American-Eurasian Journal of Sustainable Agriculture

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1 Copyright 2014, American-Eurasian Network for Scientific Information publisher American-Eurasian Journal of Sustainable Agriculture ISSN: JOURNAL home page: March; 8(3): pages Published Online 2014 May 15. Research Article Effect of Temperature on the Functional Response of Bracon hebetor Say (Hymenoptera: Braconidae) to Various Densities of the Host, Ephestia cautella (Walker) Larvae 1 Al-Taweel, A.A., 2 Mohsen, A.A., 1 Hamad, B. Sh. and 2 Mahmood, E.A. 1 Ministry of Sci. and Tech., Directorate of Agric. Res. /IPC Center, Baghdad /Iraq. 2 College of Science for Women, Baghdad University, Baghdad/Iraq. Received: 23 January 2014 ; Received: 19 April 2014; Accepted: 26 April 2014; Available online: 15 May AENSI PUBLISHER All rights reserved ABSTRACT The effects of host density and temperature on the functional response of Bracon hebetor Say (HYMENOPTERA: BRACONIDAE) parasitizing Ephestia cautella (Walker) larvae were evaluated at three constant temperatures (14, 26, and 35 C) and four host densities (10, 20, 40, and 80 numbers). A type II functional response was obtained at all temperatures tested. The maximum parasitism rate was observed in density of 80 hosts, ranged from 25 at 14 C to 40 at 35 then to 45 at 26 C. The searching efficiency (a) was highest at 26 C (2.5) and then at 35 C (2) and then at 14 C (0.94). The estimated value of handling time (Th) was , and day for 26, 35 and 14 C respectively. The maximum rate of parasitism was observed at 14, 26 and 35 C (32.94, and larvae/24 h, respectively). The results suggest that Bracon hebetor has potential as a bio control agent against E. cautella. Keyword: E. cautella, B. hebetor, Functional response. INTRODUCTION Bracon hebetor Say (Hymenoptera: Braconidae) is a gregarious, ectoparasitoid that attacks larvae of several species of Lepidoptera, mainly pyralidae moths infesting stored products. It is an important potential biological control agent of stored product moths [7]. It has been widely used in studies of host parasitoid interactions because of its high reproductive rate, short generation time and considerable range of host species [12]. B. hebetor females prefer to attack last (fifth) instar larval hosts [2,4]. It has shown a high fecundity and rate of increase, which makes it a promising natural enemy against stored product moth like Ephestia cautella that considered as is one of the most important storage pests in terms of its economic impact. In warm- temperature and sub-tropical. An important goal of basic ecological studies is to determine which attributes of parasitoids contributed to the success of biological control [3]. The behavioral response of parasitoids to host density is potentially related to its success [6,17]. This is described by the functional response, the relationship between prey or host density and the attack rate of predators or parasitoids [15,33]. Different biotic and abiotic factors may influence the functional response, such as temperature and prey/parasitoid or host species [30,26]. There is some evidence indicating that temperature can influence the functional response of parasitoids [23,10,11,37]. Therefore, the objective of the current study was to determine the effect of temperature on the functional response of B. hebetor to different densities of E. cautella larvae. The results obtained from this study will be useful in using B. hebetor in a biological control program against E. cautella. Materials and Methods Rearing Ephestia cautella and Bracon hebetor: A colony of E. cautella was established using growth chamber set up at 25 ± 2 C, 60 ± 5% relative humidity and a photoperiod 16: 8 h (L:D). Artificial Corresponding Author: Al-Taweel, A.A., Ministry of Sci. and Tech., Directorate of Agric. Res. /IPC Center, Baghdad /Iraq.

2 72 Al-Taweel, A.A. et al, 2014 / American-Eurasian Journal of Sustainable Agriculture 8(3), March, Pages: diet as described earlier was used for E. cautella maintenance [13,27]. Through this method sufficient numbers of larvae were obtained to rear B. hebetor continuously under laboratory condition and to carry functional response test [27]. Functional Response: In order to determine the functional response of B. hebetor to various host densities, individual parasitoid wasps were exposed to four host densities (treatments) (10, 20, 40, and 80 hosts per arena) at three constant temperatures (14, 26, and 35 C). The experimental arena consisted of cylindrical plastic vials (3 cm diameters and 11.5 cm height). Two drops of 20 % honey water solution were dropped onto the inner wall of the cylindrical plastic vial as food for feeding the adult parasitoids. Before initiating the functional response experiments we determined that B. hebetor preferred last (fifth) instar larvae of E cautella, therefore we used this larval stage in functional response experiments. For each host density, a pair of male and female of newly emerged parasitoids (<24 h old) was introduced into each arena for 24 h and then removed. Data Analysis: The type of functional response was determined using a logistic regression model. In this model, the proportion of hosts parasitized (Na/N) as a function of initial host density (N) is the effective way to distinguish type of functional response [19]. Na/N=exp(P0+P1N+P2N 2 +P3N 3 )/1+exp(P0+P1N+ P2N 2 +P3N 3 ) Where Na is the number of hosts parasitized, N is the initial host density and Po, P1, P2 and P3 are the intercept, linear, quadratic, and cubic coefficients, respectively. These parameters were estimated using maximum likelihood estimation method [19]. The data were fitted to a polynomial function that describes the relationship between Na/N and N. Linear coefficient (P1) in type II and III functional response is negative and positive, respectively [8,19]. A type II functional response rises at a decelerating rate to an upper asymptote (inversely density-dependent response), while the type III response is sigmoid (density dependent response) [14]. After determining the type of functional response, searching efficiency (a) and handling time (Th) parameters were estimated by random parasitoid equation [31]: Na= N {1-exp (- atp/ 1+a /ThN)} Where Na is the number of host parasitized, N is the number of host available, T is the total time of the experiment (=24 h), a is the instantaneous search rate, P is the number of parasitoid and Th is the handling time. The parameters of the functional response equation (a and Th) were estimated with linear regression: 1/ln(N Na/ N)= -Th/T.P N -1/T. a.p Results: Results of logistic regression to distinguish between type II and III responses are shown in Table 1. The negative values for the linear coefficients (P1) indicated a type II functional response for B. hebetor at all temperatures tested. Table 1: Results of logistic regression analysis of the proportion of E. cautella larvae parasitized by B. hebetor at various temperatures. Parameters Temperatures( C) 14± 1 26±1 35± 1 Constant P P P3-5E-06-2E-06-5E-06 The functional response curve of B. hebetor on different densities of E. cautella larvae at different constant temperatures is illustrated in Fig. 1. The number of hosts parasitized increased in a decreasing rate as the density increased. This confirm that, B. hebetor exhibit a type II functional response. The Rogers type II model was fitted for each temperature in order to estimate the searching efficiency and handling time (Fig 2). The searching efficiency (a), handling time (Th), maximum attack rate (T/Th) and efficiency parameter (a/th) at various constant temperatures are presented in Table 2. The temperature had effect on searching efficiency. The searching efficiency (a), increased with increasing host density at various constant temperatures. The searching efficiency (a) was highest at 26 C and lowest at 14 C. The handling time varied in response to temperature. The shortest and longest handling times were at 26 C (Th= day) and at 14 C (Th= day), respectively. The maximum attack rate ranged from larvae /day at 14 C to larvae/day at 26 C. The value of a/th indicated that B. hebetor was more efficient against E. cautella at temperature between C. The maximum value of a/th was observed at 26 C. Discussion: The effectiveness of a parasitoid depends upon its ability to locate hosts at low densities and to parasitize large numbers of hosts at high densities[17]. Functional responses may gave important information to make decision in management programs of pests [8,24,22]. Type of functional response among parasitic wasps may

3 73 Al-Taweel, A.A. et al, 2014 / American-Eurasian Journal of Sustainable Agriculture 8(3), March, Pages: change under different experimental conditions, plant cultivar, parasitoid strain and host species [5,25,21,9]. The results of this investigation indicated that temperature is an important factor affects searching efficiency and parasitism rate of B. hebetor. A type II functional response was observed at all temperatures (because parasitism rates increased in a decreasing rate as the density increased) and it was not affected by temperature. The results of this investigation indicated that B. hebetor has more ability to finding and parasitizing host (E. cautella) between temperatures of 26 and 35 C. Therefore we suggested B. hebetor for augmentative release against the E. cautella at these temperatures. The activity of B. hebetor adults reduced at lower temperature (14 C). Fig. 1: Functional response of Bracon hebetor to different densities of Ephestia cautella larvae at three temperatures regimes. Fig. 2: Estimating the coefficient of attack (a) and the handling time (Th) for Bracon hebetor on Ephestia cautella larvae. Table 2: Estimates of searching efficiency (a), handling time (Th), maximum attack rate(t/th) and a/th values of B. hebetor on the fifth instar larvae of E. cautella at various temperatures. Temperatures ( C) searching efficiency (a) handling time (Th) maximum attack rate a/th values (T/Th) 14± ± ± Yu et al. [36] reported a typically type II functional response of B. hebetor to different host densities of Plodia interpunctella in 28 C. Shojaei et al. [32] studied the effect of temperature on the functional response of Habrobracon hebetor Say attacking different densities of fifth instar larvae of Indian moth, Plodia interpunctella Hübner and pointed out type III functional response model was fit to 20 C and 28 C, respectively, type II functional response model fit to 35 C, handling time and instantaneous search rate varied with temperature. Type II functional response was obtained at all temperatures tested (10, 15, 20, 25, 30 and 32.5 C) and host density of Diaeretiella rapae (M Intosh) parasitizing Diuraphis noxia (Mordvilko), the maximum parasitism rate was observed in density of 64 hosts, ranged from 3.00 ± 0.67 at 10 C to ± 0.94 at 25 C, the searching efficiency (a) was highest at 15 C and then decreased linearly as the temperature increased to 32.5 C,the searching efficiency ranged from ± h-1 at 15 C to ± h at 10 C,the handling time (Th) decreased linearly with increasing temperature from 10 to 25 C. Morales-Ramos and Cate [28] reported temperature as the third most important factor (after

4 74 Al-Taweel, A.A. et al, 2014 / American-Eurasian Journal of Sustainable Agriculture 8(3), March, Pages: host density and parasitoid age) affecting parasitism rates of Catolaccus grandis (Burks). Taylor [34] pointed out that host characteristics could be tremendously important affecting B. hebetor parasitism. Allahyari [1] stated the type functional response and estimated parameters for an insect species could be affected by some factors such as host plant, temperature and type of prey/parasitoid or host. Ranjie [29] stated parasitism of Cardiochiles philippinensis on Cnaphalocrocis medinalis was affected by host density and temperature. Higher rates of parasitism occurred in the range from 25 to 30ºC. Also Kalyebi et al. [20] found temperature had a significant effect on the functional response of six indigenous Trichogrammatid egg parasitoids in Kenya, and for all tests, optimum temperature for maximum parasitism was 30ºC. In conclusion: The present study provides basic information on the influence of density and temperature on behavioral response of B. hebetor exploiting its host E. cautella larvae as essential step in the development of biological control approaches against this pest. References 1. Allahyari, H., P.A. Fard and J. Nozari, Effects of host on functional response of offspring in two populations of Trissolcus grandis on the sunn pest. J. Appl. Entomol., 128: Antolin, M.F., P.J. Ode and M.R. Strand, Variable sex ratios and ovicide in an outbreeding parasitic wasp. Anim. Behavior., 49: Beddington, J.R., C.A. Free and J.A. Lawton, Characteristics of successful natural enemies in models of biological control of insect pests. Nature, 273: Benson, J.F., Intraspecific competition in the population dynamics of Bracon hebetor Say (Hymenoptera: Braconidae). J. Anim. Ecol., 42: Bernal, J.S., T.S. Bellows and D. Gonzalez, Functional response of Diaeretiella rapae (McIntosh) (Homoptera: Aphididae) to Diuraphis noxia (Mordvilko) (Homoptera: Aphididae) hosts. Journal of Applied Entomology, 118: Berryman, A.A., The theoretical foundations of biological control. In: Hawkins, B. A., Cornaell, H. V. (Eds.). Theoretical Approaches to Biological Control. Cambridge University Press, Cambridge, Brower, J.H., L. Smith, P.V. Vail and P.W. Flinn, Biological control, pp: De Clercq, P., J. Mohaghegh and L. Tirry, Effect of host plant on the functional response of predator Podisus nigripinus (Heteroptera: Pentatomidae). Biological Control, 18: Fathipour, Y., K. Kamali, J. Khalghani and G. Abdollahi, Functional response of Trissolcus grandis (Hymenoptera: Scelionidae) to different egg densities of Eurygaster integriceps (Heteroptera: Scutelleridae) and effects of wheat genotypes on it. Applied Entomology and Phytopathology, 68: Flinn, P.W., Temperature-dependent functional response of the parasitoid Cephalonomia waterstoni (Gahan) (Hymenoptera: Bethylidae) attacking rusty grain beetle larvae (Coleoptera: cucujidae). Environmental Entomology, 20: Gitonga, L.M., W.A. Overholt, B. Lohr, J.K. Magambo and J.M. Mueke, Functional response of Orius albidipennis (Hemiptera: Anthocoridae) to Megalurothrips sjostedti (Thysanoptera: Thripidae). Biological Control, 24: Gündüz, N.E.A. and A. Gülel, Effects of adult age host species on development period of parasitoid Bracon hebetor Say (Hymenoptera: Braconidae). J. Fact. Agri., 20(3): Hameed, A.A., Field and laboratory studies for using Bracon hebetor for controlling Ephestia cautella and Earias insulana. M.Sc. Thesis, College of Agriculture / Baghdad University. Baghdad/Iraq. 14. Hassel, M.P., The Dynamics of Arthropod Predatory-Prey Systems. Princeton University Press, Princeton, Holling, C.S., Some characteristics of simple types of predation and parasitism. Canadian Entomologist, 91: Hong, Y.S. and M.I. Ryoo, Effect of temperature on the functional response of Lariophagus distinguendus (Hymenoptera: Pteromalidae) to various densities of the host, Sitophilus oryzae (Coleoptera: Curculionidae). J. Econ. Entomol., 84(3): Huffaker, C.B., P.S. Messenger and P. De Bach, The natural enemy component in natural control and the theory of biological control. In: Huffaker, C.B. (Ed.). Biological Control. Academic Press, New York, Huffacker, C.B. and P.S. Messenger, Theory and practice of biological control. Academic Press, Inc. 788 pp. 19. Juliano, S.A., Nonlinear curve-fitting: predation and functional response curves. In: Scheiner S.M., Gurevitch J. (Eds.). Design and Analysis of Ecological Experiments, 2nd edn. Oxford University Press, New York, Kalyebi, A., W.A. Overholt, F. Schulthess, J.M. Mueke, S.A. Hassan and Sithanantham, Functional response of six indigenous Trichogrammatid egg parasitoids (Hymenoptera: Trichogrammatidae) in Kenya: influences of

5 75 Al-Taweel, A.A. et al, 2014 / American-Eurasian Journal of Sustainable Agriculture 8(3), March, Pages: temperatures and relative humidity. Biol. Cont., 32: Lester, P.J. and T.O. Holtzer, Patch and prey utilization behaviors by Aphelinus albipodus and Diaeretiella rapae (Hymenoptera: Aphelinidae and Aphidiidae) on Russian wheat aphid (Homoptera: Aphididae). Biological Control, 24: Li, D.X., J. Tian and Z.R. Shen, Functional response of the predator Scolothrips takahashii to hawthorn spider mite, Tetranychus viennensis: effect of age and temperature. Biological Control, 52: Mack, T.P., B.A. Bajusz, E.S. Nolan and Z. Smilowitz, Development of temperature mediated functional response equation. Environ. Entomol., 10: Mahdian, K., I. Vantornhout, L. Tirry and P. De Clercq, Effects of temperature on predation by the stinkbugs Picromerus bidens and Podisus maculiventris (Heteroptera: Pentatomidae) on noctuid caterpillars. Bulletin of Entomological Research, 96: Messina, F.J. and J.B. Hanks, Host plant alters the shape of functional response of an aphid predator (Coleoptera: Coccinellidae). Environmental Entomology, 27: Moezipour, M., M. Kafil and H. Allahyari, Functional response of richograma brassicae at different temperatures and relative humidities. Bulletin of Insectology, 62(2): Mohsen, A.A., Some aspect of IPM for controlling Ephestia cautella (Walk)(Lepidoptera: Phycitidae). M.Sc. Thesis, College of Education for Women / Baghdad University. Baghdad/Iraq. 28. Morales-Ramos, J.A. and J.R. Cate, Functional response of Catolaccus grandis (Burks) mediated functional response equation. Biol. Cont., 2: Ranjie, Z., K.L. Heong and I.T. Domingo, Relationship between temperature and functional response in Cordiochiles philippinensiss (Hymenoptera: Braconidae), a larval parasitoid of Cnaphalocrocis medinalis (Lepidoptera: Pyralidae). Environ. Entomol., 25(6): Reay-Jones, F.P.F., J. Rochat, R. Goebel and E. Tabone, Functional response of Trichogramma chilonis to Galleria mellonella and Chilo sacchariphagus eggs. Entomologia Experimentalis et Applicata, 118: Rogers, D., Random search and insect population models. J. Anim. Ecol., 41: Shojaei, Sh., S.H. Mohamad and Sh. Nouraddin, Effect of temperature on the functional response of Habrobracon hebetor say (Hymenoptera: Braconidae) to various densities of the host, plodia interpunctella hübner (Lepidoptera: Pyralidae). Pak. Entomol., 28(1): Solomon, J. E., The natural control of animal populations. Journal of Animal Ecology, 18: Taylor, A., 1988b. Host functional response and oviposition responses of Bracon hebetor. J. Anim. Ecol., 57: Tazerouni1, Z., A.T. Ali and R. Ehsan, Temperature-Dependent Functional Response of Diaeretiella rapae (Hymenoptera: Braconidae), a parasitoid of Diuraphis noxia (Hemiptera: Aphididae) J. Entomol. Res. Soc., 14(1): Yu, S.H., M.I. Ryoo, J.H. Na and W.I. Chio, Effects of host density on egg dispersion and the sex ratio of progeny of Bracon hebetor (Hymenoptera: Braconidae). J. Stored Product Res., 39: Zamani, A.A., A.A. Talebi, Y. Fathipour and V. Baniameri, Temperature-dependent functional response of two aphid parasitoids, Aphidius colemani and Aphidius matricariae (Hymenoptera: Aphidiidae), on the cotton aphid. Journal of Pest Science, 79: