| pollinating bees (hymenoptera: apiformes) of u.s. alfalfa compared for rates of pod and seed set. | alfalfa (=lucerne) flowers require visiting bees to trip the sexual column, thereby providing pollination and subsequent pod and seed set. previous studies have compared the pollination values of different bee species solely by the speed with which they handle flowers and the proportion of visited flowers tripped. in this greenhouse study, five species of bees, including the three commercially managed u.s alfalfa pollinators, are likewise compared for their floral tripping frequencies. these bee ... | 2002 | 11942760 |
| olfactory response of megachilid bees, osmia lignaria, megachile rotundata, and m. pugnata, to individual cues from old nest cavities. | the megachilid bees osmia lignaria say, megachile rotundata (f.), and m. pugnata say were tested for attraction to various components associated with their old nest cavities, or chemical extracts of these components, using a y-tube olfactory response bioassay. female bees of these species are known to nest in or near old nest cavities, implying that remnant nest components are important cues for bees looking for nest cavities. significant results show that female bees were attracted to component ... | 2007 | 17445375 |
| lethal and sublethal effects of imidacloprid on osmia lignaria and clothianidin on megachile rotundata (hymenoptera: megachilidae). | we examined lethal and sublethal effects of imidacloprid on osmia lignaria (cresson) and clothianidin on megachile rotundata (f.) (hymenoptera: megachilidae). we also made progress toward developing reliable methodology for testing pesticides on wild bees for use in pesticide registration by using field and laboratory experiments. bee larvae were exposed to control, low (3 or 6 ppb), intermediate (30 ppb), or high (300 ppb) doses of either imidacloprid or clothianidin in pollen. field experiment ... | 2008 | 18613579 |
| impact of currently used or potentially useful insecticides for canola agroecosystems on bombus impatiens (hymenoptera: apidae), megachile rotundata (hymentoptera: megachilidae), and osmia lignaria (hymenoptera: megachilidae). | pest management practices may be contributing to a decline in wild bee populations in or near canola (brassica napus l.) agroecosystems. the objective of this study was to investigate the direct contact toxicity of five technical grade insecticides--imidacloprid, clothianidin, deltamethrin, spinosad, and novaluron--currently used, or with potential for use in canola integrated pest management on bees that may forage in canola: common eastern bumble bees [bombus impatiens (cresson); hereafter bum ... | 2009 | 19253634 |
| cuticular lipids of female solitary bees, osmia lignaria say and megachile rotundata (f.) (hymenoptera: megachilidae). | the cuticular lipids of the cavity-nesting adult female solitary bees, osmia lignaria say and megachile rotundata (f.) (hymenoptera: megachilidae), were analyzed by gas chromatography (gc) and combined gc-mass spectrometry. the cuticular lipids of these female bees are mainly consisted of hydrocarbons. for o. lignaria, nearly 64% of the cuticular lipids were c(25)-c(31) mono-alkenes. for m. rotundata, 48% of the cuticular lipids were c(23)-c(33) alkanes with nearly the same quantities of the sam ... | 2009 | 19298863 |
| detoxification and stress response genes expressed in a western north american bumble bee, bombus huntii (hymenoptera: apidae). | the hunt bumble bee (bombus huntii greene, hymenoptera: apidae) is a holometabolous, social insect important as a pollinator in natural and agricultural ecosystems in western north america. bumble bees spend a significant amount of time foraging on a wide variety of flowering plants, and this activity exposes them to both plant toxins and pesticides, posing a threat to individual and colony survival. little is known about what detoxification pathways are active in bumble bees, how the expression ... | 2013 | 24330608 |
| cdna cloning, characterization and expression analysis of peroxiredoxin 5 gene in the ridgetail white prawn exopalaemon carinicauda. | peroxiredoxin is a superfamily of antioxidative proteins that play important roles in protecting organisms against the toxicity of reactive oxygen species. in this study, a full-length of peroxiredoxin 5 (designated ecprx5) cdna was cloned from the ridgetail white prawn exopalaemon carinicauda by using rapid amplification of cdna ends (race) approaches. the full-length cdna of the ecprx5 was of 827 bp, containing a 5' untranslated region (utr) of 14 bp, a 3' utr of 228 bp with a poly (a) tail, a ... | 2013 | 24141991 |
| aerobic microorganisms associated with alfalfa leafcutter bees (megachile rotundata). | characterization of microorganisms associated with alfalfa leaf-cutter bee (megachile rotundata) nectar, pollen, provisions, larval guts, and frass (excreta) in alberta demonstrated a varied aerobic microflora. yeasts were isolated frequently from nectar, pollen, and provisions but rarely from guts or frass. the most prevalent yeast taxa were: candida bombicola, cryptococcus albidus, metschnikowia reukaufii, and rhodotorula glutinis. although few filamentous fungi were found in nectar, they were ... | 1993 | 24190009 |
| interactions between fungi and bacteria influence microbial community structure in the megachile rotundata larval gut. | recent declines in bee populations coupled with advances in dna-sequencing technology have sparked a renaissance in studies of bee-associated microbes. megachile rotundata is an important field crop pollinator, but is stricken by chalkbrood, a disease caused by the fungus ascosphaera aggregata. to test the hypothesis that some gut microbes directly or indirectly affect the growth of others, we applied four treatments to the pollen provisions of m. rotundata eggs and young larvae: antibacterials, ... | 2014 | 24478297 |
| the bees among us: modelling occupancy of solitary bees. | occupancy modelling has received increasing attention as a tool for differentiating between true absence and non-detection in biodiversity data. this is thought to be particularly useful when a species of interest is spread out over a large area and sampling is constrained. we used occupancy modelling to estimate the probability of three phylogenetically independent pairs of native-introduced species [megachile campanulae (robertson)-megachile rotundata (fab.), megachile pugnata say-megachile ce ... | 2016 | 27911954 |
| honey bee viruses in wild bees: viral prevalence, loads, and experimental inoculation. | evidence of inter-species pathogen transmission from managed to wild bees has sparked concern that emerging diseases could be causing or exacerbating wild bee declines. while some pathogens, like rna viruses, have been found in pollen and wild bees, the threat these viruses pose to wild bees is largely unknown. here, we tested 169 bees, representing 4 families and 8 genera, for five common honey bee (apis mellifera) viruses, finding that more than 80% of wild bees harbored at least one virus. we ... | 2016 | 27832169 |
| the wide distribution and change of target specificity of r2 non-ltr retrotransposons in animals. | transposons, or transposable elements, are the major components of genomes in most eukaryotes. some groups of transposons have developed target specificity that limits the integration sites to a specific nonessential sequence or a genomic region to avoid gene disruption caused by insertion into an essential gene. r2 is one of the most intensively investigated groups of sequence-specific non-ltr retrotransposons and is inserted at a specific site inside of 28s ribosomal rna (rrna) genes. r2 is kn ... | 2017 | 27662593 |
| effects of residual novaluron on reproduction in alfalfa leafcutting bees, megachile rotundata f. (megachilidae). | the chitin synthesis inhibitor novaluron can suppress pests that affect alfalfa seed production, but can negatively affect reproductive success in the alfalfa pollinator megachile rotundata. novaluron is considered to be a reduced-risk insecticide because it disrupts ecdysis and is non-lethal to adult insects, but some exposed adults have fewer eggs and suppressed egg hatch. for this experiment, bees nested in field cages where they were exposed to alfalfa that had never been treated with novalu ... | 2017 | 27405042 |
| optimizing fluctuating thermal regime storage of developing megachile rotundata (hymenoptera: megachilidae). | the alfalfa leafcutting bee, megachile rotundata (f.), is the primary pollinator for alfalfa seed production in north america. under current management practice, developing pupae are incubated at 29-30°c until the adults emerge for pollination. if unfavorable spring weather delays peak alfalfa bloom, managers will cool pupae to slow development, which can increase mortality and causes sublethal effects. previously, we demonstrated that exposure to a fluctuating thermal regime (ftr) increases sur ... | 2016 | 26994099 |
| exposure to suboptimal temperatures during metamorphosis reveals a critical developmental window in the solitary bee, megachile rotundata. | metamorphosis is an important developmental stage for holometabolous insects, during which adult morphology and physiology are established. proper development relies on optimal body temperatures, and natural ambient temperature (ta) fluctuations, especially in spring or in northern latitudes, could result in interruptions to development. it is unclear how low-ta exposure may affect insects that are actively developing. to understand how suboptimal ta may affect metamorphosing insects, we used th ... | 2015 | 26658248 |
| thermoperiodism synchronizes emergence in the alfalfa leafcutting bee (hymenoptera: megachilidae). | alfalfa seed production in the northwestern united states and western canada is heavily dependent upon the pollinating services of megachile rotundata (f.) (hymenoptera: megachilidae). m. rotundata females nest in cavities either naturally occurring or in artificial nesting blocks. because of the physical nature of the nest, m. rotundata brood may have limited to no exposure to photoperiodic cues in order to regulate important circadian functions. therefore, various thermoperiod regimes were use ... | 2016 | 26385932 |
| resource effects on solitary bee reproduction in a managed crop pollination system. | population density may affect solitary bee maternal resource allocation. the number of megachile rotundata (f.), alfalfa leafcutting bee, females released for seed production of medicago sativa l., alfalfa, may limit flower availability for nest provisioning. in turn, pollinator abundance also may affect crop yield. the m. sativa pollination system presents an opportunity to test for effects of density dependence and maternal manipulation on m. rotundata reproduction. a multiyear study was perfo ... | 2015 | 26314057 |
| effects of fungicide and adjuvant sprays on nesting behavior in two managed solitary bees, osmia lignaria and megachile rotundata. | there is a growing body of empirical evidence showing that wild and managed bees are negatively impacted by various pesticides that are applied in agroecosystems around the world. the lethal and sublethal effects of two widely used fungicides and one adjuvant were assessed in cage studies in california on blue orchard bees, osmia lignaria, and in cage studies in utah on alfalfa leafcutting bees, megachile rotundata. the fungicides tested were rovral 4f (iprodione) and pristine (mixture of pyracl ... | 2015 | 26274401 |
| a simple model for pollen-parent fecundity distributions in bee-pollinated forage legume polycrosses. | a simple weibull distribution based empirical model that predicts pollen-parent fecundity distributions based on polycross size alone has been developed in outbred forage legume species for incorporation into quantitative genetic theory. random mating or panmixis is a fundamental assumption in quantitative genetic theory. random mating is sometimes thought to occur in actual fact, although a large body of empirical work shows that this is often not the case in nature. models have been developed ... | 2015 | 26105686 |
| seasonal trends in the condition of nesting females of a solitary bee: wing wear, lipid content, and oocyte size. | during the nesting season, adult females of the solitary bee megachile rotundata (f.) face considerable physical and energy demands that could include increasing wear and tear on their bodies and decreasing lipid reserves. consequently, their reproductive performance may be affected not only by extrinsic factors (e.g., weather and floral resource availability), but intrinsic changes in their own bodies. because of the potential fitness effects of seasonal changes in body condition, our objective ... | 2015 | 26019995 |
| mixed infections reveal virulence differences between host-specific bee pathogens. | dynamics of host-pathogen interactions are complex, often influencing the ecology, evolution and behavior of both the host and pathogen. in the natural world, infections with multiple pathogens are common, yet due to their complexity, interactions can be difficult to predict and study. mathematical models help facilitate our understanding of these evolutionary processes, but empirical data are needed to test model assumptions and predictions. we used two common theoretical models regarding mixed ... | 2015 | 25982695 |
| transcriptional responses to fluctuating thermal regimes underpinning differences in survival in the solitary bee megachile rotundata. | the transcriptional responses of insects to long-term, ecologically relevant temperature stress are poorly understood. long-term exposure to low temperatures, commonly referred to as chilling, can lead to physiological effects collectively known as chill injury. periodically increasing temperatures during long-term chilling has been shown to increase survival in many insects. however, the transcripts responsible for this increase in survival have never been characterized. here, we present the fi ... | 2015 | 25657206 |
| cell position during larval development affects postdiapause development in megachile rotundata (hymenoptera: megachilidae). | megachile rotundata (f.) (hymenoptera: megachilidae) is the primary pollinator of alfalfa in the northwestern united states and western canada and provides pollination services for onion, carrot, hybrid canola, various legumes, and other specialty crops. m. rotundata females are gregarious, nest in cavities either naturally occurring or in artificial nesting blocks, where they construct a linear series of brood cells. because of the physical layout of the nest, the age of the larvae within the n ... | 2014 | 24914676 |
| changes in respiratory structure and function during post-diapause development in the alfalfa leafcutting bee, megachile rotundata. | megachile rotundata, the alfalfa leafcutting bee, is a solitary, cavity-nesting bee. m. rotundata develop from eggs laid inside brood cells constructed from leaf pieces and placed in series in an existing cavity. due to the cavity nesting behavior of m. rotundata, developing bees may experience hypoxic conditions. the brood cell itself and the position of cell inside the cavity may impact the rates of oxygen diffusion creating hypoxic conditions for developing animals. we hypothesized that bees ... | 2014 | 24819205 |
| oocyte size, egg index, and body lipid content in relation to body size in the solitary bee megachile rotundata. | females of solitary, nest-provisioning bees have relatively low fecundity, but produce large eggs as part of their overall strategy of investing substantially in each offspring. in intraspecific comparisons of several species of solitary, nest-provisioning bees and wasps, the size of the mature eggs produced increases with female body size. we further examined oocyte size-body size correlations in the solitary bee megachile rotundata (f.), an important crop pollinator. we hypothesized that large ... | 2014 | 24711966 |
| extended hypoxia in the alfalfa leafcutting bee, megachile rotundata, increases survival but causes sub-lethal effects. | many insects are tolerant of hypoxic conditions, but survival may come at a cost to long-term health. the alfalfa leaf-cutting bee, megachile rotundata, develops in brood cells inside natural cavities, and may be exposed to hypoxic conditions for extended periods of time. whether m. rotundata is tolerant of hypoxia, and whether exposure results in sub-lethal effects, has never been investigated. overwintering m. rotundata prepupae were exposed to 10%, 13%, 17%, 21% and 24% o2 for 11 months. once ... | 2014 | 24662466 |
| cross-linking in the silks of bees, ants and hornets. | silk production is integral to the construction of nests or cocoons for many aculeata, stinging hymenopterans such as ants, bees and wasps. here we report the sequences of new aculeate silk proteins and compare cross-linking among nine native silks from three bee species (apis mellifera, bombus terrestris and megachile rotundata), three ant species (myrmecia forficata, oecophylla smaragdina and harpegnathos saltator) and three hornets (vespa analis, vespa simillima and vespa mandarinia). the wel ... | 2014 | 24607851 |
| health status of alfalfa leafcutting bee larvae (hymenoptera: megachilidae) in united states alfalfa seed fields. | we conducted a broad geographic survey in the northwestern united states to quantify production losses in the alfalfa leafcutting bee (megachile rotundata (f.), hymenoptera: megachilidae), a solitary pollinator used extensively in alfalfa seed production. viable larvae were found in only 47.1% of the nest cells collected at the end of the season. most of the rest of the cells contained pollen balls (typified by a provision but no larva; 16.7%), unknown causes of mortality (15.5%), or larvae kill ... | 2013 | 24128927 |
| nest marking behavior and chemical composition of olfactory cues involved in nest recognition in megachile rotundata. | in-nest observations of the solitary bee, megachile rotundata (f.), revealed that nesting females apply olfactory cues to nests for nest recognition. on their way in and out of the nest, females drag the abdomen along the entire length of the nest, and sometimes deposit fluid droplets from the tip of the abdomen. the removal of bee-marked sections of the nest resulted in hesitation and searching behavior by females, indicating the loss of olfactory cues used for nest recognition. chemical analys ... | 2013 | 23905742 |
| effects of extended prepupal storage duration on adult flight physiology of the alfalfa leafcutting bee (hymenoptera: megachilidae). | the alfalfa leafcutting bee, megachile rotundata (f.), is a solitary, cavity-nesting bee and is the primary pollinator for alfalfa seed production. bee management practices include cold storage during the prepupal stage. fluctuating thermal regimes during cold storage increases survival of cold storage and allows a doubling of the cold storage period with no decrease in survival. however, survival, characterized as successful adult emergence, is not qualitative. in this study, we determined whet ... | 2013 | 23865171 |
| a fluctuating thermal regime improves long-term survival of quiescent prepupal megachile rotundata (hymenoptera: megachilidae). | the alfalfa leafcutting bee megachile rotundata (f.) is the primary pollinator for alfalfa seed production. under standard management conditions, the alfalfa leafcutting bee develops to the diapausing prepupal stage under field conditions, after which they are cold-stored at a static temperature until the following spring, when temperatures are raised and development resumes. we have assessed the effects of a fluctuating thermal regime (ftr) during overwintering cold storage, where bees were exp ... | 2013 | 23865170 |
| intended release and actual retention of alfalfa leafcutting bees (hymenoptera: megachilidae) for pollination in commercial alfalfa seed fields. | low, medium, and high stocking densities (15,000; 30,000; and 45,000-50,000 bees per acre, respectively) of megachile rotundata (f.) (hymenoptera: megachilidae), the alfalfa leafcutting bee, were released over 4 yr in three research plots of utah alfalfa, medicago sativa l. (fabaceae), planted at seed-production rates. a low percentage of bees (46-79% of released) survived the incubation and field-emergence processes; of those bees, the number of females that established at the nesting sites was ... | 2013 | 23786042 |
| variation in alfalfa leafcutting bee (hymenoptera: megachilidae) reproductive success according to location of nests in united states commercial domiciles. | the alfalfa leafcutting bee, megachile rotundata f., is used extensively to pollinate alfalfa for seed production in western north america. however, it usually is not possible to sustain bee populations in the united states. in the managed pollination system, variable microenvironments are experienced by developing m. rotundata during the nesting season that may influence bee reproductive success. in this study, bee cells were produced in a small alfalfa field and collected from domiciles accord ... | 2013 | 23786038 |
| duration and frequency of a high temperature pulse affect survival of emergence-ready megachile rotundata (hymenoptera: megachilidae) during low-temperature incubation. | synchronizing megachile rotundata (f.) nesting activity with alfalfa bloom is essential for ensuring optimal pollination for alfalfa seed production. this is achieved by timing the initiation of spring bee incubation so that adults will emerge -2 wk before peak bloom. if weather conditions change so as to delay the bloom, bee managers will commonly expose the developing bees to a period of low-temperature incubation to slow their development. we have previously demonstrated survival during low-t ... | 2012 | 22420249 |
| temperature stress affects the expression of immune response genes in the alfalfa leafcutting bee, megachile rotundata. | environmental stresses are thought to be associated with increases in disease suceptibility, attributable to evolutionary trade-offs between the energy demands required to deal with stress vs pathogens. we compared the effects of temperature stress and pathogen exposure on the immune response of a solitary bee, megachile rotundata. using an oligonucleotide microarray with 125 genes (375 probes), we determined that both high and low temperatures increased the expression of immune response genes i ... | 2012 | 22356318 |
| effect of temperature on post-wintering development and total lipid content of alfalfa leafcutting bees. | temperature plays an important role in effective management of the alfalfa leafcutting bee [megachile rotundata (f.); megachilidae], the major commercial pollinator of seed alfalfa [medicago sativa (l.); fabaceae] in north america. to improve our understanding of threshold and optimum rearing temperatures of m. rotundata, we examined the effect of temperature on postwintering development by using a greater number of temperature treatments than applied in previous studies (19 versus eight or fewe ... | 2011 | 22251693 |
| chalkbrood transmission in the alfalfa leafcutting bee: the impact of disinfecting bee cocoons in loose cell management systems. | understanding pathogen transmission could illuminate new methods for disease prevention. a case in point is chalkbrood in the alfalfa leafcutting bee [megachile rotundata (f.)]. propagation of this solitary bee is severely hampered by chalkbrood, a larval disease caused by ascosphaera aggregata (ascomycota). alfalfa leafcutting bees nest in existing cavities in wood or hollow reeds and overwinter as larvae. in the early summer, emerging adults frequently must chew through dead, diseased siblings ... | 2011 | 22251678 |
| a fluctuating thermal regime improves survival of cold-mediated delayed emergence in developing megachile rotundata (hymenoptera: megachilidae). | a significant concern in the commercial application of the alfalfa leafcutting bee, megachile rotundata (f.) (hymenoptera: megachilidae), for pollination is synchronizing bee emergence and activity with peak crop bloom. previous studies have demonstrated that the commercial spring incubation of this species can be successfully interrupted by low temperature incubation, thereby slowing development and giving producers flexibility in timing emergence to weather conditions or crop bloom. in this st ... | 2011 | 21882678 |
| ascosphaera subglobosa, a new spore cyst fungus from north america associated with the solitary bee megachile rotundata. | ascosphaera subglobosa (eurotiomycetes: onygenales) is newly described from the pollen provisions and nesting material of the solitary leaf-cutting bee megachile rotundata in canada and the western united states. this new species, related to a. atra and a. duoformis, is distinguished from other ascosphaera species by its globose to subglobose ascospores, evanescent spore balls and unique nuclear ribosomal dna sequences (its and lsu). | 2012 | 21828215 |
| effects of the insect growth regulator, novaluron on immature alfalfa leafcutting bees, megachile rotundata. | alfalfa leafcutting bees, megachile rotundata f. (hymenoptera: megachilidae), are the most common pollinators of alfalfa in the pacific northwest. reports from users of m. rotundata in idaho, utah and colorado have indicated exceptionally poor bee return from fields treated with novaluron to control lygus spp. our goal was to evaluate novaluron toxicity to immature m. rotundata using two different possible mechanisms of exposure. one goal was to assess immature mortality via treating nectar-poll ... | 2011 | 21539417 |
| the alfalfa leafcutting bee, megachile rotundata: the world's most intensively managed solitary bee. | the alfalfa leafcutting bee (alcb), megachile rotundata f. (megachildae), was accidentally introduced into the united states by the 1940s. nest management of this eurasian nonsocial pollinator transformed the alfalfa seed industry in north america, tripling seed production. the most common alcb management practice is the loose cell system, in which cocooned bees are removed from nesting cavities for cleaning and storage. traits of alcbs that favored their commercialization include gregarious nes ... | 2011 | 20809804 |
| interrupted incubation and short-term storage of the alfalfa pollinator megachile rotundata (hymenoptera: megachilidae): a potential tool for synchronizing bees with bloom. | a useful technique for synchronizing pollinators with the alfalfa, medicago savita l. (fabaceae), bloom is to interrupt the late spring incubation of developing bee pupae and pharate adults of megachile rotundata (f.) (hymenoptera: megachilidae) with short-term low-temperature storage. however, low-temperature exposure can be stressful depending on the temperature, duration of exposure, and the developmental stage exposed. to evaluate the effect of low-temperature storage after development had a ... | 2010 | 20429433 |
| nest establishment, pollination efficiency, and reproductive success of megachile rotundata (hymenoptera: megachilidae) in relation to resource availability in field enclosures. | the alfalfa leafcutting bee, megachile rotundata (fabricius), is used to pollinate alfalfa, medicago sativa l., for seed production in the united states and canada. it is difficult to reliably sustain commercial m. rotundata populations in the united states because of problems with disease, parasites, predators, and unexplained mortality. one possible explanation for early immature mortality is that, relative to floral availability, superfluous numbers of bees are released in alfalfa fields wher ... | 2010 | 20146851 |
| genes related to immunity, as expressed in the alfalfa leafcutting bee, megachile rotundata, during pathogen challenge. | virtually nothing is known about disease resistance in solitary bees, so expressed sequence tag (est) databases were developed to search for immune response genes in the alfalfa leafcutting bee. we identified 104 putative immunity-related genes from both healthy and pathogen-challenged bee larvae, and 12 more genes using pcr amplification. the genes identified coded for proteins with a wide variety of innate immune response functions, including pathogen recognition, phagocytosis, the prophenolox ... | 2009 | 19863668 |
| prewinter management affects megachile rotundata (hymenoptera: megachilidae) prepupal physiology and adult emergence and survival. | the alfalfa leafcutting bee, megachile rotundata f. (hymenoptera: megachilidae), is widely used as a pollinator for production of alfalfa, medicago sativa l., seed, and populations of these bees can be maintained by alfalfa seed growers or can be purchased from mostly canadian bee providers. m. rotundata raised in canada have higher survival rates during the incubation that occurs after winter storage than do bees produced in the northwestern united states, but no reason has been found for this ... | 2009 | 19736750 |
| long-term storage of ascosphaera aggregata and ascosphaera apis, pathogens of the leafcutting bee (megachile rotundata) and the honey bee (apis mellifera). | survival rates of ascosphaera aggregata and ascosphaera apis over the course of a year were tested using different storage treatments. for spores, the storage methods tested were freeze-drying and ultra-low temperatures, and for hyphae, freeze-drying, agar slants, and two methods of ultra-low temperatures. spores of a. aggregata and a. apis stored well at -80 degrees c and after freeze-drying. a. aggregata hyphae did not store well under any of the methods tested while a. apis hyphae survived we ... | 2009 | 19332075 |
| fungicide tests on adult alfalfa leafcutting bees (hymenoptera: megachilidae). | chalkbrood is a serious disease of alfalfa leafcutting bee megachile rotundata (f.) (hymenoptera: megachilidae) larvae, causing upward of 20% infection in the field. the causative agent is the fungus ascosphaera aggregata. this bee is used extensively for alfalfa seed pollination in the united states. using laboratory bioassays, we previously demonstrated that fungicides can reduce chalkbrood levels in the larvae. here, we evaluate the toxicity of four fungicides, benlate, captan, orbit, and rov ... | 2008 | 18767714 |
| do weather conditions correlate with findings in failed, provision-filled nest cells of megachile rotundata (hymenoptera: megachilidae) in western north america? | cavity-nesting alfalfa leafcutting bees, megachile rotundata (f.) (hymenoptera: megachilidae), are excellent pollinators of alfalfa, medicago savita l., for seed production. in commercial settings, artificial cavities are placed in field domiciles for nesting and, thereby, bee populations are sustained for future use. for this study, cells from leafcutting bee nests were collected in late summer from commercial seed fields. over 3 yr (2003-2005), 39 samples in total of approximately equal to 1,0 ... | 2008 | 18613565 |
| laboratory bioassays to evaluate fungicides for chalkbrood control in larvae of the alfalfa leafcutting bee (hymenoptera: megachilidae). | chalkbrood, a fungal disease in bees, is caused by several species of ascosphaera. a. aggregata is a major mortality factor in populations of the alfalfa leafcutting bee, megachile rotundata (f.) (hymenoptera: megachilidae) used in commercial alfalfa seed production. four formulated fungicides, benlate 50 wp, captan, orbit, and rovral 50 wp were tested in the laboratory for efficacy against hyphal growth of a. aggregata cultures. the same fungicides, with the addition of rovral 4 f, were tested ... | 2008 | 18613563 |
| effects of the insecticide phosmet on solitary bee foraging and nesting in orchards of capitol reef national park, utah. | capitol reef national park, in southcentral utah, contains 22 small orchards planted with antique fruit varieties by mormon pioneers beginning over a century ago. the orchards continue to be managed in a pick-and-pay program, which includes spraying with phosmet to suppress codling moth (cydia pomonella l.). the park is also home to a rich diversity of flowering plants, many of which are rare, bee-pollinated, and have populations within 1 km of the orchards. over 3 yr, we studied the short-term ... | 2007 | 17716471 |
| thermal history influences diapause development in the solitary bee megachile rotundata. | respiration rate, time to pupation and the expression patterns of selected genes were examined during the diapause to post-diapause transition in the alfalfa leafcutting bee, megachile rotundata held at constant 4 degrees c in winter storage. respiration quotients were at or below 0.7 from december to may and then increased to over 0.8 in june and july. the time required for prepupae to reach the pupal stage following transfer to 29 degrees c decreased from 23 days in december to 10 days in july ... | 2006 | 17049551 |
| effects of three-dimensional and color patterns on nest location and progeny mortality in alfalfa leafcutting bee (hymenoptera: megachilidae). | abstract in alfalfa, medicago sativa l., seed production where high bee densities are released, alfalfa leafcutting bee, megachile rotundata (f.) (hymenoptera: megachilidae), females may enter several nesting holes before locating their nests. such levels of "wrong hole" visits lead to an increase in the time spent by females locating their own nests, thereby decreasing alfalfa pollination efficiency and possibly healthy brood production. the objectives of this study were to determine the effect ... | 2006 | 16813291 |
| emergence success and sex ratio of commercial alfalfa leafcutting bees from the united states and canada. | samples of overwintering alfalfa leafcutting bee, megachile rotundata (f.) (hymenoptera: megachilidae), cells were sent to the laboratory as loose cells or in nesting boards from bee managers in the united states and in canada. x-radiographs of cells were used for determining cell contents. cells containing live prepupae were incubated, and the sex of emerging adults was recorded daily. cells from which no adult emerged were dissected to determine the developmental stage of dead bees and sex of ... | 2005 | 16539094 |
| impact of disinfecting nesting boards on chalkbrood control in the alfalfa leafcutting bee. | the alfalfa leafcutting bee, megachile rotundata (f.), is a solitary, cavity-nesting bee that has been managed in large numbers to pollinate alfalfa, medicago spp., seed crops since the 1960s. propagation of these bees from 1 yr to the next has been seriously hampered by chalkbrood, a larval disease caused by the fungus ascosphaera aggregata skou. in the united states, attempts to control the disease have been fairly unsuccessful, but include removing nests from the nesting boards and then disin ... | 2005 | 16156558 |
| alfalfa leafcutting bee population dynamics, flower availability, and pollination rates in two oregon alfalfa fields. | since the 1970s, it has become increasingly difficult for u.s. alfalfa seed producers to maintain megachile rotundata (f.) populations used for alfalfa, medicago sativa l., pollination. in 1998, we monitored m. rotundata population dynamics and foraging behavior, as well as alfalfa bloom and pollination rates in two fields in eastern oregon. despite marked differences in bee management, establishment was very similar in the two fields (approximately 0.5 females per nesting cavity) and lagged pea ... | 2005 | 16156556 |
| temporal variation in overwintering gene expression and respiration in the solitary bee megachile rotundata. | partial clones of megachile rotundata hsp90, hsp70, hsc70 and actin were developed by rt-pcr. these clones were used to generate probes to screen for the expression of their respective transcripts in heat-shocked pupae and in diapausing prepupae through post-diapausing pupae. northern blot analysis revealed transcript sizes for mrhsp90, mrhsp70, mrhsc70, and mractin of 3.6, 2.3, 2.5, and 1.4kb, respectively. mrhsp90 and mrhsp70 were highly upregulated in post-diapausing pupae exposed to 40 degre ... | 2005 | 15993126 |
| lipids stimulate spore germination in the entomopathogenic ascomycete ascosphaera aggregata. | the alfalfa leafcutting bee (megachile rotundata) is solitary and managed on a large scale for pollination of alfalfa seed crops. the bees nest in holes drilled in wood or polystyrene blocks, and their larvae are highly prone to a fungal disease called chalkbrood. the most prevalent form of chalkbrood is caused by ascosphaera aggregata, but this ascomycete is difficult to culture. hyphae will grow on standard fungal media, but spore germination is difficult to achieve and highly variable. we fou ... | 2004 | 15645171 |
| comparative toxicity and hazards of pesticides to apis and non-apis bees. a chemometrical study. | the adverse effects of 158 pesticides to the honey bee (apis mellifera), the alfalfa leafcutting bee (megachile rotundata) and the alkali bee (nomia melanderi) were compared by means of various linear and non-linear multivariate analyses. a comparison exercise including the bumble bee (bombus spp.) was also performed from a more restricted set of 32 pesticides. while no difference of sensitivity was found between a. mellifera and bombus spp., m. rotundata appeared the most susceptible to pestici ... | 2006 | 14758982 |
| discrimination of closed shapes by two species of bee, apis mellifera and megachile rotundata. | in the present study, the performance of two bee species, the honeybee apis mellifera and the leaf-cutter bee megachile rotundata, in discriminating among various closed (convex) shapes was examined systematically for the first time. bees were trained to each of five different shapes, a disc, a square, a diamond and two different triangles, all of the same area, using fresh bees in each experiment. in subsequent tests, the trained bees were given a choice between the learned shape and each of th ... | 2002 | 11893770 |
| use of rapd analyses to estimate population genetic parameters in the alfalfa leaf-cutting bee, megachile rotundata. | rapd analyses were performed on five geographically isolated populations of megachile rotundata. we used haploid males of the alfalfa leaf-cutting bee, m. rotundata, to overcome the limitation of the dominance of rapd markers in the determination of population genetic parameters. sixteen primers gave rise to 130 polymorphic and 31 monomorphic bands. the unbiased estimators calculated in this study include within- and between-population heterozygosity, nucleotide divergence, and genetic distance. ... | 1996 | 18469925 |
| use of rapd analysis for in situ identification of ascosphaera aggregata and ascosphaera larvis in larval cadavers of the alfalfa leafcutting bee, megachile rotundata. | chalkbrood of the alfalfa leafcutting bee, megachile rotundata, is caused by the fungus ascosphaera aggregata. we used random amplified polymorphic dna (rapd) analysis for the in situ identification of a. aggregata and a related species, ascosphaera larvis, in larval cadavers of m. rotundata. a simple dna extraction method was developed to preferentially isolate dna from fungal spores on the cadaver surface, or from ascocysts beneath the cuticle. similar banding patterns were obtained in a. aggr ... | 1996 | 8683161 |
| p-nitrophenylacetate hydrolysis by honey bee esterases: kinetics and inhibition. | 1. the kinetics and inhibition of p-nitrophenylacetate hydrolysis by cytosolic esterases of 1-day old female honey bees, apis mellifera l., were studied. 2. the calculated values obtained were km = 2.27 x 10(-5)m and vmax = 2.48 x 10(-8) mol/s per mg protein. 3. the inhibition mechanisms examined for four organophosphorus insecticides were highly competitive in nature and based on competitive inhibition coefficients the order of toxicity was naled > dichlorvos > cis-mevinphos = trans-mevinphos. ... | 1993 | 8498090 |
| dna fingerprinting analysis in the solitary bee megachile rotundata: variability and nest mate genetic relationships. | the most conventional approach for evaluating genetic variability in an insect population involves assessing the degree of enzyme polymorphism. hymenoptera display a relatively low level of genetic variability compared with most insect species. dna probes consisting of tandemly repeated sequences are powerful tools for detecting polymorphisms when employed to develop dna fingerprinting (dnafp) profiles in a wide range of organisms. this report describes genetic variability in the solitary bee sp ... | 1992 | 1526476 |
| esterase isozymes in a solitary bee, megachile rotundata (fab.): characterization, developmental multiplicity, and adult variability. | this study describes the biochemical characterization and genetic variation of cytosolic esterases in the alfalfa leafcutting bee, megachile rotundata (fab.). esterase isozymes were separated by nondenaturing polyacrylamide gel electrophoresis and isoelectric focusing and characterized by inhibition with eserine sulfate, edta, paraoxon, and p-hydroxymercuribenzoate. based on inhibition patterns and substrate specificity, there are major differences between adults and immature forms and more subt ... | 1990 | 2125203 |
| the kinetics and inhibition of p-nitrophenylacetate-hydrolysing esterases in a solitary bee, megachile rotundata (fab.). | 1. the kinetics and inhibition of p-nitrophenylacetate hydrolysis by cytosolic esterases of female alfalfa leafcutting bees, megachile rotundata (fab.) was examined. 2. for p-nitrophenylacetate, the km = 1.24 x 10(-4) m and vmax = 2.29 x 10(-9) mol/s per mg protein. 3. regarding four organophosphate insecticides, the mechanism of inhibition in all cases was mixed (competitive and uncompetitive) and, based on inhibition constants, the order of toxicity was naled greater than paraoxon greater than ... | 1990 | 2349807 |
| spore load of ascosphaera species on emerging adults of the alfalfa leafcutting bee, megachile rotundata. | the spore load of ascosphaera species spores on larval chalkbrood cadavers and newly emergent adults of the alfalfa leafcutting bee, megachile rotundata, was determined. the spore content of chalkbrood cadavers ranged from 3 x 10 to 5 x 10. adults emerging through zero to nine cadavers carried spores on all body parts examined by scanning electron microscopy. estimates of the total number of spores obtained from a series of adult washes ranged from 9 x 10 to 8 x 10. some adult males which emerge ... | 1980 | 16345532 |
| light and temperature effects on the oxygen consumption rhythms of the leafcutter bee, megachile rotundata (fabr.). | | 1971 | 4395844 |
| light refractive emergence rhythm in the leafcutter bee, megachile rotundata (f.) (hymenoptera: apoidea). | | 1970 | 5439604 |
| sex control by bees: a voluntary act of egg fertilization during oviposition. | the alfalfa leaf-cutter bee, megachile rotundata, stops abdominal contractions briefly during oviposition of female eggs but not during oviposition of male eggs. sperm stored in the spermatheca probably is pumped onto the micropyle of the egg during this pause. the stimulus inducing fertilization seems to be associated with the depth of the nesting tunnel. | 1970 | 5409486 |