Honey bee (Apis mellifera ligustica) acetylcholinesterase enzyme activity and aversive conditioning following aluminum trichloride exposure.

BACKGROUND: Aluminum is the third most prevalent element in the earth's crust. In most conditions, it is tightly bound to form inaccessible compounds, however in low soil pH, the ionized form of aluminum can be taken up by plant roots and distributed throughout the plant tissue. Following this uptake, nectar and pollen concentrations in low soil pH regions can reach nearly 300 mg/kg. Inhibition of acetylcholinesterase (AChE) has been demonstrated following aluminum exposure in mammal and aquatic invertebrate species. In honey bees, behaviors consistent with AChE inhibition have been previously recorded; however, the physiological mechanism has not been tested, nor has aversive conditioning. RESULTS: This article presents results of ingested aqueous aluminum chloride exposure on AChE as well as acute exposure effects on aversive conditioning in an Apis mellifera ligustica hive. Contrary to previous findings, AChE activity significantly increased as compared to controls following exposure to 300 mg/L Al3+. In aversive conditioning studies, using an automated shuttlebox, there were time and dose-dependent effects on learning and reduced movement following 75 and 300 mg/L exposures. CONCLUSIONS: These findings, in comparison to previous studies, suggest that aluminum toxicity in honey bees may depend on exposure period, subspecies, and study metrics. Further studies are encouraged at the moderate-high exposure concentrations as there may be multiple variables that affect toxicity which should be teased apart further.

Learning and orientation to odor in the bug Rhodnius prolixus Stal 1859 under laboratory conditions.

Two experiments are described investigating learning and orientation in the triatomine Rhodnius prolixus. In experiment 1, Pavlovian conditioning was investigated. The experiment differed from our previous work in that the intensity of the conditioned and unconditioned stimuli were reduced and the number of training trials increased. Once again, no evidence for Pavlovian conditioning was found. In experiment 2, an "orientation arena" was developed in which the orientation of R. prolixus to a human forearm was investigated when an area of the forearm was impregnated with the odor of ruda or almizcle compared to a forearm with no odor. The various paths of the animal from the bottom of the arena until ascending and piercing the forearm, located at the top of the arena, was scored using a grid system and videotaped. The results indicated that under the no odor condition R. prolixus predominately travels in a straight line from the bottom of the arena to the top where the forearm is located. In contrast, the most variable number of paths occurred with exposure to ruda. Exposure to almizcle elicited straight line paths but other paths were evident, although not as variable as that observed with ruda.

A build-it-yourself inexpensive lock-out device.

This paper describes a low-cost easily constructed and readily portable "lock-out system" suitable for college bowl and related quiz games. Suggestions on how to use the device are presented.

The development of an ethanol model using social insects I: behavior studies of the honey bee (Apis mellifera L.).

BACKGROUND: The purpose of this experiment was to test the feasibility of creating an animal model of ethanol consumption using social insects. Honey bees were selected as the model social insect because much is known about their natural history, physiology, genetics, and behavior. They are also inexpensive to procure and maintain. Of special interest is their use of communication and social organization. METHODS: Using both between- and within-experiment designs, studies were conducted with harnessed foragers to determine whether honey bees would consume ethanol mixed with sucrose (and, in some cases, water). Shuttle-box and running-wheel studies were conducted to examine the effect of ethanol on locomotion. The effect of ethanol on stinging behavior in harnessed foragers was investigated. The effect of ethanol on Pavlovian conditioning of proboscis extension was also investigated. Finally, in a self-administration study, foraging honey bees were trained to fly to an artificial flower containing ethanol. RESULTS: (1) Harnessed honey bees readily consume 1%, 5%, 10%, and 20% ethanol solutions; (2) 95% ethanol will also be consumed as long as the antennae do not make contact with the solution; (3) with the exception of 95% ethanol, consumption as measured by contact time or amount consumed does not differ in animals that consume 1%, 5%, 10%, and 20% ethanol solutions; (4) exposure to a lesser (or greater) concentration of ethanol does not influence consumption of a greater (or lesser) concentration; (5) consumption of 10% and 20% ethanol solutions decreases locomotion when tested in both a shuttle-box and running-wheel situation; (6) consumption of 1%, 5%, 10%, and 20% ethanol does not influence stinging behavior in harnessed foragers; (7) ethanol solutions greater than 5% significantly impair Pavlovian conditioning of proboscis extension; and (8) free-flying honey bee foragers will readily drink from an artificial flower containing 5% ethanol. CONCLUSIONS: The experiments on consumption, locomotion, and learning suggest that exposure to ethanol influences behavior of honey bees similar to that observed in experiments with analogous vertebrates. The honey bee model presents unique research opportunities regarding the influence of ethanol in the areas of language, social interaction, development, and learning. Although the behavioral results are interesting, similarity between the physiologic effects of ethanol on honey bees and vertebrates has not yet been determined.

The effect of insecticides on learning in the Africanized honey bee (Apis mellifera L.).

The present study was designed to examine the effects of endosulfan, decis, baytroid, and sevin on the learning ability of Africanized honey bees (Apis mellifera L.). Although these insecticides were recommended by the government of Brazil to control the cotton boll weevil, the effects on bees have been unknown. Results of the present research show that: (1) bees readily consume each of the pesticides when placed in a sucrose solution; (2) the odors of the pesticides are not repellent to bees, and such odors can serve as conditioned stimuli; (3) learning occurs to various degrees when the insecticides are combined with the sucrose solution and used as an unconditioned stimulus; and (4) feeding the insecticides to the bees 1 h prior to conditioning leads to differing mortality. Because of the importance of bees for honey production, as well as pollination of cotton and other crops, recommendations are made for the use of decis and other measures for boll weevil control.http://link. springer-ny.com/link/service/journals/00244/bibs/37n4p529.++ +html

Some preliminary studies on the ability of Africanized honey bees (Apis mellifera L.) to tolerate cold temperatures when placed inside a refrigerator.

Cold is often suggested as an ecological mechanism to prevent the migration of Africanized honey bees. The ability of Africanized honey bees to tolerate cold temperatures was investigated. In one study an observation hive was placed inside a refrigerator at 25 degrees C. The study was conceptualized as a choice experiment in which the colony could remain in a cold environment or leave for a warm environment. Analysis indicated that the bees remained at 9 +/- 1 degrees C for 14 days before leaving. In a second series of studies, testing the tolerance to 0 degree C, 280 bees were placed individually in small metal tubes. The data gathered included survival rate, time to regain consciousness, and ability to feed. Analysis indicated that Africanized bees can survive for up to 3 hr. at 0 degree C with few ill effects. At 4 hr., however, the survival rate is low. Limitations of the study, the use of cold as a possible deterrent to honey bee mites, and suggestions for additional research are discussed.

Learning in the Africanized honey bee: Apis mellifera L.

Several series of experiments are reported that investigate learning in the Africanized honey bee. In the first series, classical conditioning of proboscis extension was studied by confining bees to small metal tubes where they received pairings of an odor with a 3-s feeding of sucrose. After a number of odor-sucrose pairings, the bees began to extend their proboscis to the odor. Controls include Unpaired, Discrimination, and Pseudoconditioning Groups. This technique was used to look at conditioning to a light CS, and to the odors of beeswax, geraniol, citral, and hexanal. The results indicate that acquisition was best when sucrose was paired with the odor of beeswax. Conditioning to the remaining odors was roughly similar, but acquisition did not occur using a light. In a second series of experiments, odors were no longer followed by sucrose feedings and the conditioned response slowly disappeared. With the exception of geraniol as a CS, this extinction effect did not occur if the animals continued to be fed on an unpaired schedule. In a third series of experiments, conditioned inhibition was demonstrated when geraniol was used as conditioned stimuli, but no effect was found when the odors of hexanal, citral and wax were used. In a fourth series of experiments, unrestrained bees flew back and forth from the laboratory to the hive, where they were taught to distinguish targets based on color and odor. With this technique, color and odor discrimination in the Africanized bees was demonstrated. In addition, it was found that more intruder bees visited the experimental station when the stimuli used were olfactory rather than visual.

A demonstration of virtual reality in free-flying honeybees: Apis mellifera.

Two experiments are reported on virtual reality illusion in free-flying honeybees. In the first experiment, subjects are trained on a simultaneous discrimination between two colored targets, one of which contains a sucrose reward. The ability to be influenced by a virtual reality illusion was assessed during an extinction test in which the training stimuli were a mirage of those used during acquisition. The results indicate that the bees consistently attempt to land on the previously rewarded color despite the fact that it is not there. In a second experiment, bees were unable to discriminate between two simultaneously presented, identically colored targets--one of which was real, the other a mirage.

Conditional withholding of proboscis extension in honeybees (Apis mellifera) during discriminative punishment.

Proboscis extension conditioning of honeybee workers was used to test the ability of bees to respond to appetitive and aversive stimuli while restrained in a harness that allows subjects to move their antennae and mouthparts (Kuwabara, 1957; Menzel, Erber, & Masuhr, 1974). Subjects were conditioned to discriminate between two odors, one associated with sucrose feeding and the other associated with a 10 V AC shock if they responded to the sucrose unconditioned stimulus (US) in the context of that odor. Most Ss readily learned to respond to the odor followed by sucrose feeding and not to the odor associated with sucrose stimulation plus shock. Furthermore, in the context of the odor associated with shock, significantly more subjects withheld or delayed proboscis extension on stimulation with the sucrose US than they did in the context of the odor associated with feeding. Thus, restrained honeybees can readily learn to avoid shock according to an odor context by withholding proboscis extension to a normally powerful releaser. Analysis of individual learning curves revealed that subjects differed markedly in performance on this task. Some learn the discrimination quickly, whereas others show different kinds of response patterns.

Lever-press conditioning in the crab.

An operant chamber has been developed for studying lever-press conditioning in the green crab Carcinus maenas. In one series of experiments, animals were presented with a single bar and were reinforced with food for every bar press. Performance increased over time and high rates of responding were observed after 2 days of training. The response rate was always higher than that for a yoked (noncontingent) control group. When the contingencies were switched, the animals adjusted to the new conditions. Discrimination in the lever-press apparatus was demonstrated in a second experiment in which crabs had to choose between two bars, one (S+) caused food to be dispensed while the other (S-) was inactive. Experimental animals pressed the S+ bar at a significantly higher rate than the S- bar. When the contingencies associated with the lever were reversed, animals learned to switch to the correct bar by the second day. It was not necessary to reinforce every response: animals maintained high rates of responding on a schedule where every other response was reinforced. Animals used different methods of pressing the bar; the most common was extension of the claw, predominantly at the meropodite-carpopodite joint.

Electromyographic Record of Classical Conditioning of Eye Withdrawal in the Crab.

Classical (Pavlovian) conditioning of the eye withdrawal reflex of the green crab, Carcinus maenas, was studied by recording electromyograms (EMGs) from the main abductor muscle of the eye (19a). The EMG record was a reliable indicator of the response, and it was always correlated with physical movement of the eye, whether evoked by the unconditioned stimulus (a puff of air to the eye), or by the conditioned stimulus (a mild vibration of the carapace). The EMG was used to study the acquisition of conditioned responses in animals with an immobilized eye. Six of eight experimental animals developed responses to the conditioned stimulus in a manner similar to that for animals with freely moving eyes; unpaired controls showed few responses. The results indicate that eye movement is not required for learning. Behavioral tests after conditioning and after the eyes had been freed supported this conclusion. The results exclude theories of classical conditioning of eye withdrawal that invoke a role for stimuli due to eye movement (such as a change in visual field).

Signaled avoidance in the eye withdrawal reflex of the green crab.

Learning in a signaled avoidance procedure was studied in the eye withdrawal reflex of the green crab, Carcinus maenas. A puff of air to the eye, which causes eye retraction, was used as the unconditioned stimulus (US). A mild vibration on the carapace, which has no effect on untrained animals, was used as a warning (conditioned) stimulus (CS). Eye withdrawal during the CS led to the omission of the otherwise scheduled US. Acquisition was rapid, reaching about 75% avoidance after 30 trials. Extinction occurred slowly over the course of 40 CS-only trials. Yoked controls did not perform as well. The behavior of experimental animals in the avoidance procedure was found to be essentially identical to the performance of animals subjected to a classical conditioning paradigm in which CS responses had no effect on US presentation. Additional groups of animals were subjected to experiments in which (a) avoidance conditioning (60 trials) was followed by classical conditioning (40 trials) or (b) classical conditioning was followed by avoidance. The behavior of these groups was, again, essentially identical. The results suggest that there may be an underlying Pavlovian mechanism for the learned response, although the contribution of an operant process is not excluded. The results expand the range of invertebrate animals in which fundamental conditioning phenomena can be demonstrated, and may provide a neuronal model for learning in a signaled avoidance procedure.

Classical conditioning of the eye withdrawal reflex in the green crab.

Eye withdrawal in the green crab, Carcinus maenas was conditioned by pairing a mild vibration to the carapace as a conditioned stimulus (CS) with a puff of air to one of the eyes as an unconditioned stimulus (US). Animals subjected to repeated pairings showed an increased probability of eye retraction during CS presentation. Significantly less responding was found in several control groups subjected to backward conditioning, unpaired stimuli, stimuli alone, or simply time in the apparatus. Although conditioned animals showed few responses to CS alone after 24 hr, retention could be demonstrated by acquisition that was much more rapid on day 2 than on day 1. Conditioning could also be effected in the eye when it was restrained, a result consistent with reports in the literature that this reflex does not require proprioceptive feedback. Because the neuromuscular circuitry of eye withdrawal is already well defined in Carcinus, this is a promising candidate for studying the neuronal basis of classical conditioning.

Operant punishment of eye elevation in the green crab, Carcinus maenas.

Extension of the eye after reflex withdrawal was suppressed by punishing each extension with a brief puff of air. Experimental animals showed a decrease in the rate of responding, and an increase in the latency to the next response during 30-min sessions. The effect of punishment per se was controlled for by the use of yoked animals that received punishments whenever the experimental (master) animals did. This control group did not show the increased latency, and kept the eye erect for most of the session. Experiments were performed with pairs of animals, one eye of each used as master or control, or, alternatively, with single animals in which one eye served as the yoked control for the other. This latter group gave more reliable and reproducible differences between master and yoke than the pairs of animals. Retention was tested by subjecting animals to three sessions separated by a 12-hr rest. The results indicated some savings but this was not a dramatic effect. To demonstrate that the learning was operant in nature, that is, that it depended on the contingency between the act of eye extension and punishment, experiments were performed in which a delay was introduced between the response and the onset of punishments. A delay of 20 s was found to completely eliminate the learned suppression: animals showed latencies close to that of naive animals and responded at a constant high rate throughout the session. Delays of 10, 5, and 2.5 s were found to have a decreasing effect on the learning, and a delay of 1.25 s produced behavior that was within experimental error of that of animals subjected to immediate punishment.