scholarly journals Functional Response and Intraspecific Competition in the Fall Armyworm, Spodoptera frugiperda (Lepidoptera: Noctuidae)

Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 806
Author(s):  
Qilin Ren ◽  
Muhammad Haseeb ◽  
Jingyu Fan ◽  
Pengxiang Wu ◽  
Tianqi Tian ◽  
...  
Keyword(s):  
Pest Management ◽  
Functional Response ◽  
Intraspecific Competition ◽  
Management Strategies ◽  
Fall Armyworm ◽  
Handling Time ◽  
Search Rate ◽  
Functional Responses ◽  
Practical Applications ◽  
Larval Stages

Functional responses of the fall armyworm (FAW) larvae at each stage, and their intraspecific competition associated with cannibalism, provide insights into developing pest management strategies for the FAW. To help use insecticides more sparingly, the functional response and intraspecific competition of the FAW larvae were evaluated under the laboratory conditions. The results showed that all stages of the FAW larvae displayed a type II functional response to diet. Based on Holling’s disc equation, the search rate (a) and handling time (Th) of sixth instar larvae (a = 0.493; Th = 0.37 min) were the highest, and the shortest of all larval stages, respectively. Intraspecific competition curves fitted the data for fourth to sixth larval stages of the FAW, and the coefficient of intraspecific competition (m) assessed by the intraspecific competition equation were highest for fifth instar larvae (m = 0.48). The present study indicates that 5th and 6th instar larvae can cause the most plant damage (accounted for 88.9% of larval consumption), and these stages should be the focus of any pest management strategy. Intraspecific competition, especially cannibalism, impacts the feeding patterns of the FAW larvae and needs close attention. Understanding the functional response and intraspecific competition of the FAW larvae contributes greatly to practical applications of insecticides, increasing the effectiveness of chemical sprays and decreasing ecological damage.

Use of Functional Response Modeling to Evaluate the Effect of Temperature on Predation of Amblyseius swirskii (Acari: Phytoseiidae) Adults Preying on Tetranychus urticae (Acari: Tetranychidae) Nymphs

2021 ◽  
Author(s):  
Azadeh Farazmand ◽  
Masood Amir-Maafi
Keyword(s):  
Functional Response ◽  
Tetranychus Urticae ◽  
Attack Rate ◽  
Handling Time ◽  
Effect Of Temperature ◽  
Coefficient Of Determination ◽  
Temperature Threshold ◽  
Amblyseius Swirskii ◽  
Functional Responses ◽  
Wide Range

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.

scholarly journals Functional Response of Chrysoperla carnea (Neuroptera: Chrysopidae) Larvae on Saissetia oleae (Olivier) (Hemiptera: Coccidae): Implications for Biological Control

Agronomy ◽  
2020 ◽  
Vol 10 (10) ◽  
pp. 1511
Author(s):  
Abdelkader Meni Mahzoum ◽  
María Villa ◽  
Jacinto Benhadi-Marín ◽  
José Alberto Pereira
Keyword(s):  
Functional Response ◽  
Attack Rate ◽  
Larval Instar ◽  
Food Resource ◽  
Handling Time ◽  
Scale Insects ◽  
Chrysoperla Carnea ◽  
Larval Stages ◽  
The Third ◽  
Saissetia Oleae

Chrysoperla carnea (Stephens) (Neuroptera: Chrysopidae) is a voracious predator of soft-bodied insects such as juveniles of scale insects and the black scale Saissetia oleae (Olivier) (Hemiptera: Coccidae) is an important pest of several crops, such as the olive tree. However, the predatory efficiency of C. carnea on S. oleae has been unstudied yet. The present work aimed to study the functional response of larvae of C. carnea fed on S. oleae nymphs. In a controlled laboratory environment, increasing densities of S. oleae second and third nymph stages were offered to newly emerged specimens of the three larvae instars of C. carnea. After 24 h, the number of killed S. oleae was recorded and the functional response of C. carnea was assessed. The three larval stages of C. carnea displayed a type-II functional response, i.e., killed prey increased with higher S. oleae densities up to a maximum limited by the handling time. The attack rate did not significantly differ among the three instars while the maximum attack rate was significantly higher for the third instar. The handling time of the first larval instar of C. carnea was higher than that of the third instar. Our results demonstrated that S. oleae could act as a food resource for all larval stages of C. carnea. Furthermore, the third larval stage of the predator was the most efficient in reducing S. oleae densities. These results suggest that C. carnea larvae could contribute to S. oleae control in sustainable agriculture.

scholarly journals The Influence of Food Density, Flock Size, and Disturbance on the Functional Response of Bewick’s Swans (Cygnus columbianus bewickii) in Wintering Habitats

Animals ◽  
2019 ◽  
Vol 9 (11) ◽  
pp. 946 ◽  
Author(s):  
Chao Yu ◽  
Lizhi Zhou ◽  
Nazia Mahtab ◽  
Shaojun Fan ◽  
Yunwei Song
Keyword(s):  
Feeding Behavior ◽  
Functional Response ◽  
Habitat Management ◽  
Feeding Rate ◽  
Handling Time ◽  
Foraging Strategies ◽  
Food Density ◽  
Flock Size ◽  
Functional Responses ◽  
Cygnus Columbianus

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.

scholarly journals Functional response of the predatory mite Amblyseius swirskii (Acari: Phytoseiidae) to Eotetranychus frosti (Tetranychidae) and Cenopalpus irani (Tenuipalpidae)

Acarologia ◽  
2020 ◽  
Vol 60 (1) ◽  
pp. 30-39
Author(s):  
Fereshteh Bazgir ◽  
Jahanshir Shakarami ◽  
Shahriar Jafari
Keyword(s):  
Biological Control ◽  
Functional Response ◽  
Attack Rate ◽  
Biological Control Agent ◽  
Handling Time ◽  
Rate Coefficients ◽  
Immature Stages ◽  
Amblyseius Swirskii ◽  
Functional Responses ◽  
Phytoseiid Mites

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.

scholarly journals Uji Pemangsaan dan Tanggap Fungsional Predator Chysoperla carnea Stephens (Neuroptera: Crysopidae) Terhadap Phenacoccus manihoti Matile-Ferrero (Hemiptera: Pseudococcidae)

2021 ◽  
Vol 11 (1) ◽  
pp. 76
Author(s):  
I WAYAN DIRGAYANA ◽  
I WAYAN SUPARTHA ◽  
I NYOMAN WIJAYA
Keyword(s):  
Functional Response ◽  
Block Design ◽  
Handling Time ◽  
Control Agent ◽  
Phenacoccus Manihoti ◽  
Functional Responses ◽  
Randomized Block Design ◽  
Predatory Capacity ◽  
Short Time ◽  
Prey Searching

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.

scholarly journals Predator type influences the frequency of functional responses to prey in marine habitats

2020 ◽  
Vol 16 (1) ◽  
pp. 20190758 ◽  
Author(s):  
Robert P. Dunn ◽  
Kevin A. Hovel
Keyword(s):  
Functional Response ◽  
Handling Time ◽  
Type Ii ◽  
Population Stability ◽  
Functional Responses ◽  
Type Iii ◽  
Marine Habitats ◽  
Per Capita ◽  
Predatory Fishes ◽  
Parameter Values

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.

scholarly journals The functional response of, Chrysoperla carnea (Stephens) larvae on different nymphal instars of Dubas bug Ommatissus lybicus De Berg.

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
Keyword(s):  
Functional Response ◽  
Attack Rate ◽  
Larval Instar ◽  
Handling Time ◽  
Chrysoperla Carnea ◽  
Type Ii ◽  
Nymphal Instar ◽  
Functional Responses ◽  
Larval Instars ◽  
The Third

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 ).

scholarly journals Detecting the Conspecific: Herbivory-Induced Olfactory Cues in the Fall Armyworm (Lepidoptera: Noctuidae)

Metabolites ◽  
2021 ◽  
Vol 11 (9) ◽  
pp. 583
Author(s):  
David A. Ingber ◽  
Shawn A. Christensen ◽  
Hans T. Alborn ◽  
Ivan Hiltpold
Keyword(s):  
Pest Management ◽  
Management Strategies ◽  
Fall Armyworm ◽  
Head Capsule ◽  
Larval Feeding ◽  
Bt Toxins ◽  
Management Context ◽  
Feeding Trials ◽  
Corn Plants ◽  
Lepidoptera Noctuidae

The fall armyworm, Spodoptera frugiperda (Smith), is a polyphagous pest whose larval feeding threatens several economically important crops worldwide with especially severe damage to corn (Zea mays L.). Field-derived resistance to several conventional pesticides and Bt toxins have threatened the efficacy of current management strategies, necessitating the development of alternative pest management methods and technologies. One possible avenue is the use of volatile organic compounds (VOCs) and other secondary metabolites that are produced and sequestered by plants as a response to larval feeding. The effects of conspecific larval feeding on fall armyworm oviposition preferences and larval fitness were examined using two-choice oviposition experiments, larval feeding trials, targeted metabolomics, and VOC analyses. There was a significant preference for oviposition on corn plants that lacked larval feeding damage, and larvae fed tissue from damaged plants exhibited reduced weights and head capsule widths. All larval feeding promoted significantly increased metabolite and VOC concentrations compared to corn plants without any feeding. Metabolite differences were driven primarily by linoleic acid (which is directly toxic to fall armyworm) and tricarboxylic acids. Several VOCs with significantly increased concentrations in damaged corn plants were known oviposition deterrents that warrant further investigation in an integrated pest management context.

scholarly journals Temperature and host dependent functional response of Anisopteromalus calandrae (How.) and Choetospila elegans (Westw.) parasitods in parasitizing wheat infesting Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae)

2019 ◽  
Vol 47 (1) ◽  
pp. 41-47
Author(s):  
MM Rahman ◽  
W Islam
Keyword(s):  
Functional Response ◽  
Host Density ◽  
Handling Time ◽  
Rhyzopertha Dominica ◽  
Search Rate ◽  
C Elegans ◽  
Seed Flour ◽  
Whole Wheat ◽  
Rhizopertha Dominica ◽  
Anisopteromalus Calandrae

Rhizopertha dominica (F.) (Coleoptera: Bostrichidae) is an internal feeder of whole wheat seed, flour, etc. R. dominica is parasitized by two pteromalid ectoparasitoids, Anisoptetromalus calandrae (How.) and Choetospila elegans (Westw.) in the larval and pupal stages. The effects of host density and temperature on the functional response of the parasitoids in parasitizing the larval and pupal stages of the hosts were examined. Four temperatures and five host densities were used. A functional response equation was used in which a quadratic component that included temperature was substituted for handling time. Functional response of parasitization by A. calandrae and C. elegans fit a formula of Hassell et al. (1977) type III model. The maximum rate of parasitization of A. calandrae was 8.6 larvae/24 hrs and 7.2 larvae/24 hrs of C. elegans at 30ºC, respectively. Handling time and instantaneous search rate varied with temperatures. The ability of A. calandrae and C. elegans to find and parasitize R. dominica over a broad range of temperatures demonstrate it as a good candidate for natural control of the pest. Bangladesh J. Zool. 47(1): 41-47, 2019

scholarly journals Experimental duration and predator satiation levels systematically affect functional response parameters

2017 ◽  
Author(s):  
Yuanheng Li ◽  
Björn C. Rall ◽  
Gregor Kalinkat
Keyword(s):  
Food Web ◽  
Functional Response ◽  
Large Data ◽  
Handling Time ◽  
Set Covering ◽  
Parameter Estimates ◽  
Functional Responses ◽  
Predator Satiation ◽  
Data Set ◽  
Wide Range

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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