Harrington Wells

Spontaneous flower constancy and learning in honey bees as a function of colour

When presented with an artificial flower patch of blue and yellow pedicellate flowers, individual honey bees, Apis mellifera L., became constant to one of the two flower colours, rarely even sampling the alternative colour. Some bees visited only blue flowers while others visited only yellow flowers. This paper describes the onset of constancy for bees that had had no experience with the experimental apparatus. In 3020 visits, bees failed to land on or drink from the flower colour on which they first landed only 17 times. This behaviour was not modified by quality or quantity of reward, training to the experimental site, group effects or presence of odour during trials. However, when we trained bees to a target painted with two colours and then forced them to sample monomorphic flower patches in sequence, all bees visited the only colour present: yellow or blue. When we subsequently offered these same bees yellow and blue flowers simultaneously (rewarded choices), they became constant. Eleven of 23 bees showed constancy to the less rewarding flower morph without even sampling the alternative. Those bees failed to sample even though they had previously been forced to visit the alternative flower morph, which offered a reward with twice the calories/volume. Constancy is thus spontaneous in honey bees, but it can be hidden by some experimental protocols designed to study learning.1997The Association for the Study of Animal Behaviour

Mate location, population growth and species extinction

The effects of mate location efficiency on the dynamics of population growth and extinction were modeled with a view towards future species conservation efforts. Mate location is shown to be based on the Allee principle. Higher population densities produce greater mate location success rates. Low population densities generate population growth rates that are smaller than mortality rates, and, thus, produce a condition leading to species extinction. A survey of animal phyla suggests that selection for behaviors, morphology and physiology, which either temporarily increase mating season population densities or effectively increase population densities by increasing the distance from which a mate can be recognized, has shaped the evolution of species. A mechanism is provided for understanding this process of extinction, and a framework is presented for constructing a management plan for species at risk.

HONEY BEE FORAGING ECOLOGY: OPTIMAL DIET, MINIMAL UNCERTAINTY OR INDIVIDUAL CONSTANCY?

SUMMARY (1) Experiments using honey bees and artificial flower patches were designed to test three alternative foraging ecology models: optimal diet, minimal uncertainty, and individual constancy. Honey bee responses to a mixed colour flower patch and to flower morph associated differences in reward quantity, quality, and frequency were measured. (2) Each honey bee visiting a patch of randomly distributed blue and yellow flowers was constant to one colour, even though that behaviour was suboptimal. (3) When reward quantity was unequal between the two flower morphs each bee was constant to one colour, even though that behaviour often resulted in suboptimal reward. (4) When reward quality was unequal between the two colour morphs each bee was constant to one colour, even though that behaviour often resulted in suboptimal reward. (5) When reward frequency was higher in one flower morph than in the other each bee was constant to one colour, even though that behaviour often failed to maximize reward or minimize uncertainty.

Foraging decisions in nectarivores: unexpected interactions between flower constancy and energetic rewards

Foraging decisions are based on a suite of choices that include energetics and physiological constraints. Although travelling farther to harvest a greater net energetic reward is beneficial, many animals opt for a smaller net reward that requires less travel. Recent discoveries of a visual basis for flower constancy in the honeybee, Apis mellifera, led us to examine older reports that colour cues are superceded by energetic considerations. Here we show that when individual bees foraged on pedicellate artificial flowers varying in colour and interfloral distance, their behaviour depended on the colours in the choice test. Colours of similar spectral reflectance (blue versus white), that would be clustered in the bees visual colour space, elicited more visits to the closest flower when rewards were equal, but individuals travelled a greater distance to harvest a higher energetic reward when reward quality varied. Bees chose the closest flower more often when reward volume decreased while quality remained constant. Yet, even when all flowers were identical (morphology and reward), and only interfloral distance varied, bees did not always visit the closest flower. A dramatic difference was seen when the dimorphism was yellow-blue, colours quite separate in the bee colour space and known to elicit constancy behaviour. Here, bees visited the closest flower only 5% of the time, and varying reward volume did not elicit different behaviour. Animals thus display differential foraging behaviour with respect to environmental cues that must be considered when asking questions about other behavioural parameters.

Nectarivore foraging ecology: rewards differing in sugar types

Abstract. 1 Honey bees, visiting artificial flower patches, were used as a model system to study the effects of sugar type (sucrose, glucose, fructose, and mixed monosaccharide), caloric reward, and floral colour on nectarivore foraging behaviour. Observed behaviour was compared to the predictions of various (sometimes contradictory) foraging models. 2 Bees drank indiscriminately from flowers in patches with a blue‐white flower dimorphism when caloric values of rewards were equal (e.g. 1M sucrose in both colours; 1 M sucrose versus 2 M monosaccharide of either type), but when nectar caloric rewards were unequal, they switched to the flower colour with the calorically greater reward. 3 In yellow‐blue dimorphic flower patches, on the other hand, bees did not maximize caloric reward. Rather, bees were individually constant, some to blue, others to yellow, regardless of the sugar types or energy content of the rewards provided in the two flower morphs. 4 The results suggest that optimal foraging theory (maximization of net caloric gain per unit time) is a robust predictor of behaviour with regard to the sugar types common to nectars; such optimal foraging is, however, limited by a superstructure of individual constancy.

Ethological Isolation of Plants 2. Odour Selection By Honeybees

SummaryThe behaviour of honeybees (Apis mellifera) foraging in a patch of artificial flowers was studied experimentally with colour and odour as manipulated variables. Honeybees associated food with colour and/or odour and established individually constant foraging patterns. In a patch of colour-dimorphic flowers some bees were constant to yellow and some to blue flowers when all flowers provided clove-scented rewards. The colour-constancy of individual bees was not altered when the scent of all rewards was changed to peppermint. However, when the scent of only one colour morph was changed, some bees remained constant to colour, whereas others switched colour attachment and remained constant to odour. In a patch of uniformly coloured but odour-dimorphic flowers some bees were constant to peppermint-scented and some were constant to cinnamon-scented flowers. A change in the colour of all flowers did not reduce the level of odour-constant foraging. Individual constancy to either colour or to odour can be su...

Honeybee Responses to Reward Size and Colour in an Artificial Flower Patch

SummaryWe describe an artificial flower patch suitable for quantitative ecological studies of plant-pollinator interactions. The number of flowers visited per trip by honeybees foraging on the patch was negatively dependent on mean nectar yield per flower in a logarithmic relationship. The relationship held whether all flowers provided reward or some were empty. Individual foragers on a mixed-colour patch of flowers were constant to one colour.

Aversive conditioning in honey bees (Apis mellifera anatolica): a comparison of drones and workers

SUMMARY Honey bees provide a model system to elucidate the relationship between sociality and complex behaviors within the same species, as females (workers) are highly social and males (drones) are more solitary. We report on aversive learning studies in drone and worker honey bees (Apis mellifera anatolica) in escape, punishment and discriminative punishment situations. In all three experiments, a newly developed electric shock avoidance assay was used. The comparisons of expected and observed responses were performed with conventional statistical methods and a systematic randomization modeling approach called object oriented modeling. The escape experiment consisted of two measurements recorded in a master–yoked paradigm: frequency of response and latency to respond following administration of shock. Master individuals could terminate an unavoidable shock triggered by a decrementing 30 s timer by crossing the shuttlebox centerline following shock activation. Across all groups, there was large individual response variation. When assessing group response frequency and latency, master subjects performed better than yoked subjects for both workers and drones. In the punishment experiment, individuals were shocked upon entering the shock portion of a bilaterally wired shuttlebox. The shock portion was spatially static and unsignalled. Only workers effectively avoided the shock. The discriminative punishment experiment repeated the punishment experiment but included a counterbalanced blue and yellow background signal and the side of shock was manipulated. Drones correctly responded less than workers when shock was paired with blue. However, when shock was paired with yellow there was no observable difference between drones and workers.

Isolation, Virulence, and Antimicrobial Resistance of Methicillin-Resistant Staphylococcus aureus (MRSA) and Methicillin Sensitive Staphylococcus aureus (MSSA) Strains from Oklahoma Retail Poultry Meats.

Staphylococcus aureus is one the top five pathogens causing domestically acquired foodborne illness in the U.S. Only a few studies are available related to the prevalence of S. aureus and MRSA in the U.S. retail poultry industry. The objectives of this study were to determine the prevalence of S. aureus (MSSA and MRSA) in retail chicken and turkey meats sold in Tulsa, Oklahoma and to characterize the recovered strains for their antimicrobial resistance and possession of toxin genes. A total of 167 (114 chicken and 53 turkey) retail poultry samples were used in this study. The chicken samples included 61 organic samples while the rest of the poultry samples were conventional. The overall prevalence of S. aureus was 57/106 (53.8%) in the conventional poultry samples and 25/61 (41%) in the organic ones. Prevalence in the turkey samples (64.2%) was higher than in the chicken ones (42.1%). Prevalence of S. aureus did not vary much between conventional (43.4%) and organic chicken samples (41%). Two chicken samples 2/114 (1.8%) were positive for MRSA. PFGE identified the two MRSA isolates as belonging to PFGE type USA300 (from conventional chicken) and USA 500 (from organic chicken) which are community acquired CA-MRSA suggesting a human based source of contamination. MLST and spa typing also supported this conclusion. A total of 168 Staphylococcus aureus isolates (101 chicken isolates and 67 turkey isolates) were screened for their antimicrobial susceptibility against 16 antimicrobials and their possession of 18 different toxin genes. Multidrug resistance was higher in the turkey isolates compared to the chicken ones and the percentage of resistance to most of the antimicrobials tested was also higher among the turkey isolates. The hemolysin hla and hld genes, enterotoxins seg and sei, and leucocidins lukE-lukD were more prevalent in the chicken isolates. The PVL gene lukS-lukF was detected only in chicken isolates including the MRSA ones. In conclusion, S. aureus is highly prevalent in poultry retail meats sold in Oklahoma with a very low presence of human-originated MRSA. Multidrug resistance is not only prevalent in the MRSA isolates, but also in many MSSA poultry strains, particularly turkey.

Varroa (Varroa destructor) and tracheal mite (Acarapis woodi) incidence in the Republic of Turkey

SUMMARY This is the first extensive study of the incidence of varroa (Varroa destructor) and tracheal mites (Acarapis woodi) in Turkish honey bees (Apis mellifera). Samples were taken from 204 colonies in 39 apiaries spread over five regions of Turkey. Fifty bees from each colony were dissected in the laboratory and examined under stereo and compound microscopes using four different techniques to detect the presence of A. woodi. Presence of varroa was determined from samples of approximately 200 workers from each of the sampled colonies. Neither A. woodi nor other Acarapis spp. were found in any of the 10 200 bees examined. Conversely, varroa was found in 84 of the 204 colonies sampled. Varroa incidence per apiary was approximately Poisson distributed with a mean of 2.17 infested colonies per five sampled. The data suggest that for unknown reasons tracheal mites appear to be very rare in Turkey, but not varroa, which has endemic rather than epidemic disease distribution properties.