Functional and numerical responses of Iphiseius degenerans (Berlese) (Acari: Phytoseiidae) to different biological stages of Eutetranychus orientalis (Klein) (Acari: Tetranychidae)*

Author(s):  
İsmail Döker ◽  
Kemal Yalcin ◽  
Kamil Karut ◽  
Cengiz Kazak

Functional and numerical responses of the predatory mite, Iphiseius degenerans (Berlese) (Acari: Phytoseiidae) to four different biological stages (egg, larva, protonymph and adult male) of the citrus brown mite, Eutetranychus orientalis (Klein) (Acari: Tetranychidae) were determined under laboratory conditions. In the experiments, six different prey densities (5, 10, 20, 40, 60 and 80) for each biological stage of the prey were provided to the predatory mite for 24 hours. Results showed that the proportion of prey consumption of I. degenerans decelerated with increasing prey densities of all biological stages of the prey. Logistic regression analysis indicated that I. degenerans showed a Type II functional response regardless of prey stage. The attack rate (α) and the handling time (Th) varied based on the biological stages. The highest α (1.596) and the lowest Th (0.014) values were determined when the predator fed on adult males and larvae of E. orientalis, respectively. The numerical response curves were similar to those of Type II functional response. The efficiency of conversion of ingested food (ECI) of female I. degenerans decreased on all biological stages when prey density increased. The highest and the lowest average daily mean number of eggs laid by I. degenerans were found as 0.45 and 1.90 when it fed on eggs and larvae of its prey, respectively. According to the results, I. degenerans has a potential to be used as a predator in biological control of E. orientalis.

2022 ◽  
Vol 154 ◽  
Author(s):  
Desh Deepak Chaudhary ◽  
Bhupendra Kumar ◽  
Geetanjali Mishra ◽  
Omkar

Abstract In the present study, we assessed functional response curves of two generalist coccinellid beetles (Coleoptera: Coccinellidae), specifically Menochilus sexmaculatus and Propylea dissecta, using fluctuating densities of aphid prey as a stimulus. In what may be the first such study, we investigated how the prey density experienced during the early larval development of these two predatory beetle species shaped the functional response curves of the late instar–larval and adult stages. The predators were switched from their rearing prey-density environments of scarce, optimal, or abundant prey to five testing density environments of extremely scarce, scarce, suboptimal, optimal, or abundant prey. The individuals of M. sexmaculatus that were reared on either scarce- and optimal- or abundant-prey densities exhibited type II functional response curves as both larvae and adults. However, individuals of P. dissecta that were reared on scarce- and abundant-prey densities displayed modified type II functional response curves as larvae and type II functional response curves as adults. In contrast, individuals of P. dissecta reared on the optimal-prey density displayed type II functional response curves as larvae and modified type II functional response curves as adults. The fourth-instar larvae and adult females of M. sexmaculatus and P. dissecta also exhibited highest prey consumption (T/Th) and shortest prey-handling time (Th) on the scarce-prey rearing density. Thus, under fluctuating-prey conditions, M. sexmaculatus is a better biological control agent of aphids than P. dissecta is.


2009 ◽  
Vol 9 (1) ◽  
pp. 15-21
Author(s):  
Hidrayani Hidrayani ◽  
Aunu Rauf ◽  
S. Sosromarsono ◽  
U. Kartosuwondo

The preference and functional response of Parasitoid Hemiptarsenus varicornis (Girault) (Hymenoptera:Eulophidae) on host larvae of potato leafminers. The preference of Hemiptarsenus varicornis (Girault) on host larvae of potato leafminers (Liriomyza huidobrensis) and their  functional response on host abundance were studied in laboratory. The preference test was conducted by releasing a female parasitoid in a cage containing two redbean leaves, one with 2nd instar and another one with 3rd instar.  The functional response test was conducted by providing 3rd instar  with density 1, 4, 6, 8, 10, and 13  larvae  per leaf. The result showed that  H. varicornis had the preference on 3rd instar  larvae compared to 2nd instar, either for parasitisation or paralysis. Based on logistic regression analysis it was found that the parasitoid showed type II functional response on the increase of host abundance. The searching rate (a) and handling time (Th) for paralysis were 0.038 and 1.473 based on disk equation model, and 0.076 and 2.060 on ramdom equation model.  For parasitisation activity, the value of  a and Th were  0.012 and 4.649 based on disk equation model, and 0.014 and 5.075 on random equation model.


2011 ◽  
Vol 51 (4) ◽  
pp. 423-428 ◽  
Author(s):  
Reza Sabaghi ◽  
Ahad Sahragard ◽  
Reza Hosseini

Functional and Numerical Responses ofScymnus SyriacusMarseul (Coleoptera: Coccinellidae) to the Black Bean Aphid,Aphis FabaeScopoli (Hemiptera: Aphididae) Under Laboratory ConditionsFunctional and numerical responses are basic to any investigation of predator-prey relationships and key components in the selection of predators for biological control. In this study, functional and numerical responses of the female and male ladybeetles,Scymnus syriacusMarseul to different densities of third instar nymphs ofAphis fabae(i.e.5, 10, 20, 30, 40, 60 and 80) as prey, were studied in a growth chamber (25°C, 65±5% RH and a photoperiod of 16L : 8D h) on the broad bean,Vicia fabaeLinn. Using the logistic regression, a type II functional response for both female and male ladybeetles was determined. Using Nonlinear least-square regression, the searching efficiency (a') and handling times (Th) of the female and male adults were estimated as 0.123±0.006 h, 0.434±0.012 h and 0.115±0.008 h, 0.514±0.016, respectively. The Rogers model was used to estimate the maximum theoretical predations (T/Th) for female and male, which were 55.18 and 46.64, respectively. These results indicated a higher efficiency in female ladybeetles. The reproductive numerical response, in terms of eggs laid, increased curvlinearly with increasing prey density. The reproductive response trend was similar to the shape of the type II functional response. This similarity means both responses are interlinked and function simultaneously. The efficiency of the ingested food conversion (ECI) of the females decreased with prey density, as females laid 25±0.65 eggs when exposed to the highest prey density (80) and 3±0.44 eggs at lowest prey density (5).


1997 ◽  
Vol 32 (3) ◽  
pp. 271-280 ◽  
Author(s):  
R. L. Meagher ◽  
L. A. Locke

Predation rates for the anthocorid predator Lyctocoris campestris (F.) against varying densities of late-instar Plodia interpunctella (Hübner) were compared in whole corn, whole wheat, or rolled oat stored commodities. More prey were attacked in corn and wheat than in oats, and female predators generally fed on more larvae than did male predators. Predation increased with an increase in prey density. This relationship was best described by a Type II functional response equation. Our results suggest that commodity type affects the number of prey attacked by this predator.


2014 ◽  
Vol 105 (1) ◽  
pp. 121-128 ◽  
Author(s):  
D.D. Chaudhary ◽  
B. Kumar ◽  
G. Mishra ◽  
Omkar

AbstractIn the present study, resource partitioning by natural conspecific size variants (small and large) of ladybird,Menochilus sexmaculatus(Fabricius) females, in response to varying prey densities was assessed using functional and numerical responses as measures of prey density. The prey provided was small (second) and large (fourth) instars ofAphis craccivoraKoch. Results revealed that under choice condition, small and large females ofM. sexmaculatusconsumed higher number of small and large instars, respectively. Small females exhibited a modified Type II functional response on small aphid instars and a Type II functional response on fourth aphid instars. Large females exhibited a Type II functional response when provided either second or fourth aphid instars. Numerical response in terms of numbers of eggs laid by both the females increased with increase in the density of either of the aphid instars. However, in small females, oviposition had a positive correlation with the numbers of small and large aphid instars consumed; being strong for the small aphid instars. While in large females, oviposition was positively correlated with the numbers of large aphid instars consumed and not small aphid instars. It therefore seems that intraspecific resource partitioning inM. sexmaculatusoccurs prominently in large females than the small females.


2016 ◽  
Vol 283 (1828) ◽  
pp. 20151557 ◽  
Author(s):  
Allert I. Bijleveld ◽  
Robert B. MacCurdy ◽  
Ying-Chi Chan ◽  
Emma Penning ◽  
Rich M. Gabrielson ◽  
...  

Negative density-dependence is generally studied within a single trophic level, thereby neglecting its effect on higher trophic levels. The ‘functional response’ couples a predator's intake rate to prey density. Most widespread is a type II functional response, where intake rate increases asymptotically with prey density; this predicts the highest predator densities at the highest prey densities. In one of the most stringent tests of this generality to date, we measured density and quality of bivalve prey (edible cockles Cerastoderma edule ) across 50 km² of mudflat, and simultaneously, with a novel time-of-arrival methodology, tracked their avian predators (red knots Calidris canutus ). Because of negative density-dependence in the individual quality of cockles, the predicted energy intake rates of red knots declined at high prey densities (a type IV, rather than a type II functional response). Resource-selection modelling revealed that red knots indeed selected areas of intermediate cockle densities where energy intake rates were maximized given their phenotype-specific digestive constraints (as indicated by gizzard mass). Because negative density-dependence is common, we question the current consensus and suggest that predators commonly maximize their energy intake rates at intermediate prey densities. Prey density alone may thus poorly predict intake rates, carrying capacity and spatial distributions of predators.


2004 ◽  
Vol 64 (2) ◽  
pp. 309-316 ◽  
Author(s):  
L. da Rocha ◽  
L. R. Redaelli

This study evaluated the functional response of the predator Cosmoclopius nigroannulatus on first instar nymphae of Spartocera dentiventris, both species associated with Nicotina tabacum. The experiment was carried out in laboratory conditions: 27 ± 1ºC; 80 ± 5%, RH; 12 h, photophase. Ten newly emerged adults of each sex of C. nigroannulatus were used in each of five densities (5, 15, 25, 35, and 45 individuals) of S. dentiventris nymphae. The predators were observed every 24 h for five days, when the number of dead and/or consumed nymphae was recorded. The results showed a positive correlation between the number of ingested nymphae and the increase in prey density. Females ingested more nymphae than the males. The estimated handling time per prey (Th) was higher in males (3.07 h) than in females (1.93 h), with total handling time (Th x Na) increased with density. Other components of the functional response, such as attack rate (a'), searching time (Ts), and search efficiency (E) showed, in neither males nor females, a negative correlation regarding density. The results indicated a higher predatory efficiency in the females. The components of the functional response fitted significantly the randomic model of the Holling discs equation (Na = N {1 - exp[- a'(T - ThNa)]}), evidencing a functional response of type II.


2021 ◽  
Vol 26 (3) ◽  
pp. 543-556
Author(s):  
Yaghoub Fathipour ◽  
Bahador Maleknia ◽  
Abdoolnabi Bagheri ◽  
Mahmoud Soufbaf ◽  
Myron P. Zalucki

Parameters that describe foraging behavior play a key role in selection of natural enemies used in biological control programs. These parameters are greatly affected by patch condition and food source type. This study was carried out to evaluate foraging behavior in Neoseiulus barkeri (Hughes) (Acari: Phytoseiidae), a predatory mite of Tetranychus urticae Koch under different patch and diet conditions. The predation rate of N. barkeri at different egg and nymph densities of T. urticae (2, 4, 8, 16, 32, 64, 128) was investigated in both limited and unlimited patches either in the presence or absence of pollen as an additional food source under laboratory conditions. A Type II functional response was determined for N. barkeri on eggs or nymphs of T. urticae in both unlimited and limited patches. The type of functional response was not affected by presence or absence of pollen. The numerical response, in terms of eggs laid, increased curvilinear with increasing prey density. The numerical response was similar in shape to a Type II functional response. The efficiency of conversion of ingested food (ECI) of female N. barkeri decreased in all treatments when prey density increased. The type of patch (limited or unlimited) and prey stage (egg or nymph in the presence or absence of pollen) can affect searching efficiency (a) and handling time (Th) (functional response) as well as daily fecundity and ECI (numerical response) of the phytoseiid predator mite, N. barkeri with implications for its use in biological control.


2020 ◽  
Author(s):  
Said OUASSAT ◽  
Latifa Allam

Abstract Background The functional response of a predator is one of the fundamental methods in ecological studies. Typhlodromus (T.) setubali (Dosse) is an indigenous predaceous mite recently re-described in Morocco. It was reported on various crops around the Mediterranean basin. This study aims to assess the functional response of T. (T.) setubali to the densities of 2, 4, 8, 16, 32, 64, and 128 immature stages of Panonychus ulmi under the controlled conditions of 26 ± 1 °C, 65 ± 5 % RH and 16:8 h L: D photoperiod. The logistic regression was used to determine the functional response and the oviposition activity of predator females was followed to evaluate the numerical response. Thereafter, both parameters (the attack rate (α) and handling time (Th)) were estimated and the results were entirely discussed. Results Logistic regression analysis revealed a Holling type II functional response, indicating that the number of P. ulmi killed by T. (T.) setubali females increased as the prey density increased. The values of attack rate (α) and handling time (Th) were 0.029 prey/ day and 0.573 prey, respectively. The oviposition of females increased above the prey density of 6.54 mites/cm2 and the highest value (m) was 1.86 eggs/ day. Finally, the prey density needed to achieve half the maximum response (n) was estimated to be 2.15 prey.Conclusions The functional response analysis is one of the most rigorous methods for understanding the ecophysiology of a predator. The proportions of prey consumed by T. (T.) setubali were higher at lower densities for P. ulmi immatures, implying that T. (T.) setubali should be more effective at suppressing the red spider mite populations at lower densities. Further laboratory-based studies are needed to draw biological conclusions.


2001 ◽  
Vol 36 (1) ◽  
pp. 1-8 ◽  
Author(s):  
Shoil M. Greenberg ◽  
Benjamin C. Legaspi ◽  
Walker A. Jones

Functional responses and mutual interference were compared in an indigenous parasitoid, Encarsia pergandiella Howard (Hymenoptera: Aphelinidae), with that of an exotic parasitoid, Eretmocerus mundus Mercet (Aphelinidae) from Spain, attacking the silverleaf whitefly, Bemisia argentifolii Bellows and Perring (Homoptera: Aleyrodidae). Type II functional response curves were fitted to the data and were used to calculate handling time. Eretmocerus mundus attacked more whitefly nymphs than E. pergandiella. Handling times estimated from the functional responses were 72 min for E. pergandiella and 12 min for E. mundus, suggesting that lower attack rates for the former parasitoid may be attributed to longer handling times. The statistically estimated handling time for E. mundus was compared with an estimate derived from empirical observations of parasitoid behavior. Actual observations of handling time, defined as oviposition, host feeding and associated preening, yielded a mean handling time of <2 min, suggesting that functional response experiments may not produce reliable estimates of handling time. The mutual interference coefficient m of E. mundus was numerically higher than that for E. pergandiella (0.238 vs 0.184, respectively). Although there were no significant differences in m, the comparison raises the interesting question of whether parasitoids with higher attack rates may also have higher levels of mutual interference under conditions of high parasitoid density (e.g., mass rearing).


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