scholarly journals THERMODYNAMICS IN NESTS OF TWO MELIPONA SPECIES IN BRASIL

1983 ◽  
Vol 13 (2) ◽  
pp. 453-466 ◽  
Author(s):  
David W. Roubik ◽  
◽  
Francisco Javier Aquilera Peralta ◽  
Keyword(s):  
Ambient Temperature ◽  
Time Lag ◽  
Temperature Fluctuations ◽  
Nest Structure ◽  
Brood Chamber ◽  
Nest Cavity ◽  
Melipona Species ◽  
Brood Temperature ◽  
Average Brood ◽  
Brood Nest

SUMMARY Thermodynamics within 10 nests of Melipona rufiventris and M. seminigra were recorded during 48 horurs with thermocouple probes. Strikingly similar patterns were found for both species. Homeostasis did not occur; temperatures within the brood area, honey and pollen stored in pots and nest cavity space all followed ambient temperature fluctuations. Nest temperatures were consistently higher than ambient in all portions of the nest except the upper extremith of vertically elongate hives. Near the brood, temperature fluctuations were damped and displayed a time lag of one to two hours in following ambient temperature. The thoracic temperature of resting worker bees was near 34°C, and the average brood temperature was 31 — 32°. The involucrum surrounding the brood retained a portion of radiated heat from immatures and workers resting between combs, and brood temperature was two to three degrees higher than internal nest temperature immediately outside the involucrum. The brood chamber, the largest nest structure, contained from 2000 to 6000 immatures, and adult bee populations were less than 1000. The brood nest acts as a heat source at the base of the nest and dissipates heat upwards, creating a thermal gradient. Immature bees appear to supply most of the heat for the nest, and excess heat is shunted by fanning workers through the nest entrance, usually connected to the brood area. There is no evidence of evaporative cooling from water brought into the nest in these or other species of Meliponinae.

scholarly journals Efficacy and temperature dependence of 60% and 85% formic acid treatment against Varroa destructor

Apidologie ◽  
2021 ◽  
Author(s):  
Xenia STEUBE ◽  
Patricia BEINERT ◽  
Wolfgang H. KIRCHNER
Keyword(s):  
Formic Acid ◽  
Ambient Temperature ◽  
Varroa Destructor ◽  
Acid Treatment ◽  
Treatment Success ◽  
Late Summer ◽  
Active Principle ◽  
Brood Chamber ◽  
Model Treatment ◽  
Lower Variability

AbstractThe ectoparasitic mite Varroa destructor is considered one of the main threats to the western honey bee (Apis mellifera). Efficient pest management is crucial, and the evaporation of formic acid (FA) is an active principle that could be adopted. However, the usage of FA has an extreme variable efficacy depending on several conditions, ambient temperature among them. Cooler conditions, as they usually occur in Central Europe in late summer and autumn, can negatively affect treatment success. Our study aims to evaluate factors that influence the efficacy of different FA treatments. Over a period of 8 years, we investigated the effect of ambient temperature, hive size and dispenser type on the treatment success with 60% and 85% FA and consolidated those factors in a linear regression model. Treatment with 60% FA shows higher variability, and often lowered efficacy, especially in double brood chamber hives. In contrast, 85% FA treatment achieves higher efficacy and lower variability and shows significantly diminished dependence on ambient temperature.

scholarly journals Spatiotemporal Response of Vegetation to Rainfall and Temperature fluctuations in the Sahel. Case study in the Forest Reserve of Fina, Mali

2021 ◽  
Author(s):  
Karamoko Sanogo ◽  
Birhanu B. Zemadim ◽  
Souleymane Sanogo ◽  
Ashatu Abdulkadiri ◽  
Abdramane BA
Keyword(s):  
Air Temperature ◽  
Arid Zone ◽  
Time Lag ◽  
Temperature Fluctuations ◽  
Vegetation Response ◽  
Forest Reserve ◽  
Forest Reserves ◽  
Climate Fluctuation ◽  
Spatiotemporal Response

Forests constitute a key component of the Earth system but the sustainability of the forest reserves in the semi-arid zone is a real concern since its vegetation is very sensitive to the climate fluctuation. The understanding of the mechanisms for the interaction vegetation-climate is poorly studied in the context of African Sahel. In this study, the characteristics of the vegetation response to the fluctuations of precipitation and temperature is determined for the forest reserve of Fina. Rainfall estimates, air temperature and NDVI are used to establish the lag correlations between fluctuations of vegetation and climate variables at both seasonal and interannual bases. Results shows increasing tendency of NDVI started from the 1990s coinciding the recovery of the rainfall from the 1980s drought and the obtained correlation(r=0.66) is statistically significant (pvalue<0.01). The strongest responses of vegetation to rainfall and temperature fluctuations were found after 30 and 15 days, respectively. Moreover, at shorter time lag (e.g. 15 days) more pronounced vegetation responses to both rainfall and temperature were found in agricultural dominated land while at longer time lag (e.g. 30 days) stronger response was observed in Bare dominated land. The vegetation response to the climate fluctuation is modulated by the land use/cover dynamics. Keywords: NDVI, Rainfall, Air temperature, vegetation response, Fina Forest Reserve, Mali.

scholarly journals Small-scaled association between ambient temperature and campylobacteriosis incidence in Germany

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Julia Oberheim ◽  
Christoph Höser ◽  
Guido Lüchters ◽  
Thomas Kistemann
Keyword(s):  
Climate Change ◽  
Ambient Temperature ◽  
Time Lag ◽  
Daily Minimum Temperature ◽  
Time Lags ◽  
Recent Part ◽  
The Impact ◽  
Incidence Increase ◽  
Observation Period

Abstract Campylobacteriosis is the leading bacterial cause of human diarrheal illness worldwide. Campylobacteriosis incidence exhibits seasonality and has been attributed to ambient temperature. However, the role of ambient temperature on campylobacteriosis remains poorly understood. To examine the impact of ambient temperature on local campylobacteriosis in Germany, weekly incidences on NUTS-3 level were analysed using a novel small-scaled approach, regression and time lags. Campylobacteriosis incidence correlated positively with temperatures between − 5 and 28 °C. The sigmoid regression model estimated an incidence increase of 0.52 per 5 °C temperature rise in the observation period. The weekly average of daily minimum temperature was most significant at a time lag of two weeks and showed the steepest incidence increase of 0.13 per 1 °C temperature increase in a temperature corridor of 5.1 to 12.2 °C. The impact of average minimum temperatures on campylobacteriosis incidence is crucial, likely to be indirect and especially relevant in the recent part of the infection chain. Vectors or human behaviour are presumably more directly linked with temperature than the pathogen’s microbiology and should be examined. These variables outweigh the direct temperature-pathogen relationship when the whole chain of infection is considered. In the context of climate change, campylobacteriosis is likely to increase in Germany due to an increased temperature effect.

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