Amount Of Brood Research Articles

A critical number of workers in a honeybee colony triggers investment in reproduction.

Social insect colonies, like individualorganisms, must decide as they develop how to allocate optimally their resources among survival, growth, and reproduction. Only when colonies reach a certain state do they switch from investing purely in survival and growth to investing also in reproduction. But how do worker bees within a colony detect that their colony has reached the state where it is adaptive to begin investing in reproduction? Previous work has shown that larger honeybee colonies invest more in reproduction (i.e., the production of drones and queens), however, the term 'larger' encompasses multiple colony parameters including number of adult workers, size of the nest, amount of brood, and size of the honey stores. These colony parameters were independently increased in this study to test which one(s) would increase a colony's investment in reproduction via males. This was assayed by measuring the construction of drone comb, the special type of comb in which drones are reared. Only an increase in the number of workers stimulated construction of drone comb. Colonies with over 4,000 workers began building drone comb, independent of the other colony parameters. These results show that attaining a critical number of workers is the key parameter for honeybee colonies to start to shift resources towards reproduction. These findings are relevant to other social systems in which a group's members must adjust their behavior as a function of the group's size.

Animal personality aligns task specialization and task proficiency in a spider society.

Classic theory on division of labor implicitly assumes that task specialists are more proficient at their jobs than generalists and specialists in other tasks; however, recent data suggest that this might not hold for societies that lack discrete worker polymorphisms, which constitute the vast majority of animal societies. The facultatively social spider Anelosimus studiosus lacks castes, but females exhibit either a "docile" or "aggressive" phenotype. Here we observed the propensity of individual females of either phenotype to perform various tasks (i.e., prey capture, web building, parental care, and colony defense) in mixed-phenotype colonies. We then measured the performance outcomes of singleton individuals of either phenotype at each task to determine their proficiencies. Aggressive females participated more in prey capture, web building, and colony defense, whereas docile females engaged more in parental care. In staged trials, aggressive individuals were more effective at capturing prey, constructing webs, and defending the colony, whereas docile females were more effective at rearing large quantities of brood. Thus, individuals' propensity to perform tasks and their task proficiencies appear to be adaptively aligned in this system. Moreover, because the docile/aggressive phenotypes are heritable, these data suggest that within-colony variation is maintained because of advantages gleaned by division of labor.

Effect of dietary aflatoxin B 1 on growth, fecundity and tissue accumulation in gibel carp during the stage of gonad development

A 24-week feeding trial was conducted to evaluate the effect of dietary aflatoxin B-1 (AFB(1)) on growth, physiological responses, histological changes, fecundity and accumulation in gibel carp (Carassius auratus gibelio) during the stage of gonad development. Triplicate groups of gibel carp ( initial body weight 57.6 +/- 0.1 g) were fed with three semipurified diets (Diets 1 to 3) designed to contain 0, 20, and 2000 mu g AFB(1) kg(-1) diets (determined level was 3.3, 22.3, and 1646.5 mu g AFB(1) kg(-1) diet, respectively). The results showed that, after 24 weeks of AFB1 exposure, there was no significant difference in final body weight between AFB(1) exposure groups and the control group. No external changes, unusual behavior or significant difference in mortality were observed in the fish fed with AFB(1). There were no significant differences in feeding rate (FR), specific growth rate (SGR) or feed efficiency (FE) between the control and experimental groups. Fish fed with various levels of AFB(1) showed no significant differences in activities of serum alanine aminotransferase (ALT), and aspartate aminotransferase (AST) compared to the control group. No significant histological lesions in hepatopancreas and midgut were identified between the control and increasing AFB(1) treatments. However, gonadosomatic index (GSI), absolute brood amount (AF), relative brood amount (RF) and oocyte diameter in the groups fed the diets with AFB(1) were significantly lower than the control group. AFB(1) accumulation in fish ovaries and muscles increased significantly as the AFB(1) concentration increased in diets. AFB(1) in muscles in all the groups were all below the safety limitation of 5 mu g kg(-1) wet weight. These results indicate that AFB(1) exposure up to approximately 2000 mu g AFB(1) kg(-1) diet showed no evident effect on growth and liver function of gibel carp, but it would do harm to fecundity of the fish. (C) 2014 Elsevier B.V. All rights reserved.

Hygienic Behavior in Honey Bees (Hymenoptera: Apidae): Effects of Brood, Food, and Time of the Year

Hygienic behavior in honey bees is a heritable trait of individual workers that confers colony-level resistance against various brood diseases. Hygienic workers detect and remove dead or diseased brood from sealed cells. However, this behavior is quite rare, with only c.10% of unselected colonies showing high levels of hygiene. Beekeepers can potentially increase this by screening colonies for hygiene and breeding from the best. However, the level of hygiene expressed by a colony is variable, which poses a challenge to colony selection. In this study, we systematically varied two factors thought to be of importance in influencing hygiene levels, "nectar" availability, by feeding or not feeding sucrose syrup, and brood amount, by adding or removing brood, to determine what effect they had on hygienic behavior. We tested 19 colonies repeatedly over a 4-mo period using the freeze-killed brood assay, a standard technique to quantify hygienic behavior. Two days after freeze-killed brood treatment, our colonies showed a wide range of brood removal levels, with colony means ranging from 31.7 +/- 22.5 to 93 +/- 6.9 (mean % +/- SD). Neither the food nor the brood manipulation had an effect on hygiene levels. Colony size and time of year were also nonsignificant. The only significant effect was a three-way interaction between syrup availability, amount of brood, and time of the year, resulting in reduced hygienic behavior early in the season (spring), in colonies with added brood that were not fed sucrose syrup. Overall, these results suggest that hygienic behavior is not greatly affected by environmental conditions typical of a real-life beekeeping, and that screening of colonies can be done anytime without special regard to nectar conditions or brood levels.

Performance evaluation of indigenous and exotic honey bee (Apis mellifera L.) races in Assir region, southwestern Saudi Arabia

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 6:00am, 10:00am and 6:00pm, while the lowest numbers were recorded at 8:00am, 12:00pm and 4:00pm. 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.

Repression and recuperation of brood production in Bombus terrestris bumble bees exposed to a pulse of the neonicotinoid pesticide imidacloprid.

Currently, there is concern about declining bee populations and some blame the residues of neonicotinoid pesticides in the nectar and pollen of treated crops. Bumble bees are important wild pollinators that are widely exposed to dietary neonicotinoids by foraging in agricultural environments. In the laboratory, we tested the effect of a pulsed exposure (14 days ‘on dose’ followed by 14 days ‘off dose’) to a common neonicotinoid, imidacloprid, on the amount of brood (number of eggs and larvae) produced by Bombus terrestris L. bumble bees in small, standardised experimental colonies (a queen and four adult workers). During the initial ‘on dose’ period we observed a dose-dependent repression of brood production in colonies, with productivity decreasing as dosage increased up to 98 µg kg−1 dietary imidacloprid. During the following ‘off dose’ period, colonies showed a dose-dependent recuperation such that total brood production during the 28-day pulsed exposure was not correlated with imidacloprid up to 98 µg kg−1. Our findings raise further concern about the threat to wild bumble bees from neonicotinoids, but they also indicate some resilience to a pulsed exposure, such as that arising from the transient bloom of a treated mass-flowering crop.

Field-Level Sublethal Effects of Approved Bee Hive Chemicals on Honey Bees (Apis mellifera L)

In a study replicated across two states and two years, we tested the sublethal effects on honey bees of the miticides Apistan (tau fluvalinate) and Check Mite+ (coumaphos) and the wood preservative copper naphthenate applied at label rates in field conditions. A continuous covariate, a colony Varroa mite index, helped us disambiguate the effects of the chemicals on bees while adjusting for a presumed benefit of controlling mites. Mite levels in colonies treated with Apistan or Check Mite+ were not different from levels in non-treated controls. Experimental chemicals significantly decreased 3-day brood survivorship and increased construction of queen supercedure cells compared to non-treated controls. Bees exposed to Check Mite+ as immatures had higher legacy mortality as adults relative to non-treated controls, whereas bees exposed to Apistan had improved legacy mortality relative to non-treated controls. Relative to non-treated controls, Check Mite+ increased adult emergence weight. Although there was a treatment effect on a test of associative learning, it was not possible to statistically separate the treatment means, but bees treated with Apistan performed comparatively well. And finally, there were no detected effects of bee hive chemical on colony bee population, amount of brood, amount of honey, foraging rate, time required for marked released bees to return to their nest, percentage of released bees that return to the nest, and colony Nosema spore loads. To our knowledge, this is the first study to examine sublethal effects of bee hive chemicals applied at label rates under field conditions while disambiguating the results from mite control benefits realized from the chemicals. Given the poor performance of the miticides at reducing mites and their inconsistent effects on the host, these results defend the use of bee health management practices that minimize use of exotic hive chemicals.

Internal ambience of bee colonies submitted to strengthening management by adding broods

This study aimed to investigate the ideal brood area to be introduced for strengthening Apis mellifera colonies, considering variations in the hive's internal ambience. Therefore, eight colonies were equipped with data loggers for recording variations in temperature and humidity inside the hives. Then, these colonies were split in four treatments involving the swapping of four, three, two and one brood comb between strong and weak colonies. Growth in the amount of brood and food stores to the four colony strengthening treatments was assessed counting the comb cells to record changes in the brood and food area. The colonies tended to restore their normal thermoregulation within four hours after they had been manipulated and the hive cover had been closed, which quickly increased brood area in the receiving colonies. Results showed that adding up to three brood combs constitute an important alternative for strengthening Apis mellifera colonies because it did not interfere with nest thermoregulation, speeded up population growth in weak colonies and did not affect the development of strong colonies.

Growth Performance, Body Lipid, Brood Amount, and Rearing Environment Response to Supplemental Neutral Phytase in Zebrafish (Danio Rerio) Diet

The present study was to evaluate the effects of neutral phytase supplementation on growth performance, survival ratio (SR), body lipid, brood amount, and rearing environment in zebrafish. The control diet was not supplemented phytase, and three levels of phytase (500, 1000, or 1500 U kg(-1)) was added to the three other diets (named as PP500, PP1000, and PP1500). Triplicate groups (twelve 100-L tanks) of zebrafish (initial mean weight, 0.284±0.012 g) were fed twice daily (08:00 and 16:00 h) to satiation for 12 weeks. The results showed that supplemental phytase in the diet improved weight gain (60.49%, 86.63%, 99.06%, and 111.88% in control, PP500, PP1000, and PP1500) and the specific growth ratio of zebrafish (p<0.05). Dietary phytase addition increased the whole body lipid content of zebrafish. The brood amounts (116, 123, and 124 eggs in PP500, PP1000, and PP1500) of fish fed with phytase-supplemented diets were little higher than the control (mean egg was 112). The ammonia-nitrogen concentration in water of fish fed with phytase-supplemented diet was significantly lower than the control. The nitrite concentration in water was also decreased in water of fish fed with phytase-supplemented diet. The SR was increased with the increasing of dietary phytase despite no significant difference was observed among each group. The present study first suggested that neutral phytase could be applied in the zebrafish diet. Furthermore, phytase addition increased the growth, body lipid, brood amount, and SR of zebrafish, and meanwhile decreased the ammonia-nitrogen and nitrite concentrations in rearing water.

The Amitraz Strips Efficacy in Control of Varroa Destructor After Many Years Application of Amitraz in Apiaries

Summary Amitraz is a varroacide used the longest (over thirty years) and most commonly by Polish beekeepers. This involves high risk of V. destructor developing amitraz resistance. Therefore it is necessary to monitor the effectiveness of treatments to ensure appropriate protection of the honeybee colonies. The objective of this study was to evaluate the efficacy of amitraz used as the contact varroacide (Biowar 500 formulation) to control V. destructor in honeybee colonies. Field studies were conducted in 2011 and 2012. In both years, the amitraz treatments started in the last weeks of August. Two strips of Biowar 500 (500 mg of amitraz per strip) were inserted into each colony and removed after 8 weeks. The control colonies were left untreated for 8 weeks. After removing the strips the control therapy was conducted in all colonies. The average efficacy of amitraz (E%) calculated for the two years combined, after 6 and 8 weeks of treatment, amounted to 90.6% and 94.6%, respectively. As a result of the natural mortality in the control colonies, the population of parasites lowered only by 16.4% and 23.9% during 6 and 8 weeks. The efficacy of the strips was lower in colonies with larger amount of brood.

Colony strength in the spring inspection and its impact on the amount of foraged pollen at the time of red clover pollination

In this study, the impact of honey bee colony strength in the spring inspection on the colony strength at the time of pollination, the amount of foraged pollen and on the colony strength in autumn was observed. The honey bee colonies were, after the spring inspection, divided into two groups, based on the amount of bees. The weak colonies, in spring inspection, had an average up to 4 frames occupied by bees and the strong colonies, in the spring inspection, had more than 6 frames occupied by bees. In addition to the amount of bees, the amount of brood and food supplies were assessed in the inspections. It was determined that the stronger colonies had more pollen foragers in all three year of observation. The quantity of foraged pollen, in addition to strength in the spring inspection, was influenced by year. In two years (first and third) more pollen and larger quantity of red clover pollen was collected by the strong colonies, while in the second year, more pollen and a large quantity of red clover pollen was collected by weak colonies. In the fall inspections was found that the strong colonies still had more bees and brood, more pollen and, also, more honey in relation to the weak colonies.

Variability of production characteristics of distinguished lines of bees in western Serbia

Condition for achieving high performance results in beekeeping is focused on the use of high-quality breeding queen bee. Because that a large amount of research are based on the examination of properties of selected lines of bees and choosing the best queen mothers in the aim of selection and improving the production characteristics of honey bees from the territory of Serbia. The amount of bees, brood, honey and pollen was investigated in two spring and one autumn survey and productivity controlled in the pasture of accacia. Line 1 had the greatest amount of brood (1.23, 4.04 and 5.39), while line 3 had the best spring development. The best quality of brood in all three exams had the lines 1 and 3 (3.00, 3.00 and 2.95) as well as the best productivity compared to the average yield of all other three lines. All tested lines were exhibited variability, which provides enough possibility for their further improvement and single out the mother queenbees with best results.

The relation between the production of “Echizen-Uni” (Salted gonads of sea-urchin in Fukui Pref.) and the amount of brood of the herring in Hokkaido

The relation between the production of “Echizen-Uni” (Salted gonads of sea-urchin in Fukui Pref.) and the amount of brood of the herring in Hokkaido

Effects of Brood Pheromone Modulated Brood Rearing Behaviors on Honey Bee (Apis mellifera L.) Colony Growth

A hallmark of eusociality is cooperative brood care. In most social insect systems brood rearing labor is divided between individuals working in the nest tending the queen and larvae, and foragers collecting food outside the nest. To place brood rearing division of labor within an evolutionary context, it is necessary to understand relationships between individuals in the nest engaged in brood care and colony growth in the honey bee. Here we examined responses of the queen, queen-worker interactions, and nursing behaviors to an increase in the brood rearing stimulus environment using brood pheromone. Colony pairs were derived from a single source and were headed by open-mated sister queens, for a total of four colony pairs. One colony of a pair was treated with 336 µg of brood pheromone, and the other a blank control. Queens in the brood pheromone treated colonies laid significantly more eggs, were fed longer, and were less idle compared to controls. Workers spent significantly more time cleaning cells in pheromone treatments. Increasing the brood rearing stimulus environment with the addition of brood pheromone significantly increased the tempo of brood rearing behaviors by bees working in the nest resulting in a significantly greater amount of brood reared.

The nurse’s load: Early-life exposure to brood-rearing affects behavior and lifespan in honey bees ( Apis mellifera)

Long-lived honey bees ( Apis mellifera) develop in fall. This pattern may be explained by reduced nurse loads. When the amount of brood in colonies declines as a function of adverse foraging conditions, adult bees build up surplus nutrient stores that include vitellogenin, a behavioral affector protein that also can increase lifespan. Although the seasonal reduction in exposure to nursing tasks predictably results in vitellogenin accumulation, the assumption that long-lived adults thereby develop is confounded by a concomitant decline in foraging effort. Foraging activity reduces lifespan, and is influenced by colony resource consumption, brood pheromones, availability of nectar and pollen, and weather. Here, we perform the first controlled experiment where the nursing environment of pre-foraging sister bees was set to vary, while their foraging environment later was set to be the same. We measure vitellogenin, age at foraging onset and lifespan. We establish that reduced brood-rearing increases vitellogenin levels, and delays foraging onset and death. Longevity is largely explained by the effect of nursing on the onset of foraging behavior, but is also influenced by the level of brood-rearing independent of behavioral change. Our findings are consistent with the roles of vitellogenin in regulation of honey bee behavior and lifespan.

The efficacy of dusting honey bee colonies with powdered sugar to reduce varroa mite populations

SummaryControlling varroa mite (Varroa destructor Anderson and Trueman) populations in honey bee (Apis mellifera L.) colonies with acaricides has been a challenge for beekeepers due to the rapid development of resistant mite populations. For this reason, many beekeepers are adopting Integrated Pest Management strategies as alternatives to chemocentric varroa control schemes. One non-chemical tool that has been used for varroa control is dusting bee colonies with powdered sugar. The objective of our study was to determine the efficacy of powdered sugar as a varroa control by comparing mite populations, adult bee populations, and brood area in untreated colonies with those in colonies dusted every two weeks for 11 months with 120 g powdered sugar per application. We found that dusting colonies with powdered sugar did not significantly affect the adult bee population (treated: 10061.72 ± 629.42; control: 10691.00 ± 554.44) or amount of brood (treated: 4521.91 ± 342.84 cm2; control: 4472.55 ± 365.85 cm2). We also found no significant differences between the total number of mites per colony (treated: 2112.15 ± 224.62; control: 2197.80 ± 207.75), number of mites per adult bee (treated: 0.080 ± 0.010; control: 0.097 ± 0.010), or number of mites per capped brood cell (treated: 0.112 ± 0.013; control: 0.106 ± 0.018). All data are mean ± s.e. Within the limits of our study and at the application rates used, we did not find that dusting colonies with powdered sugar afforded significant varroa control.

Small hive beetle,Aethina tumida, populations I: Infestation levels of honeybee colonies, apiaries and regions

The small hive beetle (SHB) is a parasite and scavenger of honeybee colonies. Here we provide the first comprehensive systematic data on colony infestation levels with adult SHB for 226 colonies at 31 apiaries in South Africa, Australia, Florida and Maryland. Inside colonies, SHB distribution was influenced by the presence of bees with more SHB in the brood nest in the absence of bees. SHB distribution among colonies at an apiary was different from a random distribution but colony phenotypes (number of bees, amount of brood or stores) did not influence infestation levels. Apiaries next to large scale honey extraction facilities (honey houses) showed higher infestation levels and regions with more damage had higher SHB population levels. Consequently, methods of reducing SHB populations, such as the removal of dead colonies and the prevention of SHB reproduction in honey houses, seem to be important for pest management.

Dwindling pollen resources trigger the transition to broodless populations of long‐lived honeybees each autumn

Abstract 1. Each autumn in northern regions, honeybee colonies shift from populations of short‐lived workers that actively rear brood to broodless populations of long‐lived winter bees. To determine if dwindling pollen resources trigger this transition, the natural disappearance of external pollen resources was artificially accelerated or delayed and colonies were monitored for effects on the decline in brood‐rearing activity and the development of populations of long‐lived winter bees.2. Delaying the disappearance of pollen resources postponed the decline in brood rearing in colonies. Colonies with an extended supply of pollen reared workers longer into October before brood rearing ended than control colonies or colonies for which pollen supply was cut short artificially in autumn.3. Colonies with extended pollen supply produced more workers throughout autumn than colonies with less pollen, but the development of the population of long‐lived winter bees was delayed until relatively later in autumn. Colonies produced similar numbers of winter bees, regardless of the timing of the disappearance of pollen resources.4. Mean longevity of autumn‐reared workers was inversely related to the amount of brood remaining to be reared in colonies when workers eclosed. Consequently, long‐lived workers did not appear in colonies until brood rearing declined, which in turn was controlled by the availability of pollen.5. Dwindling pollen resources provide a powerful cue that initiates the transition to populations of broodless winter bees because it directly affects the brood‐rearing capacity of colonies and indirectly indicates deteriorating environmental conditions associated with the approach of winter.

Varroa destructor (Mesostigmata: Varroidae) in Costa Rica: population dynamics and its influence on the colony condition of Africanized honey bees (Hymenoptera: Apidae)

The development of Varroa destructor Anderson & Trueman (Mesostigmata: Varroidae) population dynamics in Africanized honey bees, Apis mellifera L. (Hymenoptera: Apidae) colonies was monitored from February to July 2004 in Atenas, Costa Rica. A correlation between the mite infestation level and the colony condition was evaluated. For each colony, infestation of varroa in adult bees was measured twice a month. Sticky boards were placed on the bottom boards of each colony to collect fallen mites. The condition of the colonies was evaluated by measuring the amount of brood and adult bees. Our results consistently showed that mite infestation on adult bees increased significantly in the experimental colonies, rising to 10.0% by the end of the experiment. In addition, the mean mite fall increased significantly over the course of the study in the treated (R = 0.72, P < 0.05) and untreated colonies (R = 0.74, P < 0.05) to a level of 63.8 and 73.5 mites per day, respectively. The increase in varroa infestation coincided with a decrease in the amount of brood. Furthermore, adult bees with deformed wings or even without wings crawling in front of their hive occurred in highly infested colonies (mite infestation = 10.0% or more).

A scientific note on honey bee foraging activity and airborne pollen flow

Several factors affect a honey bee colony’s collection of pollen. Most studies on this topic have focused on the colony’s response to stimuli located within the nest, principally the amount of brood and stored pollen (Hrassnigg and Crailsheim, 1998; Dreller et al., 1999; Fewell and Bertram, 1999; Rotjan et al., 2002; Vaughan and Calderone, 2002). One area that has not received adequate attention is the relationship between pollen collection and its availability in the natural environment. During the last few years, aerobiology studies demonstrated a link between airborne pollen concentration and the number of flowers in the area surrounding the sampler (Reddi and Reddi, 1985; Besselat and Cour, 1990; Cunha et al., 2003; Thibaudon and Lachasse, 2005). The aim of our work was to compare the total airborne pollen flow, collected with airborne samplers, with the total amount of pollen collected by honey bee colonies. Sampling was done in the northwest littoral of Portugal, in two rural areas, Cesar (40◦55’N, 8◦25’W, 300 m altitude) and Vairao (41◦20’N, 8◦40’W, 100 m), and one urban area, Porto (41◦11’N, 8◦39’W, 50 m). Airborne pollen flow and bee-collected pollen were studied in 2003 and 2004 at Cesar and Vairao, and in 2004 at Porto. At Cesar and Vairao, the airborne pollen content was sampled using two “Cour-type” samplers (Cour, 1974) placed at 12 m and 7 m, respectively, above ground level. The pollen was trapped in filters which were changed weekly. After acetolysis (Erdtman, 1960),