Michel B. C. Sokolowski

An Assessment of Fixed Interval Timing in Free-Flying Honey Bees (Apis mellifera ligustica): An Analysis of Individual Performance

Interval timing is a key element of foraging theory, models of predator avoidance, and competitive interactions. Although interval timing is well documented in vertebrate species, it is virtually unstudied in invertebrates. In the present experiment, we used free-flying honey bees (Apis mellifera ligustica) as a model for timing behaviors. Subjects were trained to enter a hole in an automated artificial flower to receive a nectar reinforcer (i.e. reward). Responses were continuously reinforced prior to exposure to either a fixed interval (FI) 15-sec, FI 30-sec, FI 60-sec, or FI 120-sec reinforcement schedule. We measured response rate and post-reinforcement pause within each fixed interval trial between reinforcers. Honey bees responded at higher frequencies earlier in the fixed interval suggesting subject responding did not come under traditional forms of temporal control. Response rates were lower during FI conditions compared to performance on continuous reinforcement schedules, and responding was more resistant to extinction when previously reinforced on FI schedules. However, no “scalloped” or “break-and-run” patterns of group or individual responses reinforced on FI schedules were observed; no traditional evidence of temporal control was found. Finally, longer FI schedules eventually caused all subjects to cease returning to the operant chamber indicating subjects did not tolerate the longer FI schedules.

A PARADIGM FOR OPERANT CONDITIONING IN BLOW FLIES (PHORMIA TERRAE NOVAE ROBINEAU-DESVOIDY, 1830)

An operant conditioning situation for the blow fly (Protophormia terrae novae) is described. Individual flies are trained to enter and reenter a hole as the operant response. Only a few sessions of contingent reinforcement are required to increase response rates. When the response is no longer followed by food, the rate of entering the hole decreases. Control procedures revealed that rate of responding is not a simple overall result of feeding or of aging. The flies entered into the hole only if the response was required to obtain the food.

Social Reinforcement Delays in Free-Flying Honey Bees (Apis mellifera L.)

Free-flying honey bees (Apis mellifera L.) reactions were observed when presented with varying schedules of post-reinforcement delays of 0 s, 300 s, or 600 s. We measured inter-visit-interval, response length, inter-response-time, and response rate. Honey bees exposed to these post-reinforcement delay intervals exhibit one of several patterns compared to groups not encountering delays, and had longer inter-visit-intervals. We observed no group differences in inter-response time. Honey bees with higher response rates tended to not finish the experiment. The removal of the delay intervals increased response rates for those subjects that completed the trials.

The effect of pymetrozine (Plenum WG-50®) on proboscis extension conditioning in honey bees (Apis mellifera: Hybrid var. Buckfast)

Experiments are designed to examine the effects of pymetrozine (Plenum WG-50), a recent systemic pesticide of the pyridine-azomethin family, on Pavlovian conditioning of harnessed foragers. In one set of experiments bees learned a task in which they associated a conditioned stimulus with feeding. A second set of experiments required the bees to learn a discrimination task. Within each experiment, bees received 5 μl of sucrose only, the recommended field dose of Plenum (5 μL of .3 gL(-1), .16 gL(-1) of pymetrozine measured), or 100 times the field dose of Plenum WG 50 thirty minutes prior to training (5 μL of 30 gL(-1), 14 gL(-1) of pymetrozine measured). The Plenum WG 50 was diluted with .88 M sucrose to facilitate the drinking of the pesticide. In addition to varying the concentration, we also investigated the effect of Plenum WG 50 on bees confined to an observation hive and a hive located outside. The results indicated that prior exposure to Plenum WG 50 affected Pavlovian conditioning only when bees were exposed to 100 times the recommended dosage.

Ethanol Self‐Administration in Free‐Flying Honeybees (Apis mellifera L.) in an Operant Conditioning Protocol

BACKGROUND This study examines the effect of ethanol (EtOH) on continuous reinforcement schedules in the free-flying honeybee (Apis mellifera L.). As fermented nectars may be encountered naturally in the environment, we designed an experiment combining the tools of laboratory research with minimal disturbance to the natural life of honeybees. METHODS Twenty-five honeybees were trained to fly from their colonies to a fully automated operant chamber with head poking as the operant response. Load size, intervisit interval, and interresponse times (IRTs) served as the dependent variables and were monitored over the course of a daily training session consisting of many visits. Experimental bees were tested using an ABA design in which sucrose only was administered during condition A and a 5% EtOH sucrose solution was administered during condition B. Control bees received sucrose solution only. RESULTS Most bees continued to forage after EtOH introduction. EtOH significantly reduced the load size and the intervisit interval with no significant effect on IRTs. However, a look on individual data shows large individual differences suggesting the existence of different kinds of behavioral phenotypes linked to EtOH consumption and effects. CONCLUSIONS Our results contribute to the study of EtOH consumption as a normal phenomenon in an ecological context and open the door to schedule-controlled drug self-administration studies in honeybees.

Children's competition in a natural setting: evidence for the ideal free distribution

Little is known of the foraging abilities of children in modern cultures, especially when children forage in groups. Here we present a test of optimal foraging theory in groups of street children working for money. The children we observed were selling bottles of water to drivers distributed in two lanes at a crossroad of Istanbul, Turkey. As predicted by the ideal free distribution (a model of optimal group foraging), the ratio of children working in the two lanes was sensitive to the ratio of cars (and therefore the ratio of potential buyers) present in each lane. Deviations from the ideal free model arose largely from numerical restrictions on the set of possible ratios compatible with a small group size. When these constraints were taken into account, optimal behavior emerged as a robust aspect of the childrens group distribution. Our results extend to human children aspects of group foraging that were previously tested in human adults or other animal species.

Pitfalls of Behavioral Selectionism

Numerous analogies have been offered to relate evolutionary and behavioral phenomena. B. F. Skinner (1981/1988), in particular, has suggested that similar processes of selection operate at the levels of evolution, behavior, and culture. This essay examines Skinner’s proposed analogy between natural selection and operant reinforcement. We argue that the analogy fails to characterize a shared causal structure. Operant reinforcement mimics superficial aspects of natural selection through entirely different mechanisms; hence no detailed understanding of operant behavior can be expected from selectionist notions. Selection analogies with respect to reinforced behavior are generally useless and probably misleading. The failure of Skinner’s selection metaphor reflects on the current relations of some parts of psychology to evolutionary theory.

A portable system for studying discrete-trial group choice

Whether groups of people or animals behave optimally in relation to resources is an issue of interest to psychology, ecology, and economics. In behavioral ecology, the simplest model of optimal group choice is the ideal free distribution (IFD). The IFD model has been tested in humans with discrete or continuous inputs and through manual or automated procedures (e.g., Kraft, Baum, & Burge, 2002; Madden, Peden, & Yamagushi, 2002). Manual procedures tend to be time consuming, however, whereas automated procedures typically require access to a computer network. In this article, we describe a new automated system for discrete-trial tests of the IFD model. Our protocol involves a single computer connected to a digital projector (for stimulus presentation) and a network of gamepads (for registering choices). The system is comparatively inexpensive, easy to install, easy to transport, and it permits the automated collection of group data in minimal time. We show that the data generated through this protocol are comparable to those previously reported in the IFD literature.

Effect of oral exposure to the acaricide pirimicarb, a new varroacide candidate, on Apis mellifera feeding rate: Effect of pirimicarb on Apis mellifera feeding rate

BACKGROUND The ectoparasitic honey bee mite Varroa destructor is a main cause of the gradual decline in honey bees Apis mellifera. Beekeepers currently utilize a wide range of different synthetic acaricides, organic acids and essential oils to keep mite populations under control. Previous work has indicated that pirimicarb may be a new varroacide candidate. The aim of this study was to observe chronic effects on feeding activity in worker honey bees after oral exposure to 1.05 mm pirimicarb. The long-term effects of 24 h exposure to pirimicarb were also tested. RESULTS After three successive trials, no mortality could be detected at the tested concentration, although oral exposure to pirimicarb had a significant effect on honey bees feeding behavior. Pirimicarb added to a sucrose solution led to a rapid decrease in food intake. These tendencies may be reversed when the pesticide is removed. However, recovery seemed to be trial dependent. CONCLUSION This study highlights seasonal variation in honey bee susceptibility, which should be considered in toxicology studies.