Effects of surfactins, Bacillus lipopeptides, on the behavior of an aphid and host selection by its parasitoid

Abstract

BACKGROUND: Lipopeptides extracted from the Bacillus genus are emerging biopesticides, especially in protecting crops against phytopathogens. Among the three main families of lipopeptides, surfactins have been identified as having insecticidal properties against several insect orders. However, the sublethal effects of these promising biopesticides on insect pests and their natural enemies remain largely unknown. The aim of this study was to evaluate the effects of surfactins topically applied on black bean aphid Aphis fabae mortality. First, the effects of surfactins on aphid mortality were determined by delivering increasing concentrations to adults and nymphs. Second, the sublethal effects of surfactins on locomotor activity and feeding behavior of surviving aphids were evaluated using the electropenetrography method. Finally, the effect of host exposure to surfactins on host selection behavior by Aphidius matricariae parasitoid females was analyzed. RESULTS: Four surfactins concentrations were studied (0.5, 1, 2.5 and 5 g L -1 ). There was concentration-dependent mortality in response to surfactins at 24 h after treatment. Surfactins impacted aphid behavior when delivered at 1 g L -1 by inducing a greater locomotor activity and a reduction in feeding activity. By contrast, at the third trophic level, exposure of aphid hosts to surfactins did not affect behaviors leading to host recognition and acceptance by parasitoid females.CONCLUSION: This study highlighted the consequences of aphid exposure to surfactins in the context of bottom-up regulation. Although surfactins could directly impact aphid behavior, they had no apparent consequences on the host selection behavior exhibited by parasitoid wasps.

Additive Effect of the Composition of Endophytic Bacteria Bacillus subtilis on Systemic Resistance of Wheat against Greenbug Aphid Schizaphis graminum Due to Lipopeptides

“…Previously, the insecticidal activity of surfactin against several species of aphids (Hemiptera), cabbage moth Plutella xylostella (Lepidoptera), and cucumber beetle Diabrotica balteata (Coleoptera), was shown for the first time [ 45 ]. Later, surfactin was shown to be aphicidal against the green peach aphid Myzus persicae [ 18 ] and the rosy apple aphid Dysaphis plantaginea [ 21 ]. Recently, the insecticidal activity of other LPs, such as bacillopeptin and plipastatin (fengycin family), has been shown [ 21 , 22 ].…”

“…Later, surfactin was shown to be aphicidal against the green peach aphid Myzus persicae [ 18 ] and the rosy apple aphid Dysaphis plantaginea [ 21 ]. Recently, the insecticidal activity of other LPs, such as bacillopeptin and plipastatin (fengycin family), has been shown [ 21 , 22 ]. To date, the insecticidal and aphicidal activities of iturin have been shown only as part of the composition of LPs [ 19 ].…”

“…The composition of LPs (surfactin + iturin) was studied, which showed an additive aphicidal effect against S. graminum ( Figure 2 ). There are only two works on the antibiotic activity of artificial compositions of LPs, one of which is devoted to the study of the fungicidal activity of fengycin + surfactin and mycosubtilin + surfactin composition against the pathogen the apple scab Venturia inaequalis [ 46 ], and the second focuses on the aphicidal activity of the triple composition plipastatin + mycosubtilin + surfactin (PMS) against rosy apple aphid Dysaphis plantaginea [ 21 ]. Thus, when studying the fungicidal activity of LPs, a composition of mycosubtilin + surfactin (80:20) showed a synergistic effect and good reproducibility of the results in field experiments against apple scab [ 46 ].…”

“…Thus, when studying the fungicidal activity of LPs, a composition of mycosubtilin + surfactin (80:20) showed a synergistic effect and good reproducibility of the results in field experiments against apple scab [ 46 ]. In the second study, the highest mortality of the rosy apple aphid was caused by surfactin, affecting the feeding behavior of the insect, while mycosubtilin and a composition of PMS in LP at ratio 33:33:33% caused the lowest mortality, but most of all affected the motoric activity of aphids [ 21 ].…”

“…Currently, the insecticidal properties of LPs of bacteria B. subtilis are being actively studied and certain success has been achieved. There are studies that show the insecticidal activity of LPs against the orders Diptera, Coleoptera, Hemiptera, and Lepidoptera [ 11 , 18 , 19 , 20 , 21 ]. However, scientists are interested in the elicitor role of these metabolites in triggering protective signaling pathways in plants [ 10 , 17 , 20 , 22 , 23 ].…”