Beekeeping in the Desert: Foraging Activities of Honey Bee during Major Honeyflow in a Hot-Arid Ecosystem

This study investigated the outgoing and pollen-gathering foraging activities of Apis mellifera jemenitica (AMJ) and Apis mellifera carnica (AMC) under a hot-arid environment in the presence of nectar-rich melliferous Ziziphus nummularia flora. The data revealed the differential effects of weather conditions and Z. nummularia flora on the foraging activities of the studied honey bee subspecies in the Rawdat-Khuraim oasis in central Saudi Arabia. Z. nummularia exhibited two flowering seasons, from June–July (season I) and August–October (season II), with a significantly higher mean flowering density observed during season II (404 flowers/m2) than during season I (235 flowers/m2). AMJ showed significantly higher foraging activities (outgoing and pollen-gathering) than AMC (exotic bees) during all months in each flowering season. The mean outgoing and pollen-gathering foraging rates of AMJ (32.40 ± 0.67 and 4.88 ± 0.40 workers/colony/min, respectively) were significantly higher than those of AMC (15.93 ± 1.20 and 2.39 ± 0.23 workers/colony/min, respectively). The outgoing and pollen-gathering foraging activities of the two subspecies fluctuated throughout the different times of day. Foraging activities were considerably high at sunrise (SR) and low at noon (N) during both flowering seasons. We also observed seasonal variations in the foraging activities of both bee subspecies. The mean foraging activities (outgoing and pollen-gathering) were slightly higher in season I (27.43 ± 1.21 and 4.46 ± 0.45 workers/colony/min, respectively) than in season II (21.71 ± 0.86 and 3.02 ± 0.22 workers/colony/min, respectively). The thermal window analysis revealed a significant difference between the flight activities (bees exiting and returning to the nest throughout the day) of AMJ and AMC; AMJ had a higher temperature threshold than AMC. The outgoing and pollen-gathering foraging activities within each bee subspecies were positively correlated. The present study can help researchers understand the performances of honeybees and the association of their performances with weather and nectar-rich flora conditions.

The Aerosol Module in the Community Radiative Transfer Model (v2.2 and v2.3): accounting for aerosol transmittance effects on the radiance observation operator

The Community Radiative Transfer Model (CRTM), a sensor-based radiative transfer model, has been used within the Gridpoint Statistical Interpolation (GSI) system for directly assimilating radiances from infrared and microwave sensors. We conducted numerical experiments to illustrate how including aerosol radiative effects in CRTM calculations changes the GSI analysis. Compared to the default aerosol-blind calculations, the aerosol influences reduced simulated brightness temperature (BT) in thermal window channels, particularly over dust-dominant regions. A case study is presented, which illustrates how failing to correct for aerosol transmittance effects leads to errors in meteorological analyses that assimilate radiances from satellite IR sensors. In particular, the case study shows that assimilating aerosol-affected BTs affects analyzed temperatures in the lower atmosphere significantly in several different regions of the globe. Consequently, a fully-cycled aerosol-aware experiment improves 1–5 day forecasts of wind, temperature, and geopotential height in the tropical troposphere and Northern Hemisphere stratosphere. Whilst both GSI and CRTM are well documented with online user guides, tutorials and code repositories, this article is intended to provide a joined-up documentation for aerosol absorption and scattering calculations in the CRTM and GSI. It also provides guidance for prospective users of the CRTM aerosol option and GSI aerosol-aware radiance assimilation. Scientific aspects of aerosol-affected BT in atmospheric data assimilation are briefly discussed.

The Impact of Aerosols on Satellite Radiance Data Assimilation Using NCEP Global Data Assimilation System

Aerosol radiative effects have been studied extensively by climate and weather research communities. However, aerosol impacts on radiance in the context of data assimilation (DA) have received little research attention. In this study, we investigated the aerosol impacts on the assimilation of satellite radiances by incorporating time-varying three-dimensional aerosol distributions into the radiance observation operator. A series of DA experiments was conducted for August 2017. We assessed the aerosol impacts on the simulated brightness temperatures (BTs), bias correction and quality control (QC) algorithms for the assimilated infrared sensors, and analyzed temperature fields. We found that taking the aerosols into account reduces simulated BT in thermal window channels (8 to 13μm) by up to 4 K over dust-dominant regions. The cooler simulated BTs result in more positive first-guess departures, produce more negative biases, and alter the QC checks about 20%/40% of total/assimilated observations at the wavelength of 10.39μm. As a result, assimilating aerosol-affected BTs produces a warmer analyzed lower atmosphere and sea surface temperature which have better agreement with measurements over the trans-Atlantic region.

Dung beetle species introductions: when an ecosystem service provider transforms into an invasive species

Dung beetle introduction programmes were designed to accelerate exotic livestock dung degradation and to control dung breeding pestiferous flies and livestock parasites. The introduction programmes provided exotic dung beetle species with an opportunity to cross natural barriers and spread beyond their native range. There are no reports that explain what probable adaptation mechanisms enable particular dung beetle species to be the most successful invader. Here we identify the morphological, biological, physiological, ecological and behavioural attributes of the four most widespread and successful dung beetle species in introduced areas on a global scale in relation to the assumption that these species are different from other exotic and native dung beetles. We have recognised Digitonthophagus gazella (Fabricius), Onthophagus taurus (Schreber), Euoniticellus intermedius (Reiche) and Aphodius fimetarius (Linnaeus) as the most successful invaders based on their spread, predominance, distribution range and the reports of invasion. Each of these four species has different natural history traits that increase their fitness making them successful invaders. D. gazella has high fecundity and spreading ability, can instantly locate and colonise fresh and nutritious dung, and has a broad thermal window. O. taurus has morphological plasticity, high fecundity, high brood survival rate due to bi-parenting, and is adapted to extreme thermal and moisture conditions. E. intermedius has remnant-dung feeding abilities, a wide thermal window, functioning best at upper-temperature levels, and successful breeding and survival abilities at extremely low soil moisture conditions. A. fimetarius is small-sized, has high breeding and dispersal abilities, and is adapted to lower thermal and upper moisture extremes and variable soil conditions. Discussed here are perspectives on adaptive attributes of dung beetle species that are important to consider during their selection for redistributions. We have elaborated on the fitness and success characteristics of the four species individually. Further, we recommend a prior-introduction baseline monitoring of native dung beetle assemblages so as to evaluate the future impact of exotic dung beetle introductions on the recipient ecosystem.

Heat dissipation capacity influences reproductive performance in an aerial insectivore

Climatic warming will likely increase the frequency of extreme weather events, which may reduce an individual’s capacity for sustained activity due to thermal limits. We tested whether the risk of overheating may limit parental provisioning of an aerial insectivorous bird in population decline. For many seasonally breeding birds, parents are thought to operate close to an energetic ceiling during the 2-3 week chick-rearing period. The factors determining the ceiling remain unknown, although it may be set by an individual’s capacity to dissipate body heat (the heat dissipation limitation hypothesis). To test this hypothesis, over two breeding seasons we experimentally trimmed the ventral feathers of female tree swallows (Tachycineta bicolor) to provide a thermal window. We then monitored maternal provisioning rates, nestling growth rates, and fledging success. We found the effect of our experimental treatment was context-dependent and varied with environmental conditions. Females with trimmed plumage fed their nestlings at higher rates than controls when conditions were hot and non-windy, but the reverse was true under cool and windy conditions. On average, nestlings of trimmed females were heavier than controls, and had a higher probability of fledging. We suggest that removal of a thermal constraint allowed females to increase provisioning rates, but additionally provided nestlings with a thermal advantage via increased heat transfer during maternal brooding. Our data provide partial support for the heat dissipation limitation hypothesis, and suggest that depending on weather patterns, heat dissipation capacity can influence reproductive success in aerial insectivores.

Reproductive biology of little tunny Euthynnus alletteratus (Rafinesque, 1810) in the southwest Gulf of Mexico

The aim of this study was to describe the reproductive dynamic of Euthynnus alletteratus in the southwest Gulf of Mexico. The annual variation of the volume fraction occupied by gametes and tissues in gonads were related with main body indexes, such as the gonadosomatic index (IG), the hepatosomatic index (IH), and the nutrition index (IN), and compared with the sea surface temperature. A total of 951 E. alletteratus individuals were sampled, where a sex ratio of 1:1 and a size interval strongly skewed towards organisms with a fork length (LF) of 36–40 cm were observed. The IG showed an increase from March to September with maximum values in April and July. Two clearly defined peaks were observed, and they were consistent with the histological analysis, where the percentage of ripe gametes predominated from April to September. The optimum thermal window for reproductive activity was from 24 to 28 °C. The size of first sex maturity was 34.35 cm of LF for males and 34.60 (LF) for females, without significant difference between sexes.

Local cold adaption increases the thermal window of temperate mussels in the Arctic

Species expand towards higher latitudes in response to climate warming, but the pace of this expansion is related to the physiological capacity to resist cold stress. However, few studies exist that have quantified the level of inter-population local adaptation in marine species freeze tolerance, especially in the Arctic. We investigated the importance of cold adaptation and thermal window width towards high latitudes from the temperate to the Arctic region. We measured upper and lower lethal air temperatures (i.e. LT and LT50) in temperate and Arctic populations of blue mussels (Mytilus edulis), and analysed weather data and membrane fatty acid compositions, following emersion simulations. Both populations had similar upper LT (~38 °C), but Arctic mussels survived 4°C colder air temperatures than temperate mussels (−13 vs. −9°C, respectively), corresponding to an 8% increase in their thermal window. There were strong latitudinal relationships between thermal window width and local air temperatures, indicating Arctic mussels are highly adapted to the Arctic environment where the seasonal temperature span exceeds 60°C. Local adaptation and local habitat heterogeneity thus allow leading-edge M. edulis to inhabit high Arctic intertidal zones. This intraspecific pattern provides insight into the importance of accounting for cold adaptation in climate change, conservation and biogeographic studies.

Testing the heat dissipation limit theory in a breeding passerine

The maximum work rate of animals has recently been suggested to be determined by the rate at which excess metabolic heat generated during work can be dissipated (heat dissipation limitation (HDL) theory). As a first step towards testing this theory in wild animals, we experimentally manipulated brood size in breeding marsh tits ( Poecile palustris ) to change their work rate. Parents feeding nestlings generally operated at above-normal body temperatures. Body temperature in both males and females increased with maximum ambient temperature and with manipulated work rate, sometimes even exceeding 45°C, which is close to suggested lethal levels for birds. Such high body temperatures have previously only been described for birds living in hot and arid regions. Thus, reproductive effort in marsh tits may potentially be limited by the rate of heat dissipation. Females had lower body temperatures, a possible consequence of their brood patch serving as a thermal window facilitating heat dissipation. Because increasing body temperatures are connected to somatic costs, we suggest that the HDL theory may constitute a possible mediator of the trade-off between current and future reproduction. It follows that globally increasing, more stochastic, ambient temperatures may restrict the capacity for sustained work of animals in the future.