The ontogeny of immunity in the honey bee, Apis mellifera L. following an immune challenge

The honey bee, Apis mellifera, is an ideal system for investigating ontogenetic changes in the immune system, because it combines holometabolous development within a eusocial caste system. As adults, male and female bees are subject to differing selective pressures: worker bees (females) exhibit temporal polyethism, while the male drones invest in mating. They are further influenced by changes in the threat of pathogen infection at different life stages. We investigated the immune response of workers and drones at all developmental phases, from larvae through to late stage adults, assaying both a constitutive (phenoloxidase, PO activity) and induced (antimicrobial peptide, AMP) immune response. We found that larval bees have low levels of PO activity. Adult workers produced stronger immune responses than drones, and a greater plasticity in immune investment. Immune challenge resulted in lower levels of PO activity in adult workers, which may be due to the rapid utilisation and a subsequent failure to replenish the constitutive phenoloxidase. Both adult workers and drones responded to an immune challenge by producing higher titres of AMPs, suggesting that the cost of this response prohibits its constant maintenance. Both castes showed signs of senescence in immune investment in the AMP response. Different sexes and life stages therefore alter their immune system management based on the combined factors of disease risk and life history.     

Influence of methoprene and temperature on diapause termination in adult females of the over-wintering solitary bee, Osmia rufa L

Females of Osmia rufa, as most species in this genus, enter an obligatory diapause, overwintering as an imago inside a cocoon until the ensuing spring when after emergence – mating, egg development and oviposition occur. Diapause in this species is initiated in November, undergoes 2 months of a pre-wintering period that is terminated at the end of January, after 1 month of maintenance. In this study, factors that affect the termination of adult diapause in the female of this species were investigated. The experimental material consisted of bees that were brought from nests kept in natural conditions 1 month prior to natural termination of diapause. Three different experimental treatments were planned to evaluate the potential effect of methoprene and temperature on diapause termination. During the 5 day experimental period the first group of females was kept at 4 °C, the second group at 15 °C and the last group of females was kept at 20 °C. All groups of females were treated with methoprene topically at a dose of 200 μg. After methoprene application a significant increase (p < 0.001) in the size of terminal oocytes was recorded in the three experimental groups. However, no changes in the size of terminal oocytes between acetone treated and untreated control groups were observed. The number of oocytes progressively increased following topical application of methoprene compared to non-treated or acetone treated females. In successive applications of 200 μg methoprene gradual changes in ovary and fat body protein concentration were observed. As compared to controls, protein content in ovaries isolated from methoprene-treated females increased, whereas it decreased in fat body. The least differences in oocyte size and protein concentration in ovary and fat body between control groups and with methoprene application occurred at 4 °C. Differences increased and were higher in females kept at 20 °C and increased rapidly after methoprene application. Exposure to increasing temperature regimes accelerated the juvenile hormone (JH) induced termination of diapause. Taken together, our results indicate that temperature may play an important role in termination of diapause in O. rufa, but its role is secondary to that played by JH.     

Pathological effects of the microsporidium Nosema ceranae on honey bee queen physiology (Apis mellifera)

Nosema ceranae, a microsporidian parasite originally described in the Asian honey bee Apis cerana, has recently been found to be cross-infective and to also parasitize the European honey bee Apis mellifera. Since this discovery, many studies have attempted to characterize the impact of this parasite in A. mellifera honey bees. Nosema species can infect all colony members, workers, drones and queens, but the pathological effects of this microsporidium has been mainly investigated in workers, despite the prime importance of the queen, who monopolizes the reproduction and regulates the cohesion of the society via pheromones. We therefore analyzed the impact of N. ceranae on queen physiology. We found that infection by N. ceranae did not affect the fat body content (an indicator of energy stores) but did alter the vitellogenin titer (an indicator of fertility and longevity), the total antioxidant capacity and the queen mandibular pheromones, which surprisingly were all significantly increased in Nosema-infected queens. Thus, such physiological changes may impact queen health, leading to changes in pheromone production, that could explain Nosema-induced supersedure (queen replacement).     

Patterns of parasite infection in bumble bees (Bombus spp.) of Northern Virginia

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Can ants equal honeybees as effective pollinators of the energy crop Jatropha curcas L. under Mediterranean conditions?

Jatropha curcas L. is the subject of many research and breeding programs concerned with its potential as an oil crop for biodiesel production. Despite an increasing amount of information regarding this relatively new crop, pollination requirements of this plant are largely neglected. The aim of the study was to evaluate the relative significance of ants and honeybees as potential pollinators of J. curcas grown under Mediterranean conditions. Jatropha curcas plants bloomed throughout the summer and fall, peaking twice, in early summer and late fall. During this period, the plants were visited by 70 species of insects representing 45 families from seven orders, with most species rarely being observed. Ants and Honeybees were the most common species, accounting for >95% of all flower visits. The foraging behavior of the honeybees followed the pattern of bloom phenology, especially during the summer, and mostly promoted cross‐pollination. Ants on the other hand, mostly promoted self pollination showing no such correlative behavior, reacting often too late to nectar availability, and were highly susceptible to climatic changes. Pollinator exclusion treatments revealed that during summer, fruit and seed sets, as well as seed size and oil and protein contents, were relatively similar for ant and bee‐pollinated flowers. During fall, however, reproductive success of bee‐pollinated flowers was relatively high (66%), while fruit set of ant‐pollinated flowers was significantly reduced from 71 to 11%. In conclusion, while both groups are equal in their pollination effectiveness in the summer, during the fall the honeybees are almost the sole pollinators of the plant. Based on bloom phenology and pollination activity data, the honeybees are responsible for the pollination of more than 80% of the annual reproductive potential of J. curcas, under Mediterranean conditions.     

Innate attractant for long‐tongued bumblebee,Bombus diversus diversus in floral scent of bumblebee‐pollinated epiparasitic plant,Monotropastrum humile (Ericaceae)

The epiparasitic plant Monotropastrum humile (D. Don) Hara is pollinated by workers of the long‐tongued bumblebee, Bombus diversus diversus (Smith). The interaction between the floral scents of this plant and bumblebee was investigated using electrophysiological and behavioral techniques. Three components (linalool, α‐terpineol and geraniol) elicited strong responses in antennae from B. d. diversus workers and are innate attractants, suggesting floral scents play an important role in attracting these pollinators and successful pollination.     

明亮熊蜂和意大利蜜蜂为温室草莓的授粉行为比较观察

蜜蜂和熊蜂都是理想的授粉昆虫,但熊蜂比蜜蜂更适合为温室果菜授粉,主要由于熊蜂和蜜蜂授粉时的活动方式不同。作者对明亮熊蜂和意大利蜜蜂为日光温室草莓授粉时的行为和活动方式进行了比较研究。结果表明,明亮熊蜂和意大利蜜蜂的授粉行为相似,但活动方式不同。明亮熊蜂开始访花的时间（8:00～8:05）比意大利蜜蜂（9:25～9:40）早,停止访花的时间（15:55～16:05）却比意大利蜜蜂（15:20～15:30）晚;开始访花的温度（12～13℃）也比意大利蜜蜂（>15℃）低,意大利蜜蜂在早晨和阴天不访花。明亮熊蜂个体的日活动时间271.43±4.48 s,明显比意大利蜜蜂个体的日活动时间180.00±2.64 s长,差异显著;而采集时间为105.71±1.16 s,显著长于意大利蜜蜂的76.43±3.83 s。明亮熊蜂每分钟平均访花数为8.44±0.44,极显著高于意大利蜜蜂每分钟的平均访花数2.38±0.15;明亮熊蜂访花间隔为3.81±0.42 s,极显著短于意大利蜜蜂的6.0±0.48 s。明亮熊蜂访花具有选择性,每天访早期花平均为55%,意大利蜜蜂则无选择性,每天访早期花平均为34%,二者差异显著;在9:00～12:00明亮熊蜂访早期花平均为75%,意大利蜜蜂访早期花则仅为31%。熊蜂在花间和花簇间活动频繁,平均移动距离为5.2 m;而意大利蜜蜂很少在花簇间移动,平均移动距离只有1.1 m。据此得出明亮熊蜂为日光温室草莓授粉的活动特性优越于意大利蜜蜂,从而产生更高的授粉效益。     

An exploration of the relationship between recruitment communication and foraging in stingless bees

Social information is widely used in the animal kingdom and can be highly adaptive. In social insects, foragers can use social information to find food, avoid danger, or choose a new nest site. Copying others allows individuals to obtain information without having to sample the environment. When foragers communicate information they will often only advertise high-quality food sources, thereby filtering out less adaptive information. Stingless bees, a large pantropical group of highly eusocial bees, face intense inter- and intra-specific competition for limited resources, yet display disparate foraging strategies. Within the same environment there are species that communicate the location of food resources to nest-mates and species that do not. Our current understanding of why some species communicate foraging sites while others do not is limited. Studying freely foraging colonies of several co-existing stingless bee species in Brazil, we investigated if recruitment to specific food locations is linked to 1) the sugar content of forage, 2) the duration of foraging trips, and 3) the variation in activity of a colony from 1 day to another and the variation in activity in a species over a day. We found that, contrary to our expectations, species with recruitment communication did not return with higher quality forage than species that do not recruit nestmates. Furthermore, foragers from recruiting species did not have shorter foraging trip durations than those from weakly recruiting species. Given the intense inter- and intraspecific competition for resources in these environments, it may be that recruiting species favor food resources that can be monopolized by the colony rather than food sources that offer high-quality rewards.     

Escalation of Aggressive Interactions During Staged Encounters in Halictus ligatus Say (Hymenoptera: Halictidae), with a Comparison of Circle Tube Behaviors with Other Halictine Species'

Circle tube experiments on the primitively eusocial bee, Halictus ligatus, were performed for a variety of combinations of caste and size. Push, Lunge, and Back without reverse behaviors enabled us to determine the dominant individual in most comparisons. Behavioral differences were readily detected within the first 15 min except for different-size forager–forager and same-size foundress–foundress pairs, for which 30 min of observations was required. In same-size forager–forager pairs, no differences in behaviors between individuals were detected even after 90 min. In extended observations, decreases in the frequency of the mild dominant behaviors were accompanied by a switch to the highly aggressive mandibular hold on the neck, particularly in different-size foundress–foundress and gyne–gyne pairs. Three workers were killed by their own queen as a result of this escalation of aggression. We discuss caste-based differences in the circle tube setting in terms of behaviors expected under more normal conditions and compare our data with published results from other species.     

Antimicrobial potentials of medicinal plant’s extract and their derived silver nanoparticles: A focus on honey bee pathogen

Infectious (or Communicable) diseases are not only the past but also the present problem in developing as well as developed countries. It is caused by various pathogenic microbes like fungi, bacteria, parasites and virus etc. The medicinal plants and nano-silver have been used against the pathogenic microbes. Herbal medicines are generally used for healthcare because they have low price and wealthy source of antimicrobial properties. Like medicinal plants, silver nanoparticles also have emergent applications in biomedical fields due to their immanent therapeutic performance. Here, we also explore the various plant parts such as bark, stem, leaf, fruit and seed against Gram negative and Gram-positive bacteria, using different solvents for extraction i.e. methanol, ethyl acetate, chloroform, acetone, n. hexane, butanol, petroleum ether and benzene. Since ancient to date most of the countries have been used herbal medicines, but in Asia, some medicinal plants are commonly used in rural and backward areas as a treatment for infectious diseases. In this review, we provide simple information about medicinal plants and Silver nanoparticles with their potentialities such as antiviral, bactericidal and fungicidal. Additionally, the present review to highlights the versatile applications of medicinal plants against honey bee pathogen such as fungi (Ascosphaera apis), mites (Varroa spp. and Tropilaelaps sp.), bacteria (Melissococcus plutonius Paenibacillus larvae), and microsporidia (Nosema apis and Nosema ceranae). In conclusion, promising nonchemical (plant extracts) are innocuous to adult bees. So, we strongly believed that this effort was made to evaluate the status of medicinal plants researches globally.