Plant-feeding insects have evolved an array of subtle discrimination capabilities involving their... more Plant-feeding insects have evolved an array of subtle discrimination capabilities involving their chemical senses. During the last 25 years an extensive list of plant chemicals that are detected by the contact and olfactory chemical senses of insects has accumulated. This list together with some 25–30 species of insects for which we have electrophysiological data on their chemical senses form the basis for our understanding of the chemical control of feeding. Many additional experiments at the behavioral level leave little doubt that the feeding of insects is regulated by some “umwelt” of plant chemicals, but the unique messages offered by host and nonhost plants have yet to be discovered (Dethier and Crnjar, 1982). The dynamic aspects of plant chemistry, as well as the many plant surface compounds that may have behavioral significance add to the complexity of this task (Fobes et al., 1985; Berenbaum, 1985; Gibson and Pickett, 1983; Woodhead, 1983). In addition, several types of physiological feedbacks that are important in regulating feeding have many details yet to be resolved (Shirahashi and Yano, 1984; Bernays and Simpson, 1982). These limitations in our understanding of the regulation of insect feeding come sharply into focus when we attempt to understand the importance of plant allelochemicals that inhibit feeding.
This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hiv... more This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hive bees, stored pollen, and wax in migratory colonies over time and compared exposure to colony health. We summarized the pesticide burden using three different additive methods: (1) the hazard quotient (HQ), an estimate of pesticide exposure risk, (2) the total number of pesticide residues, and (3) the number of relevant residues. Despite being simplistic, these models attempt to summarize potential risk from multiple contaminations in real-world contexts. Colonies performing pollination services were subject to increased pesticide exposure compared to honey-production and holding yards. We found clear links between an increase in the total number of products in wax and colony mortality. In particular, we found that fungicides with particular modes of action increased disproportionally in wax within colonies that died. The occurrence of queen events, a significant risk factor for colony health and productivity, was positively associated with all three proxies of pesticide exposure. While our exposome summation models do not fully capture the complexities of pesticide exposure, they nonetheless help elucidate their risks to colony health. Implementing and improving such models can help identify potential pesticide risks, permitting preventative actions to improve pollinator health. The impact of pesticides on pollinators remains an ongoing concern, especially as new research highlights the complex web of pesticide residues entering the internal hive environment and colony food stream 1,2. Honey bees (Apis mellifera) provide critical pollination services valued at over $200 billion worldwide 3 and $17 billion in the US 4. Despite increased attention, colony losses have remained elevated since 2006 in the US 5-11 and other countries have reported losses as well 12-14. Honey bee colonies have been proposed as terrestrial biomonitors 15,16 because workers from the same colony typically forage up to 6 km away (with max distances reported as 13.5 km 17) from the hive 18 , encompassing over 100 km 2 , and return with accumulated contaminants to the hive. A single colony, therefore, can act as a terrestrial sentinel, expanding radially into the surrounding environment to collect food resources and acquiring contaminants including pesticide-laced pollen that is then stored in the colony as "beebread. " Commercial beekeepers have increasingly struggled with high rates of colony morbidity and mortality, in part because of increased pressure of the parasitic varroa mite (Varroa destructor) 9,10,19 , pathogens (primarily viruses and bacterial infections) 20 , pesticide contamination of hive matrices 21,22 , poor nutrition 23-25 , and frequent queen losses 26. Human health exposure science has called for a top-down approach to understanding environmental causes of disease by examining changes to the body's internal chemical environment over time from chemical contaminants (referred to as the exposome, the totality of exposures received during life 27), instead of
ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes ... more ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes contained in a single-channel multiunit recording. The ANN performs very well when compared with Template Matching and Principal Components, two of the conventional optimal spike classification methods that have been widely used for sorting action potentials
International Journal of Insect Morphology & Embryology, 1980
ABSTRACT Sensilla on the labial tip of the tarnished plant bug, Lygus lineolaris, were examined w... more ABSTRACT Sensilla on the labial tip of the tarnished plant bug, Lygus lineolaris, were examined with scanning and transmission electron microscopy in order to provide morphological evidence indicative of their function. The tripartate apex of the labium consists of 2 lateral lobes and an apical plate. Each lateral lobe possesses a field of 11 thick-walled, uniporous peg sensilla, 5–6 μm long and a thick-walled, nonporous hair sensillum, 18–22 μm long. The uniporous peg sensilla are innervated by 3 or 5 bipolar neurons. The nonporous hair sensillum has no dendrites within its lumen. The apical plate is a noninnervated structure which possesses terminal cuticular projections 5–8 μm long. Morphological evidence supports previously reported physiological evidence that the uniporous peg sensilla have a chemosensory function.
Populations of pollinators are in decline worldwide. These declines are best documented in honey ... more Populations of pollinators are in decline worldwide. These declines are best documented in honey bees and are due to a combination of stressors. In particular, pesticides have been linked to decreased longevity and performance in honey bees; however, the molecular and physiological pathways mediating sensitivity and resistance to pesticides are not well characterized. We explored the impact of coumaphos and fluvalinate, the two most abundant and frequently detected pesticides in the hive, on genome-wide gene expression patterns of honey bee workers. We found significant changes in 1118 transcripts, including genes involved in detoxification, behavioral maturation, immunity, and nutrition. Since behavioral maturation is regulated by juvenile hormone III (JH), we examined effects of these miticides on hormone titers; while JH titers were unaffected, titers of methyl farnesoate (MF), the precursor to JH, were decreased. We further explored the association between nutrition-and pesticide-regulated gene expression patterns and demonstrated that bees fed a pollen-based diet exhibit reduced sensitivity to a third pesticide, chlorpyrifos. Finally, we demonstrated that expression levels of several of the putative pesticide detoxification genes identified in our study and previous studies are also upregulated in response to pollen feeding, suggesting that these pesticides and components in pollen modulate similar molecular response pathways. Our results demonstrate that pesticide exposure can substantially impact expression of genes involved in several core physiological pathways in honey bee workers. Additionally, there is substantial overlap in responses to pesticides and pollen-containing diets at the transcriptional level, and subsequent analyses demonstrated that pollen-based diets reduce workers' pesticide sensitivity. Thus, providing honey bees and other pollinators with high quality nutrition may improve resistance to pesticides.
Comparative Biochemistry and Physiology Part C: Comparative Pharmacology, 1976
A simplified biochemical profile consisting of whole body levels of cholesterol, lipid+ uric acid... more A simplified biochemical profile consisting of whole body levels of cholesterol, lipid+ uric acid. and soluble protein was obtained on mass-reared ..lmhom,mu.s +!randis Boheman of three adult ages for 8 successive weeks representing four generations. 2. All parameters showed signilicant variation with adult age. sex. and chemosterilant treatment. 3. Levels of cholesterol, uric acid. and solt, ble protein were significantly depressed in weevils treated with busulfan. 4. The feasibility of obtaining biochemical data on large numbers of insects as a means of quality control is verified, but the utility of this approach requires the long-term accumulation of such information prior to its application.
Annals of The Entomological Society of America, Jul 1, 1983
Tarnished plant bugs spent more time feeding than non-locomotion, locomotion, tapping, or probing... more Tarnished plant bugs spent more time feeding than non-locomotion, locomotion, tapping, or probing on mustard, alfalfa, and cotton plants. More time was spent feeding on mustard than on any other host plant. Frequency and duration of rostral tapping and time to initiate feeding were inversely related to duration of feeding. There was no significant difference in the mean number of stylet probes on any host plant. Ingestion of sucrose was decreased from significantly greater amounts ( P = 0.05) to amounts not significant from that of water, by allowing the insects to contact a P -mercuribenzoate (PMB)-saturated disc placed over a feeding container. Ingestion was decreased to amounts significantly lower than that of water when PMB was added to sucrose below parafilm-covered feeding containers. It is suggested that differential inhibition of rostral tip and epipharyngeal chemosensilla by PMB is responsible for this reduction in ingestion. A model of the sequence of events, with sensory input involved in host selection and feeding of the tarnished plant bug, is proposed.
The behavior of adults of clerid beetle Thanasimus dubius (F.) preying upon adult southern pine b... more The behavior of adults of clerid beetle Thanasimus dubius (F.) preying upon adult southern pine beetles, Dendroctonus frontal~s Zimmerman, in an arena in the laboratory is described by classifying the acts according to their consequences. A sequence of five stereotyped acts is performed by the predator: either searching or ambush, seizure of prey, alignment of prey, consumption of prey, and grooming. Handling time by the predator consists of the sums of the durations of the four acts of seizure through grooming, which was not significantly different for male and female predators, but was significantly longer for male prey (13.81 min) than for female prey (10.49 min). Consumption of prey (8-9 min) is the major component of handling time. Predators searched or waited in ambush an average of 5.8 rnin befare seizing a prey, and captured prey with an efficiency of 72%. Blinding predators had no significant effect on their efficiency at capturing prey. Maxillary and labial palpectomy alone or in combination significantly reduced efficiency of capture, and reduced numbers of prey consumed. Resume Le comportement des adultes du cleride Thanasimus dubius (F.), predateur des adultes du dendroctone mtridional du pin, Dendroctonus frontalis Zimmerman, a Ctt ttudit en arkne au laboratoire, et dtcrit en classifiant les actes accomplis d'aprks leurs constquences. Le predateur effectue une stquence de cinq actes stertotypes: recherche de la proie ou ambuscade, assaut de la proie, orientation de la proie, consommation de la proie, et nettoyage. Le temps de manipulation ("handling time") dCfini comme etant la somme des quatre derniers actes (l'assaut jusqu'au nettoyage) ne differe pas significativement pour les mtles et les femelles du predateur, mais se revkle significativement plus long pour les proies maes (13.81 min) que pour les proies femelles (10.49 min). La consommation de la proie (8-9 min) est la composante majeure du temps de manipulation. Le predateur recherche sa proie ou s'embusque pour une duree moyenne de 5.8 min avant d'assaillir sa proie, laquelle est capturte avec une efficacitt de 72%. L'efficacite de capture n'est pas affectee de f a~o n significative lorsque la vue du predateur est rendue inoperante. L'ablation des palpes maxillaires ou labiaux, ou des deux a la fois, reduit significativement l'efficacite de capture et le nombre de proies consommtes.
ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes ... more ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes contained in a single-channel multiunit recording. The ANN performs very well when compared with Template Matching and Principal Components, two of the conventional optimal spike classification methods that have been widely used for sorting action potentials
a and B. R. NORMENT. Partial characterization of lethal and neluoactive wmponents of the brown re... more a and B. R. NORMENT. Partial characterization of lethal and neluoactive wmponents of the brown recluse spider (Loxosceles reclusa) venom. Toxicon 17, 347-354, 1979.-Loxosceles reclusa venom was separated by Sephadex G-50 gel filtration into three 280 nm absorbing peaks, two of which contained components lethal to insects. The heavy molecular weight (mol. wt) protein found in peak 1 caused knockdown and mortality in Musca domestics 20-24 hr after injection. The low mol, wt (less than 10,000) polypeptide in peak 2 was heat stable at 90°C and caused knockdown within 30 min and mortality within four hr after injection. Both whole venom and peak 2 contained components which caused a dramatic increase in the amplitude and frequency of the endogenous activity of the ventral nerve cord of Periplaneta americana. The neuroactive factor stimulated this activity to 680-fold and with 5 min produced a block which was reversible by saline irrigation. Gel filtration elutions of the low mol. wt lethal factor and the neuruactive factor overlapped but did not coincide. 1NTRODUC I70N Tlm sROwrr recluse spider, Loxosceles reclusa Gertsch and Mulaik, is a medically important arachnid found in the southern two-thirds of the Mississippi-Missouri-0hio River Basin (ArmStsoN, 1973). Envenomation by this spider often results in a spreading, necrotic lesion (DILLAHA et al., 1963) and can produce systemic manifestations including hemolytic anemia (DExrtY et al., 1964). Although the effects of L. reclusa venom have been studied on at least five vertebrate species (ATxINS et al., 1958 ; GxoTxnus, 1968 ; SMrrli and Mlexs, 1968), no chemotherapeutic agent which will specifically inhibit formation of the pathological lesion has been found. ELGI?ItT et al. (1974) established that antiserum has to be administered within 30 min after the bite to inhibit local necrosis. Antivenin therapy would, therefore, normally be of little practical use in preventing dermonecrosis, since individuals may be unaware that envenomation by L. reclusa has occurred until 6-8 hr later. The effects of L. reclusa venom on insects, the natural prey ofthe spider, have also been studied. NoRMENT and SMITH (1968) observed reduced hemocyte counts in the common house cricket, Acheta domesticus, following venom injection. Insect tissues were also found to undergo pathological changes following either experimental venom injection (NoItM$NT and VINSON, 1969) or envenomation by the spider (ESICAFI and NOI2MENT, 1976). The purpose of this study was to investigate the toxicities and pathophysiological effects of L. reclusa venom upon insects. MATERIALS AND METHODS Adult L. reclusa were collected in north and central Mississippi, maintained in the laboratory at room temperature, and fed greater wax moth, Galleria mellonella, larvae every two weeks. Venom was extracted
The elegant behavioral experiments of Dethier (1955) on the chemosensory control of feeding in th... more The elegant behavioral experiments of Dethier (1955) on the chemosensory control of feeding in the blow fly set the stage for the first recordings of individual cell responses by Hodgson et al. (1955). The animals clearly accepted some substances and rejected others, leading Dethier to infer that one chemosensory cell coded for acceptance and another for rejection. When electrophysiological techniques became available, the resulting data indicated that more than one sensory cell mediates each of these behaviors. Further electrophysiological experimentation led to the elucidation of how salt-, sugar-, and water-sensitive cells can interact to regulate feeding behavior (Dethier, 1976). Since then many investigators have incorporated electrophysiology as an invaluable tool in conjunction with behavioral experiments for elucidating the chemosensory basis of behavior.
Recently, the widespread distribution of pesticides detected in the hive has raised serious conce... more Recently, the widespread distribution of pesticides detected in the hive has raised serious concerns about pesticide exposure on honey bee (Apis mellifera L.) health. A larval rearing method was adapted to assess the chronic oral toxicity to honey bee larvae of the four most common pesticides detected in pollen and wax -fluvalinate, coumaphos, chlorothalonil, and chloropyrifos -tested alone and in all combinations. All pesticides at hive-residue levels triggered a significant increase in larval mortality compared to untreated larvae by over two fold, with a strong increase after 3 days of exposure. Among these four pesticides, honey bee larvae were most sensitive to chlorothalonil compared to adults. Synergistic toxicity was observed in the binary mixture of chlorothalonil with fluvalinate at the concentrations of 34 mg/L and 3 mg/L, respectively; whereas, when diluted by 10 fold, the interaction switched to antagonism. Chlorothalonil at 34 mg/L was also found to synergize the miticide coumaphos at 8 mg/L. The addition of coumaphos significantly reduced the toxicity of the fluvalinate and chlorothalonil mixture, the only significant non-additive effect in all tested ternary mixtures. We also tested the common 'inert' ingredient N-methyl-2-pyrrolidone at seven concentrations, and documented its high toxicity to larval bees. We have shown that chronic dietary exposure to a fungicide, pesticide mixtures, and a formulation solvent have the potential to impact honey bee populations, and warrants further investigation. We suggest that pesticide mixtures in pollen be evaluated by adding their toxicities together, until complete data on interactions can be accumulated.
Feeding decisions are made by the insect central nervous system based on neural input from chemor... more Feeding decisions are made by the insect central nervous system based on neural input from chemoreceptors responding to phytochemical stimuli. A computational model is being developed that simulates feeding decisions by a caterpillar choosing among acceptable and unacceptable plants. Inputs to the model are electrophysiological recordings from the gustatory neurons of the caterpillar. The objectives are to determine which components
Separating neural signals from noise can improve brain-computer interface performance and stabili... more Separating neural signals from noise can improve brain-computer interface performance and stability. However, "spike-sorting" suffers from a lack of ground truth for classifying waveforms, and most algorithms for separating neural action potentials from noise are not suitable for use in real time and have shown mixed effects on decoding performance. Our goals were to automate the intuition of human spike-sorters to operate in real time with an easily tunable parameter governing the stringency with which spike waveforms are classified. We trained an artificial neural network with one hidden layer on neural waveforms that were hand-labeled as either spikes or noise. The network output was a likelihood metric for each waveform it classified, and we tuned the network's stringency by varying the minimum likelihood value for a waveform to be considered a spike. Using the network's labels to exclude noise waveforms, we decoded remembered target location during a memory-guided saccade task from electrode arrays implanted in prefrontal cortex of rhesus macaque monkeys. The network classified waveforms in real time, and its classifications were qualitatively similar to those of a human spike-sorter. Compared to decoding with threshold crossings, in most sessions we improved decoding performance by removing waveforms with low spike likelihood values. Furthermore, decoding with our network's classifications became more beneficial as time since array implantation increased. Our classifier serves as a feasible preprocessing step, with little risk of harm, that could be applied to both offline neural data analyses and online decoding. New & Noteworthy Analysis of neural data from extracellular electrodes typically involves a manual step in which the experimenter isolates neural signals from noise. This process, known as spike-sorting, is tedious and subjective. We used waveforms sorted by a human as training data to create an artificial neural network to separate spikes from noise. We found that this network operated in real time and was suitable for both offline data processing and online decoding.
... Also, only 1/3 of observa-tions were of males. The regression program used for this analysis ... more ... Also, only 1/3 of observa-tions were of males. The regression program used for this analysis was described by Daniel & Wood (1971). ... computer program used for the analysis were de-scribed by Hocking (1976). ... 100 j~ ~ II III'* Ol '" 90 II : th ~ Ilj >- I' fH "tl ~ 80 1/1 0 II c .~ 70 a-0 ...
Seed damage caused by the clover head weevil (Hypera meles F.) on crimson clover (Trifolium incar... more Seed damage caused by the clover head weevil (Hypera meles F.) on crimson clover (Trifolium incarnatum L.) limits the utilization of this forage species. In laboratory studies weevil oviposition was greater in the second basal internode of clover stems than in any other internode. Of eight crimson clover inbred lines and five cultivars tested in the field for larval seed feeding damage, one inbred line showed decreased larval survival and decreased seed damage. An estimate of actual seed damage was obtained from five seed head samples harvested from each of 40 plants. Numbers of seeds damaged by larval calyx boring were positively correlated (P<0.05) with seed damage estimates based on numbers of pupae per seed head for the cultivars ‘Chief’ (r=0.65) and ‘Tibbee’ (r=0.61), but estimates were attained in approximately onesixth the time required to visually count bored seed. Estimating seed damage in this manner will greatly increase the amount of germplasm which can be evaluated for weevil resistance.
the surface area of each disk that has been eaten. The experiment is terminated when a criterion ... more the surface area of each disk that has been eaten. The experiment is terminated when a criterion amount has been consumed or when a certain amount of time has expired. The natural variability of biological systems requires that a large number repetitions (~20) of each behavioral experiment be performed. We discuss the implementation of an automated apparatus for recording and quantifying food choice behavior by small animals. A computer controls the apparatus by positioning a video camera over each one of twelve petri dishes. When the camera is in position, an image of the underlying dish is captured and the digitized image is returned to the computer for further processing. Within the computer a digital image processing procedure analyzes and quantifies the observed behavior. To eliminate the tedium of repeated visual observations and to minimize operator error, we have developed a device which automatically records and analyzes food choice behavior. The implementation of this device is the focus of this paper.
Plant-feeding insects have evolved an array of subtle discrimination capabilities involving their... more Plant-feeding insects have evolved an array of subtle discrimination capabilities involving their chemical senses. During the last 25 years an extensive list of plant chemicals that are detected by the contact and olfactory chemical senses of insects has accumulated. This list together with some 25–30 species of insects for which we have electrophysiological data on their chemical senses form the basis for our understanding of the chemical control of feeding. Many additional experiments at the behavioral level leave little doubt that the feeding of insects is regulated by some “umwelt” of plant chemicals, but the unique messages offered by host and nonhost plants have yet to be discovered (Dethier and Crnjar, 1982). The dynamic aspects of plant chemistry, as well as the many plant surface compounds that may have behavioral significance add to the complexity of this task (Fobes et al., 1985; Berenbaum, 1985; Gibson and Pickett, 1983; Woodhead, 1983). In addition, several types of physiological feedbacks that are important in regulating feeding have many details yet to be resolved (Shirahashi and Yano, 1984; Bernays and Simpson, 1982). These limitations in our understanding of the regulation of insect feeding come sharply into focus when we attempt to understand the importance of plant allelochemicals that inhibit feeding.
This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hiv... more This study measured part of the in-hive pesticide exposome by analyzing residues from live in-hive bees, stored pollen, and wax in migratory colonies over time and compared exposure to colony health. We summarized the pesticide burden using three different additive methods: (1) the hazard quotient (HQ), an estimate of pesticide exposure risk, (2) the total number of pesticide residues, and (3) the number of relevant residues. Despite being simplistic, these models attempt to summarize potential risk from multiple contaminations in real-world contexts. Colonies performing pollination services were subject to increased pesticide exposure compared to honey-production and holding yards. We found clear links between an increase in the total number of products in wax and colony mortality. In particular, we found that fungicides with particular modes of action increased disproportionally in wax within colonies that died. The occurrence of queen events, a significant risk factor for colony health and productivity, was positively associated with all three proxies of pesticide exposure. While our exposome summation models do not fully capture the complexities of pesticide exposure, they nonetheless help elucidate their risks to colony health. Implementing and improving such models can help identify potential pesticide risks, permitting preventative actions to improve pollinator health. The impact of pesticides on pollinators remains an ongoing concern, especially as new research highlights the complex web of pesticide residues entering the internal hive environment and colony food stream 1,2. Honey bees (Apis mellifera) provide critical pollination services valued at over $200 billion worldwide 3 and $17 billion in the US 4. Despite increased attention, colony losses have remained elevated since 2006 in the US 5-11 and other countries have reported losses as well 12-14. Honey bee colonies have been proposed as terrestrial biomonitors 15,16 because workers from the same colony typically forage up to 6 km away (with max distances reported as 13.5 km 17) from the hive 18 , encompassing over 100 km 2 , and return with accumulated contaminants to the hive. A single colony, therefore, can act as a terrestrial sentinel, expanding radially into the surrounding environment to collect food resources and acquiring contaminants including pesticide-laced pollen that is then stored in the colony as "beebread. " Commercial beekeepers have increasingly struggled with high rates of colony morbidity and mortality, in part because of increased pressure of the parasitic varroa mite (Varroa destructor) 9,10,19 , pathogens (primarily viruses and bacterial infections) 20 , pesticide contamination of hive matrices 21,22 , poor nutrition 23-25 , and frequent queen losses 26. Human health exposure science has called for a top-down approach to understanding environmental causes of disease by examining changes to the body's internal chemical environment over time from chemical contaminants (referred to as the exposome, the totality of exposures received during life 27), instead of
ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes ... more ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes contained in a single-channel multiunit recording. The ANN performs very well when compared with Template Matching and Principal Components, two of the conventional optimal spike classification methods that have been widely used for sorting action potentials
International Journal of Insect Morphology & Embryology, 1980
ABSTRACT Sensilla on the labial tip of the tarnished plant bug, Lygus lineolaris, were examined w... more ABSTRACT Sensilla on the labial tip of the tarnished plant bug, Lygus lineolaris, were examined with scanning and transmission electron microscopy in order to provide morphological evidence indicative of their function. The tripartate apex of the labium consists of 2 lateral lobes and an apical plate. Each lateral lobe possesses a field of 11 thick-walled, uniporous peg sensilla, 5–6 μm long and a thick-walled, nonporous hair sensillum, 18–22 μm long. The uniporous peg sensilla are innervated by 3 or 5 bipolar neurons. The nonporous hair sensillum has no dendrites within its lumen. The apical plate is a noninnervated structure which possesses terminal cuticular projections 5–8 μm long. Morphological evidence supports previously reported physiological evidence that the uniporous peg sensilla have a chemosensory function.
Populations of pollinators are in decline worldwide. These declines are best documented in honey ... more Populations of pollinators are in decline worldwide. These declines are best documented in honey bees and are due to a combination of stressors. In particular, pesticides have been linked to decreased longevity and performance in honey bees; however, the molecular and physiological pathways mediating sensitivity and resistance to pesticides are not well characterized. We explored the impact of coumaphos and fluvalinate, the two most abundant and frequently detected pesticides in the hive, on genome-wide gene expression patterns of honey bee workers. We found significant changes in 1118 transcripts, including genes involved in detoxification, behavioral maturation, immunity, and nutrition. Since behavioral maturation is regulated by juvenile hormone III (JH), we examined effects of these miticides on hormone titers; while JH titers were unaffected, titers of methyl farnesoate (MF), the precursor to JH, were decreased. We further explored the association between nutrition-and pesticide-regulated gene expression patterns and demonstrated that bees fed a pollen-based diet exhibit reduced sensitivity to a third pesticide, chlorpyrifos. Finally, we demonstrated that expression levels of several of the putative pesticide detoxification genes identified in our study and previous studies are also upregulated in response to pollen feeding, suggesting that these pesticides and components in pollen modulate similar molecular response pathways. Our results demonstrate that pesticide exposure can substantially impact expression of genes involved in several core physiological pathways in honey bee workers. Additionally, there is substantial overlap in responses to pesticides and pollen-containing diets at the transcriptional level, and subsequent analyses demonstrated that pollen-based diets reduce workers' pesticide sensitivity. Thus, providing honey bees and other pollinators with high quality nutrition may improve resistance to pesticides.
Comparative Biochemistry and Physiology Part C: Comparative Pharmacology, 1976
A simplified biochemical profile consisting of whole body levels of cholesterol, lipid+ uric acid... more A simplified biochemical profile consisting of whole body levels of cholesterol, lipid+ uric acid. and soluble protein was obtained on mass-reared ..lmhom,mu.s +!randis Boheman of three adult ages for 8 successive weeks representing four generations. 2. All parameters showed signilicant variation with adult age. sex. and chemosterilant treatment. 3. Levels of cholesterol, uric acid. and solt, ble protein were significantly depressed in weevils treated with busulfan. 4. The feasibility of obtaining biochemical data on large numbers of insects as a means of quality control is verified, but the utility of this approach requires the long-term accumulation of such information prior to its application.
Annals of The Entomological Society of America, Jul 1, 1983
Tarnished plant bugs spent more time feeding than non-locomotion, locomotion, tapping, or probing... more Tarnished plant bugs spent more time feeding than non-locomotion, locomotion, tapping, or probing on mustard, alfalfa, and cotton plants. More time was spent feeding on mustard than on any other host plant. Frequency and duration of rostral tapping and time to initiate feeding were inversely related to duration of feeding. There was no significant difference in the mean number of stylet probes on any host plant. Ingestion of sucrose was decreased from significantly greater amounts ( P = 0.05) to amounts not significant from that of water, by allowing the insects to contact a P -mercuribenzoate (PMB)-saturated disc placed over a feeding container. Ingestion was decreased to amounts significantly lower than that of water when PMB was added to sucrose below parafilm-covered feeding containers. It is suggested that differential inhibition of rostral tip and epipharyngeal chemosensilla by PMB is responsible for this reduction in ingestion. A model of the sequence of events, with sensory input involved in host selection and feeding of the tarnished plant bug, is proposed.
The behavior of adults of clerid beetle Thanasimus dubius (F.) preying upon adult southern pine b... more The behavior of adults of clerid beetle Thanasimus dubius (F.) preying upon adult southern pine beetles, Dendroctonus frontal~s Zimmerman, in an arena in the laboratory is described by classifying the acts according to their consequences. A sequence of five stereotyped acts is performed by the predator: either searching or ambush, seizure of prey, alignment of prey, consumption of prey, and grooming. Handling time by the predator consists of the sums of the durations of the four acts of seizure through grooming, which was not significantly different for male and female predators, but was significantly longer for male prey (13.81 min) than for female prey (10.49 min). Consumption of prey (8-9 min) is the major component of handling time. Predators searched or waited in ambush an average of 5.8 rnin befare seizing a prey, and captured prey with an efficiency of 72%. Blinding predators had no significant effect on their efficiency at capturing prey. Maxillary and labial palpectomy alone or in combination significantly reduced efficiency of capture, and reduced numbers of prey consumed. Resume Le comportement des adultes du cleride Thanasimus dubius (F.), predateur des adultes du dendroctone mtridional du pin, Dendroctonus frontalis Zimmerman, a Ctt ttudit en arkne au laboratoire, et dtcrit en classifiant les actes accomplis d'aprks leurs constquences. Le predateur effectue une stquence de cinq actes stertotypes: recherche de la proie ou ambuscade, assaut de la proie, orientation de la proie, consommation de la proie, et nettoyage. Le temps de manipulation ("handling time") dCfini comme etant la somme des quatre derniers actes (l'assaut jusqu'au nettoyage) ne differe pas significativement pour les mtles et les femelles du predateur, mais se revkle significativement plus long pour les proies maes (13.81 min) que pour les proies femelles (10.49 min). La consommation de la proie (8-9 min) est la composante majeure du temps de manipulation. Le predateur recherche sa proie ou s'embusque pour une duree moyenne de 5.8 min avant d'assaillir sa proie, laquelle est capturte avec une efficacitt de 72%. L'efficacite de capture n'est pas affectee de f a~o n significative lorsque la vue du predateur est rendue inoperante. L'ablation des palpes maxillaires ou labiaux, ou des deux a la fois, reduit significativement l'efficacite de capture et le nombre de proies consommtes.
ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes ... more ABSTRACT This paper presents an Artificial Neural Network (ANN) capable of sorting neural spikes contained in a single-channel multiunit recording. The ANN performs very well when compared with Template Matching and Principal Components, two of the conventional optimal spike classification methods that have been widely used for sorting action potentials
a and B. R. NORMENT. Partial characterization of lethal and neluoactive wmponents of the brown re... more a and B. R. NORMENT. Partial characterization of lethal and neluoactive wmponents of the brown recluse spider (Loxosceles reclusa) venom. Toxicon 17, 347-354, 1979.-Loxosceles reclusa venom was separated by Sephadex G-50 gel filtration into three 280 nm absorbing peaks, two of which contained components lethal to insects. The heavy molecular weight (mol. wt) protein found in peak 1 caused knockdown and mortality in Musca domestics 20-24 hr after injection. The low mol, wt (less than 10,000) polypeptide in peak 2 was heat stable at 90°C and caused knockdown within 30 min and mortality within four hr after injection. Both whole venom and peak 2 contained components which caused a dramatic increase in the amplitude and frequency of the endogenous activity of the ventral nerve cord of Periplaneta americana. The neuroactive factor stimulated this activity to 680-fold and with 5 min produced a block which was reversible by saline irrigation. Gel filtration elutions of the low mol. wt lethal factor and the neuruactive factor overlapped but did not coincide. 1NTRODUC I70N Tlm sROwrr recluse spider, Loxosceles reclusa Gertsch and Mulaik, is a medically important arachnid found in the southern two-thirds of the Mississippi-Missouri-0hio River Basin (ArmStsoN, 1973). Envenomation by this spider often results in a spreading, necrotic lesion (DILLAHA et al., 1963) and can produce systemic manifestations including hemolytic anemia (DExrtY et al., 1964). Although the effects of L. reclusa venom have been studied on at least five vertebrate species (ATxINS et al., 1958 ; GxoTxnus, 1968 ; SMrrli and Mlexs, 1968), no chemotherapeutic agent which will specifically inhibit formation of the pathological lesion has been found. ELGI?ItT et al. (1974) established that antiserum has to be administered within 30 min after the bite to inhibit local necrosis. Antivenin therapy would, therefore, normally be of little practical use in preventing dermonecrosis, since individuals may be unaware that envenomation by L. reclusa has occurred until 6-8 hr later. The effects of L. reclusa venom on insects, the natural prey ofthe spider, have also been studied. NoRMENT and SMITH (1968) observed reduced hemocyte counts in the common house cricket, Acheta domesticus, following venom injection. Insect tissues were also found to undergo pathological changes following either experimental venom injection (NoItM$NT and VINSON, 1969) or envenomation by the spider (ESICAFI and NOI2MENT, 1976). The purpose of this study was to investigate the toxicities and pathophysiological effects of L. reclusa venom upon insects. MATERIALS AND METHODS Adult L. reclusa were collected in north and central Mississippi, maintained in the laboratory at room temperature, and fed greater wax moth, Galleria mellonella, larvae every two weeks. Venom was extracted
The elegant behavioral experiments of Dethier (1955) on the chemosensory control of feeding in th... more The elegant behavioral experiments of Dethier (1955) on the chemosensory control of feeding in the blow fly set the stage for the first recordings of individual cell responses by Hodgson et al. (1955). The animals clearly accepted some substances and rejected others, leading Dethier to infer that one chemosensory cell coded for acceptance and another for rejection. When electrophysiological techniques became available, the resulting data indicated that more than one sensory cell mediates each of these behaviors. Further electrophysiological experimentation led to the elucidation of how salt-, sugar-, and water-sensitive cells can interact to regulate feeding behavior (Dethier, 1976). Since then many investigators have incorporated electrophysiology as an invaluable tool in conjunction with behavioral experiments for elucidating the chemosensory basis of behavior.
Recently, the widespread distribution of pesticides detected in the hive has raised serious conce... more Recently, the widespread distribution of pesticides detected in the hive has raised serious concerns about pesticide exposure on honey bee (Apis mellifera L.) health. A larval rearing method was adapted to assess the chronic oral toxicity to honey bee larvae of the four most common pesticides detected in pollen and wax -fluvalinate, coumaphos, chlorothalonil, and chloropyrifos -tested alone and in all combinations. All pesticides at hive-residue levels triggered a significant increase in larval mortality compared to untreated larvae by over two fold, with a strong increase after 3 days of exposure. Among these four pesticides, honey bee larvae were most sensitive to chlorothalonil compared to adults. Synergistic toxicity was observed in the binary mixture of chlorothalonil with fluvalinate at the concentrations of 34 mg/L and 3 mg/L, respectively; whereas, when diluted by 10 fold, the interaction switched to antagonism. Chlorothalonil at 34 mg/L was also found to synergize the miticide coumaphos at 8 mg/L. The addition of coumaphos significantly reduced the toxicity of the fluvalinate and chlorothalonil mixture, the only significant non-additive effect in all tested ternary mixtures. We also tested the common 'inert' ingredient N-methyl-2-pyrrolidone at seven concentrations, and documented its high toxicity to larval bees. We have shown that chronic dietary exposure to a fungicide, pesticide mixtures, and a formulation solvent have the potential to impact honey bee populations, and warrants further investigation. We suggest that pesticide mixtures in pollen be evaluated by adding their toxicities together, until complete data on interactions can be accumulated.
Feeding decisions are made by the insect central nervous system based on neural input from chemor... more Feeding decisions are made by the insect central nervous system based on neural input from chemoreceptors responding to phytochemical stimuli. A computational model is being developed that simulates feeding decisions by a caterpillar choosing among acceptable and unacceptable plants. Inputs to the model are electrophysiological recordings from the gustatory neurons of the caterpillar. The objectives are to determine which components
Separating neural signals from noise can improve brain-computer interface performance and stabili... more Separating neural signals from noise can improve brain-computer interface performance and stability. However, "spike-sorting" suffers from a lack of ground truth for classifying waveforms, and most algorithms for separating neural action potentials from noise are not suitable for use in real time and have shown mixed effects on decoding performance. Our goals were to automate the intuition of human spike-sorters to operate in real time with an easily tunable parameter governing the stringency with which spike waveforms are classified. We trained an artificial neural network with one hidden layer on neural waveforms that were hand-labeled as either spikes or noise. The network output was a likelihood metric for each waveform it classified, and we tuned the network's stringency by varying the minimum likelihood value for a waveform to be considered a spike. Using the network's labels to exclude noise waveforms, we decoded remembered target location during a memory-guided saccade task from electrode arrays implanted in prefrontal cortex of rhesus macaque monkeys. The network classified waveforms in real time, and its classifications were qualitatively similar to those of a human spike-sorter. Compared to decoding with threshold crossings, in most sessions we improved decoding performance by removing waveforms with low spike likelihood values. Furthermore, decoding with our network's classifications became more beneficial as time since array implantation increased. Our classifier serves as a feasible preprocessing step, with little risk of harm, that could be applied to both offline neural data analyses and online decoding. New & Noteworthy Analysis of neural data from extracellular electrodes typically involves a manual step in which the experimenter isolates neural signals from noise. This process, known as spike-sorting, is tedious and subjective. We used waveforms sorted by a human as training data to create an artificial neural network to separate spikes from noise. We found that this network operated in real time and was suitable for both offline data processing and online decoding.
... Also, only 1/3 of observa-tions were of males. The regression program used for this analysis ... more ... Also, only 1/3 of observa-tions were of males. The regression program used for this analysis was described by Daniel & Wood (1971). ... computer program used for the analysis were de-scribed by Hocking (1976). ... 100 j~ ~ II III'* Ol '" 90 II : th ~ Ilj >- I' fH "tl ~ 80 1/1 0 II c .~ 70 a-0 ...
Seed damage caused by the clover head weevil (Hypera meles F.) on crimson clover (Trifolium incar... more Seed damage caused by the clover head weevil (Hypera meles F.) on crimson clover (Trifolium incarnatum L.) limits the utilization of this forage species. In laboratory studies weevil oviposition was greater in the second basal internode of clover stems than in any other internode. Of eight crimson clover inbred lines and five cultivars tested in the field for larval seed feeding damage, one inbred line showed decreased larval survival and decreased seed damage. An estimate of actual seed damage was obtained from five seed head samples harvested from each of 40 plants. Numbers of seeds damaged by larval calyx boring were positively correlated (P<0.05) with seed damage estimates based on numbers of pupae per seed head for the cultivars ‘Chief’ (r=0.65) and ‘Tibbee’ (r=0.61), but estimates were attained in approximately onesixth the time required to visually count bored seed. Estimating seed damage in this manner will greatly increase the amount of germplasm which can be evaluated for weevil resistance.
the surface area of each disk that has been eaten. The experiment is terminated when a criterion ... more the surface area of each disk that has been eaten. The experiment is terminated when a criterion amount has been consumed or when a certain amount of time has expired. The natural variability of biological systems requires that a large number repetitions (~20) of each behavioral experiment be performed. We discuss the implementation of an automated apparatus for recording and quantifying food choice behavior by small animals. A computer controls the apparatus by positioning a video camera over each one of twelve petri dishes. When the camera is in position, an image of the underlying dish is captured and the digitized image is returned to the computer for further processing. Within the computer a digital image processing procedure analyzes and quantifies the observed behavior. To eliminate the tedium of repeated visual observations and to minimize operator error, we have developed a device which automatically records and analyzes food choice behavior. The implementation of this device is the focus of this paper.
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Papers by James Frazier