Gut bacteria of the cowpea beetle mediate its resistance to dichlorvos and susceptibility to Lippia adoensis essential oil

Abstract

Bacteria inhabiting the gut of insects provide many benefits to their hosts, such as aiding in food digestion, reproduction, and immunity, tissue homeostasis, adaptation to environment and resistance to pathogen and pesticides. The cowpea beetle, Callosobruchus maculatus , is a serious cosmopolitan pest of pulses. This beetle has lent itself as a guinea pig for several ecological studies. It harbors a consortium of bacterial communities in its gut, but the evidence for their role in its physiology is fragmentary. In this work, we hypothesized that gut microbiota mediates C . maculatus resistance to dichlorvos (DDVP or O , O -dimethyl O -2,2-dichlorovinylphosphate) and represent the target of Lippia adoensis (Gambian Tea Bush) essential oil (EO). Symbiotic and aposymbiotic beetles were exposed to artificial cowpea seeds earlier treated with DDVP or EO. Adult mortality and changes in gut bacterial community composition and abundance were examined at F 1 and F 5 generations. The susceptibility of experimental beetles to DDVP was significantly affected by their symbiotic status. The adult mortality decreased across generations in DDVP treatments, and remained significantly higher in aposymbiotic groups. In EO treatments, the mortality was consistent irrespective of symbiotic status and experimental generations. When compared to DDVP and the Control, EO treatments had significantly lower bacterial richness and diversity, as well as lower abundance of Proteobacteria, Firmicutes, and Bacteroidetes. These results support our hypothesis and describe the responses of gut microbial communities to pesticide treatments. This could be of interest for developing new management strategies of this pest.

Bacterial Communities in Three Parts of Intestinal Tracts of Carpenter Bees (Xylocopa tenuiscapa)

“…However, Bifidobacterium , Dysgonomonas and family Pseudomonadaceae were found to be predominant only in the hindgut. Dysgonomonas had been identified in many insects’ guts [ 51 , 54 , 55 ]. It is involved in lignocellulose degradation.…”

“…It is involved in lignocellulose degradation. Members of the family Pseudomonadaceae were identified in cowpea beetles, Callosobruchus maculatus [ 55 ] and honey bees’ guts [ 13 ].…”

Symbiotic bacteria motivate the foraging decision and promote fecundity and survival of Bactrocera dorsalis (Diptera: Tephritidae)

“…For example, the gut microbiome of the vinegar fly Drosophila melanogaster was shown to indirectly influence the foraging behavior of the host by modulating their immune system, lipid and carbohydrate accumulation [19–21] and olfactory sensitivity for the own benefits of bacteria [22]. Gut bacteria was shown to be implicated in the resistance and susceptibility of Callosobruchus maculatus to dichlorvos and essential oil [23]. Intestinal probiotic Klebsiella oxytoca (member of Enterobacteriaceae family) restored the ecological fitness of irradiated B. dorsalis males by promoting food intake and metabolic activities [24].…”

Symbiont-Mediated Insecticide Detoxification as an Emerging Problem in Insect Pests

“…Briefly, Lasioderma serricorne, Culex pipiens, Anopheles stephensi , Bactrocera dorsalis, Plutella xylostella, Spodoptera frugiperda, Nilaparvata lugens, Blatella germanica , and Callosobruchus maculatus have all been found in association with bacteria mediate or modulate increased pesticide tolerance ( Shen and Dowd, 1991 ; Berticat et al, 2002 ; Soltani et al, 2017 ; Cheng et al, 2017 ; de Almeida et al, 2017 ; Xie et al, 2018 ; Pang et al, 2018 ; Pietri et al, 2018 ; Akami et al, 2019 ; Table 1 ). Using reductive antibiotic treatment approaches and in vitro , culturing assays many of these studies directly link the presence and/or metabolic capabilities of symbiotic microbes to pesticide detoxification abilities ( Shen and Dowd, 1991 ; de Almeida et al, 2017 ; Cheng et al, 2017 ; Soltani et al, 2017 ; Pietri et al, 2018 ; Xie et al, 2018 ; Akami et al, 2019 ; Table 1 ). And, similar to the example in R. pedestris , specific Arsenophonus strains have being linked to pesticide susceptibility in a leafhopper species ( Pang et al, 2018 ).…”