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Floral displays often signal the presence of nectar, but nectar may not always be present due to previous visits by nectarivores or temporal changes in nectar availability. But how does the presence of empty flowers impact the preferences of foraging honey bees for the available flowers? We aimed to test if previously rewarding flowers changed the preference relationship between neighboring flowers, and if empty flowers impacted overall visitation, in the honey bee Apis mellifera. Using artificial flowers, we showed that although empty flowers did not influence foraging choices in A. mellifera workers, empty flowers did increase movement between flowers in the patch. The presence of empty flowers also resulted in increased rates of patch abandonment. Our results suggest that while empty flowers may not directly impact foraging preferences in bees, they can have an impact on visitation within patches and in the surrounding area, with possible knock-on effects for the pollination of both the emptied flower and neighboring plants. [ABSTRACT FROM AUTHOR]

Bumblebees (Bombus) are charismatic and important pollinators. They are one of the best-studied insect groups, especially in terms of ecology, behavior, and social structure. As many species are declining, there is a clear need to understand more about them. Microbial symbionts, which can influence many dimensions of animal life, likely have an outsized role in bumblebee biology. Recent research has shown that a conserved set of beneficial gut bacterial symbionts is ubiquitous across bumblebees. These bacteria are related to gut symbionts of honeybees, but have not been studied as intensively. Here, we synthesize studies of bumblebee gut microbiota, highlight major knowledge gaps, and suggest future directions. Several patterns emerge, such as symbiont-host specificity maintained by sociality, frequent symbiont loss from individual bees, symbiont-conferred protection from trypanosomatid parasites, and divergence between bumblebee and honeybee microbiota in several key traits. For many facets of bumblebee–microbe interactions, however, underlying mechanisms and ecological functions remain unclear. Such information is important if we are to understand how bumblebees shape, and are shaped by, their gut microbiota. Bumblebees may prove a useful system for microbiome scientists, providing insights into general principles of host–microbe interactions. We also note how microbiota could influence bumblebee traits and responses to stressors. Finally, we propose that tinkering with the microbiota could be one way to aid bumblebee resilience in the face of global change. [ABSTRACT FROM AUTHOR]

Most studies on collective decision making in honeybees have been performed on the cavity-nesting Western honeybee, Apis mellifera. In more recent years, the open-nesting red dwarf honeybee Apis florea has been developed as a model organism of collective decision making in the context of nest-site selection. These studies have shown that the specifics of the species' nest-site requirements affect collective decision making. In particular, when potential nesting sites are abundant, as is the case in A. florea, the process of collective decision making can be simplified. Here, we ask if A. florea simply follows the availability of floral resources in their environment when deciding on an area to move into. We determined the locations danced for by three colonies the day before, of and after reproductive swarming. Our results suggest that colonies of A. florea indeed track the availability of forage in their environment and that swarms move in the general direction of forage rather than towards a specific nest site. [ABSTRACT FROM AUTHOR]

Vibrations and sounds, collectively called vibroacoustics, play significant roles in intracolony communication in termites, social wasps, ants, and social bees. Modalities of vibroacoustic signal production include stridulation, gross body movements, wing movements, high-frequency muscle contractions without wing movements, and scraping mandibles or tapping body parts on resonant substrates. Vibroacoustic signals are perceived primarily via Johnston's organs in the antennae and subgenual organs in the legs. Substrate vibrations predominate as vibroacoustic modalities, with only honey bees having been shown to be able to hear airborne sound. Vibroacoustic messages include alarm, recruitment, colony activation, larval provisioning cues, and food resource assessment. This review describes the modalities and their behavioral contexts rather than electrophysiological aspects, therefore placing emphasis on the adaptive roles of vibroacoustic communication. Although much vibroacoustics research has been done, numerous opportunities exist for continuations and new directions in vibroacoustics research. [ABSTRACT FROM AUTHOR]

Colonies of social insects coordinate many activities in response to changing colony needs. One example is the maintenance of pollen stores in the nest by honey bees ( Apis mellifera L.). To adjust pollen intake in an appropriate manner, individual foragers must assess the colony's need for pollen. This assessment could be done either directly, through physical contact with larvae and stored pollen, or indirectly, using information obtained from other bees in the colony. We investigated the mechanisms by which foragers assess their colony's need for pollen. We segregated foragers from non-foragers using either a single screen that permitted contact between the two groups of bees, or a double screen that prevented contact. We supplied the segregated foragers in colonies of both of the screen treatment groups with either a comb containing 300 g pollen (P+) or a comb without pollen (P-). To create a need for pollen in the non-forager compartment of each colony, we provided that compartment with combs bearing 3-5 d old larvae but without any pollen. Foragers on combs with pollen returned 3.5% of the time with pollen, while foragers on combs without pollen returned with pollen 20.7% of the time (P < 0.005). Foragers able to contact their non-foraging nestmates through a single screen (S1) returned with pollen 12.6% of the time, while foragers prevented from contacting nestmates by a double screen (S2) returned with pollen loads 11.7% of the time (P > 0.80). The interaction between the pollen and screen treatments was not significant. These results suggest that foragers adjust their foraging behavior based on their direct assessment of the amount of pollen stored in the colony, and that non-foragers do not provide an excitatory indirect stimulus to foragers. [ABSTRACT FROM AUTHOR]

The larvae of mutillid wasps are parasitoids of insect host stages which are not actively feeding and are enclosed in some sort of package (cell, cocoon, puparium). The literature dealing with mutillids living in association with eusocial insects is surveyed and evaluated, and some new host records are provided. Relatively few mutillid species are involved despite the potential for prolific reproduction on social hosts. The problems faced by such parasitoids are greater than those encountered when using solitary hosts. Several species of mutillids parasitise social halictine bees, a few parasitise bumble bees and a few occasionally attack honey bees; a few are parasitoids of commensals or symbionts of ants. Their possible occurrence in the nests of other eusocial insects is briefly discussed. [ABSTRACT FROM AUTHOR]

Young queens start a new colony either without (independently) or with the help of workers (dependently). When colony reproduction is dependent and young queens are produced in excess, conflicts among queens are predicted to occur. Honey bee colonies reproduce dependently by swarming. The mother queen leaves with a "prime swarm" before daughter queens reach adulthood. Several young queens are produced, and often fight to death after emergence. Surviving queen(s) inherit the established nest or a portion of workers which then depart in an "afterswarm". Honey bee queens show traits considered to be adaptations for fighting and conflict with other queens, such as early venom production and fast development. During fights one of the queens often releases rectal fluid. The function of this "spraying" behaviour is unclear. Possible functions of spraying are to affect worker intervention in fights, to act as a chemical weapon, or to interrupt fights. We staged fights between 24 queen pairs to investigate the temporal pattern of behaviour in spraying and non-spraying fights. Spraying occurred in 67% of the fights, usually upon physical contact, and it resulted in at least temporary separation of the queens in 81% of the spraying fights. Spraying fights were characterized by a significantly lower proportion of time spent in escalated aggression than non-spraying fights and a significantly shorter first escalated bout. This provides quantitative evidence that spraying interrupts fights and suggests that its function is to provide a temporary respite to the spraying queen. [ABSTRACT FROM AUTHOR]

The net reproductive rate of unmanaged honeybee colonies has never been fully determined for honey bees in temperate climates. In this study, five overwintered colonies in Kansas, USA, were allowed to swarm naturally (Winston. 1980). These colonies and their swarms were studied over the winter (i.e. one generation). The net reproductive rate R was estimated to be 2.18. Afterswarms were found to contribute substantially (41.2%) to this net reproductive rate. The autumn and spring food reserves and brood areas of established colonies and colonies established from prime swarms and afterswarms are compared. Winter survival of afterswarms was related to autumn honey stores, and the brood areas of surviving afterswarms were smaller than those of prime swarms or established colonies. [ABSTRACT FROM AUTHOR]