Variation in predator foraging behaviour changes predator–prey spatio‐temporal dynamics

Abstract

Summary1. Foraging underlies the ability of all animals to acquire essential resources and thus provides a critical link to understand population dynamics. A key issue is how variation in foraging behaviour affects foraging efficiency and predator-prey interactions in spatially heterogeneous environments. However, there is very little quantitative information available on this topic. 2. We evaluated the impact of variation in predator foraging on population dynamics of the predatory mite, Phytoseiulus persimilis, and its prey, the twospotted spider mite, Tetranychus urticae, in a heterogeneous environment. 3. Through artificial selection, we generated predator lines with high levels of prey consumption, conversion efficiency or dispersal, which were otherwise similar in foraging and life history. With these lines, we experimentally compared the effect of these traits on temporal and spatial patterns of predators and prey. 4. We initiated the experiments in a 24-plant landscape, which contained two discrete prey patches (i.e. prey-infested plants) under two initial predator-prey population ratios (1 : 10 and 1 : 30). Predators were introduced into one of the prey patches and were left to forage for 24 days. 5. Predator population growth was similar among the three selected lines, but the high conversion efficiency line produced the most predators and had the highest predator-prey ratio, and the high consumption and high dispersal lines were intermediate. The unselected line showed the least predator growth and lowest predator-prey ratio throughout the experiment. 6. Initial predator-prey ratio did not affect the impact of the selected lines on prey population growth at the high (1 : 10) ratio. However, at the low predator-prey ratio (1 : 30), the unselected line had a much greater prey numbers than the selected lines. 7. Predators and prey were each individually aggregated, but the high conversion efficiency and high dispersal lines showed stronger spatial association and correlation with prey, while the high consumption line was less closely associated or correlated with the prey. 8. These results indicate that there may be multiple, equally effective strategies by which predators exploit prey in patchy landscapes, but suggest that the long-term dynamics may not be stable under all of these strategies.

Analyzing spatial patterns linked to the ecology of herbivores and their natural enemies in the soil

“…For example, aboveground studies using SADIE have analyzed the spatial patterns of vegetation (Maestre, 2003), seed banks (González-Andújar et al, 1999), epidemics (Moreno et al, 2007), and various taxa of invertebrates (Winder et al, 1999; Rossi, 2003; Archard et al, 2004), to address theoretical and applied questions regarding agroecosystems. The studies to date primarily provide an understanding of interspecific interactions or responses to environmental heterogeneity (Perry and Dixon, 2002; Diaz et al, 2010; Nachappa et al, 2011). Several studies have employed SADIE methodology to enhance the manipulation of multiple natural enemies in ephemeral habitats, mainly in annual crops, which are characterized by temporal and spatial discontinuity for herbivorous pests and their natural enemies that exploit such habitats.…”

Does experimental evolution produce better biological control agents? A critical review of the evidence

“…In the studies we reviewed, this has received little attention (Morse & Croft, 1981;Field & Hoy, 1986;Liu et al, 2003;Nachappa et al, 2011). In the studies we reviewed, this has received little attention (Morse & Croft, 1981;Field & Hoy, 1986;Liu et al, 2003;Nachappa et al, 2011).…”

“…In entomopathogenic nematodes, a few studies performed artificial selection on the host-finding ability of Steinernema feltiae (Filipjev) towards several hosts (Gaugler et al, 1989;Gaugler & Campbell, 1991;Tomalak, 1994;Salame et al, 2010). Although the selection process entailed several correlated responses in other life-history traits, all selected strains performed better than control strains when tested on entire plants, both in terms of predation rates and of population growth (Nachappa et al, 2011). Crosseffectiveness of a selected strain against an alternative pest was also observed (Grewal et al, 1993).…”

Mathematical Model for Two-Spotted Spider Mites System: Verification and Validation

“…Each female can produce 60 eggs in her lifetime. Phytoseiulus persimilis has five developmental stages: egg, nonfeeding larva, protonymph, deutonymph, and adult [3]. However, it often needs to be reintroduced because it relies exclusively on mites for food, eventually consuming all available prey.…”

“…The population of Tetranychus urticae completes a generation every 7 -10 days, depending on the temperature. They have five stages of development: egg, larva, protonymph, deutonymph, and adult [3].…”