New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory

New method for rearing Spodoptera frugiperda in laboratory shows that larval cannibalism is not obligatory. Here we show, for the first time, that larvae of the fall armyworm (FAW), Spodoptera frugiperda (Lepidoptera, Noctuidae), can be successfully reared in a cohort-based manner with virtually no cannibalism. FAW larvae were reared since the second instar to pupation in rectangular plastic containers containing 40 individuals with a surprisingly ca. 90% larval survivorship. Adult females from the cohort-based method showed fecundity similar to that already reported on literature for larvae reared individually, and fertility higher than 99%, with the advantage of combining economy of time, space and material resources. These findings suggest that the factors affecting cannibalism of FAW larvae in laboratory rearings need to be reevaluated, whilst the new technique also show potential to increase the efficiency of both small and mass FAW rearings.

Biological aspects of Leucothyreus ambrosius Blanchard (Coleoptera, Melolonthidae, Rutelinae)

Biological aspects of Leucothyreus ambrosius Blanchard (Coleoptera, Melolonthidae, Rutelinae). Coleopterans of the family Melolonthidae comprise a large group of species that feed on different food sources, including plant roots, stems, and leaves, in addition to plant materials at different decomposition stages. Several species are found in the genus Leucothyreus, occurring in different regions of Brazil, including the various biomes in the country. Information on the biology of species of the genus Leucothyreus is scarce, therefore, we conducted studies on the biological aspects of Leucothyreus ambrosius Blanchard, 1850. The period of adult occurrence was determined with a light trap installed between a cropped and pasture area in the municipality of Aquidauana, Mato Grosso do Sul State, Brazil. Adults collected in the field were used to form insect pairs and the studies were initiated in the entomology laboratory as the adults began ovipositing. Adults were observed flying in the field from October to December. Eggs were obtained as pairs were formed and a colony was established, the embryonic period lasting 14.6 days on average. The larval period in the 1st instar lasted 21.6 days, in the 2nd instar 19.6 days, and in the 3rd instar, 85.6 days. The head capsule width was 1.48 mm in the 1st instar, 2.44 mm in the 2nd, and 3.83 mm in 3rd larval instar. The pupal stage had an average duration of 35.5 days. The egg to adult period lasted 173.3 days. Morphometric information for the larval and adult stages is presented in this study.

Larval development of Physocephala (Diptera, Conopidae) in the bumble bee Bombus morio (Hymenoptera, Apidae)

Larval development of Physocephala (Diptera, Conopidae) in the bumble bee Bombus morio (Hymenoptera, Apidae). In the summer of 2012, a high incidence of conopid larvae was observed in a sample of female B. morio collected in remaining fragments of semidecidual forest and Cerrado, in the municipality of Sorocaba, state of São Paulo, Brazil. The larval development of conopid flies was studied, beginning at the larval instars (LO to L3) and PUP, until the emergence of the imago under laboratory conditions and inside the host. At the first instar, or LO, the microtype larvae measured less than 1 mm in length. During the transition from L1 to L3, the larvae grew in length. At L3, the larvae doubled their length (4 mm) and then started to develop both in length and width, reaching the PUP stage with 10 mm in length and 7 mm in width. The main characteristic that differentiates L3 from the early instars is the larger body size and the beginning of posterior spiracle development. The development from PUP to puparium took less than 24h. The bees died ten days after the fly oviposition, or just before full PUP development. The early development stages (egg-LO to L1) were critical for larva survival. The pupa was visible between the intersegmental sternites and, 32 days after pupation, a female imago of Physocephala sp. emerged from one bee. The puparium and the fly measured approximately 10 mm in length. In a single day of collection, up to 45% of the bumble bees collected were parasitized by conopid flies.

Larval development of Spodoptera eridania (Cramer) fed on leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 proteins and its non-Bt isoline

This study aimed to evaluate, in controlled laboratory conditions (temperature of 25±2 °C, relative humidity of 60±10%, and 14/10 h L/D photoperiod), the larval development of Spodoptera eridania (Cramer, 1784) (Lepidoptera, Noctuidae) fed with leaves of Bt maize expressing Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 insecticide proteins and its non-Btisoline. Maize leaves triggered 100% of mortality on S. eridania larvae independently of being Bt or non-Bt plants. However, it was observed that in overall Bt maize (expressing a single or pyramided protein) slightly affects the larval development of S. eridania, even under reduced leaf consumption. Therefore, these results showed that Cry1F and Cry1F + Cry1A.105 + Cry2Ab2 can affect the larval development of S. eridania, although it is not a target pest of this plant; however, more research is needed to better understand this evidence. Finally, this study confirms that non-Bt maize leaves are unsuitable food source to S. eridania larvae, suggesting that they are not a potential pest in maize fields.

Spatial and temporal dynamics of drosophilid larval assemblages associated to fruits

The study of organisms and their resources is critical to further understanding population dynamics in space and time. Although drosophilids have been widely used as biological models, their relationship with breeding and feeding sites has received little attention. Here, we investigate drosophilids breeding in fruits in the Brazilian Savanna, in two contrasting vegetation types, throughout 16 months. Specifically, larval assemblages were compared between savannas and forests, as well as between rainy and dry seasons. The relationships between resource availability and drosophilid abundance and richness were also tested. The community (4,022 drosophilids of 23 species and 2,496 fruits of 57 plant taxa) varied widely in space and time. Drosophilid assemblages experienced a strong bottleneck during the dry season, decreasing to only 0.5% of the abundance of the rainy season. Additionally, savannas displayed lower richness and higher abundance than the forests, and were dominated by exotic species. Both differences in larval assemblages throughout the year and between savannas and gallery forests are consistent with those previously seen in adults. Although the causes of this dynamic are clearly multifactorial, resource availability (richness and abundance of rotten fruits) was a good predictor of the fly assemblage structure.

Biology and reproductive capacity of Spodoptera eridania (Cramer) (Lepidoptera, Noctuidae) in different soybean cultivars

This study aimed to evaluate the development, survival and reproductive capacity of Spodoptera eridania in four soybean cultivars. The experiment was conducted in the laboratory, in a climatic chamber at 25 °C ± 1 °C, 70 ± 10% relative humidity and 12 h photophase. The cultivars used were: FMT Tabarana, BRS/MT Pintado, FMT Tucunaré and Monsoy 8757, all conventional cultivars with medium cycles. All cultivars tested allowed the development of S. eridania. However, Monsoy 8757 was the cultivar that most affected the prolonged in the duration larval, pupal and total cycle, showed lower pupal weight as well as reduction in the intrinsic rate increase. These results contribute to the management of this species in regions of outbreaks in soybean areas.

Bionomy of two flies of sanitary and forensic importance: Peckia (Sarcodexia) lambens (Wiedemann) and Oxysarcodexia amorosa (Schiner) (Diptera, Sarcophagidae)

ABSTRACTThis study aims to elucidate the bionomy of Peckia(Sarcodexia) lambens and Oxysarcodexia amorosa to provide data for medical, veterinary and forensic entomology analyses. We analyzed larval stage duration (L1–L3), weight of the mature larvae (L3), pupal stage duration, L1–adult duration, adult emergence and viability of larvae and adults of both species. Larval viability of P. (S.) lambens was 82% and the mean duration of the larval stage was 3.51 ± 0.99 days. The mature larvae had a mean weight of 33.67 ± 7.13 mg. The mean duration of the pupal stage was 8.26 ± 0.93 days and the mean duration of the L1–adult was 11.53 ± 1.22 days. Mean lifespan for females and males was 39.33 ± 1.52 and 57.33 ± 4.72 days, respectively. Larval viability of O. amorosa was 76% and mean duration of larval stage was 3.51 ± 0.64 days. Mature larvae had a mean weight of 28.28 ± 3.38 mg. Mean duration of the pupal stage was 10.14 ± 0.63 days and mean duration of the L1–adult was 13.60 ± 0.69 days. Mean lifespan for females and males was 83.66 ± 15.94 and 84.00 ± 19.97 days, respectively. Oxysarcodexia amorosa showed a L1–adult stage longer than P. (S.) lambens; however both species showed low viability. O. amorosa laid more larvae than P. (S.) lambens, this fact may occur because O. amorosa had longer life duration.

Equilibrium Unemployment and the Duration of Unemployment Benefits

This paper uses microdata to evaluate the impact on the steady-state unemployment rate of an increase in maximum benefit duration. We evaluate a policy change in Austria that extended maximum benefit duration and use this policy change to estimate the causal impact of benefit duration on labor market flows. We find that the policy change leads to a significant increase in the steady-state unemployment rate and, surprisingly, most of this increase is due to an increase in the inflow into rather than the outflow from unemployment.

Some like it hot: temperature and acidification modulate larval development and settlement of the sea urchin Arbacia lixula

We studied the effects of temperature and pH on larval development, settlement and juvenile survival of a Mediterranean population of the sea urchin Arbacia lixula. Three temperatures (16, 17.5 and 19 °C) were tested at present pH conditions (pHT 8.1). At 19 °C, two pH levels were compared to reflect present average (pHT 8.1) and near-future average conditions (pHT 7.7, expected by 2100). Larvae were reared for 52-days to achieve the full larval development and complete the metamorphosis to the settler stage. We analyzed larval survival, growth, morphology and settlement success. We also tested the carry-over effect of acidification on juvenile survival after 3 days. Our results showed that larval survival and size significantly increased with temperature. Acidification resulted in higher survival rates and developmental delay. Larval morphology was significantly altered by low temperatures, which led to narrower larvae with relatively shorter skeletal rods, but larval morphology was only marginally affected by acidification. No carry-over effects between larvae and juveniles were detected in early settler survival, though settlers from larvae reared at pH 7.7 were significantly smaller than their counterparts developed at pH 8.1. These results suggest an overall positive effect of environmental parameters related to global change on the reproduction of A. lixula, and reinforce the concerns about the increasing negative impact on shallow Mediterranean ecosystems of this post-glacial colonizer.

Effects of prior repeated-sprints with different recovery duration on oxygen uptake kinetics during subsequent heavy-exercise.

Introduction: Prior repeated-sprints (6) has become an interesting method to resolve the debate surrounding the principal factors that limits the oxygen uptake (V'O2) kinetics at the onset of exercise [i.e., muscle O2 delivery (5) or metabolic inertia (3)]. The aim of this study was to compare the effects of two repeated-sprints sets of 6x6s separated by different recovery duration between the sprints on V'O2 and muscular de-oxygenation [HHb] kinetics during a subsequent heavy-intensity exercise. Methods: 10 male subjects performed a 6-min constant-load cycling test (T50) at intensity corresponding to half of the difference between V'O2max and the ventilatory threshold. Then, they performed two repeated-sprints sets of 6x6s all-out separated by different recovery duration between the sprints (S1:30s and S2:3min) followed, after 7-min-recovery, by the T50 (S1T50 and S2T50, respectively). V'O2, [HHb] of the vastus lateralis (VL) and surface electromyography activity [i.e., root-mean-square (RMS) and the median frequency of the power density spectrum (MDF)] from VL and vastus medialis (VM) were recorded throughout T50. Models using a bi-exponential function for the overall T50 and a mono-exponential for the first 90s of T50 were used to define V'O2 and [HHb] kinetics respectively. Results: V'O2 mean value was higher in S1 (2.9±0.3l.min-1) than in S2 (1.2±0.3l.min-1); (p<0.001). The peripheral blood flow was increased after sprints as attested by a higher basal heart rate (HRbaseline) (S1T50: +22%; S2T50: +17%; p≤0.008). Time delay [HHb] was shorter for S1T50 and S2T50 than for T50 (-22% for both; p≤0.007) whereas the mean response time of V'O2 was accelerated only after S1 (S1T50: 32.3±2.5s; S2T50: 34.4±2.6s; T50: 35.7±5.4s; p=0.031). There were no significant differences in RMS between the three conditions (p>0.05). MDF of VM was higher during the first 3-min in S1T50 than in T50 (+6%; p≤0.05). Conclusion: The study show that V'O2 kinetics was speeded by prior repeated-sprints with a short (30s) but not a long (3min) inter-sprints-recovery even though the [HHb] kinetics was accelerated and the peripheral blood flow was enhanced after both sprints. S1, inducing a greater PCr depletion (1) and change in the pattern of the fibres recruitment (increase in MDF) compared with S2, may decrease metabolic inertia (2), stimulate the oxidative phosphorylation activation (4) and accelerate V'O2 kinetics at the beginning of the subsequent high-intensity exercise.

Impact of prolonged antihypertensive duration of action on predicted clinical outcomes in imperfectly adherent patients: comparison of aliskiren, irbesartan and ramipril.

Background: Most patients miss occasional doses of antihypertensives. The use of 'forgiving' drugs (i.e. drugs with duration of action longer than the 24-h dosing interval) may allow an adequate blood pressure (BP) reduction to be maintained despite missed doses. Aim:To quantify the effects of adherence level and duration of action on estimated mean systolic BP (SBP) reduction and cardiovascular disease (CVD) risk. Method:For 1250 patients, we simulated 256-day dosing histories with realistically distributed drug holidays based on a study of electronically monitored dosing records. Adherence was set to the desired level by altering the proportion of doses missed. Mean office SBP-lowering effect (aliskiren 300 mg, -14.1 mmHg; irbesartan 300 mg, -13.3; ramipril 10 mg, -10.1 mmHg) and the rate of SBP increase after stopping treatment (off-rate; aliskiren, 1.0 mmHg/day; irbesartan, 3.6 mmHg/day; ramipril, 4.0 mmHg/day) were taken from the results of a randomised, double-blind trial. SBP was averaged over time and patient to estimate mean reductions in SBP and 10-year CVD risk (Framingham risk equation, baseline absolute 10-year CVD risk: 27%). Results:Predicted reductions in SBP and CVD risk with aliskiren were larger and less affected by imperfect adherence than the reductions with irbesartan or ramipril. For aliskiren, reducing adherence from 90% to 60% led to a predicted rise in SBP of 1.0 mmHg and three additional CVD events per 1000 treated patients; larger predicted differences were observed for irbesartan (2.5 mmHg; 7.5 events/1000 treated patients) and ramipril (2.2 mmHg; 6.7 events/1000 treated patients). Conclusion:To offset the effects of imperfect adherence, a common challenge with antihypertensives, for better BP management it may be prudent to prescribe 'forgiving' drugs.

Soil shear strength under non-irrigated and irrigated short duration grazing systems

Pasture productivity can drop due to soil compaction caused by animal trampling. Physical and mechanical alterations are therefore extremely important indicators for pasture management. The objective of this research was to: draw and evaluate the Mohr failure line of a Red Yellow Latossol under different pasture cycles and natural forest; calculate apparent cohesion; observe possible physical alterations in this soil; and propose a correction factor for stocking rates based on shear strength properties. This study was conducted between March/2006 and March/2007 on the Experimental Farm of Fundação de Ensino Superior de Passos, in Passos, state of Minas Gerais. The total study area covered 6 ha, of which 2 ha were irrigated pasture, 2 ha non-irrigated pasture and 2 ha natural forest. Brachiaria brizantha cv. MG-5 Vitória was used as forage plant. The pasture area was divided into paddocks. The Mohr failure line of samples of a Red Yellow Latossol under irrigated pasture equilibrated at a tension of water content of 6 kPa indicated higher shear strength than under non-irrigated pasture. The shear strength under irrigated pasture and natural forest was higher than under non-irrigated pasture. At a tension of water content of 33 kPa no difference was found in shear strength between management and use. Possible changes in soil structure were caused by apparent cohesion. The values of the correction factor were close to 1, which may indicate a possible soil compaction in prolonged periods of management.

Political economy of municipal water service privatization in Spain: a duration model analysis

This empirical work applies a duration model to the study of factors determining privatization of local water services. I assess how factors determining privatization decision evolve as time goes by. A sample of 133 Spanish municipalities during the six terms of office taken place during the 1980-2002 period is analyzed. A dynamic neighboring effect is hypothesized and successfully tested. In a first stage, private water supply firms may try to expand to regions where there is no service privatized, in order to spread over this region after having being installed thanks to its scale advantages. Other factors influencing privatization decision evolve during the two decades under study, from the priority to fix old infrastructures to the concern about service efficiency. Some complementary results regarding political and budgetary factors are also obtained