Efficacy of modified hive entrances and a bottom screen device for controlling Aethina tumida (Coleoptera: Nitidulidae) infestations in Apis mellifera (Hymenoptera: Apidae) colonies

This study was designed to test whether hive entrances reduced with polyvinyl chloride pipe reduce the ingress of Aethina tumida Murray into Apis mellifera L. colonies and whether screen-mesh bottom boards alleviate side effects associated with restricted entrances. Forty-eight colonies distributed equally between two locations each received one of six experimental treatments: 1) conventional solid bottom board and open entrance, 2) ventilated bottom board and open entrance, 3) conventional bottom and 1.9-cm-i.d. pipe entrance, 4) conventional bottom and 3.8-cm pipe entrance, 5) screen bottom and 1.9-cm pipe entrance, and 6) screen bottom and 3.8-cm pipe entrance. Results were inconsistent between apiaries. In apiary 1, colonies with 3.8-cm pipe entrances had fewer A. tuzmida than colonies with open entrances, but this benefit was not apparent in apiary 2. Pipe entrances tended to reduce colony and brood production in both apiaries, and these losses were only partly mitigated with the addition of screened bottom boards. Pipe entrances had no measurable liability concerning colony thermoregulation. There were significantly fewer frames of adult A. mellifera in colonies with 3.8- or 1.9-cm pipe entrances compared with open entrances but more in colonies with screens. There were more frames of pollen in colonies with open or 3.8-cm pipe entrances than 1.9-cm entrances. We conclude that the efficacy of reduced hive entrances in reducing ingress of A. tumida remains uncertain due to observed differences between apiaries. Furthermore, there were side effects associated with restricted entrances that could be only partly mitigated with screened bottom boards.     

Evaluation of an upper hive entrance for control of Aethina tumida (Coleoptera: Nitidulidae) in colonies of honey bees (Hymenoptera: Apidae)

This investigation was conducted to test whether an upper hive entrance may result in reduced Aethina tumida Murray (Coleoptera: Nitidulidae) population buildup in newly established honey bee, Apis mellifera L., colonies over an 8-mo period. The upper hive entrance consisted of a 3.5-cm-i.d. polyvinyl chloride pipe positioned 20 cm above the hive bottom. Sixteen bee colonies were established using five-frame nucleus hives with a 0.9-kg (2-1b) package of bees with queen. Eight colonies were placed in each apiary, and each colony received one of two treatments: 1) conventional hive lower entrance and 2) modified upper hive entrance. This investigation was conducted in two distant apiaries where A. tumida had been a major problem to local beekeepers for a minimum of 2 yr. Results showed no overall differences between treatment effects on A. tumida counts over the test period, but there was a reduction in bee brood measured in colonies having an upper hive entrance. We conclude that the upper pipe entrance is not recommended in areas where A. tumida are well established and have become problematic. The expected reduction of brood in colonies as a result of using an upper hive entrance will lead to less productive units for honey production and pollination activities. Other control measures will be necessary to maintain tolerable levels of A. tumida in honey bee colonies at high pest densities.     

Pollen Contamination of Honey by Bees inside the Hive

This paper aims to assess to what degree and in what way the brood chamber affects the pollen content of the honey. Twenty-nine pieces of comb containing only honey were cut from different frames of hives. The percentage of cells in each frame occupied by the brood chamber and the distance between these cells and the cut piece were recorded. A honey sample was extracted from each comb piece, avoiding any contamination with pollen, its sediment examined under the microscope and its botanical constituents identified and counted. The results show that the pollen content of honey was higher in samples from frames containing brood or pollen cells; in these samples the pollen content was positively correlated with the amount of these cells in the frame and the proximity of the honey to them. The proportion of pollen grains from principally nectariferous plants was lower in honeys with a high pollen content.     

Evaluation of the time of uncapping and removing dead brood from cells by hygienic and non-hygienic honey bees

Most research on hygienic behavior has recorded the time taken by the colony to remove an experimental amount of dead brood, usually after one or two days. We evaluated the time that hygienic (H) and non-hygienic (NH) honey bees take to uncap and remove dead brood in observation hives after the brood was killed using the pin-killing assay. Four experimental colonies were selected as the extreme cases among 108 original colonies. Thirty brood cells were perforated with a pin in two H and two NH colonies and observations were made after 1, 2, 3, 4, 5, 6, and 24 h. Different stages of uncapping and removing were recorded. Differences in uncapping and removal between H and NH colonies were significant for all comparisons made at the different times after perforation. Using observation hives one obtains a better and faster discrimination between H and NH colonies than in full size colonies. It is possible to differentiate H and NH within a few hours after perforating the cells.     

Estimating reproductive success of Aethina tumida (Coleoptera: Nitidulidae) in honey bee colonies by trapping emigrating larvae

The small hive beetle (Aethina tumida Murray) is a scavenger and facultative predator in honey bee colonies, where it feeds on pollen, honey, and bee brood. Although a minor problem in its native Africa, it is an invasive pest of honey bees in the United States and Australia. Adult beetles enter bee hives to oviposit and feed. Larval development occurs within the hive, but mature larvae leave the hive to pupate in soil. The numbers leaving, which can be estimated by trapping, measure the reproductive success of adult beetles in the hive over any given period of time. We describe a trap designed to intercept mature larvae as they reach the end of the bottom board on their way to the ground. Trap efficiency was estimated by releasing groups of 100 larvae into empty brood boxes and counting the numbers trapped. Some larvae escaped, but mean efficiency ranged from 87.2 to 94.2%. We envision the trap as a research tool for study of beetle population dynamics, and we used it to track numbers of larvae leaving active hives for pupation in the soil. The traps detected large increases and then decreases in numbers of larvae leaving colonies that weakened and died. They also detected small numbers of larvae leaving strong European and African colonies, even when no larvae were observed in the hives.     

Efficacy of strips coated with Metarhizium anisopliae for control of Varroa destructor (Acari: Varroidae) in honey bee colonies in Texas and Florida

Strips coated with conidia of Metarhizium anisopliae (Metschinkoff; Deuteromycetes: Hyphomycetes) to control the parasitic mite, Varroa destructor (Anderson and Trueman) in colonies of honey bees, Apis mellifera (Hymenoptera: Apidae) were compared against the miticide, tau-fluvalinate (Apistan) in field trials in Texas and Florida (USA). Apistan and the fungal treatments resulted in successful control of mite populations in both locations. At the end of the 42-day period of the experiment in Texas, the number of mites per bee was reduced by 69-fold in bee hives treated with Apistan and 25-fold in hives treated with the fungus; however mite infestations increased by 1.3-fold in the control bee hives. Similarly, the number of mites in sealed brood was 13-fold and 3.6-fold higher in the control bee hives than in those treated with Apistan and with the fungus, respectively. Like the miticide Apistan, the fungal treatments provided a significant reduction of mite populations at the end of the experimental period. The data from the broodless colonies treated with the fungus indicated that optimum mite control could be achieved when no brood is being produced, or when brood production is low, such as in the early spring or late fall. In established colonies in Florida, honey bee colony development did not increase under either Apistan or fungal treatments at the end of the experimental period, suggesting that other factors (queen health, food source, food availability) play some major role in the growth of bee colonies. Overall, microbial control of Varroa mites with fungal pathogens could be a useful component of an integrated pest management program for the honey bee industry.     

Thievery,home ranges,and nestmate recognition inEctatomma ruidum

Summary Thievery of food items among colonies of a ponerine ant,Ectatomma ruidum was common; nonnestmates in colonies or near the colony entrances receive incoming food items and carry them to their own colony. In our study area 7 of 10 colonies were victimized by thief ants. Colonies have discrete home ranges and home range size is correlated with the number of workers in the colony. Worker ants discriminate nestmates from non-nestmates when non-nestmates are presented at colony entrances, but individuals from different colonies were not observed to engage in agonistic interactions away from nest entrances. Non-nestmates gain entrance to colonies when the entrance is unguarded. Many instances of non-nestmates being removed from colonies by residents were observed. The costs and benefits of theft under these circumstances are considered.     

The thermal environment of nests of the Australian stingless bee, Austroplebeia australis

The greatest diversity of stingless bee species is found in warm tropical regions, where brood thermoregulation is unnecessary for survival. Although Austroplebeia australis (Friese) naturally occurs in northern regions of Australia, some populations experience extreme temperature ranges, including sub-zero temperatures. In this study, the temperature was monitored in A. australis colonies’ brood chamber (n = 6) and the hive cavity (n = 3), over a 12-month period. The A. australis colonies demonstrated some degree of thermoconformity, i.e. brood temperature although higher correlated with cavity temperature, and were able to warm the brood chamber throughout the year. Brood production continued throughout the cold season and developing offspring survived and emerged, even after exposure to very low (?0.4 °C) and high (37.6 °C) temperatures. Austroplebeia australis, thus, demonstrated a remarkable ability to survive temperature extremes, which has not been seen in other stingless bee species.     

Interactions Increase Forager Availability and Activity in Harvester Ants

Social insect colonies use interactions among workers to regulate collective behavior. Harvester ant foragers interact in a chamber just inside the nest entrance, here called the ''entrance chamber''. Previous studies of the activation of foragers in red harvester ants show that an outgoing forager inside the nest experiences an increase in brief antennal contacts before it leaves the nest to forage. Here we compare the interaction rate experienced by foragers that left the nest and ants that did not. We found that ants in the entrance chamber that leave the nest to forage experienced more interactions than ants that descend to the deeper nest without foraging. Additionally, we found that the availability of foragers in the entrance chamber is associated with the rate of forager return. An increase in the rate of forager return leads to an increase in the rate at which ants descend to the deeper nest, which then stimulates more ants to ascend into the entrance chamber. Thus a higher rate of forager return leads to more available foragers in the entrance chamber. The highest density of interactions occurs near the nest entrance and the entrances of the tunnels from the entrance chamber to the deeper nest. Local interactions with returning foragers regulate both the activation of waiting foragers and the number of foragers available to be activated.     

Life Inside an Acorn: How Microclimate and Microbes Influence Nest Organization in Temnothorax Ants

Nests provide a buffer against environmental variation, but conditions may also vary at different locations within a nest. Conditions can vary based on abiotic factors, such as moisture and temperature, as well as biotic factors, such as the presence of microbes and potential pathogens. Therefore, characterizing how animals adjust their position inside their nests to track microclimate preferences while at the same time preventing pathogen exposure is necessary to understand the benefits nests provide. Here we studied how colonies of the acorn‐nesting ant Temnothorax curvispinosus responded to experimental manipulation of moisture, temperature, and microbial growth inside their nests. Colonies showed no response to differences in moisture and moved to the bottom of the acorn regardless of moisture treatment. When nests were heated from the top to simulate warming by the sun, workers preferentially moved brood to the warm, upper half of the acorn, which would stimulate brood development. Finally, the strongest factor that influenced colony position was the presence of microbes inside the nest—colonies avoided the bottom of the nest when it was inoculated with microbes, and colonies in new acorns shifted to the top of the acorn over time as mold and other microbes had time to grow. The relatively strong response of T. curvispinosus to microbial growth inside their nests suggests that pathogen pressures—in addition to microclimate—have a significant impact on how colonies use nest spaces. Social insects are known to invest heavily in antimicrobial compounds that kill or slow the growth of microbes, but avoidance may represent an additional line of defense to prevent pathogen exposure.     

The microenvironment of house mice on Marion Island (sub-Antarctic)

On Marion Island, house mice ( Mus musculus) establish burrow systems that range from unbranched corridors 0.5 m long with a single chamber (in some instances without a chamber) to complexly branched systems extending over an area of up to 4 m² and containing up to four chambers. Total underground area occupied by burrow systems (chambers plus corridors) was from 5 to 23 m² ha^-1, corresponding to burrow-system volumes of 250-1,300 dm³ ha^-1. In autumn, about three-quarters of chambers contained small food caches. Most (87%) entrances to burrow systems faced away from prevailing winds, especially winds that bring snow, hail or rain. Seasonal and diurnal temperature variations in burrows are considerably dampened (daily minimum in burrows seldom drops below 2°C), compared with the air just above the vegetation canopy. Over the whole year, total night-time warmth in a burrow (heat sum, 24,883 degree hours) was 53% greater than at the top of the canopy (16,317 degree hours). Burrows' entrances are generally connected above ground by runways (paths and tunnels through the vegetation). Runways also represent a warmer environment than the air above the canopy during the breeding season at night (13,466 degree hours at the runway surface compared with 11,900 degree hours at the top of the canopy). House mice, which are living close to their physiological limits, temperature-wise, on Marion Island thus evade the worst extremes of the island's climate by constructing burrows and above-ground runways and this is an important factor in their survival.     

Sociometry and sociogenesis of colonies of the harvester ant, Pogonomyrmex badius: distribution of workers, brood and seeds within the nest in relation to colony size and season

1. The vertical distribution in the nest of chambers, workers, callow workers, brood and seeds was studied in the harvester ant, Pogonomyrmex badius, in northern Florida. On each of four sample dates (May, July, October, January), six to seven colonies, chosen to represent the full range of sizes, were excavated. All chamber contents were collected and counted. Chambers were mapped and measured. In a preliminary study, two nests were excavated after preventing vertical migration by driving barriers into the wall of a pit next to the nest, severing the vertical tunnels. The vertical distribution of these barrier-nests differed little from unrestrained nests, indicating that unrestrained excavation produced a reasonable picture of vertical distributions. 2. Nest depth, chamber number and total area increased with colony size. Chamber area declined sharply with depth, as did chamber number, such that more than half of the total area was found in the upper quarter of the nest. 3. The proportion of dark-coloured (older) workers also declined strongly with depth, but this decline was weaker in the spring, and depended to a modest degree on colony size. Conversely, in the distribution of callow (young) workers, the proportion increased towards the bottom of the nest. Mean worker age was inversely related to the depth at which workers were found. The proportion of the brood also increased towards the bottom of the nest, with worker brood, sexual brood, pupae and larvae all being distributed similarly. 4. By contrast, seeds were stored at a preferred absolute depth between 40 and 100 cm. Colonies shallower than 100 cm stored seeds in their deepest chambers. Larger colonies stored most seeds in the upper third of the nest, but patterns were somewhat erratic because chambers were either filled completely with seeds or were empty. 5. Because chamber area decreased sharply with depth, the densities (individuals cm^–2) of all colony members, including dark workers, were lowest near the surface and highest in the deepest parts of the nest. Here, worker densities ranged from 2 to 8 cm^–2, and brood from 2 to 25 cm^–2. 6. The regularity of the patterns of distribution suggests that harvester ant colonies have considerable spatial and temporal structure, which serves or is the outcome of important colony processes. A simple mechanism that could generate several of these patterns is discussed. New workers produced deep in the nest move upwards as they age. As they leave the brood zone they change from brood care to general nest duties, including increased nest excavation, leading to the top-heavy pattern of nest area. As they appear at the surface, they change to guarding and foraging. Thus, age polyethism may be partly the result of this upward migration of workers.     

Brood Pheromone Modulation of Pollen Forager Turnaround Time in the Honey Bee (<Emphasis Type="Italic">Apis mellifera</Emphasis> L.)

Foraging for pollen is an important behavior of the honey bee because pollen is their sole source of protein. Through nurse bees, larvae are the principal consumers of pollen. Fatty acid esters extractable from the surface of larvae, called brood pheromone, release multiple colony-level and individual foraging behaviors increasing pollen intake. In this study pollen forager turnaround time was measured in observation hives supplemented with brood pheromone versus a blank control treatment. Treatment with brood pheromone significantly decreased pollen forager turnaround time in the hive between foraging bouts by approximately 72%. Concurrently, brood pheromone increased the ratio of pollen to non-pollen foragers entering colonies. Brood pheromone has been shown to release most of the mechanisms known to increase pollen intake by colonies acting as an important regulator of colony foraging decisions and growth.     

Netted crop covers reduce honeybee foraging activity and colony strength in a mass flowering crop

The widespread use of protective covers in horticulture represents a novel landscape‐level change, presenting the challenges for crop pollination. Honeybees (Apis mellifera L) are pollinators of many crops, but their behavior can be affected by conditions under covers. To determine how netting crop covers can affect honeybee foraging dynamics, colony health, and pollination services, we assessed the performance of 52 nucleus honeybee colonies in five covered and six uncovered kiwifruit orchards. Colony strength was estimated pre‐ and postintroduction, and the foraging of individual bees (including pollen, nectar, and naïve foragers) was monitored in a subset of the hives fitted with RFID readers. Simultaneously, we evaluated pollination effectiveness by measuring flower visitation rates and the number of seeds produced after single honeybee visits. Honeybee colonies under cover exhibited both an acute loss of foragers and changes in the behavior of successful foragers. Under cover, bees were roughly three times less likely to return after their first trip outside the hive. Consequently, the number of adult bees in hives declined at a faster rate in these orchards, with colonies losing on average 1,057 ± 274 of their bees in under two weeks. Bees that did forage under cover completed fewer trips provisioning their colony, failing to reenter after a few short‐duration trips. These effects are likely to have implications for colony health and productivity. We also found that bee density (bees/thousand flowers) and visitation rates to flowers were lower under cover; however, we did not detect a resultant change in pollination. Our findings highlight the need for environment‐specific management techniques for pollinators. Improving honeybee orientation under covers and increasing our understanding of the effects of covers on bee nutrition and brood rearing should be primary objectives for maintaining colonies and potentially improving pollination in these systems.     

Intra-and intercolony patterns of nest dispersion in the ant Lasius neoniger: correlations with territoriality and foraging ecology

Colonies of the ant Lasius neoniger have multiple nest entrances that are distributed throughout a colony's foraging area. Associated with each nest entrance is a group of workers that show strong fidelity to that nest entrance. Territorial expansion, as indicated by increases in the number of nest entrances per colony, is correlated with foraging activity. Although there is variation between colonies in the seasonal pattern of territorial expansion, most nests become active in early summer, increase the size of the area foraged until midsummer, and then decrease the number of active nest entrances in late summer. Over the study plot as a whole, the dispersion pattern of nest entrances changed from clumped, or tending to be clumped, in early spring to random in mid-and late summer. Within colonies, nest entrances were significantly overdispersed. Intra-and interspecific competition negatively affected foraging, and workers from a given nest entrance were most successful at retrieving prey less than approximately 15–20 cm from the entrance. The average distance between nest entrances within a colony was 37.7±3.3 cm (mean±95% confidence interval, n=115), which is approximately twice the distance at which workers can retrieve prey. The polydomous nest structure of L. neoniger appears to partition territory within a colony by spatial subdivision of its foragers, and thus may reduce loss of prey to competitors.     

The power and efficiency of brood incubation in queenless microcolonies of bumble bees (Bombus terrestris L.)

1. Ground‐nesting colonies of bumble bees incubate their brood at > 30 °C if floral forage provides sufficient energy and the thermogenic power of the colony can counteract cool soil conditions. To explore the basis of incubation, the thermogenic power and sugar consumption of orphaned nests of bumble bee workers (microcolonies) were investigated under laboratory conditions. 2. This study tested experimentally the effect of variation in worker number (ranging from four to 12 adults) on a microcolony's capacity to regulate brood temperature and recover from acute cold exposure. Microcolonies were provided with ad libitum sugar syrup and minimal insulation and maintained at an ambient temperature of c. 25 °C. Energy conversion efficiency was estimated by comparing sugar consumption with the power required for artificial incubation. The joint energetics of foraging and incubation were modelled in wild colonies to explore the effect of colony size and landscape quality on thermoregulation. 3. The results showed that all sizes of microcolonies regulated brood temperature at c. 31 °C under laboratory conditions, which required 96 mW of thermogenic power. It was estimated that individual workers of B. terrestris generated an incubatory power of 35 mW. The smallest microcolonies had the highest conversion efficiency (57%), apparently because few workers were required for incubation. 4. Modelling indicated that small microcolonies of three to seven adult workers have the capacity for normal brood incubation in the wild, but that the minimum viable colony size increases as floral forage becomes poorer or more distant. 5. These preliminary findings suggest the feasibility of identifying the minimum conditions (forage quality, soil temperature, and colony size) necessary for brood incubation by queenright colonies in the wild.     

Live Varroa jacobsoni (Mesostigmata: Varroidae) fallen from honey bee (Hymenoptera: Apidae) colonies

The proportion of Varroa jacobsoni Oudemans that were alive and mobile when they fell from honey bees, Apis mellifera L., in hives was measured during a 20-wk period to determine the potential use of systems that prevent these mites from returning to the bees. Traps designed to discriminate between the live, fallen mites and those that are dead or immobile were used on hive bottom boards. A large fraction of the fallen mites was alive when acaricide was not in use and also when fluvalinate or coumaphos treatments were in the hives. The live proportion of mitefall increased during very hot weather. The proportion of mitefall that was alive was higher at the rear and sides of the hive compared with that falling from center frames near the hive entrance. More sclerotized than callow mites were alive when they fell. A screen-covered trap that covers the entire hive bottom board requires a sticky barrier to retain all live mites. This trap or another method that prevents fallen, viable mites from returning to the hive is recommended as a part of an integrated control program. It also may slow the development of acaricide resistance in V. jacobsoni and allow the substitution of less hazardous chemicals for the acaricides currently in use.     

Effect of triflumuron on brood development and colony survival of free-flying honeybee, Apis mellifera L.

Abstract:  The effect of the insect growth regulator (IGR) triflumuron (Alsystin^® 25 WP) on honeybee, Apis mellifera L. (Hym., Apidae), was studied in a semi-field test. Free-living colonies were fed one litre per hive of sucrose syrup containing 0, 0.025, 0.25 or 2.5 g of triflumuron. A significant reduction in flight activity was noted 6–10 weeks post-treatment at the two higher doses. These colonies reared less brood than before treatment. While the comb area occupied by uncapped brood was as high as [0.025 and 0.25 g active ingredient (a.i.)] or higher (2.5 g a.i.) than before treatment, there was a significant decline in capped brood at the two higher doses, indicating enhanced larval mortality. No capped brood was reared in the hive treated at the highest dose from 3–9 weeks post-treatment. Yet there was a significant accumulation of pollen and honey in the brood compartment at all doses. All colonies except the one treated at the highest dose survived the following winter. However, at 43 weeks post-treatment, hives treated at intermediate and low doses showed a significant increase in uncapped brood and a significant decrease in capped brood. This study revealed a strong residual toxicity of triflumuron to brood and substantiated its classification as hazardous to honeybee.     

Parental behaviour in Copris lunaris (Coleoptera, Scarabaeidae): care and defence of brood balls and nest

Abstract. 1. Nesting female beetles righted brood balls (so as to replace the egg or larva in the uppermost position) and repaired damaged balls. This behaviour required the presence of an egg or larva in the ball, or of a short-lasting material found just after oviposition. The shape of the ball was also a righting stimulus since artificial ellipsoids were stood on end.
2. Balls containing dichloromethane extracts of C.lunaris brood were righted and repaired. Eggs and larvae of several other Scarabaeidae did not release these responses but were destroyed.
3. Righting behaviour was released when brood was absent from the top of the ball. The beetle then crawled vertically downwards and, if it encountered the displaced apex, a novel rolling action followed which automatically turned the ball towards the correct position.
4. An opening made in the nest was repaired with soil excavated from the chamber floor. Clunaris adults and Aphodius fossor larvae were attacked if they were encountered in the nest.     

THE INFLUENCE OF STORED POLLEN AND OF COLONY SIZE ON THE BROOD REARING OF HONEYBEES

Four hundred and thirty records of the numbers of bees in honeybee colonies and of the amounts of brood and pollen present have been kept during various months of the years 1945-53, and the data have been used to calculate total and partial regression coefficients showing the influence of stored pollen and of colony size on brood rearing throughout the year.
It was found that pollen storage and colony size were correlated but that, even allowing for this, colony size and pollen both independently influenced brood rearing.
The annual distribution of the total regression coefficients of brood on pollen was somewhat similar to the brood curve itself, rising from a minimum in October and November to a maximum in midsummer, while the partial regression coefficients showed less clearly marked but similar features.
Both total and partial regression coefficients showing the influence of colony size on the amount of brood reared were also at a minimum in October and November, but reached their peaks in May.
The quantities of brood present in these colonies at Aberdeen, Scotland, followed a pattern similar to that given by Nolan for colonies near Washington, D.C.