Tolerance and functional response of Neoseiulus californicus (McGregaor) to starvation stress

Author(s):  
Xiao-Bo Li ◽  
Rui Zhu ◽  
Tian-Ci Yi ◽  
Jian-Jun Guo ◽  
Dao-Chao Jin

The ability to endure starvation is important for predatory mite survival and its effectiveness as biological control agent. We studied the longevity and functional response of the prodator mite Neoseiulus californicus (McGregaor) under starvation stress. N. californicus individuals were treated as three groups: the mites were provided with nothing (group I), with fresh bean leaves (group II), and with water (group III) to the larvae, protonymphs, deutonymphs, adult males and females. Functional response of N. californicus to Tetranychus urticae Koch eggs was evaluated after starvation for 0 h, 24 h, 48 h, and 72 h. Results showed that all life stages of N. californicus in group III had the longest survival time among the three groups. Adult females had the strongest ability to endure starvation with a mean survival time of 8.16 d. Females had the ability to lay eggs, but the number of eggs laid was less than a mean of 1.2 eggs per female in the three starvation groups. N. californicus exhibited a Holling’s Type II functional response at all hunger levels. The handling time (Th) and attack rate (α) of the predator were not significantly different in all hunger levels. Predation rate of starved 0 h to 72 h initially increased and then decreased. The highest predation rate was recorded when the predators were starved for 24 h.

2017 ◽  
Vol 22 (2) ◽  
pp. 159 ◽  
Author(s):  
Yaghoub Fathipour ◽  
Maryam Karimi ◽  
Azadeh Farazmand ◽  
Ali Asghar Talebi

The lifetime functional response and predation rate of Amblyseius swirskii Athias-Henriot on eggs of the two-spotted spider mite, Tetranychus urticae Koch were determined under laboratory conditions using cucumber leaf discs. Densities of 2, 4, 8, 16, 32, 64 and 128 prey were offered to 3, 4, 5, 6, 7, 12, 17, 22 and 27-day-old A. swirskii individuals. Based on the logistic regression, the functional response of twelve-day-old A. swirskii was type III, while the other ages showed type II. The Rogers model was used to estimate searching efficiency (a) and handling time (Th). The longest handling time (1.387±0.315 h) was observed in the protonymphal stage, while the shortest handling time and highest maximum attack rate (T/Th) were estimated at the age of seven-days (0.396±0.057 h and 60.67 prey/day, respectively). In the functional response experiments, results of the highest prey density used (128 eggs) showed that the highest number of prey consumed by A. swirskii individuals aged twelve and seventeen-days old (35.6 and 43.1 eggs, respectively). It is concluded that A. swirskii could be an efficient biological control agent of T. urticae at the middle-age of its life and at higher prey densities. 


2016 ◽  
Vol 2016 ◽  
pp. 1-9 ◽  
Author(s):  
Sara Zarghami ◽  
Mohammad Saeed Mossadegh ◽  
Farhan Kocheili ◽  
Hossein Allahyari ◽  
Arash Rasekh

Nephus arcuatusKapur is an important predator ofNipaecoccus viridis(Newstead), in citrus orchards of southwestern Iran. This study examined the feeding efficiency of all stages ofN. arcuatusat different densities ofN. viridiseggs by estimating their functional responses. First and 2nd instar larvae as well as adult males exhibited a type II functional response. Attack rate and handling time were estimated to be 0.2749 h−1and 5.4252 h, respectively, for 1st instars, 0.5142 h−1and 1.1995 h for 2nd instars, and 0.4726 h−1and 0.7765 h for adult males. In contrast, 3rd and 4th instar larvae and adult females ofN. arcuatusexhibited a type III functional response. Constantband handling time were estimated to be 0.0142 and 0.4064 h for 3rd instars, respectively, 0.00660 and 0.1492 h for 4th instars, and 0.00859 and 0.2850 h for adult females. The functional response of these six developmental stages differed in handling time. Based on maximum predation rate, 4th instar larvae were the most predatory (160.9 eggs/d) followed by adult females (84.2 eggs/d). These findings suggest thatN. arcuatusis a promising biocontrol agent ofN. viridiseggs especially for 4th instar larvae and adult females.


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.


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.


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):  
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.


2015 ◽  
Vol 148 (1) ◽  
pp. 112-117 ◽  
Author(s):  
Agustín Hernández-Juárez ◽  
Luis A. Aguirre-Uribe ◽  
Aideé González-Ruíz ◽  
Julio C. Chacón-Hernández ◽  
Jerónimo Landeros-Flores ◽  
...  

AbstractThe effect of the insecticide endosulfan on the predatory efficiency of the green lacewing, Chrysoperla carnea Stephens (Neuroptera: Chrysopidae) on the eggs of tobacco budworm, Heliothis virescens (Fabricius) (Lepidoptera: Noctuidae) and fall armyworm, Spodoptera frugiperda (Smith) (Lepidoptera: Noctuidae) was measured with Holling’s disc equation. Though the type II functional response was maintained in C. carnea exposed to endosulfan, the functional response parameters: attack rate (a′), handling time (Th), total handling time (Tht), searching time (Ts), and search efficiency (E) were affected for both prey offered. The predator took more time to identify, pursue, capture, consume, and digest the prey, and in general, the efficiency of the predator as a biological control agent was adversely affected.


Insects ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 530
Author(s):  
Gonçalo Abraços-Duarte ◽  
Susana Ramos ◽  
Fernanda Valente ◽  
Elsa Borges da Silva ◽  
Elisabete Figueiredo

Dicyphine mirids are important biological control agents (BCAs) in horticultural crops. Dicyphus cerastii Wagner can be found in protected tomato crops in Portugal, and has been observed feeding on several tomato pests. However, the predation capacity of this species is poorly studied. In order to investigate the predation capacity of D. cerastii, and how it is affected by prey size and mobility, we evaluated the functional response (FR) and predation rate of female predators on different densities of four prey species: Myzus persicae 1st instar nymphs (large mobile prey), Bemisia tabaci 4th instar nymphs, Ephestia kuehniella eggs (large immobile prey) and Tuta absoluta eggs (small immobile prey). Experiments were performed on tomato leaflets in Petri dish arenas for 24 h. Dicyphus cerastii exhibited type II FR for all prey tested. The predator effectively preyed upon all prey, consuming an average of 88.8 B. tabaci nymphs, 134.4 E. kuehniella eggs, 37.3 M. persicae nymphs and 172.3 T. absoluta eggs. Differences in the FR parameters, attack rate and handling time, suggested that prey size and mobility affected predation capacity. Considering the very high predation rates found for all prey species, D. cerastii proved to be an interesting candidate BCA for tomato crops.


2021 ◽  
pp. 000313482110385
Author(s):  
Jisheng Zhu ◽  
Wang Hu ◽  
Yang Zhang ◽  
Peng Du ◽  
Weidong Xiao ◽  
...  

Background Chemotherapy is the standard of treatment for metastatic gallbladder carcinoma (GBC). It is unclear whether chemotherapy plus surgery improves the survival outcomes of patients with isolated liver metastases from GBC. We aimed to investigate the survival benefits of chemotherapy plus surgery in GBC with isolated liver metastases compared to those of chemotherapy alone. Methods We identified 406 patients with isolated liver metastases from GBC who underwent chemotherapy alone or chemotherapy plus surgery between 2010 and 2015 from Surveillance, Epidemiology, and End Results. Patients were divided into 3 subgroups: group I, chemotherapy alone (n = 263); group II, chemotherapy combined with cholecystectomy (n = 116); and group III, chemotherapy combined with cholecystectomy plus hepatectomy (n = 27). The cancer-specific survival and overall survival were evaluated. Results Compared with group I, group II revealed a longer survival time (P < .001). In addition, the survival time of the group III was also prolonged (P < .001). Multivariate cox analysis showed that treatment strategy was an independent prognostic factor. Conclusion Chemotherapy combined with resection of the primary tumor plus or not plus resection of the metastatic lesions may be beneficial in GBC with isolated liver metastases.


1986 ◽  
Vol 65 (6) ◽  
pp. 745-750 ◽  
Author(s):  
Ann R. Stroink ◽  
Harold J. Hoffman ◽  
E. Bruce Hendrick ◽  
Robin P. Humphreys

✓ The authors reviewed the cases of 49 children, ranging in age from 9 months to 15 years, who were diagnosed by computerized tomography (CT) as having brain-stem glioma. Four distinct groups of brain-stem gliomas were identified based on CT scan characteristics: Group I included isodense contrast-enhancing tumors that were dorsally exophytic into the fourth ventricle; Group II(a) included hypodense nonenhancing intrinsic tumors of the brain stem; Group II(b) included intrinsic tumors of the brain stem with hyperdense exophytic components extending ventrally and laterally into the cerebellopontine and prepontine cisterns; Group III included intrinsic cystic tumors with contrast-enhancing capsules; and Group IV included focally intrinsic tumors of the brain stem that were isodense and enhanced brightly on administration of contrast medium. The clinical presentation, efficacy of surgical intervention, pathology, and prognosis of these tumors were correlated within these groupings. Eleven patients had Group I tumors, all of which were surgically resected; 10 of the 11 lesions were proven to be low-grade gliomas. These patients had an excellent prognosis; 10 of the 11 survived, with a mean follow-up period of 4.5 years. There were 18 patients with Group II(a) tumors; although tumor biopsy was attempted on eight of these, pathological diagnosis at the time of surgery was made in only one case. These patients did poorly; the mean survival time was 6.2 months. The seven Group II(b) tumor patients demonstrated a similarly poor prognosis: all of them died within 23 months of diagnosis, with a mean survival time of 12 months. Only two of six patients undergoing biopsy had sufficient tissue for histological verification. Three of the four patients with Group III tumors died; their mean survival time was 11.5 months. Successful histological examination was carried out in all four cases. The nine Group IV tumor patients did reasonably well; seven of these patients remain alive, with a mean follow-up period of 2.3 years. Histological diagnosis was obtained in three of the seven patients who were explored in this group. This classification system has proven to be of value in determining prognosis and efficacy of surgical intervention.


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