Search Results (20)

To be effective, the fight against Varroa mites requires beekeepers to be highly inventive and constantly update their knowledge regarding the adaptation of the mites and the latest proven methods for combating them. Biotechnical methods are not only great support but are also slowly becoming a necessity in this battle. They are already being used in the apiary management practices of professional beekeepers and breeders. This paper summarizes the results of previous research on various biotechnical methods and other non-chemical elements supporting the fight against mites. It should be noted that none of the methods mentioned will be effective enough to be used on its own, and the best results are achieved by integrating a specific method (or several) with the use of a selected medicinal substance. After analyzing attempts to use each of the methods separately and in combination, it was found that the most effective method is achieving a broodless state in the bee colony and then applying a medicinal substance, which, in the vast majority of experiments, is oxalic acid. Next, limiting the brood to one or several combs and then removing the brood containing the majority of mites (trap combs) has proven to be highly effective. There are also references to methods that seem promising but have not been fully tested and researched in the field. Studies confirming the economic justification for the use of biotechnical methods are also presented. Full article

Many social and environmental variables can affect the interactions among individuals in an insect colony that fundamentally structure its social organization. Along with important attributes such as age and caste, immunity-related factors such as the performance of sanitary tasks or exposure to a pathogen can also influence an individual’s social interactions and their place in the resulting social network. Most work on this subject has supported the hypothesis that health-compromised individuals will exhibit altered social or spatial behavior that presumably limits the spread of infection. Here, we test this hypothesis using honey bee workers recently involved in hygienic behavior, an important set of sanitary tasks in which unhealthy brood are uncapped and then removed from the colony. Using static social networks, we quantify the interaction patterns of workers recently involved in hygienic tasks and compare their network centrality to non-hygienic workers. Using dynamic networks, we analyze the capability of hygienic workers to spread a potential infection throughout the colony. We find no substantial differences in how connected hygienic workers are in the network, and we show that hygienic workers would spread a novel infection throughout the colony to the same extent as non-hygienic workers. Our results suggest that experience with certain sanitary tasks may not necessarily produce rapid changes in social behavior. This work highlights the importance of considering the benefits of remaining socially integrated in important information networks and the temporal limitations for how quickly organized immune responses can occur in response to potential infections. Full article

Beekeeping faces several challenges, such as the Varroa mite. Few studies have measured the economic performance of farms in relation to the practices used for Varroa control. Our study analyzed various biotechniques (total brood removal, TBR; queen caging, QC; royal cell insertion, CI) and other methods (chemical treatments, CT; thymol use, THY) adopted by Italian beekeepers to show whether the adoption of biotechniques leads to farm profitability or a necessary trade-off between sustainability and profitability. Beekeepers were interviewed about the methods and operations conducted on their farms. The net incomes (NIs) of the farms were calculated and inter- and intrafarm comparisons were performed. A detailed schema of each practice was designed. The net income derived from TBR was the highest in eight out of the nine case studies, followed by CI and then QC. The NI calculated for farms using CT was lower than that for farms using other methods in two of the case studies. We also analyzed different biotechniques applied by the same farm and found that the NI resulting from TBR was higher than that achieved from the use of QC and CI. Our study suggests that use of biotechniques represents a long-term sustainable solution for reducing the level of Varroa infestation, which affects farm net income. Full article

The majority of honeybee farms in industrialized countries currently base their Varroa destructor control programs on the use of acaricides in conjunction with other management practices. However, the outcomes of these practices are often misunderstood and have only been studied to a limited extent. Better yields are guaranteed by having hives with low infection levels in the spring. Therefore, it is crucial to understand which beekeeping practices can result in increased control effectiveness. This study aimed to analyze the potential effects of environmental factors and beekeeping practices on the dynamics of V. destructor population. Experimental evidence was obtained by interpolating percentage infestation data from diagnoses conducted on several apiaries in the Calabria region (Southern Italy) with data acquired from a questionnaire on pest control strategies. Data on climatic temperature during the different study periods were also taken into account. The study was conducted over two years and involved 84 Apis mellifera farms. For each apiary, the diagnosis of infestation was made on a minimum of 10 hives. In total, 840 samples of adult honeybees were analyzed in the field to determine the level of infestation. In 2020, 54.7% of the inspected apiaries tested positive for V. destructor, and in 2021, 50% tested positive, according to a study of the field test findings (taking into account a threshold of 3% in July). A significant effect of the number of treatments on parasite prevalence was found. The results showed a significant reduction in the infestation rate in apiaries that received more than two treatments each year. Furthermore, it was shown that management practices, such as drone brood removal and frequent queen replacement, have a statistically significant impact on the infestation rate. The analysis of the questionnaires revealed some critical issues. In particular, only 50% of the interviewed beekeepers diagnosed infestation on samples of adult bees, and only 69% practiced drug rotation. In conclusion, it is only possible to maintain the infestation rate at an acceptable threshold by implementing integrated pest management (IPM) programs and using good beekeeping practices (GBPs). Full article

The Italian beekeeping industry has grown steadily during the last decade, according to data from the national beekeeping registry, which came into existence in February 2015. Winter colony losses remain a matter of concern for beekeepers in Italy, and administration of the questionnaire defined by the Coloss Association could contribute to a better understanding of this phenomenon. To evaluate the percentage trends over time in honeybee colony losses arising from various causes, we used the quasi-binomial generalized linear modelling (GzLM) approach, taking the year as an independent variable. We set our level of significance at 5% and performed the data analysis only for the seven regions that sent data continuously from 2014 to 2020. We considered the percentage of losses due to queen-related problems, natural disasters, and dead or empty colonies, given that these questions remained unchanged over the years. The survey also revealed that the percentage trend for respondents using drone brood removal showed a significant increase. In general, the percentage of colony losses due to queen-related problems remained lower than 8%, and the percentage of colony losses associated with natural disasters was very low (<2%). The mean percentages of losses due to dead or empty colonies ranged from 6 to 17% in the considered period. In addition, we took account of the responses relating to treatments against Varroa mite infestation, given the importance attributed to this honeybee parasite. Unlike the other variables, we calculated the percentages related to the types of beekeeper treatments against Varroa destructor based on the respondents, not on the colonies. What emerged was that almost every beekeeper used at least one type of treatment against V. destructor. In general, the trend of respondents appeared stable at 0.3% during the last four years. Full article

Bird nests function as vessels for eggs and nestlings, and an environment for rearing offspring. However, foreign objects falling into bird nests and nestling eggshells may be harmful. Moreover, the smell of fecal sacs increases the risk of detection by predators. Many bird species have evolved nest sanitation to prevent damage to their nests. Furthermore, egg rejection evolved in some birds to thwart brood parasites that lay eggs in their nests. We studied 133 nests of barn swallows (Hirundo rustica) in an island population through a nest content manipulation experiment to determine nest sanitation and egg rejection behaviors and their relationship. Swallows rejected non-egg foreign objects more frequently (100% vs. 58.6%) and sooner than parasite eggs, which supports the hypothesis that nest sanitation is a pre-adaptation to egg rejection. However, nest sanitation did not increase egg rejection, either in probability or latency. Furthermore, both sexes incubated the eggs, cleaned the nests, and removed parasite eggs, implying that both are confronted with natural selection related to nest sanitation and brood parasitism. However, females invested more time in these behaviors than males. This provides evidence for the evolutionary relationship of nest sanitation and egg rejection behaviors in barn swallows. Full article

The use of infra-red photography video recording is very useful for conducting behavioristic studies of honeybees against many brood diseases. The removal of dead or diseased brood from capped cells by honeybee workers is a heritable trait that confers colony-level resistance. This work aimed to compare the hygienic behavior of the native (Yemeni bees, A. mellifera jemenitica) and the exotic (Carniolan bees, A. m. carnica) honeybee races in Saudi Arabia using an infra-red photography video recording. In addition, hygienic behavior towards the related and non-related combs was examined. Therefore, it is possible to obtain honeybee colonies with greater disease resistance. The pin-killing method and infra-red photography video recording were used for the evaluation of hygienic behavior in colonies of the two races. Significant differences in hygienic behavior between the two races were detected at the beginning of the experiment. Under the environmental conditions of eastern Saudi Arabia, the Yemeni honeybee colonies showed a higher number of uncapped and cleaned cells containing dead brood in either the brood comb from the same colony, or the brood comb from the same race but a different colony, or brood comb from a different race. It was concluded that the honeybee’s ability to detect and clean the dead brood from comb cells can be correlated with race and it is more efficient for the non-related individuals of the same race than from a related or another race. The outstanding performance of a few individuals in the expression of various traits indicates their usefulness in carrying out breeding programs for Varroa resistance. Full article

The date stone beetle, Coccotrypes dactyliperda, is a cryptic spermatophagus species that spends almost its entire life cycle inside the seeds of palms, esp. Phoenix sp. Only during dispersal, when the host seed has been largely eaten out, do females emerge for a short period of time in search of a fresh seed in which to establish new brood galleries. Previous work indicated that C. dactyliperda might be photophobic, preferring to emerge from seeds during night hours, whereas anecdotal evidence suggested that the beetles might be photophilic in terms of their movements post emergence. This paper examines the photosensitivity of the species under controlled laboratory conditions. The results show that C. dactyliperda, once removed from the brood chamber, is attracted by and moves faster to a light source, but that the color of the lit surface (red, blue, green, black) has no influence on either direction or crawl speed. Full article

Honey bee broods (larvae and pupae) can be consumed as human food, offering a rich nutritional value. Therefore, the objective of this work was to present an overview of the nutritional value of the honey bee brood and its gastronomic potential. The results indicated that honey bee broods are rich in protein (including essential amino acids), fat (essentially saturated and monounsaturated fatty acids), carbohydrates, vitamin C and those of the B complex, and minerals such as potassium, magnesium, calcium, and phosphorous. The results further highlight some variability according to the stage of development, with increasing content of fat and protein and decreasing carbohydrates from the larval to the pupal stages. The production of the honey bee brood in the hive, as well as its removal, can impact the wellbeing of the hive. This limits the production potential of the brood aimed at application for gastronomic purposes. The consumption and purchase of honey bee broods as food may be accessible in specialised markets where, for example, ethnic communities consume this type of food. However, in some markets, insects or products produced from insects are not readily accepted because of neophobia and disgust. The role of culinary chefs allied to traditional ways of preparing culinary dishes that include honey bee broods are relevant to motivate more people in western societies to consume of these types of food products. Full article

The efficiency of the hygienic behaviour in bee colonies towards dead brood was assessed in small-cell combs (SMCombs) and in standard-cell combs (STCombs). Each colony had both types of combs in the nest on a permanent basis. Simultaneous keeping of a colony on standard- and small-cell combs is a novel approach to the use of small-cell combs in beekeeping. The number of killed pupae removed within 24 h was the measure of the hygienic behaviour efficiency. Regardless of the year, the brood in the SMCombs was uncapped and removed significantly more efficient (p ≤ 0.01) than in the STCombs (number of non-uncapped cells: in 2020 SMCombs = 3.79, STCombs = 11.62; in 2021 SMCombs = 2.34, STCombs = 5.28 and completely removed cells: in 2020 SMCombs = 87.46, STCombs = 80.04; in 2021 SMCombs = 96.75, STCombs = 92.66). In colonies kept simultaneously on standard- and small-cell combs, the width of the comb cells has a significant effect on the efficiency of removal of dead brood, which is removed more efficient from small-cell combs than from standard-cell combs. Full article

Elaborated kettle trap flowers to temporarily detain pollinators evolved independently in several angiosperm lineages. Intensive research on species of Aristolochia and Ceropegia recently illuminated how these specialized trap flowers attract particular pollinators through chemical deception. Morphologically similar trap flowers evolved in Riocreuxia; however, no data about floral rewards, pollinators, and chemical ecology were available for this plant group. Here we provide data on pollination ecology and floral chemistry of R. torulosa. Specifically, we determined flower visitors and pollinators, assessed pollen transfer efficiency, and analysed floral scent chemistry. R. torulosa flowers are myiophilous and predominantly pollinated by Nematocera. Pollinating Diptera included, in order of decreasing abundance, male and female Sciaridae, Ceratopogonidae, Scatopsidae, Chloropidae, and Phoridae. Approximately 16% of pollen removed from flowers was successfully exported to conspecific stigmas. The flowers emitted mainly ubiquitous terpenoids, most abundantly linalool, furanoid (Z)-linalool oxide, and (E)-β-ocimene—compounds typical of rewarding flowers and fruits. R. torulosa can be considered to use generalized food (and possibly also brood-site) deception to lure small nematocerous Diptera into their flowers. These results suggest that R. torulosa has a less specific pollination system than previously reported for other kettle trap flowers but is nevertheless specialized at the level of Diptera suborder Nematocera. Full article

For the development of novel selection traits in honey bees, applicability under field conditions is crucial. We thus evaluated two novel traits intended to provide resistance against the ectoparasitic mite Varroa destructor and to allow for their straightforward implementation in honey bee selection. These traits are new field estimates of already-described colony traits: brood recapping rate (‘Recapping’) and solidness (‘Solidness’). ‘Recapping’ refers to a specific worker characteristic wherein they reseal a capped and partly opened cell containing a pupa, whilst ‘Solidness’ assesses the percentage of capped brood in a predefined area. According to the literature and beekeepers’ experiences, a higher recapping rate and higher solidness could be related to resistance to V. destructor. During a four-year field trial in Switzerland, the two resistance traits were assessed in a total of 121 colonies of Apis mellifera mellifera. We estimated the repeatability and the heritability of the two traits and determined their phenotypic correlations with commonly applied selection traits, including other putative resistance traits. Both traits showed low repeatability between different measurements within each year. ‘Recapping’ had a low heritability (h² = 0.04 to 0.05, depending on the selected model) and a negative phenotypic correlation to non-removal of pin-killed brood (r = −0.23). The heritability of ‘Solidness’ was moderate (h² = 0.24 to 0.25) and did not significantly correlate with resistance traits. The two traits did not show an association with V. destructor infestation levels. Further research is needed to confirm the results, as only a small number of colonies was evaluated. Full article

Co-evolution is a major driving force shaping the outcome of host-parasite interactions over time. After host shifts, the lack of co-evolution can have a drastic impact on novel host populations. Nevertheless, it is known that Western honey bee (Apismellifera) populations can cope with host-shifted ectoparasitic mites (Varroa destructor) by means of natural selection. However, adaptive phenotypic traits of the parasites and temporal variations in host resistance behavior are poorly understood. Here, we show that mites made adaptive shifts in reproductive strategy when associated with resistant hosts and that host resistance traits can change over time. In a fully-crossed field experiment, worker brood cells of local adapted and non-adapted (control) A.mellifera host colonies were infested with mites originating from both types of host colonies. Then, mite reproduction as well as recapping of cells and removal of infested brood (i.e., Varroa Sensitive Hygiene, VSH) by host workers were investigated and compared to data from the same groups of host colonies three years earlier. The data suggest adaptive shifts in mite reproductive strategies, because mites from adapted hosts have higher probabilities of reproduction, but lower fecundity, when infesting their associated hosts than mites in treated colonies. The results confirm that adapted hosts can reduce mite reproductive success. However, neither recapping of cells nor VSH were significantly expressed, even though the latter was significantly expressed in this adapted population three years earlier. This suggests temporal variation in the expression of adaptive host traits. It also appears as if mechanisms not investigated here were responsible for the reduced mite reproduction in the adapted hosts. In conclusion, a holistic view including mite adaptations and studies of the same parasite/host populations over time appears overdue to finally understand the mechanisms enabling survival of V.destructor-infested honey bee host colonies. Full article

There is increasing recognition that environmental nano-biological interactions in model species, and the resulting effects on progeny, are of paramount importance for nanomaterial (NM) risk assessment. In this work, Daphnia magna F0 mothers were exposed to a range of silver and titanium dioxide NMs. The key biological life history traits (survival, growth and reproduction) of the F1 intergenerations, at the first (F1B1), third (F1B3) and fifth (F1B5) broods, were investigated. Furthermore, the F1 germlines of each of the three broods were investigated over 3 more generations (up to 25 days each) in continuous or removed-from NM exposure, to identify how the length of maternal exposure affects the resulting clonal broods. Our results show how daphnids respond to NM-induced stress, and how the maternal effects show trade-offs between growth, reproduction and survivorship. The F1B1 (and following germline) had the shortest F0 maternal exposure times to the NMs, and thus were the most sensitive showing reduced size and reproductive output. The F1B3 generation had a sub-chronic maternal exposure, whereas the F1B5 generation suffered chronic maternal exposure where (in most cases) the most compensatory adaptive effects were displayed in response to the prolonged NM exposure, including enhanced neonate output and reduced gene expression. Transgenerational responses of multiple germlines showed a direct link with maternal exposure time to ‘sub-lethal’ effect concentrations of NMs (identified from standard OECDs acute toxicity tests which chronically presented as lethal) including increased survival and production of males in the F1B3 and G1B5 germlines. This information may help to fine-tune environmental risk assessments of NMs and prediction of their impacts on environmental ecology. Full article

For beekeepers, the beehive stock represents a fundamental means of ensuring the continuity of their activity, whether they are professionals or hobbyists. The evaluation of this asset for economic purposes requires knowledge of the rhythms and adaptations of honey bee colonies during the annual seasons. As in any breeding activity, it is necessary to establish the numerical and economic size of the species bred. Beekeepers are interested in this evaluation to monitor beehive stock. For keeping economic accounts of stock, a specific tool has been developed and proposed, here called the “Honey Bee Colony Inventory (HBCI)”. The HBCI can be used as either a final or preventive scheme to assess the numbers of honey bee colonies and nuclei, and the mortality rate, in order to calculate the monetary value. This tool allows the strength of honey bee colony stocks to be monitored, including fluctuations throughout the year, and will prove useful for determining solutions to maintain or increase how long stocks last. Data can be registered in countries such as Italy where the veterinary authorities request data on the stock owned and its variations. Due to widespread Varroa mite infestations, in recent years, beekeepers have experimented with a range of different biotechniques that have included queen caging as well as drone and total brood removal. To verify its effectiveness for gathering honey bee colony data, the HBCI was used in nine beekeeping farms applying different biotechniques to control Varroa mites: chemical treatment, total brood removal, queen caging and old queen replacement by royal cell insertion. The results are compared and discussed. Out of the nine farms, seven showed negative monetary value according to the HBCI, as expected, due to multiple factors such as the unfavorable climate trend of 2017 in the studied area. The positive aspect is that the application of this tool will allow farmers to monitor, manage and maintain their beehive stocks. Full article