Ibrahim Cakmak

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.

A survey of Varroa destructor strains on Apis mellifera in Turkey

190 Notes and commentsthat the presence of queen cells in a colony does not necessar-ily indicate a queen change will occur.The presence of queen cells and cells which appear to haveemerged are used in beekeeping to signal a need for actions toprevent swarming or to replace a failing queen with a queen ofa desired stock rather than allow the colony to supersede. Theunusual queen cells we observed throughout the brood nest arelikely to be interpreted as supersedure cells rather than swarmcells. Beekeepers may unnecessarily re-queen some Russiancolonies if they attempt to prevent supersedure by requeening.Supersedure is a frequent occurrence in honey bee colonies(Butler, 1957), usually has a favourable outcome for the colony,and might be profitably ignored by beekeepers. Supersedure canoften occur without beekeepers noticing the event. Generalrequeening of all colonies on a yearly or every other year sched-ule may be a better strategy to assure that colonies have queensof a desired stock.The adaptive value of this unusual queen rearing behaviour is notclear. The seasonality of far- eastern Russia provides a shortgrowing season with a limited opportunity for honey produc-tion followed by a winter dearth that may last up to six months(Crane, 1990). Perhaps these queen cells, in various stages ofdevelopment, provide an opportunity for colonies to morequickly replace a queen during the short active season shouldshe fail.

Determination of Acute Oral Toxicity of Flumethrin in Honey Bees

ABSTBACT Flumethrin is one of many pesticides used for the control and treatment of varroatosis in honey bees and for the control of mosquitoes and ticks in the environment. For the control of varroatosis, flumethrin is applied to hives formulated as a plastic strip for several weeks. During this time, honey bees are treated topically with flumethrin, and hive products may accumulate the pesticide. Honey bees may indirectly ingest flumethrin through hygienic behaviors during the application period and receive low doses of flumethrin through comb wax remodeling after the application period. The goal of our study was to determine the acute oral toxicity of flumethrin and observe the acute effects on motor coordination in honey bees (Apis mellifera anatoliaca). Six doses (between 0.125 and 4.000 µg per bee) in a geometric series were studied. The acute oral LD50 of flumethrin was determined to be 0.527 and 0.178 µg per bee (n = 210, 95% CI) for 24 and 48 h, respectively. Orally administered flumethrin is highly toxic to honey bees. Oral flumethrin disrupted the motor coordination of honey bees. Honey bees that ingested flumethrin exhibited convulsions in the antennae, legs, and wings at low doses. At higher doses, partial and total paralysis in the antennae, legs, wings, proboscises, bodies, and twitches in the antennae and legs were observed.

Foraging Response of Turkish Honey Bee Subspecies to Flower Color Choices and Reward Consistency

Foraging behavior of Apis mellifera caucasica, A.m. carnica and A.m. syriaca in Turkey was studied for intrinsic subspecies-based differences. Models of forager flower-color fidelity, risk sensitive behavior and maximizing net gain were tested. Foragers were presented artificial flower patches containing blue, white and yellow flowers. Some bees of each subspecies showed high fidelity to yellow flowers, while others favored blue and white flowers. The degree of fidelity, however, differed among subspecies and was dependent upon which color was favored. Bees of all subspecies demonstrated risk indifferent behavior regardless of whether they favored yellow flowers or blue and white flowers. Flower handling time differed among subspecies and increased with reward quantity, and when a reward was present. Flight time between consecutive flowers also differed among honey bee subspecies. Foragers of all subspecies had a higher net gain when visiting flowers with consistent rewards.

Pavlovian conditioning of the proboscis extension reflex in harnessed foragers using paired vs. unpaired and discrimination learning paradigms: tests for differences among honeybee subspecies in Turkey*

Experiments utilized three honeybee subspecies from very distinct biomes (Apis mellifera caucasica, A.m. carnica, A.m. syriaca). In experiment one a simple association between odor and a sucrose feeding was readily established in all three subspecies. This association decreased when the conditioned stimulus was no longer followed by a feeding. Neither the learning rate nor extinction rate differed among subspecies. Unpaired controls confirmed that the acquisition of the odor-food association is learned. In experiment two, an attempt to uncover subspecies differences was tested through the ability of bees to discriminate between two odors, one of which is paired with a feeding. Rapid learning occurred in all subspecies and no significant subspecies differences were observed. Finally, discrimination learning was used as an added control to test for honeybee response to an olfactory versus mechanical (air) stimulus.ZusammenfassungDie Effektivität der Rüsselreflex-Konditionierung in drei Honigbienen-Rassen wurde in der Zentraltürkei untersucht. Obwohl die Bienen sich morphologisch stark unterscheiden, gibt es bisher erstaunlich wenig vergleichende Untersuchungen zum Lernverhalten.Aus zwei Gründen konzentrierten wir uns bei unseren ersten Untersuchungen auf einfaches diskriminatives Lernen. Erstens hatten wir solche Lernversuche in einigen früheren Studien zur Wirkung von Pestiziden auf Honigbienen verwendet. Zweitens helfen diskriminative Experimente bei der weiteren Interpretation des Lernens, da z. B. der Wind, der beim Anbieten von Duftstoffen über Luftströme erzeugt wird, per se als konditionierender Reiz wirken kann. In diskriminativen Lernversuchen müssen die Bienen auf einen von zwei angebotenen Düften reagieren, während der Wind, der während der Duftstoffapplikation erzeugt wird, konstant gehalten wird. Ohne diese diskriminative Kontrolle könnte man nicht sicher sein, dass die Biene auch wirklich auf den vermeintlichen Duft als Konditionierungsreiz reagiert. Diskriminative Experimente ermöglichen auch komplexere Versuchsanordnungen wie z. B. Reversal-Lernen.In Experiment 1 wurden 40 Bienen aus verschiedenen Völkern von Apis mellifera caucasica, A.m. carnica und A.m. syriaca getestet. Innerhalb jeder Bienenrasse erhielten 20 Bienen je 12 verbundene KS-US angeboten (KS = konditionierender Stimulus, US = unkonditionierender Stimulus) angeboten und danach 12 Extinktionsversuche, in denen der US ausgelassen wurde. Die Extinktionsversuche sollten Aufschluss über die Dauerhaftigkeit der Reizantwort innerhalb der einzelnen Bienenrassen geben. Als Kontrolle für Pseudokonditionierung erhielt eine zweite Gruppe von Bienen unverbundene KS-US angeboten. Die Dauer des KS war 3 Sekunden, die des US 2 Sekunden und das Intervall zwischen den Versuchsdurchgängen (ITT) betrug 10 Minuten.Das zweite Experiment unterschied sich vom ersten lediglich dadurch, dass zwei konditionierende Stimuli (KS) angeboten wurden, die Extinktion nicht untersucht wurde und ITT von 10 auf 5 Minuten reduziert wurde. Von 20 Bienen jeder Rasse erhielten die Hälfte KS+ (Zimt) und einen KS-(Wintergrün) ohne anschließendes Füttern. Für die restlichen 10 Bienen jeder Gruppe wurden die Düfte für CS+ und CS− in umgekehrter Reihenfolge angeboten.Bei den Ergebnissen konnten keine Unterschiede zwischen den drei Bienenrassen festgestellt werden. Die Abbildung 1 zeigt, dass die Lernkurven für Apis mellifera caucasica, A.m. carnica, und A.m. syriaca sowohl in der Lern- als auch in der Extinktionsphase ähnlich sind. Die Abbildung 2 bestätigt darüber hinaus, dass alle drei Bienenrassen rasch zwischen den zwei KS unterscheiden können und es dabei keine Rassenunterschiede gibt.Obwohl wir keine Rassenunterschiede bei der einfachen und diskriminativen Konditionierung feststellen konnten, ist diese Rüsselreflex-Konditionierung nur ein erster Schritt bei der Untersuchung potentieller Unterschiede in der Lernfähigkeit verschiedener Bienenrassen. Laufende Untersuchungen an frei fliegenden Sammlerinnen mögen hier weitere Aufschlüsse bringen. Sollten Lernunterschiede tatsächlich existieren, könnten sich bestimmte Bienenrassen besser für Bestäubungsmaßnahmen eignen als andere.

Africanized honey bee response to differences in reward frequency

SUMMARYDifferences in predation pressure and floral resources exist among the endemic ranges of Apis mellifera subspecies. Those environmental differences should select for heterogeneity in forager flower fidelity among honey bee subspecies, particularly when reward frequency differences are associated with competing flower types. We tested that evolutionary model by examining the foraging behaviour of Africanized honey bees (AHB), and by comparing our observations with those recorded for Italian (A. m. ligustica) and Caucasian honey bees (A. m. caucasica). The response of AHB (A. m. scutel- lata hybrid/introgressant) to reward frequency differences among flower colours was examined using artificial flower patches. Each patch contained blue, white, and yellow flowers. When rewards offered by all three flower- morphs were identical, some foragers restricted visitation to blue and white flowers, while others showed fidelity to yellow flowers. Bees visiting blue and white flowers did not show a preference fo...

Feature-positive and feature-negative learning in honey bees

SUMMARY Honey bees (Apis mellifera anatolica) were subjected to sequential trials where they were given the choice between a feature-positive and a feature-negative feeding plate. The ‘feature’ being manipulated is the presence of a single blue circle among three circles marking the location of a small sucrose reward. That is, a ‘feature-negative’ target had three white circles, while a ‘feature-positive’ target had two white circles and one blue one. Two experiments were performed. In both experiments, each bee was tested under two different reward scenarios (treatments). In the first experiment, during the feature-positive treatment bees received 4 μl of 2 mol l−1 sucrose when choosing the feature-positive plate, but received 4 μl of saturated NaCl solution (saltwater) when choosing the feature-negative plate. During the feature-negative treatment, bees were rewarded when visiting the feature-negative plate, while visitation to the feature-positive plate only offered bees the saltwater. The second experiment was a repeat of the first except that pure water was offered instead of saltwater in the non-rewarding feeding plate. As an experimental control, a set of bees was offered sequential trials where both the feature-positive and feature-negative plates offered the sucrose reward. Bee feeding plate choice differed between the feature-positive and feature-negative treatments in both experiments. Bees favored the feeding plate type with the sucrose reward in each treatment, and never consumed the saltwater or pure water when encountered in either treatment. Further, behavior of bees during both the feature-positive and feature-negative treatments differed from that of control bees. However, neither feature-positive nor feature-negative learning reached high levels of success. Further, a feature-positive effect was seen when pure water was offered; bees learned to solve the feature-positive problem more rapidly. When we tested bees using simply the choice of blue versus white targets, where one color held the sucrose reward and the other the saltwater, a bees fidelity to the color offering the sucrose reward quickly reached very high levels.

The over wintering survival of highly Varroa destructor infested honey bee colonies determined to be hygienic using the liquid nitrogen freeze killed brood assay

Summary A study was performed to test the over wintering survival of honey bee (Apis mellifera anatoliaca) colonies heavily infested with Varroa destructor which had been found to be ‘hygienic’ using a liquid nitrogen freeze killed brood assay. 563 colonies in 11 apiaries were screened for hygienic behaviour at different times of the season. Frames of bees were randomly exchanged among test colonies to equalize colony size and mite load. Double-selected hygienic and unselected control colonies were left to over winter to test for survival. Only two out of 25 colonies survived, and one of them was from the double-selected group and the other one from unselected control group. The results suggest that hygienic behaviour as determined by the freeze killed brood assay may not be a predictor of resistance to V. destructor.

Exploring a treatment strategy for long-term increase of varroa tolerance on Marmara Island, Turkey

Summary We explored practical steps to implement a sustainable treatment against Varroa destructor which is adapted to common beekeeping situations, and applies conventional control but nevertheless exerts selection pressure towards increased mite tolerance in honey bees. This approach approximates conditions of natural selection in host-parasite systems, and is supported by evidence that the impact of V. destructor decreases when bee populations are overexploited by the parasites. However, instead of a “live or let die” approach to selection, which is not feasible for commercial beekeeping, death of highly infested colonies was mimicked by treatment and requeening. We established a feasible treatment threshold based on powder sugar shaking of worker bee samples in 250 colonies kept by four beekeepers on the island of Marmara, Turkey. We subsequently requeened heavily infested colonies with queens from lightly infested colonies using simple methods. We found that although one third of the colonies were routinely left untreated, it was possible to decrease mean mite infestation levels and maintain a stable bee population in our apiaries.

A colony defence difference between two honey bee subspecies (Apis mellifera cypria and Apis mellifera caucasica)

Summary Colony defence differences between two honey bee subspecies Apis mellifera cypria and A. m. caucasica are reported. A. m. cypria formed significantly (P < 0.001) more defensive balls of bees covering intruders than A. m. caucasica in response to a predatory wasp attack. Although there were differences in ball formation, the number of bees attacking the wasp did not differ in the balls that were formed (P > 0.10). In addition to ball formation, A. m. cypria was tested for differences in frequency of attacking, shaking, shimmering, line formation and lunging when confronted with a live tethered wasp, dead tethered wasp or just the tethering line. Only the dead wasp elicited differential response. It is suggested that these difference in anti-predator behaviour are related to the high predation risks of A. m. cyrpria. Caucasian bees and their hybrids do not face to such wasp predation due to the cool weather in the Caucasus region.