Elevated CO₂ lessens predation of Chrysopa sinica on Aphis gossypii

Abstract

Most studies on the effects of elevated atmospheric CO 2 on organisms have focused on the performance of plants or herbivores. Few reports have examined the impact on the ability of predators at the third trophic level. In this experiment, we made use of open-top chambers to quantify the effects of elevated CO 2 on growth, development, and predatory ability of two successive generations of Chinese lacewing, Chrysopa sinica (Tjeder) (Neuroptera: Chrysopidae), feeding on cotton aphids, Aphis gossypii (Glover) (Hemiptera: Aphididae), which were reared on cotton, Gossypium hirsutum L. (Malvaceae), grown under elevated CO 2 (double ambient vs. ambient). Higher atmospheric CO 2 concentrations reduced the duration of larval development and the survival rate of pupae, and caused decreased weight in adult female C. sinica, but had no significant effects on survival rate of each larval stage, female adult fecundity, egg hatch rate, or adult life span. The predatory ability of larvae in the third instar and the total larval stage of C. sinica that fed on A. gossypii were significantly lower in elevated CO 2 environments. The number of aphids consumed by first-generation lacewing population did not change significantly with different CO 2 treatments; however, significantly fewer aphids were consumed by the second generation of the lacewing population with elevated CO 2 . We speculate that A. gossypii may become a more serious pest under an environment with elevated CO 2 concentrations because of the reduced predatory ability of C. sinica on A. gossypii.

How does atmospheric elevated CO2 affect crop pests and their natural enemies? Case histories from China

“…Elevated CO 2 prolonged the development time of P. japonica but reduced larval and pupal durations of H. axyridis, C. sinica and L. japonica when preying on cotton aphids (Chen et al, 2005a;Gao et al, 2008). Moreover, elevated CO 2 increased aphid predation rate by H. axyridis, but reduced predation by C. sinica (Gao et al, 2010).…”

“…They mainly feed on cotton and wheat aphids, spider mites, eggs and young larvae of lepidopteran pests (Du et al, 2004). Moreover, elevated CO 2 increased aphid predation rate by H. axyridis, but reduced predation by C. sinica (Gao et al, 2010). Lysiphlebia japonica (Hymenoptera: Aphidiidae) is also a predominant parasitoid of cotton aphids in China and can effectively suppress the population of cotton aphids in early summer (Hou et al, 1997).…”

Aphid suitability for the predatory hoverfly Episyrphus balteatus altered with elevating atmospheric CO2 and sinigrin

“…The few studies have shown inconsistent performance. For instance, the harlequin ladybird Harmonia axyridis (Pallas) (Chen et al ) and parasitoid performance increased (Chen et al ; Sun et al ), whereas others have found decreased (Gao et al ; Gao et al ) or neutral responses (Wang ; Yin et al ).…”

The responses of a funnel‐web weaving spider, Agelena labyrinthica, to elevated CO2 concentration

“…As a result, studying the effects of increased atmospheric CO 2 on organisms has become an important subject of ecological research (Foss et al., ). Studies to date have mostly investigated the influence of elevated CO 2 on plants, phytophagous insects, and natural enemy insects (predators and parasitoids) (Lincoln et al., ; Bezemer & Jones, ; Gao et al, ; Wu et al., ; Chen et al., ; Mayor et al., ; Gao et al., ; Ge et al., ; Sun et al., , b; Xu et al., ; Mamatha et al., ; Meiyappan et al., ).…”