Most theories used to explain the evolution of eusociality rest upon two key assumptions: mutations affecting the phenotype of sterile workers evolve by positive selection if the resulting traits benefit fertile kin, and that worker traits provide the primary mechanism allowing social insects to adapt to their environment. Despite the common view that positive selection drives phenotypic evolution of workers, we know very little about the prevalence of positive selection acting on the genomes of eusocial insects. We mapped the footprints of positive selection in Apis mellifera through analysis of 40 individual genomes, allowing us to identify thousands of genes and regulatory sequences with signatures of adaptive evolution over multiple timescales. We found Apoidea-and Apis-specific genes to be enriched for signatures of positive selection, indicating that novel genes play a disproportionately large role in adaptive evolution of eusocial insects. Worker-biased proteins have higher signatures of adaptive evolution relative to queen-biased proteins, supporting the view that worker traits are key to adaptation. We also found genes regulating worker division of labor to be enriched for signs of positive selection. Finally, genes associated with worker behavior based on analysis of brain gene expression were highly enriched for adaptive protein and cis-regulatory evolution. Our study highlights the significant contribution of worker phenotypes to adaptive evolution in social insects, and provides a wealth of knowledge on the loci that influence fitness in honey bees.natural selection | kin selection | social evolution | taxonomically restricted genes E usocial behavior evolved multiple times in insects and is characterized in part by extreme asymmetries in the reproductive potential of individuals (1). This asymmetry is most pronounced in advanced eusocial insects, with their fertile queen and sterile worker castes. Darwin first recognized that natural selection cannot directly optimize worker phenotypes because workers are usually sterile (2). Hamilton (3, 4) developed kinselection theory to describe the conditions that allow natural selection to indirectly optimize worker phenotypes if such phenotypes benefit their fertile kin. It is commonly believed that worker traits, such as sib-care, foraging, and colony defense, play important roles in allowing colonies to adapt to their environment (5-7). However, despite the central role of kin-selection and inclusive fitness theory in the field of Sociobiology (8, 9), we lack knowledge on the pattern and prevalence of positive selection acting on the genomes of eusocial insects.Population genomic studies provide unprecedented opportunities to detect signatures of selection on DNA sequences over different timescales (10). There are several tests of selection that can be applied to genome-wide datasets. The McDonald-Kreitman (MK) test is arguably the best method for detecting selection on protein coding sequences because of its robustness to changes in a species' demography,...

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The contribution of a bee plant species to honey production depends on the plant's nectar secretion quality and quantity, which is mainly governed by biotic and abiotic factors. The aim of the current study, was to investigate the nectar secretion dynamics and honey production potential of 14 major bee plant species of the target area. We examined the quantity and dynamics of nectar sugar per flower five times a day using a nectar sugar washing technique and direct measuring of nectar with calibrated capillary tubes. The average nectar sugar amount of the species varied from 0.41 mg/flower to 7.7 mg/flower ( < 0.0001). The honey sugar per flower was used to extrapolate the honey production potential per plant and per hectare of land. Accordingly the honey production potential of the species observed to vary from 14 kg/hectare in to 829 kg/hectare in. The nectar secretion dynamics of the species generally showed an increasing trend early in the morning, peaking toward midday, followed by a decline but different species observed to have different peak nectar secretion times. Generally, the tree species secreted more nectar sugar/flower than the herbs. The nectar secretion amount of the species was positively correlated with the ambient temperature, indicating the adaptation of the species to hot climatic conditions. However, different species were observed to have a different optimum temperature for peak nectar secretion. Despite the limited rainfall and high temperature of the area, many plants were found to have good potential for honey production. The monetary value of honey per hectare of the studied honeybee plant species can be of equal or greater than the per-hectare monetary value of some cultivated crops that require numerous inputs. In addition, the information generated is believed to be useful in apiary site selection and to estimate the honey bee colony carrying capacity of an area.

This study was conducted in the Assir region of southwestern Saudi Arabia to compare the activities of honeybee colonies of indigenous Apis mellifera jemenitica (AMJ) and imported Apis mellifera carnica (AMC) during the late summer and autumn of 2009 and 2010. The results showed that the workers of the two races exhibited relatively similar forage timings throughout the period of study (August-November). The highest numbers of foraged workers were recorded at 6:00 am, 10:00 am and 6:00 pm, while the lowest numbers were recorded at 8:00 am, 12:00 pm and 4:00 pm. Although foraging activity was negatively affected by decreased temperature, AMJ was more resistant to cold than AMC. In the first season, the smallest amount of worker brood rearing was recorded in August, and the highest amount of rearing occurred in November in both races. In the second season, the smallest amount of brood was observed in October, and the largest amount of brood was observed in November. Brood rearing and pollen collecting was significantly (P < 0.05) higher in AMJ compared with AMC, while AMC stored significantly (P < 0.05) more honey than AMJ during the tested periods. In AMJ colonies, a positive significant correlation was observed between the area of the sealed worker brood and stored pollen, while a negative but nonsignificant correlation was observed between the area of the sealed worker brood and surplus honey. In the AMC colonies, a positive significant correlation was observed between the area of the sealed brood and the stored pollen and surplus honey.

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Honeys originating from Sidr (Ziziphus spina‐christi L.) and Talh (Acacia gerrardii Benth.) trees in Saudi Arabia exhibited substantial antimicrobial activity against pathogenic gram‐positive bacteria (Bacillus cereus, Staphylococcus aureus), gram‐negative bacteria (Escherichia coli, Salmonella enteritidis), and a dermatophytic fungus (Trichophyton mentagrophytes). The diameter of zones of inhibition represents the level of antimicrobial potency of the honey samples. Precisely, Talh honey showed significantly higher antibacterial activity against all tested bacteria than Sidr honey. The antifungal activity of Talh and Sidr honey types was significantly at par against a dermatophytic fungus. The water‐diluted honey types (33% w/v) significantly induced a rise in the antimicrobial activity from that of the natural nondiluted honeys. Microbial strains displayed differential sensitivity; gram‐positive bacteria were more sensitive and presented larger inhibition zones than gram‐negative bacteria and the fungus. The sensitivity was highest in B. cereus and S. aureus, followed by T. mentagrophytes, E. coli, and S. enteritidis. The antimicrobial activity of water‐diluted honeys (Sidr and Talh) was high than that of broad‐spectrum antibacterial antibiotics (tetracycline and chloramphenicol) against bacterial strains, but these honeys were relativity less potent than antifungal antibiotics (flucoral and mycosat) against a fungal strain. Our findings indicate the antimicrobial potential of Saudi honeys to be considered in honey standards, and their therapeutic use as medical‐grade honeys needs further investigations.