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

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

1992 ◽  
Vol 27 (4) ◽  
pp. 375-382 ◽  
Author(s):  
Lincoln Smith ◽  
John W. Press

The functional response of Anisopteromalus calandrae (Howard) was measured on rice weevil, Sitophilus oryzae (L.) (Coleoptera: Curculionidae), in wheat at 30° C. Four female parasitoids, with males, were allowed to oviposit during their lifespan on 166 to 678 weevils per container. The data were fit by Rogers' (1972) random parasitoid model with rate of parasite search a = 0.32 lifespan−1 and handling time Th= 0.0027 lifespan. Volume of grain, in the range of 0.19 to 3.1 l wheat, had no effect on number of hosts parasitized when host numbers were held constant at 222, 398, and 572 weevils per container. Therefore, it may be more appropriate to consider numbers of hosts present rather than host density when studying functional response within a patch of uniformly distributed hosts.


2003 ◽  
Vol 135 (1) ◽  
pp. 93-101 ◽  
Author(s):  
C.E. Rutledge ◽  
S.D. Eigenbrode

AbstractCrop cultivar can affect the ability of natural enemies to control pest populations. Peas, Pisum sativum L. (Fabaceae), with a reduced epicuticular wax bloom have reduced pea aphid, Acyrthosiphon pisum (Harris) (Hemiptera: Aphididae), populations in the field than peas with a normal-wax bloom. In this paper we use the functional response to examine predation by Hippodamia convergens Guérin de Méneville (Coleoptera: Coccinellidae) larvae foraging on pea plants with a normal- and a reduced-wax bloom. We found that Hippodamia convergens shows a Type II functional response on both phenotypes of peas. Hippodamia convergens consumed significantly more pea aphids on reduced-wax plants than on normal-wax plants. The instantaneous search rate, a, was higher for predators on reduced-wax plants, but the handling time, Th, was similar for predators on both wax phenotypes. In addition, we tested the ability of H. convergens larvae to attach to the surface of normal-wax and reduced-wax pea leaves. We found that H. convergens larvae attach more strongly to reduced-wax peas than to normal-wax peas. These results suggest that predation of pea aphid by H. convergens is enhanced on reduced-wax peas due to increased ability of predators to attach to these plants, and as a result, search for and find aphids.


1968 ◽  
Vol 100 (7) ◽  
pp. 728-741 ◽  
Author(s):  
P. S. Messenger

AbstractUsing bioclimatic chambers to provide diurnally fluctuating temperature and humidity conditions, the relationship between fecundity of females of the aphid parasite, Praon exsoletum (Nees), and different host densities, was examined over a wide range of mean temperatures. At each temperature level the number of eggs laid by females was found to vary with host density in accordance with the functional response curve (disc equation) of Holling. Superparasitism was common at all temperature levels studied, and, irrespective of host density, eggs were found laid at random with respect to hosts present. The functional response equation was thus modified so that number of hosts attacked was determined by both number of hosts present and number of eggs laid. Using this modified disc equation, the bioclimatic characteristics of parasite oviposition were examined from rhc standpoint of varying temperature levels. Oviposition was limited to mean temperatures between 8° and 29°C; near these limits the maximum number of eggs laid and the maximum number of hosts attacked were low. At medial mean temperatures (13°–24°) the number of eggs laid per parasite was high, averaging between 70 and 110 each 12-hour day. At these same medial temperatures, according to the modified disc equation, the average "handling" time per oviposition attack was shortest, and the parasite effective searching rate fastest. Averaged over a 12-hour day (this parasite does not oviposit in darkness), females of P. exsoletum were capable of laying from seven to nine eggs per hour at temperatures between 15° and 24° respectively. In all cases, the number of hosts attacked varied with numbers of eggs laid in accordance with Thompson’s superparasitism formula.


2006 ◽  
Vol 17 (2) ◽  
pp. 90-97 ◽  
Author(s):  
Yaghoub Fathipour ◽  
Ali Hosseini ◽  
Ali Talebi ◽  
Saeid Moharramipour

Functional response and mutual interference are the most important behavioural characteristics that reveal different aspects of host–parasitoid interactions. In this study, functional response and mutual interference of the parasitoid wasp, Diaeretiella rapae (M’Intosh) attacking the cabbage aphid, Brevicoryne brassicae (Linnaeus) were investigated. Logistic regression was used to distinguish the shape of the functional response (type II or III). Nonlinear least-square regression was used to estimate the attack rate (a) and handling time (Th). Nicholson’s model and linear regression were used to determine per capita searching efficiency and interference coefficient, respectively. Logistic regression suggested a type II response on B. brassicae nymphs. The per capita parasitism decreased significantly from 80.80 (67.33%) to 11.85 (9.88%) as parasitoid densities increased from 1 to 8 females. Consequently, the per capita searching efficiency decreased significantly from 1.173 to 0.205 as parasitoid densities increased from 1 to 8. The rate of parasitism increased as the host density increased from 2 to 50, and subsequently the parasitoid density decreased from 8 to 1. Therefore, different host–parasitoid ratios could affect the efficacy of D. rapae.


Insects ◽  
2020 ◽  
Vol 11 (11) ◽  
pp. 806
Author(s):  
Qilin Ren ◽  
Muhammad Haseeb ◽  
Jingyu Fan ◽  
Pengxiang Wu ◽  
Tianqi Tian ◽  
...  

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.


1983 ◽  
Vol 115 (4) ◽  
pp. 399-415 ◽  
Author(s):  
Manfred Mackauer

AbstractThe reproductive and demographic statistics of Aphidius smithi Sharma & Subba Rao parasitizing third-instar pea aphids, Acyrthosiphon pisum Harris, were determined under constant laboratory conditions. At host densities of 5, 10, 20, 40, 60 or 100 aphids/day, the parasite lived an average of 7 days at 20.5 °C. At host densities of ≤20 aphids/day, the total number of eggs laid and the total number of hosts attacked were limited by the numbers of hosts available. Fecundity was highest with an average of 870 eggs/female at density 100; the maximum number of eggs laid by any female was 1770. Superparasitism was common at all densities, resulting in up to 84% (at density 5) of all eggs being wasted. The relationship between host density and the number of aphids attacked per egg laid was linear for densities of ≥20 aphids/day. The intrinsic rate of natural increase (r) varied with the host density. It reached maximum value at density 100, calculated as 0.358 female/female/day and assuming an overall sex ratio of 1:1 males:females. Regression equations describing r as a function of host density and parasite sex ratio are provided. It is shown that the potential rate of increase of A. smithi exceeds that of the pea aphid over a broad range of average conditions. The parasite's functional response was convex (Holling type II) and decelerated with increasing density. The intrinsic attack rate (a′) and handling time (Th) were estimated from the functional response curve as a′ = 6.62 days−1 and Th = 0.0033 day (4.7 min). The ‘random parasite’ equation satisfactorily predicted the number of aphids attacked at each density.


1979 ◽  
Vol 19 (96) ◽  
pp. 102 ◽  
Author(s):  
HJ Banks ◽  
AK Sharp

The use of carbon dioxide, added as dry ice, was demonstrated as a means of disinfestation of bagged wheat and rye enclosed in a PVC membrane. The bag stack was dosed with dry ice giving an atmosphere of about 60% CO2. Carbon dioxide levels were maintained over 22 days with additional charges of dry ice added directly on top of the stack or enclosed within a polystyrene box to regulate the CO2 release rate. A natural infestation of Rhyzopertha dominica with small numbers of other stored product pest species was controlled, with complete mortality of adult insects, but slight survival of some early stages of R. dominica. Some of the hymenopterous parasitoids, Anisopteromalus calandrae and Choetospila elegans, survived the treatment, apparently as pupae. The treatment was successful under conditions where many other methods of pest control were inapplicable because of difficulty or expense of application, as in a small bulk (2.8 tonnes), at low temperature (11-13�C), when the commodity is close to working areas and when there is a requirement for freedom from pesticide residues.


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.


2018 ◽  
Vol 25 (4) ◽  
Author(s):  
V. O. Martynov

Crop pests are the cause of economic damage in many developing countries, including Ukraine, where annual loss of crop harvest on average equals 6 million tons, valued at 840 million dollars. Pests consume grain, causing its pollution and creating favorable conditions for development of mold, which significantly decreases the food and seeding properties of grain and products of its processing. This article presents basic data on biological control and its advantages, demonstrates the variety of natural enemies of the pest beetles, which are used in biological control, analyses studies of the biological control of main crop pests and products of its processing belonging to the families Curculionidae and Tenebrionidae, and also the role of competition in  biological control. The analysis of studies on the effectiveness of different natural enemies of the main crop pest-beetles shows that the most studied parasites are Sitophilus granarius, S. zeamais, Tribolium confusum, T. castaneum, Oryzaephilus surinamensis, Rhyzopertha dominica, Acanthoscelides obtectus and Callosobruchus maculatus. Natural enemies of the rest of the species are poorly studied, and there is no data on Caulophilus latinasus, Tenebroides mauritanicus, Dermestes lardarius, Ptinus fur and Bruchidius incarnatus. The most commonly used natural enemies are Xylocoris flavipes, Anisopteromalus calandrae, the entomopathogenic fungi Metarhizium anisopliae and Beauveria bassiana, and also nematodes of the Steinernema and Heterorhabditis genera. Despite the broad spectrum of natural enemies of the main pests of the grain supply, it is necessary to further study the parasites of every species of beetle which causes economic damage. Using biological control is the most promising method against pests of crops and products of its processing, which meets the current requirements to the sanitary-ecological condition of agricultural production.


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