Effect of "spraying" by fighting honey bee queens (Apis mellifera L.) on the temporal structure of fights

To reproduce, social insect colonies rear sexual progeny, and 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 are predicted to occur. Honey bee colonies reproduce dependently by swarming. The mother queen leaves with a Óprime swarmÓ before daughter queens reach adulthood. More queens are produced than can obtain sufficient worker force, and emerging queens often fight to death. Surviving queen(s) inherit the established nest or a portion of workers which then depart in an ÓafterswarmÓ. Honey bee queens show numerous adaptations for fighting and conflict with other queens, such as early venom production and fast development. During fights one queen often releases rectal fluid. The function of this ÓsprayingÓ behaviour is unclear. Previous studies have reported that it can both attract and repel workers, and observations that it also interrupts fights. Possible functions of spraying are to affect worker intervention in fights, act as a chemical weapon, or lower worker attention towards contaminated queens. 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. In the majority of spraying fights (87%) it occurred upon physical contact. Spraying fights were characterized by significantly lower proportion of escalated aggression and a significantly shorter first escalated bout. This provides quantitative evidence that spraying interrupts fights and suggests that its function is to directly provide a temporary respite to queens

Characterization of queen specific components of the fluid released by fighting honey bee queens

Swarming honey bee (Apis mellifera L.) colonies rear supernumerary young queens that compete for the limited resources (workers) necessary for founding a new colony. Young queens often fight to death. Queens show several adaptations to fight and conflict, such as short developmental time and early onset of venom production. During fights, queens often release rectal fluid with a strong smell of wine grapes, after which they temporarily stop fighting. This potentially reduces individual overall risk of deadly injury. The fluid and one of its components, ortho-aminoacetophenone, were previously found to have a pheromonal effect on workers, but the evidence is equivocal. Recently, it has been suggested that the effects of this substance may be context- or concentration-specific. We performed semi-quantitative gas-chromatography mass spectrometry (GC/MS) analysis of the fluid (1) released by queens during their first fight, (2) released during a subsequent fight, and (3) obtained by dissecting the hindgut of queens and (4) of workers. Following preliminary results by Page et al. 1988 (Experientia 44: 270-271), we scored presence / absence of eight substances. Five substances (ortho-aminoacetophenone, decanoic acid, dodecanoic acid, octyl decanoate, and decyl decanoate) were characteristic of queens only. ortho-Aminoacetophenone was detected in all queen and in none of the worker samples, in agreement with previous findings that worker faeces do not have any pheromonal effect. The fluid released by queens on their second fight also contained ortho-aminoacetophenone, but in smaller quantities. These data substantiate previous bioassay results, and provide estimates of ortho-aminoacetophenone concentration as required to design experiments addressing the function and adaptive significance of this behaviour

Correlated expression of phenotypic and extended phenotypic traits across stingless bee species: worker eye morphology, foraging behaviour, and nest entrance architecture.

Abstract: Stingless bees are the most species-rich group of eusocial bees and show great diversity in behaviour, ecology, nest architecture, colony size, and worker morphology. How this variation relates to varying selection pressures and constraints is not well understood. Variation can be caused by selection acting on behavioural or morphological traits, both alone and in correlation across traits. Here we tested whether behavioural and morphological traits important for foraging and defence are linked to nest-entrance architecture, an extended phenotype relevant to both foraging and nest defence. Using 23 species we investigated whether eye size, nest entrance size, landing behaviour and foraging method show cross-species correlations. A phylogenetically-controlled comparative analysis revealed that species with relatively smaller eyes build relatively larger entrances, which in turn are associated with faster landing approaches and fewer landing errors by foragers, both of which could reduce predation risk. Concerning foraging, mass-recruiting species have c. 10-times larger entrance holes than species with a solitary foraging strategy. Larger entrances could help species with mass recruitment to rapidly increase forager traffic or mount a strong defensive response when under attack. Our results show that studying correlations among different traits helps understand phenotypic diversity in species rich groups

Effects of group composition and level of selection in the evolution of cooperation in artificial ants

Since ants and other social insects have long generation time, it is very difficult for biologists to study the origin of complex social organization by guided evolution (a process where the evolution of a trait can be followed during experimental evolution). Here we use colonies of artificial ants implemented as small mobile robots with simple vision and communication abilities to explore these issues. In this paper, we present results concerning the role of relatedness (genetic similarity) and levels of selection (individual and colony-level selection) on the evolution of cooperation and division of labor in simulated ant colonies. In order to ensure thorough statistical analysis, the evolutionary experiments, herein reported, have been carried out using "minimalist" simulations of the collective robotics evolutionary setup. The results show that altruistic behaviors have low probability of emerging in heterogeneous colonies evolving under individual-level selection and that colonies with high genetic relatedness display better performance

Anarchy in the UK: Detailed genetic analysis of worker reproduction in a naturally occurring British anarchistic honeybee, Apis mellifera, colony using DNA microsatellites

Anarchistic behaviour is a very rare phenotype of honeybee colonies. In an anarchistic colony, many workers’ sons are reared in the presence of the queen. Anarchy has previously been described in only two Australian colonies. Here we report on a first detailed genetic analysis of a British anarchistic colony. Male pupae were present in great abundance above the queen excluder, which was clearly indicative of extensive worker reproduction and is the hallmark of anarchy. Seventeen microsatellite loci were used to analyse these male pupae, allowing us to address whether all the males were indeed workers’ sons, and how many worker patrilines and individual workers produced them. In the sample, 95 of 96 of the males were definitely workers’ sons. Given that ≈ 1% of workers’ sons were genetically indistinguishable from queen’s sons, this suggests that workers do not move any queen-laid eggs between the part of the colony where the queen is present to the area above the queen excluder which the queen cannot enter. The colony had 16 patrilines, with an effective number of patrilines of 9.85. The 75 males that could be assigned with certainty to a patriline came from 7 patrilines, with an effective number of 4.21. They were the offspring of at least 19 workers. This is in contrast to the two previously studied Australian naturally occurring anarchist colonies, in which most of the workers’ sons were offspring of one patriline. The high number of patrilines producing males leads to a low mean relatedness between laying workers and males of the colony. We discuss the importance of studying such colonies in the understanding of worker policing and its evolution

Garden varieties: how attractive are recommended garden plants to butterflies?

One way the public can engage in insect conservation is through wildlife gardening, including the growing of insect-friendly flowers as sources of nectar. However, plant varieties differ in the types of insects they attract. To determine which garden plants attracted which butterflies, we counted butterflies nectaring on 11 varieties of summer-flowering garden plants in a rural garden in East Sussex, UK. These plants were all from a list of 100 varieties considered attractive to British butterflies, and included the five varieties specifically listed by the UK charity Butterfly Conservation as best for summer nectar. A total of 2659 flower visits from 14 butterfly and one moth species were observed. We performed a principal components analysis which showed contrasting patterns between the species attracted to Origanum vulgare and Buddleia davidii. The “butterfly bush” Buddleia attracted many nymphalines, such as the peacock, Inachis io, but very few satyrines such as the gatekeeper, Pyronia tithonus, which mostly visited Origanum. Eupatorium cannibinum had the highest Simpson’s Diversity score of 0.75, while Buddleia and Origanum were lower, scoring 0.66 and 0.50 respectively. No one plant was good at attracting all observed butterfly species, as each attracted only a subset of the butterfly community. We conclude that to create a butterfly-friendly garden, a variety of plant species are required as nectar sources for butterflies. Furthermore, garden plant recommendations can probably benefit from being more precise as to the species of butterfly they attract

Lack of Evidence for an Association between Iridovirus and Colony Collapse Disorder

Colony collapse disorder (CCD) is characterized by the unexplained losses of large numbers of adult worker bees (Apis mellifera) from apparently healthy colonies. Although infections, toxins, and other stressors have been associated with the onset of CCD, the pathogenesis of this disorder remains obscure. Recently, a proteomics study implicated a double-stranded DNA virus, invertebrate iridescent virus (Family Iridoviridae) along with a microsporidium (Nosema sp.) as the cause of CCD. We tested the validity of this relationship using two independent methods: (i) we surveyed healthy and CCD colonies from the United States and Israel for the presence of members of the Iridovirus genus and (ii) we reanalyzed metagenomics data previously generated from RNA pools of CCD colonies for the presence of Iridovirus-like sequences. Neither analysis revealed any evidence to suggest the presence of an Iridovirus in healthy or CCD colonies

Honey bee foraging distance depends on month and forage type

To investigate the distances at which honey bee foragers collect nectar and pollen, we analysed 5,484 decoded waggle dances made to natural forage sites to determine monthly foraging distance for each forage type. Firstly, we found significantly fewer overall dances made for pollen (16.8 %) than for non-pollen, presumably nectar (83.2 %; P < 2.2 × 10−23). When we analysed distance against month and forage type, there was a significant interaction between the two factors, which demonstrates that in some months, one forage type is collected at farther distances, but this would reverse in other months. Overall, these data suggest that distance, as a proxy for forage availability, is not significantly and consistently driven by need for one type of forage over the other