Unsealed Brood Research Articles

The positive impact of honeybee activity on fennel crop production and sustainability

This study investigates the ecological interaction between honeybees (Apis mellifera) and fennel (Foeniculum vulgare) plants, examining the mutual benefits of this relationship. Field experiments conducted in Egypt from December 2022 to May 2023 recorded diverse insect pollinators attracted to fennel flowers, especially honeybees. Assessing honeybee colonies near fennel fields showed improvements in sealed brood (357.5–772.5 cells), unsealed brood (176.3–343.8 cells), pollen collection (53.25–257.5 units), honey accumulation (257.5–877.5 units), and colony strength (7.75–10) over three weeks. Fennel exposure explained 88–99% of variability in foraging metrics. Comparing open versus self-pollinated fennel revealed enhanced attributes with bee pollination, including higher flower age (25.67 vs 19.67 days), more seeds per umbel (121.3 vs 95.33), bigger seeds (6.533 vs 4.400 mm), heavier seeds (0.510 vs 0.237 g/100 seeds), and increased fruit weight per umbel (0.619 vs 0.226 g). Natural variation in seed color and shape also occurred. The outcomes demonstrate the integral role of honeybees in fennel agroecosystems through efficient pollination services that improve crop productivity and quality. Fennel provides abundant nutritional resources that bolster honeybee colony health. This research elucidates the symbiotic bee-fennel relationship, underscoring mutualistic benefits and the importance of ecological conservation for sustainable agriculture.

Pollen Substitute Diet for Apis Mellifera: Consumption and Effects on Colony Parameters in Sub-Tropical Himalaya

Apiculture plays an important role in improving crop productivity all over the world. The enrichment and enhancement of apiculture lies in the good health and hygiene of honey bees. Honeybees require pollen and nectar rich flowers to satisfy their nutritional requirements. But such flowers of bee’s interest are not available round the year. Therefore, honey bees require special care and management during dearth periods. The palatability, consumption and effects of protein-rich diet(s) were assessed on honey bee colonies of Apis mellifera. The colonies were also supplied with patties of diet formulated in laboratory (bee sup), diet proposed by Haydak (1967) and NBB, New Delhi (India), sugar syrup and no supplementary feed as control. Feeding trials were carried out during May to July 2017 and 2018, using 24 equalized experimental colonies receiving diet formulations for 8 weeks. The feed consumption for bee-sup was higher than Haydak’s diet during both the years. Significant differences were recorded for various colony attributes viz. sealed brood, unsealed brood, bee population, bee covered frames and honey production in the colonies provided bee-sup in comparison to Haydak’s diet, sugar syrup and control colonies. The results indicate the potential of bee-sup for improving strength, health and build up of colonies during dearth periods.

Patterns of short- and long-term responses of honey bee (Apis mellifera L.) colony to changes in its internal environment

Management of the honey bee (Apis mellifera L.) colony for honey production and pollination of crops includes the manipulation of its internal environment. It is not yet understood how the colony might respond to such manipulations in the short- (within four or five days post-treatment) and long-term (after 21 days post-treatment) and whether the once generated short-term response persists into the long-term. Five internal parameters (unsealed and sealed brood, pollen and honey area and colony strength) of the honey bee colony were manipulated and the patterns of resulting short- and long-term colony responses were studied. In the short-term, the honey bee colony showed a significant increase in pollen foraging and a decrease in nectar foraging following an increase in unsealed brood and honey stores; a significant decrease in pollen foraging and an increase in nectar foraging following an increase in pollen stores; and a significant increase in nectar foraging and no change in pollen foraging following an increase in colony strength. However, an increase in sealed brood did not cause any change in the colony foraging patterns. Majority of the short-term responses did not persist for long and wore off with the passage of time. Therefore, the patterns of the long-term responses were different from the short-term responses. In the long-term, only some responses were ‘expected and similar to the short-term responses'; some were ‘unexpected and different from short-term responses'; many were ‘new (previously not reported) and expected'; and some others were ‘new and unexpected'. The study reveals that knowledge of short-term responses would be helpful in devising management strategies to urgently stimulate a colony for nectar or pollen foraging. However, the results show that the short-term responses may or may not persist for long and the colony may need a fresh stimulus to sustain the desired response into long-term. Key words: Apis mellifera, brood, colony, foraging, honey, honey bee, nectar, pollen, pollination.

<b>Performance of Africanized honeybee colonies settled by queens selected for different traits

We evaluated varroa infestation and the performance of Africanized honeybee colonies with queens selected for honey and royal jelly production, and also unselected queens, correlating with climatic variables. In Campo Alegre, Santa Catarina State, Brazil, the experiment I used 10 Langstroth hives and in Mafra, Santa Catarina State, Brazil, the experiment II was performed with 15 Schenk hives. A mapping in areas of sealed and unsealed brood, honey and pollen was carried out on days zero, 45 and 90 days after the introduction of the queen. In the experiment I, there was interaction between the type of queen selection and the evaluation period for areas of sealed brood, honey, and total stored food. The group selected for royal jelly production presented larger sealed brood area and smaller honey area at 90 days. Varroa infestation was lower (p < 0.05) at 90 days. The type of queen selection and the evaluation period influenced the sealed brood area, the total brood and the total area occupied in the colony. The high relative humidity caused greater honey storage for the local group. The different groups of queens presented different behavior according to the environment in which they are settled.

ROLE OF POLLEN AND/OR BEE BREAD AVAILABILITY IN BROOD REARING AND CELLULAR IMMUNE SYSTEM OF HONEYBEES

The role of pollen and/or bee bread availability was evaluated on brood rearing, protein content and haemolymph of 6-days-old larvae worker honeybees. The highest area of stored pollen and/or bee bread and worker unsealed brood was recorded during August with an average 157.7±24.701 and 347.7±51.348 (sq. inch / Colony), respectively. Highly significant positive correlation was detected between stored pollen and/or bee bread and worker unsealed brood (r = 0.902**). Physiological studies on larvae and their haemolymph indicated that the, lowest protein content of both larvae and their haemolymph 22.03±6.325 % and 4.04±0.48 (µg/µl), respectively was found during April. Significant positive correlation was noticed between stored pollen and/or bee bread from one side and both larval protein content and haemolymph protein content on the other hand, (r = 0.393* and 0.345*), respectively. The highest of both total soluble solids (TSS %) and total haemocyte count (THC) was found during May and January. On the other hand, the lowest average of both (TSS %) and (THC) was noticed during April. Differential haemocytes counts (DHC) were counted in smears of their haemolymph. There were significant differences in different haemocyte types among various months. So, it turns out previously, it can be recommended for special attention protein nutrition artificially by providing nutrition supplements or pollen substitutes for bee colonies and that in periods of scarcity or lack of pollen as well as in the periods of disease spreads. In this process the chances of incidence of disease can be reduced and improve the immune system of bees. This is in addition to reducing the loss incident in bee colonies as a result of starvation.

Colony development of two Carniolan genotypes (Apis mellifera carnica) in relation to environment

SummaryThe objective of this study was to compare the colony development cycle (unsealed and sealed worker brood, drone brood, pollen and colony strength) of two Apis mellifera carnica subpopulations in two distinct environments (alpine and continental). At each test location were two sub groups of 12 colonies headed by naturally mated sister queens from either the Institute of Apiculture Lunz am See, Austria (AT) or from the Faculty of Agriculture University of Zagreb, Croatia (HR). Colony development was monitored every 14 days. The HR genotype, adapted to a continental climate, had faster spring brood development in both environments. During spring and early summer the AT genotype maintained the number of sealed brood cells at a constant level in the more favourable conditions, although the amount of unsealed brood reached its maximum in early June. The environment influenced colony development, food stores and colony strength. Interaction between genotype and environment did not affect the number of unsealed brood cells, but the difference was statistically significant for the number of sealed brood cells. The study indicated the presence of a number of genotype and environment interactions between the two honey bee genotypes and their colony traits.

A scientific note on E-β-ocimene, a new volatile primer pheromone that inhibits worker ovary development in honey bees

In social insects, larvae are completely dependent on adults to complete their development. In honey bees (Apis mellifera L.), larval development requires that larvae engage workers in nursing tasks rather than allocating energy in other activities (Le Conte and Hefetz, 2008). Indeed, in the absence of any constraint, workers tend to become active reproductive individual. The queen inhibits worker ovary development via pheromones (Hoover et al., 2003; Wossler and Crewe, 1999), but the inhibition of worker ovary development seems superior when bees are exposed to unsealed brood (Kropacova and Haslbachova, 1970, 1971). Components of the brood pheromone have already been identified and consist of a blend of 10 esters (Le Conte et al., 1989, 1990). Two of these low volatility compounds have been demonstrated to partially decrease worker ovary development (Mohammedi et al., 1998; Pankiw and Garza, 2007). Thus, we asked whether brood emits volatile compounds that could also have an effect on worker ovary activation. We identified a new highly volatile molecule from the larvae E-β-ocimene, that inhibits worker ovary maturation. We used Solid Phase Microextraction (SPME) (65 μm Carbowax) to sample volatiles emitted by different larval instars. We analyzed 20 larvae at stage 1, 2–3 or 10 larvae at stage 4–5. Larvae were kept in a 15 mL closed vial for 20 min in an incubator at 34 ◦C and 50% humidity (N = 8,

Periodic mass flights of the giant honey bee Apis dorsata in successive days at two nesting sites in different environmental conditions

SUMMARYThe investigations were conducted at Bangalore, India. A total of 627 periodic mass flights (PMFs) were observed during 10 successive days from 26 colonies of Apis dorsata at a polytechnic building site and 82 colonies at a banyan tree site at the Agricultural University 15 km away. PMF activities performed by particular A. dorsata populations were similar in successive days at a particular site. However, at the polytechnic site, where favourable environmental conditions prevailed, 84.3% of colonies performed 2.3 PMFs per colony per day, while at the banyan tree site, with less favourable conditions, only 11.3% of colonies performed 0.11 flights. We suggest that PMF activities depend in part upon the amount of unsealed brood. Individual colonies performed 0–5 PMFs in successive days. Low numbers of 1–2 PMF per day were preceded by high numbers of 4–5 flights the following day. Similarly, PMFs of low intensity were followed by flights of high intensity. However, two- or three-day cycles of similar activities were also observed. Surprisingly, no correlation was found between the sizes of the combs and the number and intensity of PMFs. We explain this by the fact that a similar amount of unsealed brood was present in combs of different sizes.

Larval Apis mellifera L. (Hymenoptera: Apidae) mortality after topical application of antibiotics and dusts.

Beekeepers apply various dusts to honey bee, Apis mellifera L., colonies to dislodge parasitic mites and control bacterial brood diseases. Anecdotal reports by beekeepers indicate that the antibiotic oxytetracycline (OTC) can be toxic when applied in powdered sugar to cells containing immature bee brood, but it was not known whether the purported toxicity is caused by the antibiotic or the sugar carrier. Additionally, the toxicity of various dusts, proposed for parasitic mite control, is poorly known. In the current studies, we tested OTC and two other antibiotics (tylosin and lincomycin, candidate compounds for use in honey bee colonies) in a powdered sugar carrier for larval toxicity. We also tested for larval toxicity, several dusts that have been proposed for mite control. OTC caused significant brood mortality of approximately 80% at the concentrations used in the hive (200 mg in 20 g sugar). In contrast, tylosin and lincomycin at the 200 mg dose were both similar to untreated controls, and only five times that concentration (1000 mg) caused significant brood mortality of approximately 65%. The addition of dusts, wheat flour, talc, and a commercially available protein supplement, BeePro, resulted in mortality levels between 65 and 80%, similar to that seen with OTC. The common antibiotic carrier, powered confectioners sugar, was nontoxic. The use of 100 unsealed brood cells was demonstrated to be a reliable means of assessing potential adverse affects of dry compounds on larval honey bees. Two new candidate antibiotics for use in honey bee colonies were less toxic to larval bees than the currently labeled antibiotic, OTC.

Hygienic behaviour in honey bees in the UK: a preliminary study

This article reports a study of the presence of hygienic behaviour in honey bee colonies in England and Wales. A freeze-killed brood assay was used, and both sealed and unsealed brood were investigated. Thirty-seven colonies across England and Wales were assessed for hygienic behaviour expression in 2000, and 41in 2001. Eight colonies (10%) were found to show hygienic behaviour, with some other colonies having a high level of removal of sealed dead larvae and pupae. In most colonies, all of the freeze-killed unsealed brood was removed. With a wider study it may be possible to correlate the presence of hygienic behaviour with disease occurrence.

Perception of the pollen need by foragers in a honeybee colony

Honeybees, Apis mellifera, adjust their pollen foraging activity according to the need for pollen within the colony, determined by the amount of stored pollen and young brood present in the hive. To clarify how pollen foragers detect the supply of pollen, we followed individual honeybees while they were returning with pollen. Pollen foragers deposited their loads on the frame where most of the unsealed brood was, independent of the position of this frame within the hive. They also inspected more cells on that frame and spent most of their time there, indicating that pollen foragers may individually evaluate the pollen requirements of the colony. In 18 normal-sized colonies we also tested whether olfactory cues provided by a frame of hungry young brood or an additional pollen frame covered by cages affect foraging activity. These experiments showed that olfactory stimulation within the colony is insufficient to increase or decrease the foraging effort, but suggest that foragers must have direct contact with the brood and pollen area to regulate their foraging activity according to the conditions in the colony. The different mechanisms by which foragers may gather the information about pollen supply are discussed.

Effect of Aliphatic Esters on Ovary Development of Queenless Bees ( Apis mellifera L.)

In honeybee queenright colonies, ovary development in workers is inhibited by queen-produced pheromones [1–4] and by the presence of the brood [5]. It seems that the presence of the unsealed brood provides an inhibitory signal stronger than the queen’s pheromone [6]. When administered orally with honey, the ethyl alcohol or acetone extracts prepared from unsealed honey bee brood show inhibitory effects on worker ovary development [7]. More recent results show that a mixture of ten fatty acid esters (methyl and ethyl esters of palmitic, linoleic, linolenic, stearic, and oleic acids) present naturally on the larval cuticle [8] induce a strong inhibitory effect on ovary development of caged bees in controlled conditions. This inhibition occurs by contact, diffusion, or ingestion of the blend [9]. Based on this preliminary work, the aim of this paper was to determine which esters are involved in the inhibition of ovary development of caged bees and to test whether these compounds maintain their effect under natural conditions. First we screened the efficiency of different esters. For this purpose each ester was mixed individually in food (bee candy: mixture of honey and powdered sugar) at a concentration of 10 (wt/wt) and was tested under controlled conditions on newly emerged bees (Apis mellifera mellifera). Each group of 120 bees was placed in a 12!10!4 cm cage, provided with a vial of tap water, pollen,

Influence of diet, age and colony condition upon intestinal proteolytic activity and size of the hypopharyngeal glands in the honeybee ( Apis mellifera L.)

Intestinal proteolytic activity, size of hypopharyngeal glands and dry weight of bees were investigated. Bees were either kept in cages (isolated or in groups) in an incubator, hived in small hives (200–300 individuals in three small combs) or in observation hives (about 2500 individuals in two combs). Artificial diets such as sucrose solution, sucrose with casein, sucrose with amino acids, honey, and honey with beebread were fed to the caged bees. Colony conditions such as the presence of brood and/or queen varied in the small hives. After emergence all bees, even those fed with sucrose solution, showed an increase in all parameters investigated. In all caged bees, except in those fed only sucrose, proteolytic activity increased at least till the 3rd day of life; the size of hypopharyngeal glands then decreased till the 8th day except in bees fed honey and beebread. In all bees that lived in small hives both these parameters increased at least till the 8th day and then were much lower and smaller in older bees that were already foragers respectively. The presence of a queen and unsealed brood neither influenced the intestinal proteolytic activity nor the size of the hypopharyngeal glands. In bees that lived in small hives these parameters developed in a similar manner to those of bees kept in observation hives. Bees fed for the first 3 days with merely a sucrose solution had low levels of proteolytic activities and small hypopharyngeal glands. If they were then put into a queenright observation hive till their 8th day, they could make up almost the entire deficiency.

The prevalence of pathogens in honey bee (Apis mellifera) colonies infested with the parasitic mite Varroa jacobsoni

SUMMARYThe prevalence of nine honey bee viruses in samples of dead adult bees from Apis mellifera colonies in the Netherlands and Germany infested with the parasitic mite Varroa jacobsoni was compared with virus incidence in uninfested colonies in Britain. In colonies with low mite populations the viruses present and their incidence during the year were similar to the results obtained from British colonies. However, in marked contrast with findings in Britain, acute paralysis virus (APV) was the primary cause of adult bee mortality in German honey bee colonies severely infested with V. jacobsoni. Dead brood from unsealed and sealed infested cells from German colonies with high mite populations also contained much APV.The evidence suggests that V. jacobsoni activates APV replication in adult bees by its feeding behaviour and transmits virus from adult honey bees to pupae. In addition, adult bees, in which APV is multiplying, transmit the virus to unsealed brood in the larval food.

Influence of the Amount of Eggs and Larvae in Honeybee Colonies on Temporal Division of Labour

SummaryThe influence of the amount of eggs and larvae (unsealed brood) in honeybee (Apis mellifera) colonies on temporal division of labour was investigated. Within normal ranges of unsealed brood, there were no changes in either foraging age or worker longevity (length of life) between colonies with low, medium and high amounts of eggs and larvae. Previous studies have shown positive correlations between unsealed brood and pollen collection. It is suggested that colonies responded first to changes in the quantity of eggs and larvae by changing the extent of pollen collection, rather than the age at which foraging occurs.

Further Investigations into Control of the Parasite Bee MiteTropilaelaps Clareaewithout Medication

SummaryThree methods for controlling Tropilaelaps clareae in honeybee (Apis mellifera) colonies without medication were tested: (1) caging the queen for more than 21 days, then releasing her a few days after all workers had emerged, (2) caging the queen for 9 days until all brood was sealed, then cutting off the cappings and shaking the brood out of the combs, and (3) removing all brood from the colony. The effectiveness of the treatments was assessed by determining percentage infestation of worker bees before, during and after treatment and recording numbers of mites falling daily on to the bottom board of the hive. With method (1) percentage infestation and numbers of mites falling on to the bottom board increased up to 10 times after 8 days, when no unsealed brood was left. Within 3 days after the last bees emerged the numbers of dying mites decreased considerably and a few days later none were found on adult bees. With method (2) the number of dying mites collected decreased considerably within 3 or 4...

Greater Wax Moth:1 Behavior of Larvae2, 3

Larval behavior of Galleria mellonella (L.) was observed in apiaries of the honey bee Apis mellifera L., and in the laboratory. The 1st instars fed on honey, and then dispersed to all colonies of the apiary where they infested brood combs, primarily in areas of unsealed brood or pollen. Larvae tunneled into cell walls until bees capped their brood, and then fed in the capped cells. After the bees emerged, worker bees captured moth larvae as cells were cleaned and repaired. Small captured larvae were eaten by bees; larvae that escaped capture until late instars were removed from the colony. Bees tried to sting large larvae, but larvae were resistant to penetration of the sting.

Benefit of the Wardecker Waterer to Colonies of Honey Bees 1 During Stress and Nonstress Situations

The Wardecker watering device was beneficial to colonies of honey bees, Apis mellifera L., stressed by confinement, heat, and lack of water in the desert southwest. The benefits included larger populations of adult bees, more sealed brood, less mortality of unsealed brood, and no mortality of queens or colonies. Colonies in the northern Rocky Mountain area where such stress did not occur did not benefit from the waterer, and those without it generally had more bees, brood, and honey.

Brood Viability in Normal Colonies ofApis Mellifera

SummaryThe rate of mortality during developmental stages, and the duration of each stage, were investigated in colonies of Apis mellifera. The final result was different for each oviposition sample; although a few ovipositions showed more or less similar viability patterns, the majority showed much divergence. The sequence of 3 days for the egg, 5 days for unsealed brood, and 12 days for sealed brood, best represented the duration of the immature stages. The viability pattern of a colony cannot be determined from a single sample of ovipositions.

Influence of Pollen Location in the Hive on its Utilization by the Honeybee Colony

SummaryPollen mixtures placed in the brood nest of honeybee colonies in proximity to brood of known ages disappeared (and were presumed to have been consumed) most rapidly when they were near unsealed brood. Consumption was greater near older larvae than near sealed brood. Pollen supplement placed above honey combs adjacent to brood was also consumed, but more slowly.