Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. ... more Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. littoralis (Boisduval), whose mass rearing or real potential has not been targeted yet. To improve the rearing in the factitious host Ephestia kuehniella Zeller, we investigated the influence of host age and number of females parasitizing simultaneously on the overall rearing success, the influence of host age on the life cycle, and the influence of host species on the parasitoid body size. The proportion of emerging C. inanitus was higher from young host eggs, but more females emerged from mature eggs. Under high parasitoid competition, we observed a reduction in non-parasitized hosts without reducing parasitoid emergence. The parasitoid life cycle was longer in females, but the mismatch between sexes was smaller in mature eggs. The parasitoid size was smaller in the factitious host than in the natural hosts. Under semi-field conditions, we investigated the competition among parasitoid ...
Bulletin OILB srop Vol. 26 (8) 2003The IOBC/WPRS Bulletin is published by the International Organ... more Bulletin OILB srop Vol. 26 (8) 2003The IOBC/WPRS Bulletin is published by the International Organization for Biological and Integrated
Nowadays and in the last years, biodiversity matters have become relevant. Different approaches h... more Nowadays and in the last years, biodiversity matters have become relevant. Different approaches have been set up in agriculture for the benefit of wildlife, and especially for the pollinator conservation (Wratten et al, 2012). An way to introduce conservation measures for increasing biodiversity into agro-ecosystems is by managing the crop margins and introducing flowering plants (Kells et al, 2001; Rands et al 2011). These can offer food and shelter not only for pollinators but for natural enemies as well, helping to mitigate their decline and this has been widely documented (Biesmeijer et al., 2006; Potts et al, 2010). Five years ago the so called ‘Operation pollinator’ was launched, a European initiative sponsored by Syngenta, active in nine countries. In Spain, the Technical University of Madrid (UPM) and the National Research Council (CSIC) participated in Madrid aiming at identifying a suitable floral mixture and its impact on wild social and non-social pollinators. During a 3...
In the present study, the influence of three sex ratios (1:1, 1:2, and 1:3; female:male) of the m... more In the present study, the influence of three sex ratios (1:1, 1:2, and 1:3; female:male) of the mirid Engytatus varians (Distant) (Hemiptera) on different biological parameters and on its offspring was evaluated. The prey preference of different developmental stages of this predator for different nymphal instars (N) of Bactericera cockerelli (Sulcer) (Hemiptera: Triozidae) was also evaluated. The fertility was significantly higher (24 nymphs/female) in the 1:3 sex ratio than in the 1:1 and 1:2 sex ratios (14 and 16 nymphs/female, respectively). The females in the 1:1 and 1:2 sex ratios lived 1.14 and 1.43 days more (27 and 28 days, respectively) than those in the 1:3 sex ratio (26 days). The nymphs derived from the females of the three sex ratios (first filial generation, F1) had five instars and a duration of 17 or 18 days. The ratio of the F1 generation females was not affected by the sex ratio of their parents. In choice tests, independent of whether the preys were placed on a si...
Pesticide use is one of the main causes of pollinator declines in agricultural ecosystems. Tradit... more Pesticide use is one of the main causes of pollinator declines in agricultural ecosystems. Traditionally, most laboratory studies on bee ecotoxicology test acute exposure to single compounds. However, under field conditions, bees are often chronically exposed to a variety of chemicals, with potential synergistic effects. We studied the effects of field-realistic concentrations of three pesticides measured in pollen and nectar of commercial melon fields on the solitary bee Osmia bicornis L. We orally exposed females of this species throughout their life span to 8 treatments combining two neonicotinoid insecticides (acetamiprid, imidacloprid) and a triazole fungicide (myclobutanil) via pollen and sugar syrup. We measured pollen and syrup consumption, longevity, ovary maturation and thermogenesis. Although bees consumed larger amounts of syrup than pollen, pesticide intake via syrup and pollen were similar. At the tested concentrations, no synergistic effects emerged, and we found no e...
The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet army... more The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), adults were assessed after exposure by ingestion. Methoxyfenozide significantly reduced adult male longevity compared with females by 1.1 and 1.5 d at 75 and 150 mg (AI)/liter, respectively. Fecundity decreased by >60% with both concentrations at 72 and 96 h after treatment, but at 48 h, no significant effect was observed. The carbohydrate, protein, and lipid content in the eggs were determined as representatives of the biochemical effects of methoxyfenozide associated with the disruption of reproductive processes. The content of carbohydrates in the eggs laid 48 h at treatment was similar to that of controls, but it increased by approximately 1.5 and 2-fold in eggs laid after 72 and 96 h, respectively, compared with controls (15 microg per egg). Protein content was reduced approximately 2.5 and approximately 3-fold for each treatment concentration, respectively, compared with the controls (25 and 23 microg per egg for 75 and 150 mg [AI]/liter, respectively) in eggs collected 72 and 96 h after treatment. Lipid content significantly decreased by approximately 1.6-fold in both treatment concentrations in eggs collected at 48 and 96 h after treatment compared with the controls (24 and 21 microg per egg for 48 and 96, respectively), but it was similar to controls (approximately 19 microg per egg) at 72 h (approximately 15 microg per egg) for both concentrations. The biochemical effects of methoxyfenozide on S. exigua egg formation detected in this work are consistent with the reduction in fertility observed, as reported previously.
Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. ... more Chelonus inanitus (L.) is an egg-larval parasitoid of noctuids Spodoptera exigua (Hübner) and S. littoralis (Boisduval), whose mass rearing or real potential has not been targeted yet. To improve the rearing in the factitious host Ephestia kuehniella Zeller, we investigated the influence of host age and number of females parasitizing simultaneously on the overall rearing success, the influence of host age on the life cycle, and the influence of host species on the parasitoid body size. The proportion of emerging C. inanitus was higher from young host eggs, but more females emerged from mature eggs. Under high parasitoid competition, we observed a reduction in non-parasitized hosts without reducing parasitoid emergence. The parasitoid life cycle was longer in females, but the mismatch between sexes was smaller in mature eggs. The parasitoid size was smaller in the factitious host than in the natural hosts. Under semi-field conditions, we investigated the competition among parasitoid ...
Bulletin OILB srop Vol. 26 (8) 2003The IOBC/WPRS Bulletin is published by the International Organ... more Bulletin OILB srop Vol. 26 (8) 2003The IOBC/WPRS Bulletin is published by the International Organization for Biological and Integrated
Nowadays and in the last years, biodiversity matters have become relevant. Different approaches h... more Nowadays and in the last years, biodiversity matters have become relevant. Different approaches have been set up in agriculture for the benefit of wildlife, and especially for the pollinator conservation (Wratten et al, 2012). An way to introduce conservation measures for increasing biodiversity into agro-ecosystems is by managing the crop margins and introducing flowering plants (Kells et al, 2001; Rands et al 2011). These can offer food and shelter not only for pollinators but for natural enemies as well, helping to mitigate their decline and this has been widely documented (Biesmeijer et al., 2006; Potts et al, 2010). Five years ago the so called ‘Operation pollinator’ was launched, a European initiative sponsored by Syngenta, active in nine countries. In Spain, the Technical University of Madrid (UPM) and the National Research Council (CSIC) participated in Madrid aiming at identifying a suitable floral mixture and its impact on wild social and non-social pollinators. During a 3...
In the present study, the influence of three sex ratios (1:1, 1:2, and 1:3; female:male) of the m... more In the present study, the influence of three sex ratios (1:1, 1:2, and 1:3; female:male) of the mirid Engytatus varians (Distant) (Hemiptera) on different biological parameters and on its offspring was evaluated. The prey preference of different developmental stages of this predator for different nymphal instars (N) of Bactericera cockerelli (Sulcer) (Hemiptera: Triozidae) was also evaluated. The fertility was significantly higher (24 nymphs/female) in the 1:3 sex ratio than in the 1:1 and 1:2 sex ratios (14 and 16 nymphs/female, respectively). The females in the 1:1 and 1:2 sex ratios lived 1.14 and 1.43 days more (27 and 28 days, respectively) than those in the 1:3 sex ratio (26 days). The nymphs derived from the females of the three sex ratios (first filial generation, F1) had five instars and a duration of 17 or 18 days. The ratio of the F1 generation females was not affected by the sex ratio of their parents. In choice tests, independent of whether the preys were placed on a si...
Pesticide use is one of the main causes of pollinator declines in agricultural ecosystems. Tradit... more Pesticide use is one of the main causes of pollinator declines in agricultural ecosystems. Traditionally, most laboratory studies on bee ecotoxicology test acute exposure to single compounds. However, under field conditions, bees are often chronically exposed to a variety of chemicals, with potential synergistic effects. We studied the effects of field-realistic concentrations of three pesticides measured in pollen and nectar of commercial melon fields on the solitary bee Osmia bicornis L. We orally exposed females of this species throughout their life span to 8 treatments combining two neonicotinoid insecticides (acetamiprid, imidacloprid) and a triazole fungicide (myclobutanil) via pollen and sugar syrup. We measured pollen and syrup consumption, longevity, ovary maturation and thermogenesis. Although bees consumed larger amounts of syrup than pollen, pesticide intake via syrup and pollen were similar. At the tested concentrations, no synergistic effects emerged, and we found no e...
The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet army... more The long-term effects of methoxyfenozide on the longevity and reproductive processes of beet armyworm, Spodoptera exigua (Hübner) (Lepidoptera: Noctuidae), adults were assessed after exposure by ingestion. Methoxyfenozide significantly reduced adult male longevity compared with females by 1.1 and 1.5 d at 75 and 150 mg (AI)/liter, respectively. Fecundity decreased by >60% with both concentrations at 72 and 96 h after treatment, but at 48 h, no significant effect was observed. The carbohydrate, protein, and lipid content in the eggs were determined as representatives of the biochemical effects of methoxyfenozide associated with the disruption of reproductive processes. The content of carbohydrates in the eggs laid 48 h at treatment was similar to that of controls, but it increased by approximately 1.5 and 2-fold in eggs laid after 72 and 96 h, respectively, compared with controls (15 microg per egg). Protein content was reduced approximately 2.5 and approximately 3-fold for each treatment concentration, respectively, compared with the controls (25 and 23 microg per egg for 75 and 150 mg [AI]/liter, respectively) in eggs collected 72 and 96 h after treatment. Lipid content significantly decreased by approximately 1.6-fold in both treatment concentrations in eggs collected at 48 and 96 h after treatment compared with the controls (24 and 21 microg per egg for 48 and 96, respectively), but it was similar to controls (approximately 19 microg per egg) at 72 h (approximately 15 microg per egg) for both concentrations. The biochemical effects of methoxyfenozide on S. exigua egg formation detected in this work are consistent with the reduction in fertility observed, as reported previously.
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