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1.
Ecotoxicol Environ Saf ; 264: 115398, 2023 Oct 01.
Article in English | MEDLINE | ID: mdl-37634482

ABSTRACT

Pesticide exposure is an important driver of bee declines. Laboratory toxicity tests provide baseline information on the potential effects of pesticides on bees, but current risk assessment schemes rely on one species, the highly social honey bee, Apis mellifera, and there is uncertainty regarding the extent to which this species is a suitable surrogate for other pollinators. For this reason, Osmia cornuta and Osmia bicornis have been proposed as model solitary bee species in the EU risk assessment scheme. The use of solitary bees in risk assessment requires the development of new methodologies adjusted to the biology of these species. For example, oral dosing methods used with honey bees cannot be readily applied to solitary bees due to differences in feeding behaviour and social interactions. In this study, we describe the "petal method", a laboratory feeding method, and validate its use in acute and chronic exposure oral tests with Osmia spp. We conducted five experiments in which we compared the performance of several artificial flowers combining visual and olfactory cues against the petal method, or in which variations of the petal method were confronted. We then use the results of these experiments to optimize the feeding arenas and propose standardized methods for both acute and chronic exposure tests. The petal method provides high levels of feeding success, thus reducing the number of bees needed. It works with a wide variety of petal species and with both female and male Osmia spp., thus ensuring reproducibility across studies. To validate the use of the petal method in ecotoxicology tests, we assess the toxicity of a standard reference insecticide, dimethoate, in O. cornuta adults and determine LD50 values for this species. The petal method should facilitate the inclusion of solitary bees in risk assessment schemes therefore increasing the protection coverage of pesticide regulation.


Subject(s)
Insecticides , Pesticides , Male , Bees , Female , Animals , Pesticides/toxicity , Reproducibility of Results , Insecticides/toxicity , Flowers , Toxicity Tests
2.
Clin Oral Implants Res ; 26(4): e8-e16, 2015 Apr.
Article in English | MEDLINE | ID: mdl-24382358

ABSTRACT

OBJECTIVE: The aim of the present systematic review and meta-analysis was to assess the role of periodontal disease as a risk factor for implant loss, peri-implantitis and implant-bone loss. MATERIALS AND METHODS: Six electronic database and a manual search resulted in 7391 unique publications; after selection only 16 studies were included in systematic review. Dichotomous data were expressed as risk ratio (RR) and 95% confidence interval (CI), while continuous data were expressed as standardized mean difference (SMD). Due to the expected inter-study heterogeneity, a random effect model was used for both type of data. The pooled effect was considered significant for a P < 0.05. RESULTS: Meta-analysis revealed that an higher and significant risk for implant loss was present in patients affected by PD (RR: 1.69, 95% CI: 1.31-2.17, P < 0.0001). A higher and significant IBL was present in patients with periodontal disease, when compared with patients periodontally healthy (SMD: 0.38, 95% CI: 0.18-0.58, P = 0.0002). Patients periodontally compromised showed an increased risk of PI, when compared with patients without periodontitis (RR: 2.17, 95% CI: 1.51-3.12, P < 0.0001) No evidence of significant heterogeneity was detected for the three outcomes. CONCLUSION: Strong evidence suggests that periodontitis is a risk factor for implant loss; moderate evidence revealed that periodontitis is a risk factor for peri-implantitis and that patients with periodontitis have higher implant-bone loss.


Subject(s)
Alveolar Bone Loss/etiology , Dental Implants , Dental Restoration Failure , Peri-Implantitis/etiology , Periodontitis/complications , Humans , Risk Factors
3.
J Periodontal Res ; 49(1): 10-9, 2014 Feb.
Article in English | MEDLINE | ID: mdl-23668676

ABSTRACT

BACKGROUND: Metronidazole (MET) has been suggested as an adjunct to scaling and root planing (SRP) in the treatment of chronic periodontitis. However, its clinical effectiveness and effects on periodontal pathogens remain to be defined. The present meta-analysis assessed the scientific evidence concerning the effect of MET adjunctive to SRP as compared to SRP alone. METHODS: A literature search of electronic databases was performed for articles published through December 16, 2012, followed by a manual search of several dental journals. A meta-analysis was conducted according to recommendations of the Cochrane Collaboration and PRISMA. Weighted mean differences (MDs) and 95% confidence intervals (CIs) were calculated for probing depth reduction, clinical attachment level gain, bleeding on probing index and suppuration. All outcomes were evaluated as changes from baseline to the end of follow-up. Heterogeneity was assessed with the chi-squared-based Cochran Q test and I(2) statistic. The level of significance was set at p < 0.05. RESULTS: After the study selection process, six randomized clinical trials were included in the meta-analysis. The results of the meta-analysis indicated that SRP + MET provided additional benefits when compared to SRP alone in terms of probing depth reduction (MD, 0.18; 95% CI, 0.09-0.28; p < 0.05) and clinical attachment level gain (MD, 0.10; 95% CI, 0.08-0.12; p < 0.05). No evidence of heterogeneity was detected. CONCLUSION: The meta-analysis results seem to support the effectiveness of adjunctive MET with SRP compared to SRP alone. However, given the low number of included studies and limitations of meta-analysis, future studies are needed to confirm these results.


Subject(s)
Anti-Infective Agents/therapeutic use , Chronic Periodontitis/therapy , Dental Scaling/methods , Metronidazole/therapeutic use , Root Planing/methods , Chronic Periodontitis/drug therapy , Combined Modality Therapy , Humans , Periodontal Attachment Loss/therapy , Periodontal Pocket/therapy , Randomized Controlled Trials as Topic
4.
Eur J Paediatr Dent ; 15(2): 90-4, 2014 Jun.
Article in English | MEDLINE | ID: mdl-25102454

ABSTRACT

AIM: In the last decade, tissue engineering has undergone enormous expansion in the fields of regenerative medicine and dentistry. In response to mechanical and chemical injuries, the dentine-pulp complex possesses a regenerative ability due to a speci?c population of mesenchymal stem cells, which have been widely described in literature. The postnatal dental pulp also contains progenitor stem cells that participate in dental regeneration. Knowledge of the regenerative potential of these cells is important in terms of understanding and applying their biological and chemical characteristics. CONCLUSION: Through the isolation and exploration of the regenerative abilities of these stem cells, new therapeutic possibilities may be possible, opening the way for improving paediatric endodontic therapy.


Subject(s)
Dental Pulp/physiology , Pediatric Dentistry , Regeneration , Stem Cells/cytology , Humans
5.
Eur J Paediatr Dent ; 15(3): 271-4, 2014 Sep.
Article in English | MEDLINE | ID: mdl-25306143

ABSTRACT

AIM: To assess the microbial level of Streptococcus Mutans and Lactobacillus spp. during rapid palatal expansion, and compare the data with untreated control patients. STUDY DESIGN: Thirty patients aged between 6-9 years were enrolled in this study (15 males and 15 females). The patients were divided into three groups: 10 patients were treated with rapid palatal expander (RPE) (Test Group 1), 10 patients were treated with Mc Namara expander, and 10 patients were enrolled in the control untreated group. Whole stimulated saliva was collected from each patient at three time points: before initiation of expansion therapy (baseline at T0), after 3 months (T1), after initiation of treatment, and after 6 months from T0 (T2). The protocol of rapid palatal expansion for the two groups was as follows: at placement of the expander 4 activations were performed by the orthodontist (1 mm expansion), followed by 4 activations per day by the parents (two in the morning and two in the evening, 1 mm per day total) to be repeated for 7 days. RESULTS: Statistics: In this study a different trend in the microbial colonisation for the two treated groups was observed. In the Test Group 1, in which patients were treated with the RPE, there was a significant difference between Strp T0 T1 and between Strp T0 and T2 (p< 0.05). There was also a significant difference between LAC T1 T0 and LAC T2 and T0 (p<0.05). In the Test Group 2, treated with McNamara expanders, it was found was a significant difference between LAC T2 T0 and LAC T1 T0. In the same group it was also found a significant difference between Strp T2 T0; T1 T0; T1 T2 (p<0.05). CONCLUSION: The level of the various species of bacteria changes during rapid palatal expansion, and this seems to depend on the type of orthodontic expander. During rapid palatal expansion treatment it is also advisable a periodical microbial monitoring using in-office bacteria tests.


Subject(s)
Bacterial Load , Lactobacillus/isolation & purification , Palatal Expansion Technique , Saliva/microbiology , Streptococcus mutans/isolation & purification , Buffers , Child , Dental Plaque Index , Female , Follow-Up Studies , Humans , Male , Oral Hygiene , Orthodontic Appliance Design , Palatal Expansion Technique/instrumentation , Saliva/metabolism , Secretory Rate/physiology
6.
Eur J Paediatr Dent ; 14(2): 131-4, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23758463

ABSTRACT

AIM: The aim of this study was to assess the dynamic activity of the mandible by means of a computerised kinesiograph in Class II patients treated with orthodontic therapy and to compare the results of this group with those of a sample of untreated Class II patients. METHODS: Twenty young adolescents who had undergone orthodontic treatment for correction of Class II malocclusion and twenty age and sex-matched adolescents exhibiting Class II malocclusion, whose parents refused the orthodontic treatment, were enrolled. Maximum vertical opening (MVO), maximum anterior-posterior movement (MAPM), maximum right deviation (MRD), maximum left deviation (MLD), MVO/ MAPM ratio, maximum velocity in opening (MVIO), maximum velocity in closure (MVIC), verticality (ID-V), anterior-posteriority (ID-AP) and laterality (ID-L) were recorded during the kinesiographic evaluations. Differences in the kinesiographic data were analysed using the Wilcoxon sum rank test; data are expressed as means and standard deviations (SD). Differences between groups in age were analysed using unpaired t-test, while differences in gender distribution were assessed using the Fisher's exact test. The level of significance was set at p < 0.05. RESULTS: No differences were detected in the distribution of sex and age between the two groups. Significant differences between the two groups were observed for MVO, MAPM, that were higher in the control group, and MLD, which was higher in the case group; no other significant differences were detected for MRD, MVO/ MAPM, MVIO, MVIC, ID-V, ID-AP, ID-L. CONCLUSION: Orthodontic treatment of young patients with Class II malocclusion may reduce the maximum vertical opening as well as the maximum anterior-posterior movement and enhance the lateral displacement; however, further studies are needed to assess the relationship between impaired mandible kinetics of orthodontic treatment in patients with Class II malocclusion and craniomandibular disorders.


Subject(s)
Malocclusion, Angle Class II/therapy , Mandible/physiopathology , Adolescent , Case-Control Studies , Female , Humans , Male , Malocclusion, Angle Class II/physiopathology , Movement , Range of Motion, Articular/physiology , Signal Processing, Computer-Assisted/instrumentation , Vertical Dimension
7.
Eur J Paediatr Dent ; 13(1): 81-3, 2012 Mar.
Article in English | MEDLINE | ID: mdl-22455535

ABSTRACT

AIM: The Myofibroma (MF) is a benign mesenchymal tumor frequently observed in the skin and subcutaneous tissue of the head-neck region. It is described mainly in infants with congenital forms and, in early childhood, with acquired forms. Less often, it can be observed in adolescents and adults. The location of a MF in the oral cavity is occasional and differential diagnosis must be established with other benign and malignant neoplasms, high or low grade, of the oral mucosa. The histology of the myofibroma shows a biphasic growth pattern: elongated spindle cells with eosinophilic cytoplasm, in the borders, polygonal cells arranged in a palisading pattern, with hyperchromatic nuclei, in the central portions. The diagnosis of MF, usually made after excision of the neoformation, is obtained by means of immunohistochemistry, in which there is positivity for vimentin and αactine smooth muscle antibodies and negativity for keratin, S-100, EMA (Epithelial Membrane Antigen) antibodies. The treatment is surgical; the prognosis is generally good with low rates of recurrence after excision. CASE REPORT: The authors describe a case of MF in a 16-year-old male subject, that came to their observation for the growth of a considerable mass attached to the gingival mucosa, describing the therapeutic strategy.


Subject(s)
Gingival Neoplasms/diagnosis , Myofibroma/diagnosis , Adolescent , Cell Nucleus/ultrastructure , Cytoplasm/ultrastructure , Diagnosis, Differential , Follow-Up Studies , Gingival Neoplasms/pathology , Humans , Male , Myofibroma/pathology , Vimentin/analysis
8.
Eur J Paediatr Dent ; 13(3 Suppl): 256-8, 2012 Oct.
Article in English | MEDLINE | ID: mdl-23046255

ABSTRACT

AIM: The purpose of this study was to investigate the prevalence of myopia among a paediatric population with malocclusions. MATERIALS AND METHODS: A total of 322 consecutive patients of the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, were enlisted for the study and 292 were selected according to the exclusion criteria. Pretreatment diagnostic data, which included radiographic cephalometric and dental cast evaluation, were recorded and presence of myopia was assessed through an ophthalmological examination. Differences in the prevalence of myopia by sex and malocclusion were analysed by using Pearson's chi-square and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (N=162), Class II division 1 (N=75), Class II division 2 (N=38), or Class III (N=12). No gender influence was found for myopia or malocclusion. No differences were recorded when analysing the influence of sex on the prevalence of myopia in classes of malocclusion. A statistical significant higher prevalence was found for subjects showing myopia in Class II division 1 malocclusion, while no other significant differences were found for prevalence in the other classes of malocclusions. DISCUSSION: Few studies investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature. A higher prevalence of myopia was found in patients with Class II division 1: as expected no other significant association was found. CONCLUSION: The findings of the present study suggest a possible association between myopia and Class II, but further studies are needed to confirm and explain this observation.


Subject(s)
Malocclusion, Angle Class II/complications , Myopia/complications , Child , Female , Humans , Italy , Male , Malocclusion/complications , Sex Distribution
9.
Eur J Paediatr Dent ; 12(2): 91-4, 2011 Jun.
Article in English | MEDLINE | ID: mdl-21668278

ABSTRACT

AIM: The purpose of this study was to investigate the prevalence of astigmatism among a paediatric population. MATERIALS AND METHODS: A total of 322 consecutive patients of the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, were enlisted for the study and 176 were selected according to the exclusion criteria. Pre- treatment diagnostic data, which included radiographic cephalometric and dental cast evaluation, were recorded and presence of astigmatism was assessed through an ophthalmological examination. Differences in the prevalence of astigmatism by sex and malocclusion were analysed by using the chi-square (Pearson's chi-square test) and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (N=122), Class II Division 1 (N=26), Class II Division 2 (N=9), or Class III (N=19); according to the transverse malocclusion patients were classified into cross-bite (N=39) and no cross-bite (N=137) groups; after ophthalmological examination astigmatism was detected in 32 patients (18.18%). Statistically significant correlations were found between astigmatism and cross-bite (p < 0.0001), while no associations were found with other malocclusions. No gender influence was found for astigmatism or malocclusion. DISCUSSION: Few study investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature. A higher prevalence of astigmatism was found in patients with cross-bite: as expected no other significant association was found. The relationship between astigmatism and cross-bite could be either related to a specific skeletal pattern, which could induce visual alterations, or to the effect of abnormal visual input on the postural system, which could induce stomatognathic alterations. CONCLUSION: The findings of the present study suggest a possible association between astigmatism and cross-bite, but future studies are needed to confirm and explain this observation.


Subject(s)
Astigmatism/epidemiology , Malocclusion/epidemiology , Adolescent , Cephalometry , Child , Female , Humans , Italy/epidemiology , Male , Malocclusion, Angle Class I/epidemiology , Malocclusion, Angle Class II/epidemiology , Malocclusion, Angle Class III/epidemiology , Models, Dental , Prevalence , Radiography, Panoramic , Sex Factors
10.
Eur J Paediatr Dent ; 12(4): 272-4, 2011 Dec.
Article in English | MEDLINE | ID: mdl-22185255

ABSTRACT

AIM: The purpose of this study was to investigate the prevalence of hyperopia and strabismus among a paediatric population with malocclusions. MATERIALS AND METHODS: From a total of 322 consecutive patients observed at the department of Orthodontics and Gnathology, Dental Clinic, University of L'Aquila, 176 were selected for the study according to the exclusion criteria. Pretreatment diagnostic data, which included radiographic, cephalometric and dental cast evaluation, were recorded and presence of hyperopia or strabismus was assessed through an ophthalmological examination. Differences in incidence rates of strabismus or hyperopia by sex and malocclusion were analysed by using the chi-square (Pearson's chi-square test) and Fisher's exact tests. RESULTS: According to the sagittal malocclusion, patients were classified as Class I (122), Class II division 1 (26), Class II Division 2 (9), or Class III (19); after ophthalmological examination, hyperopia was detected in 8.6% of patients, while strabismus was present in 3.6% of them. No gender influence was found for hyperopia, strabismus or malocclusion. DISCUSSION: Few studies investigated a possible relationship between the ocular and stomatognathic system, and no data are available in the scientific literature; the present study did not highlight differences in the prevalence of hyperopia or strabismus in the three Angle classes malocclusion. CONCLUSION: The findings of the present study did not suggest a possible association between hyperopia or strabismus and sagittal malocclusion, but future studies are needed to confirm and explain this observation.


Subject(s)
Hyperopia/complications , Malocclusion/complications , Strabismus/complications , Adolescent , Chi-Square Distribution , Child , Female , Humans , Male , Overbite/complications , Sex Factors , Statistics, Nonparametric
11.
Sci Rep ; 11(1): 6821, 2021 03 25.
Article in English | MEDLINE | ID: mdl-33767274

ABSTRACT

The sulfoximine insecticide sulfoxaflor is regarded as a potential substitute for neonicotinoids that were recently banned in the EU due to their side effects on bees. Like neonicotinoids, sulfoxaflor acts as a competitive modulator of nicotinic acetylcholine receptors. In agricultural environments, bees are commonly exposed to combinations of pesticides, and neonicotinoids are known to interact synergistically with fungicides. The objective of our study is to assess the acute oral toxicity of sulfoxaflor alone and in combination with a single dose of fluxapyroxad, a succinate dehydrogenase inhibitor (SDHI) fungicide, in three bee species: Apis mellifera, Bombus terrestris and Osmia bicornis. Because synergism may be dose-dependent, we tested a range of sulfoxaflor doses. Synergistic effects were assessed using three different approaches: Bliss criterion of drugs independence, ratio test comparing LD50s and model deviation ratio. Osmia bicornis was the most sensitive species to sulfoxaflor and both O. bicornis and A. mellifera showed significant synergism between the insecticide and the fungicide. For the most part, these synergistic effects were weak and only occurred at early assessment times and intermediate sulfoxaflor doses. The potential ecological relevance of these effects should be confirmed in field and/or cage studies. Overall, our laboratory results demonstrate that sulfoxaflor is somewhat less toxic than the recently banned neonicotinoids imidacloprid, thiamethoxam and clothianidin, but much more toxic than other neonicotinoids (acetamiprid, thiacloprid) still in use in the EU at the time this study was conducted.


Subject(s)
Amides/toxicity , Bees/drug effects , Fungicides, Industrial/toxicity , Insecticides/toxicity , Pyridines/toxicity , Sulfur Compounds/toxicity , Animals , Drug Synergism , Environmental Monitoring , Lethal Dose 50
12.
Eur J Paediatr Dent ; 11(3): 137-40, 2010 Sep.
Article in English | MEDLINE | ID: mdl-21080754

ABSTRACT

AIM: The purpose of this study was to investigate the dental caries experience in a group of 3-year-old children, through an interdisciplinary protocol, both paediatric and paedodontic, in the district of Ascoli Piceno (Marche, Italy). MATERIALS AND METHODS: A sample of 82 children, 38 males and 44 females, was recruited by four paediatricians during a preliminary study phase, which consisted of the epidemiological survey explanation to the involved children's parents and informed consents collection; the survey was first planned and then performed by one calibrated examiner, (Cohen k test was 0.85) in two days on May 2008. The examinations were performed in the nurseries of the schools attended by the children. The collected data were analysed by descriptive and association statistics: the chi² test was used to investigate the association between caries and gender, assuming as statistical significance level the p < 0.05 value. RESULTS: The study revealed that caries prevalence in the observed population was 38%, while caries free group accounted for 61%; the mean dmft was 1.06, with a standard deviation of 1.64. No statistical significance was observed in the association between caries and gender (chi²=0.65, p > 0.05). discussion: Dental caries prevalence of the surveyed population, according to the WHO 2010 objectives, was judged quite high, focusing the low caries free group (61% instead of 90% or over) and the children's preschool age; nonetheless the sample situation was not considered as critical, because the WHO 2000 goals were achieved (caries free > 50%). CONCLUSION: The interdisciplinary paedodontic paediatric protocol, used in the present study, was a useful and powerful instrument for preparing the epidemiological survey and could be the basis of future preventive programs.


Subject(s)
Dental Caries/epidemiology , Pediatric Dentistry , Pediatrics , Chi-Square Distribution , Child, Preschool , DMF Index , Epidemiologic Methods , Female , Humans , Italy/epidemiology , Male , Observer Variation , Patient Care Team , Prevalence , Sex Factors
13.
Plant Biol (Stuttg) ; 18(3): 445-54, 2016 May.
Article in English | MEDLINE | ID: mdl-26573095

ABSTRACT

The interplay between insect and plant traits outlines the patterns of pollen transfer and the subsequent plant reproductive fitness. We studied the factors that affect the pollination efficiency of a pollinator community of Dictamnus albus L. by evaluating insect behaviour and morphological characteristics in relation to flowering phenology. In order to extrapolate the pollinator importance of single taxa and of the whole pollinator guild, we calculated an index distinguishing between potential (PPI) and realized (RPI) pollinator importance. Although the pollinator species spectrum appeared rather constant, we found high intra- and inter-annual variability of pollinator frequency and importance within the insect community. Flower visitation rate strictly depended on insect abundance and on the overlap between their flying period and flower blooming. All the pollinators visited flowers from the bottom to the top of the racemes, excluding intra-plant geitonogamous pollination, and most of them showed high pollen fidelity. Only medium large-sized bees could contact the upward bending stiles while feeding on nectar, highlighting a specialisation of the plant towards bigger pollinators. Moreover, we found evidence of functional specialisation, since all pollinators were restricted to a single taxonomic group (order: Hymenoptera; superfamily: Apoidea). Both the PPI and RPI indices indicate Habropoda tarsata as the most important pollinator of D. albus. Following hand cross-pollination experiments we revealed the presence of pollination limitation in 1 of the 3 years of field study. We discuss this result in relation to flowering abundance and to possible mismatches of phenological periods between plants and insects.


Subject(s)
Bees/physiology , Dictamnus/physiology , Insecta/physiology , Animals , Flowers/physiology , Genetic Fitness , Phenotype , Plant Nectar , Pollen/physiology , Pollination , Reproduction , Seasons
14.
J Dent Res ; 92(6): 492-9, 2013 Jun.
Article in English | MEDLINE | ID: mdl-23609160

ABSTRACT

This systematic review and meta-analysis assessed the efficacy of lasers in reducing dentin hypersensitivity (DH) as compared with placebo or no treatment. Seven electronic databases and a manual search resulted in 2,538 unique publications. After selection, 13 studies were included in the meta-analysis. A CONSORT-based quality assessment revealed that 3 and 10 studies were at low and high risk of bias, respectively. A random-effects model with the generic inverse variance standardized mean difference (SMD) was used because of expected heterogeneity. Meta-analyses of the baseline-end of follow-up changes in pain revealed no differences for Er,Cr:YSSG vs. placebo (SMD = 2.49; 95% CI, -0.25 to 5.22; p = .07) but did reveal differences in favor of lasers for Er:YAG vs. placebo (SMD, 2.65; 95% CI, 1.25 to 4.05; p = .0002), Nd:YAG vs. placebo (SMD, 3.59; 95% CI, 0.49 to 6.69; p = .02), and GaAlAs vs. placebo (SMD, 3.40; 95% CI, 1.93 to 4.87; p < .00001). High and significant heterogeneity was found for all comparisons. In conclusion, Er:YAG, Nd:YAG, and GaAlAs lasers appear to be efficacious in reducing DH. However, given the high heterogeneity of the included studies, future randomized controlled clinical trials are needed to confirm these results.


Subject(s)
Dentin Sensitivity/radiotherapy , Low-Level Light Therapy/methods , Humans , Lasers, Semiconductor/therapeutic use , Lasers, Solid-State/therapeutic use , Pain Measurement , Placebos , Randomized Controlled Trials as Topic , Treatment Outcome
15.
J Insect Physiol ; 56(2): 185-94, 2010 Feb.
Article in English | MEDLINE | ID: mdl-19837077

ABSTRACT

Osmia lignaria is a solitary bee that over-winters as a fully eclosed, cocooned, unfed adult. Our objective is to understand the effect of wintering temperature on diapause maintenance and termination in this species. We measure respiration rates and weight loss in individuals exposed to various wintering temperatures (0, 4, 7, 22 degrees C, outdoors) and durations (28, 84, 140, 196, 252 days). We use time to emerge and respiration response (respiration rate measured at 22 degrees C) as indicators of diapause intensity. Adults spontaneously lower their respiration rates to approximately 0.1 ml/gh within 1 month after adult eclosion, indicating obligatory diapause. Non-wintered individuals maintain low respiration rates, but lose weight rapidly and die by mid-winter. In wintered adults, two phases can be distinguished. First, respiration response undergoes a rapid increase and then reaches a plateau. This phase is similar in bees wintered at 0, 4 and 7 degrees C. In the second phase, respiration response undergoes an exponential increase, which is more pronounced at the warmer temperatures. Composite exponential functions provide a good fit to the observed respiration patterns. Adults whose respiration response has reached 0.45 ml/gh emerge promptly when exposed to 20 degrees C, indicating diapause completion. Individuals wintered for short periods do not reach such respiration levels. When exposed to 20 degrees C these individuals lower their metabolic rate, and their emergence time is extended. The relationship between respiration rates and emergence time follows a negative exponential function. We propose two alternative models of diapause termination to interpret these results.


Subject(s)
Bees/growth & development , Bees/physiology , Animals , Cold Temperature , Oxygen/metabolism , Seasons , Temperature
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