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Bioinsecticide-predator interactions: azadirachtin behavioral and reproductive impairment of the coconut mite predator Neoseiulus baraki.

Lima DB, Melo JW, Guedes NM, Gontijo LM, Guedes RN, Gondim MG - PLoS ONE (2015)

Bottom Line: The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae).Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected.Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Agronomia, Área de Fitossanidade, Universidade Federal Rural de Pernambuco, Recife, Pernambuco, 52.171-900, Brazil.

ABSTRACT
Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems. Foremost among botanical biopesticides is the limonoid azadirachtin, whose perceived environmental safety has come under debate and scrutiny in recent years. Coconut production, particularly organic coconut production, is one of the agricultural systems in which azadirachtin is used as a primary method of pest control for the management of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae). Here, we assessed the potential behavioral impacts of azadirachtin on the coconut mite predator, N. baraki. We explored the effects of this biopesticide on overall predator activity, female searching time, and mating behavior and fecundity. Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected. In contrast, mating behavior was compromised by azadirachtin exposure particularly when male predators were exposed to the biopesticide. Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents.

No MeSH data available.


Related in: MedlinePlus

Schematic representation of time budgets of the mating behavior of the coconut mite predator Neoseiulus baraki with and without exposure to azadirachtin (n = 20). The horizontal histogram bars indicate the average duration of each behavior.The dashed bars indicate events that were repeated before copulation eventually occurred, as indicated in the transition diagrams of Fig. 2.
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pone.0118343.g003: Schematic representation of time budgets of the mating behavior of the coconut mite predator Neoseiulus baraki with and without exposure to azadirachtin (n = 20). The horizontal histogram bars indicate the average duration of each behavior.The dashed bars indicate events that were repeated before copulation eventually occurred, as indicated in the transition diagrams of Fig. 2.

Mentions: The time budgets were also recorded for each mating treatment and are exhibited in Fig. 3. The length of time spent walking and in mounting attempts when male mites were exposed to azadirachtin is notable (i.e., when only males were exposed and when both male and females were exposed), with mites incurring up to three attempts of mounting the female before copulating (Fig. 3CD). Among the three recorded durations of the behaviors leading to mating, walking and copulating were significantly different among treatments (F3,76 ≥ 2.65, P ≤ 0.05), in contrast with mounting, which was similar among treatments (overall mean = 0.41 ± 0.04 min; F3,76 = 0.68, P = 0.56). Azadirachtin-treated males spent a significantly longer amount of time walking than did untreated males before mounting untreated females. The time spent by treated males walking before mating with azadirachtin-treated females, however, led to intermediate results (Fig. 4A). A distinct trend was apparent for the time spent in copulation. Untreated couples and azadirachtin-treated couples copulated for longer periods of time, while copulation was quickest between azadirachtin-treated males and untreated females (Fig. 4B).


Bioinsecticide-predator interactions: azadirachtin behavioral and reproductive impairment of the coconut mite predator Neoseiulus baraki.

Lima DB, Melo JW, Guedes NM, Gontijo LM, Guedes RN, Gondim MG - PLoS ONE (2015)

Schematic representation of time budgets of the mating behavior of the coconut mite predator Neoseiulus baraki with and without exposure to azadirachtin (n = 20). The horizontal histogram bars indicate the average duration of each behavior.The dashed bars indicate events that were repeated before copulation eventually occurred, as indicated in the transition diagrams of Fig. 2.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4334557&req=5

pone.0118343.g003: Schematic representation of time budgets of the mating behavior of the coconut mite predator Neoseiulus baraki with and without exposure to azadirachtin (n = 20). The horizontal histogram bars indicate the average duration of each behavior.The dashed bars indicate events that were repeated before copulation eventually occurred, as indicated in the transition diagrams of Fig. 2.
Mentions: The time budgets were also recorded for each mating treatment and are exhibited in Fig. 3. The length of time spent walking and in mounting attempts when male mites were exposed to azadirachtin is notable (i.e., when only males were exposed and when both male and females were exposed), with mites incurring up to three attempts of mounting the female before copulating (Fig. 3CD). Among the three recorded durations of the behaviors leading to mating, walking and copulating were significantly different among treatments (F3,76 ≥ 2.65, P ≤ 0.05), in contrast with mounting, which was similar among treatments (overall mean = 0.41 ± 0.04 min; F3,76 = 0.68, P = 0.56). Azadirachtin-treated males spent a significantly longer amount of time walking than did untreated males before mounting untreated females. The time spent by treated males walking before mating with azadirachtin-treated females, however, led to intermediate results (Fig. 4A). A distinct trend was apparent for the time spent in copulation. Untreated couples and azadirachtin-treated couples copulated for longer periods of time, while copulation was quickest between azadirachtin-treated males and untreated females (Fig. 4B).

Bottom Line: The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae).Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected.Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents.

View Article: PubMed Central - PubMed

Affiliation: Departamento de Agronomia, Área de Fitossanidade, Universidade Federal Rural de Pernambuco, Recife, Pernambuco, 52.171-900, Brazil.

ABSTRACT
Synthetic pesticide use has been the dominant form of pest control since the 1940s. However, biopesticides are emerging as sustainable pest control alternatives, with prevailing use in organic agricultural production systems. Foremost among botanical biopesticides is the limonoid azadirachtin, whose perceived environmental safety has come under debate and scrutiny in recent years. Coconut production, particularly organic coconut production, is one of the agricultural systems in which azadirachtin is used as a primary method of pest control for the management of the invasive coconut mite, Aceria guerreronis Keifer (Acari: Eriophyidae). The management of this mite species also greatly benefits from predation by Neoseiulus baraki (Athias-Henriot) (Acari: Phytoseiidae). Here, we assessed the potential behavioral impacts of azadirachtin on the coconut mite predator, N. baraki. We explored the effects of this biopesticide on overall predator activity, female searching time, and mating behavior and fecundity. Azadirachtin impairs the overall activity of the predator, reducing it to nearly half; however, female searching was not affected. In contrast, mating behavior was compromised by azadirachtin exposure particularly when male predators were exposed to the biopesticide. Consequently, predator fecundity was also compromised by azadirachtin, furthering doubts about its environmental safety and selectivity towards biological control agents.

No MeSH data available.


Related in: MedlinePlus