The habitat templet and life history strategies of pond skaters (Heteroptera: Gerridae): reproductive potential, phenology, and wing dimorphism

1989 ◽  
Vol 67 (10) ◽  
pp. 2432-2447 ◽  
Author(s):  
John R. Spence

Reproductive traits, diapause, and wing dimorphism of four pond skater species occurring in central Alberta, Canada, are explained as adaptive responses to a complex of habitat features. Species using temporary habitats had greater fecundity, but habitat permanence alone was a poor predictor of reproductive longevity, preoviposition period, or reproductive rate. Fecundity and longevity were significantly lower and more variable in direct than in diapaused breeders. There was no geographical or annual variation in fecundity, suggesting that values observed are good measures of reproductive potential. Overwintered females of species from temporary habitats (Gerris buenoi and Limnoporus dissortis) lived longer than those from more permanent habitats (G. comatus and G. pingreensis), and, concomitantly, are able to spread reproduction over several ponds. Proportion of summer-generation bugs breeding without diapause was inversely related to habitat permanence for the Gerris species, but few nondiapause breeders occurred in L. dissortis. Diapause was not averted consistently by exposure to increasing long-day photoperiods, and sensitive stage for diapause induction varied within all species. In G. pingreensis and L. dissortis many individuals reaching the adult and fifth instar by the solstice diapaused. Diapause and wing morphism were associated only loosely in the dimorphic species. Many apterous G. pingreensis entered diapause despite early emergence. Wing morph in G. pingreensis is determined genetically but is not based in simple Mendelian inheritance. Flightless bugs occur mainly among direct breeders in G. buenoi and G. comatus but many direct breeders were macropterous. Wing morph is influenced by a photoperiod switch in G. buenoi, but there is also genetic variation. There was no significant difference in total fecundity, longevity, or juvenile development time between wing morphs of the same generation in either G. buenoi or G. pingreensis. However, flightless females had shorter preoviposition periods, leading to greater egg production over the first 20 days of reproductive life. Gerrid life histories are adaptions to a complex of factors, including but not confined to habitat stability. Other aspects of the habitat templet such as the impact of natural enemies and food input should be considered.

Author(s):  
A.J. Linnane ◽  
S.S. Penny ◽  
T.M. Ward

The annual commercial catch from the Southern Zone of the South Australian rock lobster (Jasus edwardsii) fishery is ~1900 tonnes, representing ~50% of total landings from south-east Australia. A single minimum legal size (MLS) of 98.5 mm carapace length (CL) exists across the entire zone. Fecundity (F), size at onset of maturity (SOM) and relative reproductive potential (RRP) of female rock lobsters were investigated in two major fishing regions, i.e. the North Southern Zone (NSZ) and South Southern Zone (SSZ) with a view to providing a basis for future fine-scale spatial management of the resource. F ranged from 45,292 to 466,800 eggs per female and increased proportionally with CL according to the relationship: F = 0.0584 × CL3.1642. F was significantly higher in the NSZ compared to the SSZ but was attributed to differences in lobster size between regions. There was no significant difference in the number of eggs · g−1 of egg mass between areas. SOM, estimated as the size at which 50% of females reached sexual maturity (L50) was higher in the NSZ (104.1 mm CL) compared to SSZ (92.3 mm CL). Approximately 20% of lobsters above the MLS in the commercial catch in the NSZ were under the L50 estimate. RRP, as a measure of egg production, was calculated for each size-class from the product of F, SOM and population length–frequency. The modal RRP size-classes in the NSZ were 117.5–122.5 mm CL, while in the SSZ it was 97.5–102.5 mm CL. Only 6% of RRP was contributed by female rock lobsters below the MLS in the NSZ, compared to 34% in the SSZ. Regional differences in SOM and RRP in the Southern Zone of South Australia suggest that different MLSs may be beneficial, particularly if the fishery is to be effectively managed at finer spatial scales.


2012 ◽  
Vol 64 (1) ◽  
pp. 281-285 ◽  
Author(s):  
Duraikkannu Vasanthakumar ◽  
Amsalingam Roobakkumar ◽  
Jasin Rahman ◽  
Pandian Kumar ◽  
Chandran Sundaravadivelan ◽  
...  

Green lacewing Mallada boninensis is an important predator of various soft-bodied arthropods, including red spider mites in tea. Efforts were made to develop mass rearing technology for this predator in a cost effective manner. Three combinations of artificial diets (Protinex (AD1), egg yolk (AD2) and royal jelly (AD3) based) were evaluated in comparison with standard diet (Protinex + Honey). All the tested diets influenced the egg-laying capacity of M. boninensis. The egg yolk-based diet resulted in more egg production than the other two diets. Survival of all life stages of M. boninensis was also observed on each diet and no significant difference was noticed. Results revealed that the egg yolk-based diet is the best of the three diet combinations tested in view of high fecundity and survival rate of M. boninensis.


2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Alem Tadesse Atsbeha ◽  
Teweldemedhn Gebretinsae Hailu

Chickens kept under modern production system are very small and contribute less than 2% of eggs and meat production in Ethiopia. In some parts of the country, effective microorganism (EM) has been used as a means of improving egg and meat production. However, there is information gap on the use and effect of EM on egg quality and laying performance of chickens in the local context. This study was conducted in Aksum University’s poultry farm located at the main campus in Axum, to evaluate egg laying performance and quality of eggs in layer chickens treated with effective microorganisms in feed and water. In this experiment, 180 pullets of ISA Brown chickens with uniform age and weight were used and managed in a cage system. Chickens were subjected to 4 treatments with 3 replications, and each replication consisted of 15 chickens. Data collection was started at the first egg lay. Data including feed intake, conversion ratio, and age at first laying, laying percentage, and egg quality parameters were collected. Statistical analysis was carried out using JMP. Chickens fed with EM in feed and drinking water had higher egg production percentage. There was a significant difference in egg laying percentage between the treated and control groups ( P < 0.001 ). Eggs from chickens given EM in feed and water were 6% heavier in weight than those from control birds. Lower feed daily intake (115.5 gram) and feed conversion rate (2.05) were achieved in chickens treated with EM in feed and water. Significant improvement on egg quality was revealed in chickens that received EM in feed and water. From this experiment, it can be concluded that the use of EM in feed and water improves egg production in layer chickens and therefore recommended for medium-scale poultry farms in Northern Ethiopia.


GeroPsych ◽  
2014 ◽  
Vol 27 (4) ◽  
pp. 171-179 ◽  
Author(s):  
Laurence M. Solberg ◽  
Lauren B. Solberg ◽  
Emily N. Peterson

Stress in caregivers may affect the healthcare recipients receive. We examined the impact of stress experienced by 45 adult caregivers of their elderly demented parents. The participants completed a 32-item questionnaire about the impact of experienced stress. The questionnaire also asked about interventions that might help to reduce the impact of stress. After exploratory factor analysis, we reduced the 32-item questionnaire to 13 items. Results indicated that caregivers experienced stress, anxiety, and sadness. Also, emotional, but not financial or professional, well-being was significantly impacted. There was no significant difference between the impact of caregiver stress on members from the sandwich generation and those from the nonsandwich generation. Meeting with a social worker for resource availability was identified most frequently as a potentially helpful intervention for coping with the impact of stress.


2020 ◽  
Vol 4 (1) ◽  
pp. 3-48
Author(s):  
Takehiro Iizuka ◽  
Kimi Nakatsukasa

This exploratory study examined the impact of implicit and explicit oral corrective feedback (CF) on the development of implicit and explicit knowledge of Japanese locative particles (activity de, movement ni and location ni) for those who directly received CF and those who observed CF in the classroom. Thirty-six college students in a beginning Japanese language course received either recast (implicit), metalinguistic (explicit) or no feedback during an information-gap picture description activity, and completed a timed picture description test (implicit knowledge) and an untimed grammaticality judgement test (explicit knowledge) in a pre-test, immediate post-test and delayed post-test. The results showed that overall there was no significant difference between CF types, and that CF benefited direct and indirect recipients similarly. Potential factors that might influence the effectiveness of CF, such as instructional settings, complexity of target structures and pedagogy styles, are discussed.


2020 ◽  
Vol 20 (2) ◽  
pp. 101-120
Author(s):  
Ayça Aktaç Gürbüz ◽  
Orçun YORULMAZ ◽  
Gülşah DURNA

Scientific research into the reduction of stigmatization, particularly related to specific problems such as Obsessive-Compulsive Disorder (OCD), is scarce. In the present study, we examine the impact of a video-based antistigma intervention program for OCD in a pretest-posttest control group research. After being randomly assigned to either an intervention (n= 101) or control group (n= 96), the participants reported their attitudes on a hypothetical case vignette before and after OCD vs. Multiple Sclerosis (MS) videos, and again six months later as a follow up assessment. The mixed design analyses for the group comparisons indicated that although there was no significant difference in the measures of the control group, the participants watching the anti-stigma OCD video, in which the focus was psychoeducation and interaction strategies, reported significantly lower scores on social distances and negative beliefs for the case vignettes they read, and this difference was maintained six months later. Then, the present results indicate the effectiveness of our anti-stigma intervention program for OCD. Interventions to reduce stigmatization can also be viewed as effective tools for changing the attitudes of people toward OCD, although further research and applications are needed related to specific disorders if a longlasting impact is to be achieved.


2019 ◽  
Vol 118 (7) ◽  
pp. 1-19
Author(s):  
Geethanjali N ◽  
Parveen Roja M ◽  
Lavanya D

Quality of work life is the major factor to be considered in working environment of any organization. The performance of employees and the organization lies on the ability of the employees based on working environment. The QWL leads to better working environment which improves the performance of organization. The present study has made an attempt to find the level of factors causing QWL and the impact of outcome of QWL in banks. Since the profile of the banks may be associated with the level of outcomes of QWL, the present study has made an attempt to examine it with the help of one way analysis of variance and t-test. The included outcomes of QWL are job satisfaction, job stress, organizational climate, organizational commitment, employees retention behaviour, service quality employees and service productivity of employees. The highly associated determinants of QWL and the significant difference among the PUSBs and PRSBs have been noticed. The significantly associating important profiles of the banks regarding the existence of outcome of QWL are identified.


This article presents the results of studying the impact of housing and feeding conditions on broiler chickens of Hubbard RedBro cross, as well as the quality of products obtained when using floor and cage content, in a farm. It established that when receiving a mixed feed of own production using feed raw materials grown on a farm without the use of pesticides, a statistically significant decrease in potentially dangerous substances for animal health is recorded. Compared with factory feed, it has reduced the content of pesticides by 14 times, and mercury and arsenic by 24 times, cadmium by five times, and lead by ten times. The results of the study of economic indicators of growing Hubbard RedBro cross broiler chickens, as well as the chemical composition and quality of carcasses, indicated that there was no significant difference between the floor and cell conditions of keeping. Still, the use of a diet based on eco-feeds contributed to a statistically significant decrease in the concentration of toxic metals in the muscles of the poultry of the experimental groups. As a result, it found that the use of the studied compound feed in the diets of broiler chickens increased the indicators of Biosafety and ensured the production of environmentally safe ("organic") poultry meat products.


2016 ◽  
Vol 5 (05) ◽  
pp. 4563
Author(s):  
Tariq A. Zafar

Glycated haemoglobin (HbA1c) test indicates the blood glucose levels for the previous two to three months. Using HbA1c test may overcome many of the practical issues and prevent infections such as urinary tract infections (UTIs). The study aimed to evaluate the impact of glycemic control using HbA1c test to understand patient characteristics and UTIs prevalence. Glycemic control was evaluated by measuring HbA1c for a total of 208 diabetes patients who were regularly attending diabetes center in Al-Noor specialist hospital in Makkah.  The results showed that good and moderate glycemic controlled patients were 14.9% and 16.9% respectively while the poor glycemic patients were 68.3%. Among the good improved glycemic control, 83.9% were females, 48.4% were from age group (15-44y). Among the moderately improved glycemic control, 68.4% were females, 54.3% were from age group (45-64 y) with no significant difference. The total number of the patients with positive UTIs was 55 (26.4%) while the total number of patients with negative was UTIs 153 (73.6%). Among the positive UTIs, 76.3% were with poor glycemic control while only 12.3% and 11% were moderate and good improved glycemic control respectively. Among the negative UTIs, 65.3% were with poor glycemic control while only 19% and 15.7% were with moderate and good improved glycemic control respectively.  Prevalence of UTIs among diabetic patients was not significant (p > 0.05). It was concluded that HbA1c was useful monitoring tool for diabetes mellitus and may lead to improved outcomes. Using a HbA1c test may overcome many of the practical issues that affect the blood glucose tests.


Author(s):  
C. Pandian ◽  
A. Sundaresan ◽  
A. V. Omprakash

The present study was conducted to assess the effect of supplementation of Multi-enzymes with lysophospholipids on production performance of pure line White Leghorn layers. Body weights before and after the experiment did not differ significantly across the experimental diets. Irrespective of the dietary treatments, the birds gained 3.83 per cent of live weight relative to its initial body weight. Mean per cent Hen housed egg production was significantly (Pis less than 0.05) higher in diet supplemented with 0.10 MEC-L than other groups. Mean egg weight and average daily feed consumption during 25 to 35 weeks of age indicated no significant effect of enzyme supplementation. Average daily feed consumption per bird in control, 0.05 % and 0.1% multi-enzyme supplemented groups was 108.13, 105.66 and 107.67 g respectively and birds offered control diet recorded numerically more feed intake than enzyme supplemented groups. Comparatively low feed per egg was observed in 0.10 per cent group followed by 0.05 per cent group which offers economic benefits than control diets. However, the egg quality traits between different dietary enzyme supplementation groups showed no significant difference.


Sign in / Sign up

Export Citation Format

Share Document