Ontogenetic change of prey preference in the generalist predator Zelus renardii and its influence on predator–predator interactions

Abstract

1. Two field experiments were conducted to test the hypothesis that the intensity of predation by a generalist predator on two species of prey changes with the developmental stage of the predator. The generalist predator studied was Zelus renardii Kolenati (Hemiptera: Reduviidae) and the prey were the lacewing larva, Chrysoperla carnea Stephens, and the cotton aphid, Aphis gossypii Glover. 2. Zelus renardii and lacewings feed on aphids, thereby acting as potential competitors. In addition, Z. renardii feeds on lacewings. Thus, Z. renardii is an intraguild predator of lacewings. 3. Zelus renardii exhibited changes in prey preferences across developmental stages. The older stages of Z. renardii exerted greater mortality on lacewings and fed on larger lacewing larvae than did the younger stages. 4. Lacewings suppressed aphid population growth strongly. In contrast, none of the stages of Z. renardii was an effective control agent of the cotton aphid. 5. The addition of Z. renardii frequently disrupted the effective control of aphids generated by lacewings. In one of the two replicates of the experiment, the disruption increased with the developmental stage of Z. renardii, paralleling the increase in lacewing mortality. 6. Although the developmental stage of Z. renardii can influence the prevalence of intraguild predation and the intensity of the disruption of the aphid biological control, these experiments have demonstrated that even the youngest instars of Z. renardii can cause substantial lacewing mortality and release aphid populations from regulation.

Effects of intra and interspecific interactions on the survival of two predatory ladybirds (Coleoptera: Coccinellidae) in relation to prey abundance

“…Menge and Sutherland, 1987;Begon et al, 1996). Intraguild predation is common among arthropods in agricultural (Rosenheim et al, 1993(Rosenheim et al, , 1995Cisneros and Rosenheim, 1997) and natural ecosystems (Moran and Hurd, 1994;Snyder and Hurd, 1995); therefore, intraguild predation is thought to be an important factor affecting population dynamics and community structure in several taxa of predatory arthropods (Polis et al, 1989;Spence and Carcamo, 1991;Polis and Holt, 1992;Fincke, 1994;Wagner and Wise, 1996; Holt and Polis, 1997;Mizell, 2007;Montserrat et al, 2008).Many species of predatory arthropods are attracted to sites where aphids are abundant (Sakuratani, 1977;Aalbersberg et al, 1988;Winder et al, 1994;Wyss, 1995;Nakashima and Akashi, 2005;Alhmedi et al, 2007). In these aphidophagous guilds, intraguild predation often occurs and its incidence depends on prey abundance and the developmental stages and species of the predator involved (Takahashi, 1989;Agarwala and Dixon, 1992; Rosenheim et al, 1993;Cisneros and Rosenheim, 1997;Dinter, 1998;Lucas et al, 1998;Obrycki et al, 1998;Phoofolo and Obrycki, 1998).…”

“…Menge and Sutherland, 1987;Begon et al, 1996). Intraguild predation is common among arthropods in agricultural (Rosenheim et al, 1993(Rosenheim et al, , 1995Cisneros and Rosenheim, 1997) and natural ecosystems (Moran and Hurd, 1994;Snyder and Hurd, 1995); therefore, intraguild predation is thought to be an important factor affecting population dynamics and community structure in several taxa of predatory arthropods (Polis et al, 1989;Spence and Carcamo, 1991;Polis and Holt, 1992;Fincke, 1994;Wagner and Wise, 1996; Holt and Polis, 1997;Mizell, 2007;Montserrat et al, 2008).…”

“…In these aphidophagous guilds, intraguild predation often occurs and its incidence depends on prey abundance and the developmental stages and species of the predator involved (Takahashi, 1989;Agarwala and Dixon, 1992; Rosenheim et al, 1993;Cisneros and Rosenheim, 1997;Dinter, 1998;Lucas et al, 1998;Obrycki et al, 1998;Phoofolo and Obrycki, 1998).…”

“…Intraguild predation often occurs in aphidophagous guilds (Rosenheim et al, 1993(Rosenheim et al, , 1995Cisneros and Rosenheim, 1997;Dinter, 1998;Lucas et al, 1998;Obrycki et al, 1998). In ladybird guilds, H. axyridis is thought to be a top predator (Dixon, 2000); therefore, in order to understand how H. axyridis affects the survival of other species in aphidophagous guilds it is important to have a better understanding of the ecology of all ladybirds in a guild.…”

Food webs, risks of alien enemies and reform of biological control.

“…Although Zelus bugs do eat some aphids, they have virtually no ability to control populations of the herbivore. By feeding upon the lacewing larvae, Zelus bugs disrupt the biological control of the aphid (Cisneros and Rosenheim, 1997). Another example of intra-guild predation, with similarly harmful effects upon biological control, is facultative hyperparasitism (Mills and Gutierrez, 1996) .…”