Assessment of the biological control capability of Hippodamia variegata (Col.: Coccinellidae) using functional response experiments

Abstract

Lady beetles are among the most successful predators of aphids in different environments. The functional responses of different life stages of Hippodamia variegata (Goeze) towards cotton aphids were examined in two different set-ups, a two-dimensional Petri dish set-up with detached leaves and a three-dimensional set-up with whole plants. In addition, the functional responses in two-dimensional set-ups towards cotton aphids and the pea aphids were compared. H. variegata exhibited a functional type II response to both cotton aphids and pea aphids irrespective of life stage and spatial scale of the set-up. Females and fourth instars generally had higher search rates than third instars whereas handling times were consistently lower for the fourth instar stage compared with the preceding juvenile stage and with females. The spatial dimensions did not have any significant influence on the functional responses towards cotton aphids, except for third instars which in the three-dimensional set-up reduced their search rate and increased their handling time. Fourth instars reacted in the same way to both Aphis gossypii and Acyrthosiphon pisum whereas the functional response parameters for third instars and females were significantly different on the two prey species. Our study, a part of this first-step evaluation of H. variegata as a biocontrol agent against A. gossypii and A. pisum under field condition, suggest that the voracity of all tested stages of H. variegata towards both aphid species hold good promises for a use of especially fourth instars and females in inundative biocontrol.

Lethal effect of imidacloprid on the coccinellid predator Serangium japonicum and sublethal effects on predator voracity and on functional response to the whitefly Bemisia tabaci

“…We studied the lethal toxicity of imidacloprid to S. japonicum through various exposure routes that aimed at representing various exposure scenarios (and because exposure methods could have an impact on results, Stark et al 1995;Desneux et al 2006a). We also studied the effects of imidacloprid on functional response of S. japonicum to B. tabaci eggs and on predator voracity as sublethal effects on these key predator traits (O'Neil 1997;Cabral et al 2011;Madadi et al 2011) could greatly reduce predator impact on B. tabaci. This study constitutes the basis for future guidelines for imidacloprid rational use, and it can help optimizing IPM programs involving use of both natural enemies and imidacloprid against B. tabaci in China.…”

The search rate of the African weaver ant in cashew

“…Instead, it should be possible to compare with estimates of search rates from solitary insects, but this is problematic because estimated search rates depend to a large extend on the experimental arena and may come out in different units (e.g. De Kranker et al, 2001;Madadi et al, 2011;Sentis et al, 2012;Mrosso et al, 2013). No or at least very few investigations have been dealing with estimating the search rate under field conditions.…”

Functional response of different stages ofHippodamia variegata(Col.: Coccinellidae) toDiuraphis noxia(Hemiptera: Aphididae) on two wheat cultivars

“…Aphis gossypi Glover (El-Habi, Sekkat, El-Jadd & Boumezzough, 2000), Aphis fabae Scopoli (Farhadi, Allahyari, & Juliano, 2010), Acyrthosiphon pisum Harris and A. gossypii (Madadi, Mohajeri Parizi, Allahyari, & Enkegaard, 2011), Brachycaudus helichrysi (Kaltenbach) (Saleh, AlZyoud, Ateyyat, & Swais, 2010)]. However, many of these studies were conducted in small scale (Petri dish) artificial arenas that were spatially homogenous.…”