Guard Bees Research Articles

Kin recognition in the sweat bee, Lasioglossum zephyrum.

Recognition of kin in sweat bees is dependent upon social learning. Shortly after emergence as adults, bees learn the odors of nestmates, normally relatives, and use this knowledge to keep nonnestmate (and therefore nonkin) bees out. The odors are heritable so that once a bee learns the odors of its kin, it can recognize other kin that it has never met before. An individual guard bee does not seem to use knowledge of self as a reference. Larval learning of odors, common rearing of offspring, maternal inheritance, and inbreeding effects are not sufficient to explain the recognition of unfamiliar relatives. Individual guard bees can discriminate between close and distant relatives. Kin recognition may be a secondary or serendipitous use of odors that originally evolved for the recognition of mates and nest entrances.

Nocturnal defensive responses of Africanized and European honey bees to the greater wax moth ( Galleria mellonella L.)

Colonies of honey bees ( Apis mellifera L.) in Brazil, the United States and Venezuela were presented with adult greater wax moths ( Galleria mellonella L.) at their hive entrances. Africanized colonies were quicker, more persistent, and more intense in their attacks than were European colonies. Both races attacked female moths in preference to males. Although colony size did not appear to be related to defensiveness, attack data were correlated with the numbers of bees guarding the entrance. Africanized colonies had significantly more guard bees. During successive trials, both races attacked the moths in significantly shorter times. These findings may help explain the unexpectedly low population levels of G. mellonella in some areas of South America.

Alarm substances of the stingless bee,Trigona silvestriana

2-Nonanol, 2-heptanol, octyl decanoate, and octyl octanoate were identified from the heads ofTrigona silvestriana workers. When presented at the nest, 2-nonanol, 2-heptanol, and the mixture of the four compounds elicited angular flights, landing, and buzzing of guard bees. Octyl octanoate elicited a weaker response. No response was given to octyl decanoate, to the ether solvent, or to the control volatile, vanillin.

Aerial defense of the nest by workers of the stingless bee Trigona (Tetragonisca) angustula (Latreille) (Hymenoptera: Apidae)

The stingless bee Trigona (Tetragonisca) angustula has a sophisticated defense strategy against flying insect predators at the entrance of its nest. Groups of worker bees hover on both sides in front of the nest entrance tube, facing a flight corridor leading to the nest. Intruders which enter this corridor are attacked by these bees from the side and from behind and are forced to the ground by biting bees clinging to their wings. T. angustula is subject to predation by Lestrimelitta limao, a cleptobiotic stingless bee which performs organized raids on other nests to rob food supplies, larval provisions and nest constructing material. The presence of citral, released by L. limao during the raids, leads to a rapid increase in the number of hovering guard bees in front of T. angustula nests. This recruitment in response to citral suggests that the defense behavior in T. angustula has evolved under the pressure of L. limao raids and that citral functions in T. angustula as an alarm kairomone.

Colony Defense Strategies of the Honeybees in Thailand

The colony defense strategies of the three honeybee species in Thailand were studied to examine the influence of predation on tropical honeybee societies. Each species focuses its defenses upon different stages in the predation sequence of detection—approach—consumption. This radiation in defense strategies apparently reflects each species' preadaptation by worker size (small, medium—sized, or large) and nest site (cavity or tree branch) to a different pattern of colony defense. Wasps, birds, and primates probably have difficulty finding the small, dispersed colonies of Apis florea, whose nests are built low on the branches of dense, shrubby vegetation. Once found, however, they are easily approached and overpowered because their low, exposed nests are accessible and their small workers inflict relatively painless stings. When overwhelmed, the bees quickly abandon their nest; later, they return to salvage wax. Ants find A. florea nests easily and at least one species (Oecophylla smaragdina) easily kills these small bees. However, sticky bands of resin encircling the nests' slender substrate branches prevent ants from invading A. florea nests. Cavity—nesting colonies of Apis cerana are conspicuous with their medium—sized bees streaming in and out of low, clearly visible entrance holes in caves and hollow tress. However, gaining access to A. cerana nests is difficult. Large predators cannot pass through the small entrance opening and small predators are overpowered by entrance guards. But if a large predator can breach a nest cavity's walls, it faces an only moderately powerful stinging defense. Apis cerana colonies are relatively small and their workers are not fiercely aggressive. Predators easily find the large, sometimes aggregated colonies of Apis dorsata, whose nests hang in the crowns of the tallest forest trees. But only skilled fliers and climbers can reach these lofty nests. Those which do face massive stinging attacks from the large colonies of these relatively giant, ferocious bees. Nests of both open—nesting species, Apis florea and A. dorsata, are protected by a three— to six—layer curtain of bees over the comb. Apis cerana colonies lack these curtains but are protected by their nest cavity walls. A curtain of inactive guards requires a large labor force. The high worker: brood ratio in A. florea relative to A. cerana colonies suggests that the age polyethism schedules of the open— and cavity—nesting species are tuned differently to generate the appropriate proportions of guard bees. Each species' colony defense system consists of numerous interwoven lines of adaptation, including nest site, nest architecture, colony population, labor allocation to defense, age polyethism schedule, colony mobility, and worker morphology, physiology, and behavior. Predation has been a pervasive and powerful force in the evolution of these tropical bee societies.

Nestmate recognition in sweat bees ( Lasioglossum zephyrum): Does an individual recognize its own odour or only odours of its nestmates?

We investigated the olfactory mechanism by which guard bees of Lasioglossum zephyrum decide whether to admit conspecifics to their nests. First we set up colonies of young bees, consisting of sisters from a single family or a mixture of bees from two distinct families. These bees were then introduced into colonies other than their own. Our experimental evidence shows that guards learn the odours of their nestmates, then accept or reject other bees on the basis of the similarity of the latters' odours to those of the guards' nestmates. Guards act as though they do not use their own odour as a reference for nestmate recognition. This recognition mechanism enables individuals with different odours to live together; it may also enhance the operation of kin selection by providing a more complete basis for discriminating relatives from non-relatives. No evidence was found that nestmates acquire one another's odours. Such lack of odour transfer may be characteristic of early stages in the evolution of recognition mechanisms.

Genetic Component of Bee Odor in Kin Recognition

The primitively social sweat bee, Lasioglossum zephyrum, blocks the entry into its nest of most conspecifics from other colonies. Laboratory inbreeding of these bees produced lines which showed a positive linear relationship between the coefficient of relationship of bees tested and how often they permitted non-nestmates to pass them. The most probable mechanism is a genetically determined odor coupled with a learned component by which guard bees discriminate between odors of close kin and other bees.

Behaviour Associated with Hairless-Black Syndrome of Adult Honeybees

SummaryPatterns of adult honeybee behaviour associated with the disease named hairless-black syndrome are described. Bees that were apparently healthy vigorously chewed with their mandibles at the bodies of diseased bees inside the hive and at the hive entrance, thus rendering them hairless and shiny-black in appearance. Individually marked bees engaging in these chewing attacks sometimes licked the thorax of diseased trembling bees. Bees subjected to chewing attacks usually remained passive, sometimes offering food or stroking their probocis, and rarely tried to escape. Attacking behaviour apparently occupied some bees fully for a part of their lives. The level of attacking behaviour in observation hives was cyclic, with a peak every 4–12 days, and a daily peak between 12.00 h and 16.00 h. The behaviour patterns of attacking and attacked bees differed from those of cleaning and cleaned bees. Attacking behaviour was also unlike that of guard bees attacking robbers; however, it was similar in nearly every ...

Social, stimulatory and motivational factors involved in intraspecific nest defense of a primitively eusocial halictine bee

The major releasing stimulus in intraspecific nest defense ofLasioglossum zephyrum is the odor emitted by a non-resident bee. Non-resident bees older than two days emit the releasing odor and elicit aggressiveness by guard bees, whereas younger non-resident bees are accepted more often. Defense motivation is a function of nest age and/or ontogeny. As nests become older and cells are constructed and provisioned, there is a gradual increase in guard aggressiveness, although no one attribute of nest ontogeny (such as cell construction) seems to be a definitive point at which nest defense is initiated, nor is there any specific day after the emergence of the first bee when nest defense begins. The guard plays the major role in rejecting intruders, although other members of the colony may do so if a non-resident bee passes the guard and enters the nest.

Behavioural Studies on Queen Introduction in the Honeybee 1. Effect of the Age of Workers (From a Colony with a Laying Queen) on their Behaviour towards an Introduced Virgin Queen

SummaryThe age of the workers influenced their behaviour towards a virgin queen introduced to them. Young workers (7 days old) accepted an introduced virgin queen, whereas older workers (14 or 21 days) usually rejected her. Workers 14 days old were more aggressive than those 21 days old. The “aggression score” increased linearly in workers from 8 to 12 days old. The number of pollen collectors also increased linearly throughout this period, but the number of guard bees was greatest at 10 days.

Patterns of intraspecific agonistic interactions involved in nest defense of a primitively eusocial halictine bee

Intraspecific nest defense inLasioglossum zephyrum involves specific agonistic action patterns by guard bees released by non-resident intruders. When guards are not highly motivated, intention movements are exhibited which also occur in the context of more aggressive interactions. Antennation, either mutual or by one bee, usually occurs prior to aggressive movements. Two main action patterns occur when a non-resident bee attempts to enter a nest: (1) the guard blocks the nest entrance with the abdomen, which often leads to backing movements and abdominal thrusts to eject the intruder, (2) the guard assumes a fight posture with head and abdomen extended toward the intruder; from the fighting posture, lunging often results in which the guard moves forward, alternating between head (mandibular) and abdomen (sting) thrusts. Most interactions are one-sided, with the intruder retreating from the guard, but mutual more intense fighting does occur.

Production of geraniol by honey bees of various ages

The amount of geraniol obtained by a standard procedure from the Nassanoff gland of the honey bee varied from zero to 1·5 μg per bee, depending on the age of the bees. Newly emerged bees had no geraniol. Guard bees produced ca. 0·3 μg per bee and a marked increase to ca. 1·0 μg per bee occurred when the bees began to forage.

Identification of isoamyl acetate as an active component in the sting pheromone of the honey bee.

THE sting of the honey bee (Apis mellifera L.) carries volatile substances which incite bees to aggression. This was first demonstrated by Huber1, who elicited attacks by the guard bees when he placed freshly excised stings or the odour of stings near the hive entrance. Free2 found that cotton balls containing stings were more frequently stung than control balls.

Suppression of Oviposition Rate of Scambus buolianae (Htg.) (Hymenoptera: Ichneumonidae), in Fluctuating Electrical Fields

It was suspected for many years that the electrical environment stimulates insect activity. Schùa (1952) found that alternating potentials caused guard bees to become hostile and foragers to increase their activity and food uptake. Levengood and Shinkle (1960) reported that the progeny yields of cultures of Drosophila melanogaster Meig. in an electric field were, on the average, higher than control groups and the effect of barometric pressure was considerably reduced. The present study was made to determine whether electrostatic fields of low intensity affected the oviposition rate of a hymenopterous parasite.

The Behaviour of Robber Honeybees

1. The factors which cause the characteristic swaying flight of robber honeybees have been investigated. 2. This flight occurs as an innate response to the presence of a congestion of bees, of their own or another colony, at the entrance to the hive they are robbing. 3. Foragers enter without hesitation, hives other than their own to collect syrup or honey in the absence of a congestion of bees at the entrance, even when these hives contain a colony of bees. 4. Guard bees quickly recognise would-be robber bees by their flight behaviour and confirm their identity by olfactory examination.

The Behaviour of Worker Honeybees At the Hive Entrance

1. Observations at hive entrances have been made to ascertain the relative importance of scent and behaviour in enabling a guard bee to recognise members of her own colony and to distinguish them from intruders from other colonies. 2. Guard bees are not present at the hive entrance unless the colony has been alerted. 3. Alerting of colonies is brought about by the presence of robber bees or by numbers of bees that have strayed from other colonies. 4. Guard bees attempt to intercept and inspect other bees on the alighting-board of the hive. Bees of various ages undertake guard duties. 5. Guard bees recognise members of their own colony by scent. 6. Robber bees are recognised by behaviour when attempting to enter the hive, but all other intruders are recognised by scent. 7. After recognition intruders, other than robbers, assume either a dominant or a submissive attitude. 8. A dominant intruder, usually a laden forager, enters the hive without hesitation or difficulty. 9. On interception a submissive intruder stops moving towards the hive entrance and allows herself to be subjected to extensive examination or mauling. 10. Whilst being extensively examined or mauled the submissive intruder offers food to the guards and on their refusal of it 'strops' her tongue. It is suggested that this is a displacement activity. 11. A submissive bee that is being mauled sometimes passes into a state of thanatosis. 12. Very young bees are recognised as intruders and mauled just as readily as older bees. 13. As long as an intruder remains submissive she is not stung by the guards. Intruders, including robbers, which attempt to escape from the guards are immediately seized and stung. 14. If intruders, other than robbers, succeed in remaining in a strange colony for 2-3 hours they are accepted by the bees of that colony.

Sting of Hive-Bees

THE point raised by Dr. J. G. Myers, in NATURE of August 25, p. 290, regarding the ability of the hive-bee to withdraw its sting, is not a new one, and has elicited a letter of protest from a practical beekeeper, Mr. Z. B. H. Garrett, of Ingoldsby, Long-field, Kent. When bees are ‘induced to sting’ experimentally, they frequently extricate the sting as soon as the pressure or other inducement is relaxed. Naturally a bee can withdraw its sting from the soft tissues ofj say, a wax-moth larva more easily than from the thumb of the experimenter. Another point which is generally overlooked is the age of the stinging bee. Up to three days or more after emergence, young bees can scarcely be persuaded to use their stings. The typical stinging age, as was first shown by Rosch, is towards the end of the period of domestic duties, and on the eve of the outdoor foraging period. It is reasonable to surmise that the sting glands reach their maximum development at this period of the bee's life, just as the lateral pharyngeal glands do at a somewhat earlier stage—possibly to atrophy, as do the latter with advancing age. The stings received by the beekeeper as one of the hazards of his calling are given with a will by the guard bees, which are physiologically ripe for the job. Such bees make for the eyelids, nose, or the back of the neck, and seldom attempt to remove their stings, though the beekeeper should make a point of doing so, without squeezing the venom sac, at the earliest opportunity. It is otherwise with those bees that crawl up the sleeves or trouser legs. These have no malice prepense, and do not use their stings until they find themselves trapped by the pressure of the clothing or nervous movements on the part of the beekeeper. Such bees, if undamaged and given time, can often withdraw their stings and be coaxed out towards the light.