeding on deutonmph. The lowest value of T h were obtained for the predator feeding on prey larvae, but the attack rate value obtained on larva wasn't different than that obtained on egg and protonymph. According to our results, K. aberrans could be an efficient biological control agent of T. urticae at least at low prey densities. However, further field based studies are needed to draw firm conclusions.
Functional and Numerical Responses of the Predatory Mite, Amblyseius Fallacis, to Prey Density
Environmental Entomology, 1975
Functional and numerical responses of the predatory mite, Neoseiulus longispinosus (Evans) (Acari: Phytoseiidae) to the red spider mite, Oligonychus coffeae Nietner (Acari: Tetranychidae), infesting tea were determined in a laboratory on leaf discs. Prey consumption increased with increases in temperature and prey density. Handling time decreased and successful attack rate increased with increased temperature. N. longispinosus was more voracious on larvae and nymphs than on adults of O. coffeae. Handling time was higher on adult females than on larvae. Rate of predation leveled off at temperatures greater than 25º C. Functional responses to prey density at six temperatures and to each life stage of O. coffeae approximated the Holling type II model. The oviposition rate increased with prey consumption and temperature. On average, a predator consumed 1.62 adult female prey for every egg it laid. With a fixed number of prey available, predation rate per predator decreased with increased predator density.
Egyptian Academic Journal of Biological Sciences. A, Entomology, 2009
Food consumption of the predator, Stethorus punctillum Wiese reared on immature and mature stages of the prey, Tetranychus urticae (Koch) was studied under laboratory conditions at three different constant temperatures (15, 25 and 35ºC). The larval instars consumed more immature prey individuals at 15ºC, followed by 35 ºC then 25ºC. Adult males of the predator consumed more individuals of immature preys at 35ºC, followed by 25 ºC then at 15ºC, while the predator females relatively consumed more prey individuals than the males, at the same temperatures. When the larvae of the predator reared on mature stages of the prey, they consumed more prey individuals at 15ºC, followed by 25ºC then at 35ºC. The adult males and females of the predator consumed almost the same numbers of the prey individuals. They consumed the highest number of preys at 35ºC, followed by 25ºC, while the lowest consumed number was recorded at 15ºC.
The spider mite, Tetranychus macferlani (Baker and Pritchard) (Acari: Tetranychidae) is a pest of various crops and trees with a cosmopolitan geographic range that includes the country of Bangladesh. This study was conducted to evaluate the biological control potential of the predacious mite, Neoseiulus womersleyi (Schicha) (Acari: Phytoseiidae), against T. macferlani. The consumption rate (when offered egg, larvae, protonymph, and deutonymph as prey) and functional responses (over different prey densities) of N. womersleyi were investigated in laboratory experiments. Experimental results showed that the predator consumed significantly more larvae than other stages of T. macfarlanei. Logistic regression indicated that the predator exhibited a Type II functional response on all immature stages of prey; the number of prey consumed increased with prey density up to a maximum after which it slowly decreased. The attack rate (a) and handling time (T h ) coefficients of a Type II response were estimated by fitting Holling's disc equation to the data. The lowest estimated value of a and the highest value of T h were obtained for the predator feeding on deutonymphs. The lowest value of T h was obtained for the predator feeding on larvae. However, the attack rate on larvae was not significantly different than the attack rate obtained on eggs and protonymphs. The predicted maximum daily prey consumption was 212.8 eggs, 238.1 larvae, 53.5 protonymphs, and 29.6 deutonymphs. Thus, our results suggest that N. womersleyi could be a highly efficient biological control agent of T. macfarlanei at least at low prey densities, although field studies are needed to draw firm conclusions.
The ladybird beetle, Stethorus gilvifrons, is a major predator of the red spider mite, Oligonychus coffeae, infesting tea. Biology, life table and predatory efficiency of S. gilvifrons were studied under laboratory conditions. Its average developmental period from egg to adult emergence was 19.2 days. After a mean pre-oviposition period of 5.3 days, each female laid an average of 149.3 eggs. Adult females lived for 117.3 days and males for 41.5 days. The life table of the beetle was characterized by an intrinsic rate of increase (r) of 0.066 day-1 , net reproductive rate (R 0) of 72.2 eggs/female, gross reproduction rate (Rm x) of 82.3 eggs/female, generation time (T) of 64.9 days, doubling time of 10.5 days and finite rate of increase (k) of 1.07 day-1. Population dynamics of S. gilvifrons and its prey, O. coffeae, was monitored by sampling 25 tea leaves from each experimental block grown under the prevailing field conditions. Populations of S. gilvifrons reached a peak during January to March and had low incidence during June to November. Peaks in the populations of S. gilvifrons coincided with the abundance of O. coffeae in tea fields. Weather factors such as low temperature, high humidity and heavy rainfall adversely affected the populations of S. gilvifrons. The predatory efficiency of S. gilvifrons increased during the growth of larval instars. An adult female consumed 205.0 eggs, 92.2 larvae, 81.8 nymphs and 52.4 adult mites per day.
2020
Predaceous insects is an effective important biological control agents of feeding on Tetranychus urticae Koch and decreasing the number during 2018 season to study the optimal predator: prey ratios for the release of Stethours gilvifrons (Mulsant) sacond larvae and adult stage for controlling the T. urticae on cottonplants Gossypium burbadense L. The obtained results showed that the effective control was gained after 12 days from released the second larvae and adult of the S. gilvifrons predatorwhen the predator: prey ratios were 1:15and1:25 respectively. The regression analysis between predator: prey ratios of S. gilvifrons (larvae and adults) reduction percentages cleared that there were negatively high relationship of larvae and adult predators and prey ratios, which means that the reduction rate was increased with lower predator : prey ratios and vice versa .The results assured that the best control of T.urticae populations under semi field conditions was cleared by using the l...
Scolothrips longicornis Priesner is a native predator insect in Iran and it is an active biological control agent in bean, cucumber and eggplant fields. The aim of this study was to determine functional response and mutual interference of the predatory thrips, S. longicornis under laboratory conditions (25 °C, RH 65% and a photoperiod of 16 h light: 8 h dark) fed on Tetranychus urticae Koch on cucumber. The functional response was measured by offering eggs and nymphs of T. urticae at seven densities (2, 4, 8, 16, 32, 64 and 128) to an adult female of thrips separately and the mutual interference was calculated by five densities (1, 2, 4, 8 and 16) of adult female predators on 250 nymphs of T. urticae. Both experiments were done during 24-h period. The values of the attack rate (a) and handling time (T h ) were estimated using the Royama-Rogers' model. The logistic regression showed a type II response of the predator to different densities of eggs and nymphs of T. urticae. Both parameters (a, T h ) were very similar between eggs (0.1107 and 2.4038 h, respectively) and nymphs (0.1034 and 2.4691 h, respectively). The per capita searching efficiency decreased significantly from 0.040 to 0.024 with increasing predator density from 1 to 16 females. Also the per capita predation decreased significantly from 9.800 to 4.983 with increasing predator density from 1 to16. The results revealed the high predation potential of S. longicornis, which it can be used as a sufficient biological control agent on T. urticae.