Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. <em>Spodoptera frugiperda</em> is a pest that affects corn crops among others and has a gre...Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. <em>Spodoptera frugiperda</em> is a pest that affects corn crops among others and has a great capacity to develop resistance to traditional insecticides, which represents sufficient reasons for the search for new alternatives for their control. The objective of this study was to determine the appropriate concentration and screening new natural insecticides against second instar larvae of <em>S. frugiperda</em>, under glasshouse conditions on <em>Zea mays</em> L. Natural products such as annonaceous acetogenins and some acetylated and methoxy methylated ACG derivatives and the commercial product Lambda-cyhalotrin (LC) were evaluated. The percent mortalities of <em>S. frugiperda </em>larvae in glasshouse conditions were recorded after 24, 48 and 72 h of treatment application. The results showed that the acetogenins tested were significantly (P < 0.05) different in relation to pest mortality than untreated check. After 72 h of treatment application the highest percent mortalities were obtained with the mixture of two natural products, rolliniastatin-2 (<strong>5</strong>) (100 μg/mL) + squamocin (<strong>6</strong>) (100 μg/mL) + LC (50 μg/mL) that proved the most effective and gave (100%), while rolliniastatin-2 (<strong>5</strong>) at 100 μg/mL alone, gave lowest percent mortality (65%), followed by squamocin (<strong>6</strong>) at 100 μg/mL (55%) and LC at 50 μg/mL (30%). The acetylated and methoxy methylated ACGs derivatives caused very low mortality (25% - 35%). It is recommended the mixture as a management option of <em>S. frugiperda</em> as a component of integrated pest management. The results allow us to infer that the addition of natural ACGs synergizes the insecticidal activity of the commercial product. Finding a new ecological alternative for insect control.展开更多
Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for speci...Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for species with internal fertilization.Nevertheless,species that store and use sperm of different males in different storing struc-tures and species where females are able to expel all or part of the ejaculates after cop-ulation may be able to bias fertilization.We report a series of experiments aimed at pro-viding evidence of female sperm choice in Euxesta eluta(Hendel),a species of ulidiid fly that expels and consumes ejaculates after copulation.We found no evidence of greater reproductive success for females mated singly,multiply with the same male,or mated multiply with different males.Female E.eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage,with a ventral receptacle.There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation.Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males.Protein-fed females prevented to consume the ejaculate,retained more sperm when mated to protein-fed males than when mated to protein-deprived males.Our results suggest that female E.eluta can exert control of sperm retention of higher quality males through ejaculate ejection.展开更多
文摘Annonaceous acetogenins enclose a large number of biological activities, among which the insecticidal stands out. <em>Spodoptera frugiperda</em> is a pest that affects corn crops among others and has a great capacity to develop resistance to traditional insecticides, which represents sufficient reasons for the search for new alternatives for their control. The objective of this study was to determine the appropriate concentration and screening new natural insecticides against second instar larvae of <em>S. frugiperda</em>, under glasshouse conditions on <em>Zea mays</em> L. Natural products such as annonaceous acetogenins and some acetylated and methoxy methylated ACG derivatives and the commercial product Lambda-cyhalotrin (LC) were evaluated. The percent mortalities of <em>S. frugiperda </em>larvae in glasshouse conditions were recorded after 24, 48 and 72 h of treatment application. The results showed that the acetogenins tested were significantly (P < 0.05) different in relation to pest mortality than untreated check. After 72 h of treatment application the highest percent mortalities were obtained with the mixture of two natural products, rolliniastatin-2 (<strong>5</strong>) (100 μg/mL) + squamocin (<strong>6</strong>) (100 μg/mL) + LC (50 μg/mL) that proved the most effective and gave (100%), while rolliniastatin-2 (<strong>5</strong>) at 100 μg/mL alone, gave lowest percent mortality (65%), followed by squamocin (<strong>6</strong>) at 100 μg/mL (55%) and LC at 50 μg/mL (30%). The acetylated and methoxy methylated ACGs derivatives caused very low mortality (25% - 35%). It is recommended the mixture as a management option of <em>S. frugiperda</em> as a component of integrated pest management. The results allow us to infer that the addition of natural ACGs synergizes the insecticidal activity of the commercial product. Finding a new ecological alternative for insect control.
基金supported by the Fund for Scientific and Technological Research(FONCyT PICT 2018-03521).
文摘Promiscuous mating systems provide the opportunity for females to bias fertilization toward particular males.However,distinguishing between male sperm com-petition and active female sperm choice is difficult for species with internal fertilization.Nevertheless,species that store and use sperm of different males in different storing struc-tures and species where females are able to expel all or part of the ejaculates after cop-ulation may be able to bias fertilization.We report a series of experiments aimed at pro-viding evidence of female sperm choice in Euxesta eluta(Hendel),a species of ulidiid fly that expels and consumes ejaculates after copulation.We found no evidence of greater reproductive success for females mated singly,multiply with the same male,or mated multiply with different males.Female E.eluta possesses two spherical spermathecae and a bursa copulatrix for sperm storage,with a ventral receptacle.There was no significant difference in storing more sperm in spermathecae 24 h after copulation than immediately after copulation.Females mated with protein-fed males had greater reproductive success than similar females mated to protein-deprived males.Protein-fed females prevented to consume the ejaculate,retained more sperm when mated to protein-fed males than when mated to protein-deprived males.Our results suggest that female E.eluta can exert control of sperm retention of higher quality males through ejaculate ejection.
