Effects of host on functional response of offspring in two populations of Trissolcus grandis on the sunn pest

Abstract

Trissolcus grandis Thompson is the most important egg parasitoid of Eurygaster integriceps Put. in Iran. It can be reared on some alternative hosts such as eggs of Podisus maculiventris (Say). In this study, the functional response of female wasps that emerged from the factitious host, P. maculiventris, has been compared with that of females that emerged from the primary host, E. integriceps. In both wasp groups, at 23 ± 1°C, 70 ± 10% relative humidity and 15.00 : 9.00 hours (L : D) photoperiod, a type III functional response was observed. Parameters of Holling's disk equation for both populations were estimated and compared with an equation with indicator variable. Estimated handling time for females that emerged from Eurygaster and Podisus eggs are 0.62 and 0.77 h and parameter b, which describes the change in attack rate with host density in a type III functional response, was 0.004 and 0.005, respectively. The results indicated that the functional responses of the two populations differed in handling time. Longer handling time in wasps that emerged from factitious host showed that the wasps have lower quality in comparison with the wasps that emerged from primary host. This may be the first evidence of the effect of host on functional response of offspring and a promising result for use of functional response in quality testing.

Functional and numerical responses of Amblydromalus limonicus and Neoseiulus cucumeris to eggs and first instar nymph of tomato/potato psyllid (Bactericera cockerelli)

“…Functional response may be influenced by different factors, e.g. abiotic, such as temperature and relative humidity, and biotic, such as prey or host species (Donnelly & Phillips 2001;Hoddle 2003;Allahyari et al 2004;Faria et al 2004); the presence of alternative food (Wei & Walde 1997); predator sex (Parajulee et al 1994) and predator age and feeding history (Eveleigh & Chant 1981). In addition, the host plant may also influence functional response, for instance indirectly, by affecting prey palatability or offering prey refuges (Messina & Hanks 1998) or directly, by plant structure such as trichome or by sticky exudates that reduce searching efficiency (Cedola et al 2001).…”

Effects of Azadirachtin, Cypermethrin, Methoxyfenozide and Pyridalil on Functional Response of Habrobracon Hebetor Say (HYM.: Braconidae)

“…The analysis of functional responses were comprised of two distinct steps (Juliano 1993;Messina and Hanks 1998;De Clercq et al 2000;Juliano 2001;Mohaghegh et al 2001;Allahyari et al 2004). In the first step, the curve shape or type of functional response was established, typically by determining if the data fit a type II or III functional response.…”

“…In the second step, a nonlinear least square regression was used [Nonlinear (NLIN) procedure with Multivariate Secant or False Position (DUD) method in SAS (2002)] to estimate the functional response parameters of the Holling's disc equation (Williams and Juliano 1985) Then, the obtained parameters were compared [T h and either a (for type II)]. The coefficient of determination was calculated as r 2 = 1 -residual sum of squares/corrected total sum of squares (Allahyari et al 2004;Farrokhi et al 2010).…”

Is host age an important factor in the bionomics of Apanteles myeloenta (Hymenoptera: Braconidae)?

“…The sign of P1 and P2 can be used to distinguish the shape of curves. A positive linear parameter (P1) and a negative quadratic parameter (P2) indicate that the functional response is type III, whereas if both parameters are negative, the functional response is type II (Juli-ano, 2001;Allahyari et al, 2004). After determining the type of functional response, the parameters handling time (Th) and attack constant (a) were estimated.…”