scholarly journals Selection of suitable predatory mites against, Panonychus citri (McGregor) (Acari: Tetranychidae) using relative control potential metrics and functional response

2021 ◽  
Vol 31 (1) ◽  
Author(s):  
Muhammad Asif Qayyoum ◽  
Zi-Wei Song ◽  
Bilal Saeed Khan ◽  
Muhammad Irfan Akram ◽  
Muhammad Zeeshan Shabbir ◽  
...  

Abstract Background Selection of suitable predators for the control of the spider mite, Panonychus citri is always a challenge due to the lack of their reliable predicted efficacy. In this laboratory study, biological control potential of Neoseiulus californicus, N. cucumeris and Scapulaseius newsami, against P. citri using the “Relative Control Potential” (RCP) metric to compare their efficacies was evaluated. The functional response type was determined at different prey densities (after 24 h). Results The type II functional responses were observed from all the tested predators feeding on 3 different life stages of P. citri, except N. cucumeris, which was fed only on eggs. All predatory mites preferred eggs of P. citri with a higher attack rate (1.397) in N. cucumeris, followed by N. californicus (1.238) and S. newsami (0.975). Handling time was also lower in N. cucumeris than other mites, with a trend as: for N. cucumeris, eggs > adults > immature stages; for N. californicus, immature stages > eggs > adults, while for S. newsami, eggs > immature stages > adults. The integration of greenhouse abundance and fecundity (%) data resulted in a higher RCP for N. cucumeris than other predators. Conclusion Neoseiulus cucumeris was selected as the most suitable predatory mite for the control of P. citri with a higher RCP and potential to maximum reproduction. S. newsami, which was used for the first time, gave almost similar results compared to N. californicus but with lower efficacy.

Acarologia ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 30-39
Author(s):  
Fereshteh Bazgir ◽  
Jahanshir Shakarami ◽  
Shahriar Jafari

Eotetranychus frosti and Cenopalpus irani Dosse are pests of apple trees that are widely distributed in apple orchards in Iran. The functional responses and predation rates of Amblyseius swirskii, one of the most commonly utilized phytoseiid mites for biological control, on these two pests were evaluated at 25 ± 1 °C, with 16:8 h L: D, and a relative humidity of 60 ± 10 % on apple leaves. The results of predation rate experiments on the two prey species indicated that the predator consumed significantly more eggs than larvae and protonymphs whereas consumption of deutonymphs were very rare. Likewise, the results of logistic regression analysis showed that A. swirskii exhibited a Type II functional response on all immature stages of E. frosti and C. irani. Handling time (Th) increased as prey size enlarged; the lowest handling times were determined as 0.4858 and 0.3819 h on eggs of E. frosti and C. irani, respectively, whereas the highest were found to be 1.4007 and 1.0190 h on deutonymphs, respectively. Amblyseius swirskii had the higher attack rate coefficient (α) on immature stages of C. irani than E. frosti. Attack rate coefficients (α) varied significantly between life stages of both pests with the highest attack rate obtained on eggs, followed by larvae, protonymphs, and deutonymphs. Results of this study suggest that A. swirskii could be a highly efficient biological control agent of E. frosti and C. irani at least at low prey densities.


Author(s):  
Azadeh Farazmand ◽  
Masood Amir-Maafi

Abstract In this research, functional responses of Amblyseius swirskii Athias-Henriot preying on different Tetranychus urticae Koch nymphal densities (2, 4, 8, 16, 32, 64, and 128) were studied at eight constant temperatures (15, 20, 25, 27.5, 30, 32.5, 35 and 37.5°C) in a circular Petri dish (3-cm diameter × 1-cm height) under lab conditions. At all temperatures, the logistic regression showed a type II functional response. A nonlinear relationship was found between temperature and attack rate and the reciprocal of handling time. The reciprocal of handling time decreased exponentially with increasing temperature. In contrast, the attack rate grew rapidly with increasing temperatures up to an optimum, showing a decreasing trend at higher temperatures. In order to quantify the functional response of A. swirskii over a broad range of temperatures and to gain a better estimation of attack rate and handling time, a temperature-settled functional response equation was suited to our data. Our model showed that the number of prey consumed increased with rising prey density. Also, the predation rates increased with increasing temperatures but decreased at extremely high temperatures. Based on our model, the predation rate begins at the lower temperature threshold (11.73°C) and reaches its peak at upper temperature threshold (29.43°C). The coefficient of determination (R2) of the random predator model was 0.99 for all temperatures. The capability of A. swirskii to search and consume T. urticae over a wide range of temperatures makes it a good agent for natural control of T. urticae in greenhouses.


Author(s):  
Sajjad Dalir ◽  
Hamidreza Hajiqanbar ◽  
Yaghoub Fathipour ◽  
Mostafa Khanamani

Abstract The age-specific functional and numerical responses of Neoseiulus cucumeris Oudemans (Mesostigmata: Phytoseiidae) on eggs of the two-spotted spider mite, Tetranychus urticae Koch (Prostigmata: Tetranychidae), were assessed in the laboratory using bean leaf discs. Densities of 2, 4, 8, 16, 32, 64, and 128 prey were provided to 4- (protonymph), 6- (deutonymph), 8-, 13-, 18-, 23-, 28-, 33-, and 40-d-old N. cucumeris individuals. The functional response of 28- and 40-d-old N. cucumeris fitted type II, whereas the other ages displayed a type III functional response. The longest handling time observed at the age of 4 d was 0.515 h, whereas the shortest handling time and highest value of maximum attack rate (T/Th) were associated with the age of the 28-d-old treatment (0.261 h and 91.95 prey/d, respectively). The numerical response of N. cucumeris showed a significant increase with increasing prey density, but its rate gradually decreased at higher densities. Therefore, the efficiency of conversion of ingested food was relatively higher at low two-spotted spider mite densities, whereas it was reduced at high two-spotted spider mite densities. The stronger functional response and predation capacity of N. cucumeris on two-spotted spider mite eggs indicated the high potential of this predatory mite as an effective biological control agent against two-spotted spider mite especially at its early and middle ages and also when higher prey densities are present.


Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 946 ◽  
Author(s):  
Chao Yu ◽  
Lizhi Zhou ◽  
Nazia Mahtab ◽  
Shaojun Fan ◽  
Yunwei Song

Perceiving how animals adjust their feeding rate under a variety of environmental conditions and understanding the tradeoffs in their foraging strategies are necessary for conservation. The Holling functional response, which describes the relationship of feeding rate and food density to searching rate and handling time, has been applied to a range of waterbirds, especially with regard to Type II functional responses that describe an increasing feeding rate with food density but at a decelerating rate as the curve approaches the asymptote. However, feeding behavior components (feeding rate, searching rate, and handling time) are influenced by factors besides prey density, such as vigilance and flock size. In this study, we aim to elucidate how Bewick’s swans (Cygnus columbianus bewickii) adopt flexible foraging strategies and vary their feeding behavior components in response to disturbance, flock size, and food density. We collected focal sampling data on the foraging behavior of swans that foraged rice grains, foxnut seeds, and tubers in paddy field, foxnut pond, and lake habitats, respectively, in Shengjin and Huangpi lakes during winter from 2016 to 2018. The observed feeding rate was not correlated with food density and displayed a positive relationship with searching rate but negative relationships with handling time, flock size, overall vigilance time, and disturbance time. Handling time was negatively correlated with food density and flock size, yet it increased with disturbance, overall vigilance time, and normal vigilance time. Searching rate was negatively correlated with food density, flock size, and disturbance time. Feeding rate was affected by the combined effects of handling time and searching rate, as well as food density and searching rate. The shape of the observed functional response could not be fitted to Holling’s disc equation. However, the disc equation of the predicted feeding rate of wintering swans was found to be driven by food density. This provides insight into how wintering waterbirds adopt appropriate foraging strategies in response to complicated environmental factors, which has implications for wildlife conservation and habitat management.


2021 ◽  
Vol 11 (1) ◽  
pp. 76
Author(s):  
I WAYAN DIRGAYANA ◽  
I WAYAN SUPARTHA ◽  
I NYOMAN WIJAYA

Predation and Functional Response Test of Predator Chysoperla carnea Stephens (Neuroptera: Crysopidae) Against Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae). This study aims to evaluate the predatory capacity of C. carnea by measuring the rate of searching capacity and handling-time of one prey and its functional response to the population density of P. manihoti. The research was conducted at the Integrated Pest Management Laboratory (IPMLab), Faculty of Agriculture, Udayana University. The study was conducted from February to May 2019. Testing of functional responses used a randomized block design with 5 treatments (3, 6, 9, 12, 15 nymphs-3) each of which was repeated 10 times. The results showed that the prey searching-capacity when the population was low (3 nymphs-3) took longer (10.37 minutes), while when the population was high it took a short time (6.23 minutes). The length of time for handling one prey in the low population was 6.08 minutes, while in the high population it was 5.48 minutes. Predator C. carnea has a tpe-2 functional response to an increase in the population of P. manihoti nymphs with the equation Y = 4.32x / 1 + 1.973x (R2 = 0.980). The rate of predation increases sharply when the population of low increases, and decreases when the increase of prey population increases. C. carnea has the potential to be developed as a control agent for P. manihoti.


2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Claudia Dupke ◽  
Anne Peters ◽  
Nicolas Morellet ◽  
Marco Heurich

Abstract Background Holling (Can Entomol 91(5):293–320, 1959) was the first to describe a functional response between a predator’s consumption-rate and the density of its prey. The same concept can be applied to the habitat selection of herbivores, specifically, the change in relative habitat use with the change in habitat availability. Functional responses in habitat selection at a home-range scale have been reported for several large herbivores. However, a link to Holling’s original functional response types has never been drawn, although it could replace the current phenomenological view with a more mechanistically based understanding of functional responses. Methods In this study, discrete choice models were implemented as mixed-effects baseline-category logit models to analyze the variation in habitat selection of a large herbivore at seasonal and diurnal scales. Thus, changes in the use of land cover types with respect to their availability were investigated by monitoring 11 land cover types commonly used by roe deer (Capreolus capreolus) in the Bavarian Forest National Park, Germany. Functional response curves were then fitted using Holling’s formulas. Results Strong evidence of non-linear functional responses was obtained for almost all of the examined land cover types. The shape of the functional response curves varied depending on the season, the time of day, and in some cases between sexes. These responses could be referenced to Holling’s types, with a predominance of type II. Conclusions Our results indicate that Holling’s types can be applied to describe general patterns of the habitat selection behavior of herbivores. Functional responses in habitat selection may occur in situations requiring a trade-off in the selection of land cover types offering different resources, such as due to the temporally varying physiological needs of herbivores. Moreover, two associated parameters defining the curves (prey density and predation rate) can aid in the identification of temporal variations and in determinations of the strength of the cost-benefit ratio for a specific land cover type. Application of our novel approach, using Holling’s equations to describe functional responses in the habitat selection of herbivores, will allow the assignment of general land cover attraction values, independent of availability, thus facilitating the identification of suitable habitats.


2020 ◽  
Vol 16 (1) ◽  
pp. 20190758 ◽  
Author(s):  
Robert P. Dunn ◽  
Kevin A. Hovel

The functional response of a consumer to a gradient of resource density is a widespread and consistent framework used to quantify the importance of consumption to population dynamics and stability. Within benthic marine ecosystems, both crustaceans and fishes can provide strong top-down pressure on prey populations. Taxon-specific differences in biomechanics or habitat use, among other factors, may lead to variable functional response forms or parameter values (attack rate, handling time). Based on a review of 189 individual functional response fits, we find that these predator guilds differ in their frequency distribution of functional response types, with crustaceans exhibiting nearly double the proportion of sigmoidal, density-dependent functional responses (Holling type III) as predatory fishes. The implications of this finding for prey population stability are significant because type III responses allow prey persistence while type II responses are de-stabilizing and can lead to extinction. Comparing per capita predation rates across diverse taxa can provide integrative insights into predatory effects and the ability of predation to drive community structure.


2017 ◽  
Vol 22 (9) ◽  
pp. 1476 ◽  
Author(s):  
Kajal Patel ◽  
Zhi-Qiang Zhang

The tomato/potato psyllid (TPP), Bactericera cockerelli, is a serious pest of some agricultural and ornamental plants, especially of the Solanaceae family. It has been an invasive species in New Zealand since 2006, heavily impacting the potato and tomato industry. The functional and numerical responses of the phytoseiid predators Amblydromalus limonicus and Neoseiulus cucumeris were examined by offering a range of prey densities (two, four, eight, 12, 16, 20, 24 and 28 TPP eggs or 1st instar nymphs) and compared on a capsicum leaf disc under 25 ± 1ºC, 85% ± 5% RH and a 14:10 h light: dark (L:D) photoperiod. Both species displayed a type 2 functional response when fed on eggs or 1st instar nymphs of TPP, indicating an increase in the number of prey killed with an increase in prey population density. The results were analysed by using a logistic regression and Holling disc equation. A. limonicus had a higher attack rate for both eggs (0.05 ± 0.01) and 1st instar nymphs (0.06 ± 0.01) than N. cucumeris, which had an attack rate of (0.03 ± 0.01) for eggs and (0.02 ± 0.01) for 1st instar nymphs of TPP. N. cucumeris had a longer handling time for both eggs (3.68 ± 0.67 hrs) and 1st instar nymphs (2.50 ± 0.79 hrs) compared with A. limonicus, with a handling time of (1.74 ± 0.23 hrs) for eggs and (1.15 ± 0.15 hrs) for 1st instar nymphs. A. limonicus consistently produced significantly more eggs than N. cucumeris across all densities when fed on either eggs or 1st instar nymphs of TPP. However, the results showed the lack of numerical response of both predator species to prey density. The stronger functional response of A. limonicus to TPP eggs and 1st instar nymphs indicates that this species can potentially be a more effective biocontrol agent of TPP than N. cucumeris.


2014 ◽  
Vol 8 (2) ◽  
pp. 80-85
Author(s):  
Bassim. Sh. Hamad ◽  
Ryadh A. Okaily ◽  
George S. B. Yousif ◽  
Ahmed M. Abdullatif ◽  
Hussain F. Alrubeai

The functional response of second and third larval instars of Chrysoperla carnea (Stephens), against different nymphal instars of Dubas bug Ommatissus lybicus De Berg. was studied.The larval instars of the predator exhibited Type II functional responses against the prey. Based on disk equation the attack rate (a) of the second larval instars of the predator were estimated to 1.03± 0.043 , 0.94± 0.015 , 0.88± 0.009 and 0.77 ± 0.02 and the handling time (Th) were 0.0031, 0.0039, 0.0083, and 0.008 day for second, third, fourth and fifth nymphal instars respectively. The third instars larvae of the predator, the attack rate against these nymphal instars were 1.11± 0.01, 1.04 ± 0.29 , 0.97± 0.017 and 0.89 with handling time 0.0019, 0.0028, 0.0064, and 0.0067 day respectively. The theoretical maximum predation(T/Th) of the second larval instars were 322, 256, 120 and114 nymphs for second, third, fourth and fifth nymphal instar respectively; while they were 526, 357, 156, and 149 for the third larval instar. According to this study this predator have a good predation potential in preying on nymph of Dubas bug especially the small nymphs (second and third ).


2017 ◽  
Author(s):  
Yuanheng Li ◽  
Björn C. Rall ◽  
Gregor Kalinkat

AbstractEmpirical feeding studies where density-dependent consumption rates are fitted to functional response models are often used to parametrize the interaction strengths in models of population or food-web dynamics. However, the relationship between functional response parameter estimates from short-term feeding studies and real-world, long-term, trophic interaction strengths remains largely untested. In a critical first step to address this void, we tested for systematic effects of experimental duration and predator satiation on the estimation of functional response parameters, namely attack rate and handling time. Analyzing a large data set covering a wide range of predator taxonomies and body sizes we show that attack rates decrease with increasing experimental duration, and that handling times of starved predators are consistently shorter than those of satiated predators. Therefore, both the experimental duration and the predator satiation level have a strong and systematic impact on the predictions of population dynamics and food-web stability. Our study highlights potential pitfalls at the intersection of empirical and theoretical applications of functional responses. We conclude our study with some practical suggestions how these implications should be addressed in the future to improve predictive abilities and realism in models of predator-prey interactions.


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