Toxicity assessment of four insecticides with different modes of action on pupae and adults of Eriopis connexa (Coleoptera: Coccinellidae), a relevant predator of the Neotropical Region

Abstract

Pesticides can be toxic to nontarget organisms including the natural enemies of agricultural pests, thus reducing the biodiversity of agroecosystems. The lethal and sublethal effects of four insecticides with different modes of action-pyriproxyfen, teflubenzuron, acetamiprid, and cypermethrin-were evaluated on pupae and adults of Eriopis connexa, an effective predator in horticultural crops. Pupal survival was reduced by pyriproxyfen (26 %) and cypermethrin (41 %). Malformations in adults emerged from treated pupae were observed after acetamiprid (82.7 and 100 % for 100 and 200 mg a.i./l, respectively), pyriproxyfen (48.6 %), and cypermethrin (13.3 %) treatments. A longer mean oviposition time was also observed in adults emerged from pupae treated with cypermethrin. Moreover, the latter insecticide as well as teflubenzuron did not reduce reproductive parameters, whereas females emerged from pyriproxyfen-treated pupae were not be able to lay eggs even when females showed large abdomens. Upon exposure of adults, survival was reduced to approximately 90 % by acetamiprid, but no reduction occurred with pyriproxyfen, teflubenzuron, or cypermethrin though the fecundity at fifth oviposition time of the female survivors was reduced. Pyriproxyfen decreased the hatching at all the oviposition times tested, whereas fertility was reduced in the fourth and fifth ovipositions by teflubenzuron and in the first and third ovipositions by cypermethrin. In conclusion, all four insecticides tested exhibited lethal or sublethal effects, or both, on E. connexa. The neurotoxic insecticides were more harmful than the insect-growth regulators, and pupae were more susceptible than adults. The toxicity of insecticides on the conservation of predators in agroecosystems of the Neotropical Region is discussed.

Toxicity assessment of two IGR insecticides on eggs and larvae of the ladybird Eriopis connexa

“…In our study, pyriproxyfen reduced both the fecundity and fertility of females when L 4 larvae were exposed. These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays 27 . In addition, other researchers reported similar results in different natural enemies such as S. japonicum , 63 H. axyridis , 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens 66 .…”

“…In our study, both eggs and larvae were susceptible to exposure to insecticides, showing not only lethal, but also sublethal effects manifested in the larval stages and in the reproductive parameters of the adults. As recorded in previous works, 27 in the present study cypermethrin was highly toxic for all life stages of E. connexa . In addition, our results show that both IGRs caused sublethal effects on the different stages of the predator E. connexa that compromise its performance as a biological controller and also may cause a decrease in its populations by affecting its reproductive parameters.…”

“…These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays. 27 In addition, other researchers reported similar results in different natural enemies such as S. japonicum, 63 H. axyridis, 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens. 66 Pyriproxyfen is a potent juvenile hormone (JH) mimic that affects hormonal balance in insects, resulting in strong suppression of embryogenesis, metamorphosis and adult formation.…”

“…The negative impacts induced by pesticides on biological control agents (predators and parasitoids) depend on several factors including life stage at exposure (immature or adult stages), insecticide concentration, route of exposure and mode of action of the compounds. [26][27][28]55 In this work, we observed that the application of biorational insecticides (pyriproxyfen and teflubenzuron) and broad- spectrum insecticides such as cypermethrin induced lethal and sublethal effects on the immature stages of E. connexa. In general, eggs and young larvae are the most sensitive life stages, whereas adults are the least sensitive.…”

Toxicity assessment of two IGR insecticides on eggs and larvae of the ladybird Eriopis connexa

“…In our study, pyriproxyfen reduced both the fecundity and fertility of females when L 4 larvae were exposed. These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays 27 . In addition, other researchers reported similar results in different natural enemies such as S. japonicum , 63 H. axyridis , 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens 66 .…”

“…In our study, both eggs and larvae were susceptible to exposure to insecticides, showing not only lethal, but also sublethal effects manifested in the larval stages and in the reproductive parameters of the adults. As recorded in previous works, 27 in the present study cypermethrin was highly toxic for all life stages of E. connexa . In addition, our results show that both IGRs caused sublethal effects on the different stages of the predator E. connexa that compromise its performance as a biological controller and also may cause a decrease in its populations by affecting its reproductive parameters.…”

“…These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays. 27 In addition, other researchers reported similar results in different natural enemies such as S. japonicum, 63 H. axyridis, 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens. 66 Pyriproxyfen is a potent juvenile hormone (JH) mimic that affects hormonal balance in insects, resulting in strong suppression of embryogenesis, metamorphosis and adult formation.…”

“…The negative impacts induced by pesticides on biological control agents (predators and parasitoids) depend on several factors including life stage at exposure (immature or adult stages), insecticide concentration, route of exposure and mode of action of the compounds. [26][27][28]55 In this work, we observed that the application of biorational insecticides (pyriproxyfen and teflubenzuron) and broad- spectrum insecticides such as cypermethrin induced lethal and sublethal effects on the immature stages of E. connexa. In general, eggs and young larvae are the most sensitive life stages, whereas adults are the least sensitive.…”

Lethal and Sublethal Effects of Insecticides Used in Cotton on Harmonia Axyridis

“…Corroborating the results obtained in the present work, other studies have demonstrated that H. axyridis pupae exposed to thiamethoxam or etofenprox had reduced survival (Youn et al, 2003). However, in E. connexa pupae, the application of cypermethrin signi cantly reduced their survival and led to the formation of adults with morphological deformities in the wings (Fogel et al, 2016). The high mortality after the emergence of the deformed insects in our study probably occurred due to dehydration and starvation since they had di culty moving and feeding.…”

Toxicity assessment of two IGR insecticides on eggs and larvae of the ladybird Eriopis connexa

“…In our study, pyriproxyfen reduced both the fecundity and fertility of females when L 4 larvae were exposed. These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays 27 . In addition, other researchers reported similar results in different natural enemies such as S. japonicum , 63 H. axyridis , 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens 66 .…”

“…In our study, both eggs and larvae were susceptible to exposure to insecticides, showing not only lethal, but also sublethal effects manifested in the larval stages and in the reproductive parameters of the adults. As recorded in previous works, 27 in the present study cypermethrin was highly toxic for all life stages of E. connexa . In addition, our results show that both IGRs caused sublethal effects on the different stages of the predator E. connexa that compromise its performance as a biological controller and also may cause a decrease in its populations by affecting its reproductive parameters.…”

“…These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays. 27 In addition, other researchers reported similar results in different natural enemies such as S. japonicum, 63 H. axyridis, 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens. 66 Pyriproxyfen is a potent juvenile hormone (JH) mimic that affects hormonal balance in insects, resulting in strong suppression of embryogenesis, metamorphosis and adult formation.…”

“…The negative impacts induced by pesticides on biological control agents (predators and parasitoids) depend on several factors including life stage at exposure (immature or adult stages), insecticide concentration, route of exposure and mode of action of the compounds. [26][27][28]55 In this work, we observed that the application of biorational insecticides (pyriproxyfen and teflubenzuron) and broad- spectrum insecticides such as cypermethrin induced lethal and sublethal effects on the immature stages of E. connexa. In general, eggs and young larvae are the most sensitive life stages, whereas adults are the least sensitive.…”

Lethal and Sublethal Effects of Insecticides Used in Cotton on Harmonia Axyridis

“…Corroborating the results obtained in the present work, other studies have demonstrated that H. axyridis pupae exposed to thiamethoxam or etofenprox had reduced survival (Youn et al, 2003). However, in E. connexa pupae, the application of cypermethrin signi cantly reduced their survival and led to the formation of adults with morphological deformities in the wings (Fogel et al, 2016). The high mortality after the emergence of the deformed insects in our study probably occurred due to dehydration and starvation since they had di culty moving and feeding.…”

Toxicity assessment of two IGR insecticides on eggs and larvae of the ladybird Eriopis connexa

“…In our study, pyriproxyfen reduced both the fecundity and fertility of females when L 4 larvae were exposed. These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays 27 . In addition, other researchers reported similar results in different natural enemies such as S. japonicum , 63 H. axyridis , 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens 66 .…”

“…In our study, both eggs and larvae were susceptible to exposure to insecticides, showing not only lethal, but also sublethal effects manifested in the larval stages and in the reproductive parameters of the adults. As recorded in previous works, 27 in the present study cypermethrin was highly toxic for all life stages of E. connexa . In addition, our results show that both IGRs caused sublethal effects on the different stages of the predator E. connexa that compromise its performance as a biological controller and also may cause a decrease in its populations by affecting its reproductive parameters.…”

“…These results corroborate those obtained in previous studies, in which the reproductive parameters of females of this predator were reduced by application of pyriproxyfen in pupal and adult bioassays. 27 In addition, other researchers reported similar results in different natural enemies such as S. japonicum, 63 H. axyridis, 55 the ectoparasitoid Aphytis melinus (DeBach) (Hymenoptera: Aphelinidae) 30 and H. convergens. 66 Pyriproxyfen is a potent juvenile hormone (JH) mimic that affects hormonal balance in insects, resulting in strong suppression of embryogenesis, metamorphosis and adult formation.…”

“…The negative impacts induced by pesticides on biological control agents (predators and parasitoids) depend on several factors including life stage at exposure (immature or adult stages), insecticide concentration, route of exposure and mode of action of the compounds. [26][27][28]55 In this work, we observed that the application of biorational insecticides (pyriproxyfen and teflubenzuron) and broad- spectrum insecticides such as cypermethrin induced lethal and sublethal effects on the immature stages of E. connexa. In general, eggs and young larvae are the most sensitive life stages, whereas adults are the least sensitive.…”

Lethal and Sublethal Effects of Insecticides Used in Cotton on Harmonia Axyridis

“…Corroborating the results obtained in the present work, other studies have demonstrated that H. axyridis pupae exposed to thiamethoxam or etofenprox had reduced survival (Youn et al, 2003). However, in E. connexa pupae, the application of cypermethrin signi cantly reduced their survival and led to the formation of adults with morphological deformities in the wings (Fogel et al, 2016). The high mortality after the emergence of the deformed insects in our study probably occurred due to dehydration and starvation since they had di culty moving and feeding.…”