Ashley N. Mortensen

Coordination of cough and swallow: a meta-behavioral response to aspiration.

Airway protections is the prevention and/or removal of material by behaviors such as cough and swallow. We hypothesized these behaviors are coordinated to respond to aspiration. Anesthetized animals were challenged with simulated aspiration that induced both coughing and swallowing. Electromyograms of upper airway and respiratory muscles together with esophageal pressure were recorded to identify and evaluate cough and swallow. During simulated aspiration, both cough and swallow intensity increased and swallow duration decreased consistent with rapid pharyngeal clearance. Phase restriction between cough and swallow was observed; swallow was restricted to the E2 phase of cough. These results support three main conclusions: 1) the cough and swallow pattern generators are tightly coordinated so as to generate a protective meta-behavior; 2) the trachea provides feedback on swallow quality, informing the brainstem about aspiration incidences; and 3) the larynx and upper esophageal sphincter act as two separate valves controlling the direction of positive and negative pressures from the upper airway into the thorax.

Standard methods for wax moth research

Summary Greater (Lepidoptera: Pyralidae, Galleria mellonella) and Lesser (Lepidoptera: Pyralidae, Achroia grisella) wax moths are ubiquitous pests of honey bee colonies globally. The economic importance of wax moths has led to a number of investigations on wax moth life history, biology, behaviour, ecology, molecular biology, physiology, and control. Despite the importance of wax moths to the apicultural industry, they are investigated considerably more as a model organism for studies in insect physiology, genomics, proteomics, etc. Those studying wax moths from an apicultural perspective typically use only a small number of the total available research methods outlined in the literature. Herein, we describe methods associated with wax moth research that we feel are important from an apicultural research perspective. Ultimately, we hope that this paper will revitalize research on wax moths, since they remain both an important honey bee colony pest and an interesting colony symbiont.

Protocol for the in vitro rearing of honey bee (Apis mellifera L.) workers

The in vitro rearing of worker honey bees (Apis mellifera L.) has become an increasingly important method in honey bee research in general, and in pesticide risk assessment specifically. Authorities from the European Organization for Economic Co-operation and Development and the United States Environmental Protection Agency are requesting data on pesticide impacts on immature bee survivorship prior to registering new crop protection products. Those using the current in vitro rearing protocols have had variable success with immature bee survival and protocol repeatability. Here, we present an improved method for the in vitro rearing of worker honey bees from larvae to adult emergence. We have achieved consistently high survival (>95%) in our control and solvent-control rearing trials. Changes in the proportion of diet components, royal jelly source, maintenance of the developing bee, and rearing environment are the main contributors for our high rearing success and are discussed herein. Our in vitro rearing protocol can be implemented as the standard protocol to determine the impact of pesticides on immature bees because of the protocol’s high control survivability, ease in end point determination, and high overall repeatability.

Central administration of nicotine suppresses tracheobronchial cough in anesthetized cats

We tested the hypothesis that nicotine, which acts peripherally to promote coughing, might inhibit reflex cough at a central site. Nicotine was administered via the vertebral artery [intra-arterial (ia)] to the brain stem circulation and by microinjections into a restricted area of the caudal ventral respiratory column in 33 pentobarbital anesthetized, spontaneously breathing cats. The number of coughs induced by mechanical stimulation of the tracheobronchial airways; amplitudes of the diaphragm, abdominal muscle, and laryngeal muscles EMGs; and several temporal characteristics of cough were analyzed after administration of nicotine and compared with those during control and recovery period. (-)Nicotine (ia) reduced cough number, cough expiratory efforts, blood pressure, and heart rate in a dose-dependent manner. (-)Nicotine did not alter temporal characteristics of the cough motor pattern. Pretreatment with mecamylamine prevented the effect of (-)nicotine on blood pressure and heart rate, but did not block the antitussive action of this drug. (+)Nicotine was less potent than (-)nicotine for inhibition of cough. Microinjections of (-)nicotine into the caudal ventral respiratory column produced similar inhibitory effects on cough as administration of this isomer by the ia route. Mecamylamine microinjected in the region just before nicotine did not significantly reduce the cough suppressant effect of nicotine. Nicotinic acetylcholine receptors significantly modulate functions of brain stem and in particular caudal ventral respiratory column neurons involved in expression of the tracheobronchial cough reflex by a mecamylamine-insensitive mechanism.

Erratum to: Differences in Varroa destructor infestation rates of two indigenous subspecies of Apis mellifera in the Republic of South Africa.

Varroa destructor Anderson & Trueman (Varroa) is a damaging pest of the Western honey bee, Apis mellifera, in North America, Europe, and Asia. However, Varroa infestations have not produced equivalent colony losses of African subspecies of honey bee throughout Africa and parts of the Americas. We surveyed the Varroa infestation rates (number of Varroa per 100 adult honey bees) in colonies of A. m. scutellata, A. m. capensis, and hybrids of the two subspecies throughout the Republic of South Africa in the fall of 2014. We found that A. m. scutellata colonies had significantly higher Varroa infestations than did A. m. capensis colonies. Furthermore, hybridized colonies of the two subspecies had Varroa infestations intermediate to those of A. m. scutellata and A. m. capensis. This is the first documentation of a clear difference in Varroa infestation rates of A. m. scutellata, A. m. capensis, and hybridized colonies in South Africa. Furthermore, our data confirm that Varroa populations in A. m. scutellata colonies are within the range of populations that are damaging to European honey bees.

Acute toxicity of five pesticides to Apis mellifera larvae reared in vitro.

BACKGROUND The reported high loss rates of managed honey bee colonies have been attributed to diverse stressors including pesticides. Honey bee larvae can be exposed to pesticides in contaminated nectar, pollen and wax. Due to the difficulties of rearing larvae in vitro, research focusing on adult bee exposure to pesticides is more common than that on larva exposure to pesticides. Herein, we aimed to assess the acute toxicity of five insecticides to honey bee larvae using an improved in vitro rearing method. RESULTS LC50 and LD50 were calculated for larvae at 72 h following a single diet exposure administered when the larvae were 84 ± 12 h old. Solvent control larval mortalities were less than 15% at 72 h. The LC50 values (mg L-1 ) for each tested pesticide were as follows: amitraz, 494.27; chlorpyrifos, 15.39; coumaphos, 90.01; fluvalinate, 27.69; and imidacloprid, 138.84. The LD50 values in µg per larva were 14.83 (amitraz), 0.46 (chlorpyrifos), 2.70 (coumaphos), 0.83 (fluvalinate) and 4.17 (imidacloprid). CONCLUSION The toxicity of the test pesticides to honey bee larvae from most to least toxic was chlorpyrifos > fluvalinate > coumaphos = imidacloprid > amitraz.

Chronic toxicity of clothianidin, imidacloprid, chlorpyrifos, and dimethoate to Apis mellifera L. larvae reared in vitro : Chronic toxicity of clothianidin, imidacloprid, chlorpyrifos, and dimethoate

BACKGROUND The effects of chronic exposure to two neonicotinoids (clothianidin and imidacloprid) and two organophosphates (chlorpyrifos and dimethoate) on survival, developmental rate and larval weight of honey bee larvae reared in vitro were determined. Diets containing chemicals were fed to larvae with the range of concentrations for each compound based on published acute toxicity experiments and residues found in pollen and nectar, both components of the larval diet. RESULTS Four concentrations of each compound and controls were tested: chlorpyrifos: 0.5, 0.8, 1.2, 8 mg/L; clothianidin: 0.1, 0.4, 2, 10 mg L-1 ; dimethoate: 0.02, 1, 6, 45 mg L-1 ; imidacloprid: 0.4, 2, 4, 10 mg L-1 ; positive control: dimethoate (45 mg L-1 ); solvent control: acetone or methanol; and negative control. A significant decrease in survival, relative to the solvent control, occurred in the 0.8, 1.2 and 8 mg L-1 chlorpyrifos, 0.4, 2 and 10 mg L-1 clothianidin, and 45 mg L-1 dimethoate diets, but not the imidacloprid diets. CONCLUSION The treatment of larval diets with clothianidin, dimethoate and imidacloprid did not affect survival, developmental rate, or weight of immature honey bees; however, treatment with chlorpyrifos did. Overall, our results are valuable for evaluating the chronic toxicity of these pesticides to developing honey bees.

Managed European-Derived Honey Bee, Apis mellifera sspp, Colonies Reduce African-Matriline Honey Bee, A . m . scutellata , Drones at Regional Mating Congregations

African honey bees (Apis mellifera scutellata) dramatically changed the South American beekeeping industry as they rapidly spread through the Americas following their introduction into Brazil. In the present study, we aimed to determine if the management of European-derived honey bees (A. mellifera sspp.) could reduce the relative abundance of African-matriline drones at regional mating sites known as drone congregation areas (DCAs). We collected 2,400 drones at six DCAs either 0.25 km or >2.8 km from managed European-derived honey bee apiaries. The maternal ancestry of each drone was determined by Bgl II enzyme digestion of an amplified portion of the mitochondrial Cytochrome b gene. Furthermore, sibship reconstruction via nuclear microsatellites was conducted for a subset of 1,200 drones to estimate the number of colonies contributing drones to each DCA. Results indicate that DCAs distant to managed European apiaries (>2.8 km) had significantly more African−matriline drones (34.33% of the collected drones had African mitochondrial DNA) than did DCAs close (0.25 km) to managed European apiaries (1.83% of the collected drones had African mitochondrial DNA). Furthermore, nuclear sibship reconstruction demonstrated that the reduction in the proportion of African matriline drones at DCAs near apiaries was not simply an increase in the number of European matriline drones at the DCAs but also the result of fewer African matriline colonies contributing drones to the DCAs. Our data demonstrate that the management of European honey bee colonies can dramatically influence the proportion of drones with African matrilines at nearby drone congregation areas, and would likely decreasing the probability that virgin European queens will mate with African drones at those drone congregation areas.

Chronic toxicity of amitraz, coumaphos and fluvalinate to Apis mellifera L. larvae reared in vitro

The effects of chronic exposure to common acaricides on Apis mellifera survival, developmental rate and larval weight were tested in the laboratory. Larvae were reared in vitro and fed a diet containing amitraz: 1.5, 11, 25 and 46 mg/L; coumaphos: 1.8, 6, 8 and 25 mg/L; or fluvalinate: 0.1, 1, 2.4 and 6 mg/L. The dependent variables were compared for groups feeding on treated diets and control diets: positive control, 45 mg/L dimethoate; solvent control; and negative control. Bee survival decreased in the 46 mg/L amitraz and 25 mg/L coumaphos treatments but not in any fluvalinate treatment. Furthermore, the developmental rate decreased in individuals treated with 46 mg/L amitraz. In our study, larvae exposed to acaricides at concentrations similar to maximum residue in pollen and honey/nectar had no detectable change in survival or developmental rate. Given that pollen and honey/nectar represent only a small part of larval diet, we suggest that residues of amitraz, coumaphos and fluvalinate at the levels we tested are unlikely to impact immature worker bee survival in the field, though our data do not preclude any sublethal effects that may result from bee exposure to these compounds or possible synergisms when they co-occur in bee colonies.

The discovery of Varroa destructor on drone honey bees, Apis mellifera, at drone congregation areas

Varroa is an external parasitic mite of honey bees and is a vector of multiple viruses that can severely weaken or cause the failure of western honey bee colonies if untreated. Effective Varroa control is dependent upon a thorough understanding of Varroa biology, including how Varroa move between host colonies. Here, we highlight that drone (male) honey bees may also play a role in Varroa dispersal. Drones were collected and the number of Varroa per 100 drones was calculated for each of five drone congregation areas (mating sites). This study is the first to confirm that drones present at drone congregation areas do carry Varroa. Further experimentation is needed to determine the extent to which drone-mediated movement may play a role in Varroa life history and/or to develop practical management strategies to limit drone-mediated movement of Varroa between honey bee hives.