Open Access. Powered by Scholars. Published by Universities.®

Life Sciences Commons

Open Access. Powered by Scholars. Published by Universities.®

Articles 1 - 30 of 57

Full-Text Articles in Life Sciences

Mating For Male-Derived Prostaglandin: A Functional Explanation For The Increased Fecundity Of Mated Female Crickets?, Amy M. Worthington, Russell A. Jurenka, Clint D. Kelly Sep 2015

Mating For Male-Derived Prostaglandin: A Functional Explanation For The Increased Fecundity Of Mated Female Crickets?, Amy M. Worthington, Russell A. Jurenka, Clint D. Kelly

Russell A. Jurenka

Direct benefits are considered to be the driving force of high female mating rates, yet species in which females do not receive material resources from males still experience increased fitness from mating frequently. One hypothesis suggests that substances within the ejaculate may boost survival or offspring production. If these materials are limiting to females, they will require continual renewal via mating and could provide a functional understanding of how high mating rates lead to increased female fitness. Using the Texas field cricket, Gryllus texensis, we investigated the sexual transfer of prostaglandin E2, an important mediator of invertebrate reproduction. We determined …


Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena Jun 2015

Hemocyte Differentiation Mediates The Mosquito Late-Phase Immune Response Against Plasmodium In Anopheles Gambiae, Ryan C. Smith, Carolina Barillas-Mury, Marcelo Jacobs-Lorena

Ryan C. Smith

Plasmodium parasites must complete development in the mosquito vector for transmission to occur. The mosquito innate immune response is remarkably efficient in limiting parasite numbers. Previous work has identified a LPS-induced TNFα transcription factor (LITAF)-like transcription factor, LITAF-like 3 (LL3), which significantly influences parasite numbers. Here, we demonstrate that LL3 does not influence invasion of the mosquito midgut epithelium or ookinete-to-oocyst differentiation but mediates a late-phase immune response that decreases oocyst survival. LL3 expression in the midgut and hemocytes is activated by ookinete midgut invasion and is independent of the mosquito microbiota, suggesting that LL3 may be a component of …


The Plasmodium Bottleneck: Malaria Parasite Losses In The Mosquito Vector, Ryan C. Smith, Joel Vega-Rodríguez, Marcelo Jacobs-Lorena Aug 2014

The Plasmodium Bottleneck: Malaria Parasite Losses In The Mosquito Vector, Ryan C. Smith, Joel Vega-Rodríguez, Marcelo Jacobs-Lorena

Ryan C. Smith

Nearly one million people are killed every year by the malaria parasite Plasmodium. Although the disease-causing forms of the parasite exist only in the human blood, mosquitoes of the genus Anopheles are the obligate vector for transmission. Here, we review the parasite life cycle in the vector and highlight the human and mosquito contributions that limit malaria parasite development in the mosquito host. We address parasite killing in its mosquito host and bottlenecks in parasite numbers that might guide intervention strategies to prevent transmission.


Immunization Against A Merozoite Sheddase Promotes Multiple Invasion Of Red Blood Cells And Attenuates Plasmodium Infection In Mice, Ryan C. Smith, Daisy D. Colón-López, Jürgen Bosch Aug 2014

Immunization Against A Merozoite Sheddase Promotes Multiple Invasion Of Red Blood Cells And Attenuates Plasmodium Infection In Mice, Ryan C. Smith, Daisy D. Colón-López, Jürgen Bosch

Ryan C. Smith

Subtilisin-like protease 2 (SUB2) is a conserved serine protease utilized by Plasmodium parasites as a surface sheddase required for successful merozoite invasion of host red blood cells and has been implicated in ookinete invasion of the mosquito midgut. To determine if SUB2 is a suitable vaccine target to interfere with malaria parasite development, the effects of SUB2-immunization on the Plasmodium life cycle were examined in its vertebrate and invertebrate hosts. Swiss Webster mice were immunized with SUB2 peptides conjugated to Keyhole limpet hemocyanin (KLH) or KLH alone, and then challenged with Plasmodium berghei. To determine the effects of immunization on …


Transgenic Mosquitoes Expressing A Phospholipase A(2) Gene Have A Fitness Advantage When Fed Plasmodium Falciparum-Infected Blood, Ryan C. Smith, Christopher Kizito, Jason L. Rasgon, Marcelo Jacobs-Lorena Oct 2013

Transgenic Mosquitoes Expressing A Phospholipase A(2) Gene Have A Fitness Advantage When Fed Plasmodium Falciparum-Infected Blood, Ryan C. Smith, Christopher Kizito, Jason L. Rasgon, Marcelo Jacobs-Lorena

Ryan C. Smith

Genetically modified mosquitoes have been proposed as an alternative strategy to reduce the heavy burden of malaria. In recent years, several proof-of-principle experiments have been performed that validate the idea that mosquitoes can be genetically modified to become refractory to malaria parasite development. We have created two transgenic lines of Anophelesstephensi, a natural vector of Plasmodium falciparum, which constitutively secrete a catalytically inactive phospholipase A2 (mPLA2) into the midgut lumen to interfere with Plasmodium ookinete invasion. Our experiments show that both transgenic lines expressing mPLA2 significantly impair the development of rodent malaria parasites, but only one line impairs the development …


Enterobacter-Activated Mosquito Immune Responses To Plasmodium Involve Activation Of Srpn6 In Anopheles Stephensi, Ryan C. Smith, Abraham G. Eappen, Marcelo Jacobs-Lorena May 2013

Enterobacter-Activated Mosquito Immune Responses To Plasmodium Involve Activation Of Srpn6 In Anopheles Stephensi, Ryan C. Smith, Abraham G. Eappen, Marcelo Jacobs-Lorena

Ryan C. Smith

Successful development of Plasmodium in the mosquito is essential for the transmission of malaria. A major bottleneck in parasite numbers occurs during midgut invasion, partly as a consequence of the complex interactions between the endogenous microbiota and the mosquito immune response. We previously identified SRPN6 as an immune component which restricts Plasmodium berghei development in the mosquito. Here we demonstrate that SRPN6 is differentially activated by bacteria in Anopheles stephensi, but only when bacteria exposure occurs on the lumenal surface of the midgut epithelium. Our data indicate that AsSRPN6 is strongly induced following exposure to Enterobacter cloacae, a common component …


Regulation Of Anti-Plasmodium Immunity By A Litaf-Like Transcription Factor In The Malaria Vector Anopheles Gambiae, Ryan C. Smith, Abraham G. Eappen, Andrea J. Radtke, Marcelo Jacobs-Lorena Oct 2012

Regulation Of Anti-Plasmodium Immunity By A Litaf-Like Transcription Factor In The Malaria Vector Anopheles Gambiae, Ryan C. Smith, Abraham G. Eappen, Andrea J. Radtke, Marcelo Jacobs-Lorena

Ryan C. Smith

The mosquito is the obligate vector for malaria transmission. To complete its development within the mosquito, the malaria parasite Plasmodium must overcome the protective action of the mosquito innate immune system. Here we report on the involvement of the Anopheles gambiae orthologue of a conserved component of the vertebrate immune system, LPS-induced TNFα transcription factor (LITAF), and its role in mosquito anti-Plasmodium immunity. An. gambiae LITAF-like 3 (LL3) expression is up-regulated in response to midgut invasion by both rodent and human malaria parasites. Silencing of LL3 expression greatly increases parasite survival, indicating that LL3 is part of an anti-Plasmodium defense …


Regional Assemblages Of Lygus (Heteroptera: Miridae) In Montana Canola Fields, Sue Blodgett, R. A. Ritter, A. W. Lenssen, M. L. Taper Oct 2010

Regional Assemblages Of Lygus (Heteroptera: Miridae) In Montana Canola Fields, Sue Blodgett, R. A. Ritter, A. W. Lenssen, M. L. Taper

Sue Blodgett

Sweep net sampling of canola (Brassica napus L.) was conducted in 2002 and 2003 to determine Lygus (Heteroptera: Miridae) species composition and parasitism levels in four regions of Montana. Regardless of region or seasonal change, Lygus elisus (Van Duzee) was the dominant species in all canola fields sampled, averaging 60–99% of the total adult populations. Lygus borealis (Kelton), Lygus keltoni (Schwartz) and Lygus lineolaris (Palisot) were detected at much lower levels. Total lygus population density was greatest in the southwest and central regions. The northeast and southwest regions had the greatest lygus species diversity. The proportion of L. elisus increased …


Insect-Damaged Corn Stalks Decompose At Rates Similar To Bt-Protected, Non-Damaged Corn Stalks, R. Michael Lehman, Shannon L. Osborne, Deirdre A. Prischmann-Voldseth, Kurt A. Rosentrater Aug 2010

Insect-Damaged Corn Stalks Decompose At Rates Similar To Bt-Protected, Non-Damaged Corn Stalks, R. Michael Lehman, Shannon L. Osborne, Deirdre A. Prischmann-Voldseth, Kurt A. Rosentrater

Kurt A. Rosentrater

The relative decomposability of corn (Zea mays L.) residues from insect (Bt)-protected hybrids and conventional hybrids cultivated under insect pressure was investigated in two studies. Above-ground biomass, residue macromolecular composition, and stalk physical strength were also measured. In the first decomposition study, chopped residues (stalks and leaves) were used from a corn rootworm-protected (Cry3Bb1) hybrid and its non-Bt near isoline that were grown in replicated plots infested with corn rootworms (Diabrotica spp.). In the second study, residue (intact stalk sections) was used from three European corn borer (ECB, Ostrinia nubilalis Hübner)-resistant (Cry1Ab) hybrids representing different seed manufacturer/maturity date series, their …


Regional Assemblages Of Lygus (Heteroptera: Miridae) In Montana Canola Fields, Andrew W. Lenssen, R. A. Ritter, Sue L. Blodgett, M. L. Taper Jan 2010

Regional Assemblages Of Lygus (Heteroptera: Miridae) In Montana Canola Fields, Andrew W. Lenssen, R. A. Ritter, Sue L. Blodgett, M. L. Taper

Andrew W. Lenssen

Sweep net sampling of canola (Brassica napus L.) was conducted in 2002 and 2003 to determine Lygus (Heteroptera: Miridae) species composition and parasitism levels in four regions of Montana. Regardless of region or seasonal change, Lygus elisus (Van Duzee) was the dominant species in all canola fields sampled, averaging 60–99% of the total adult populations. Lygus borealis (Kelton), Lygus keltoni (Schwartz) and Lygus lineolaris (Palisot) were detected at much lower levels. Total lygus population density was greatest in the southwest and central regions. The northeast and southwest regions had the greatest lygus species diversity. The proportion of L. elisus increased …


Synergism Between Entomopathogenic Nematodes And Bacillus Thuringiensis Crops: Integrating Biological Control And Resistance Management, Aaron J. Gassmann, S. Patricia Stock, Mark S. Sisterson, Yves Carriere, Bruce E. Tabashnik Jun 2008

Synergism Between Entomopathogenic Nematodes And Bacillus Thuringiensis Crops: Integrating Biological Control And Resistance Management, Aaron J. Gassmann, S. Patricia Stock, Mark S. Sisterson, Yves Carriere, Bruce E. Tabashnik

Aaron J. Gassmann

The past decade has witnessed a continual increase in the use of crops genetically modified to produce insecticidal toxins from the bacterium Bacillus thuringiensis (Bt). This presents the challenge of designing agricultural systems to manage pests and the evolution of resistance to Bt. We tested whether entomopathogenic nematodes might act synergistically with Bt crops by killing pests in non-Bt refuges and by increasing the fitness costs of resistance to Bt. We also tested whether insect mortality and fitness costs were affected by the cotton phytochemical gossypol. The entomopathogenic nematode Steinernema riobrave increased the fitness cost of Bt resistance, indicating that …


The Strength Of Seeds And Their Destruction By Granivorous Insects, Jonathan G. Lundgren, Kurt A. Rosentrater Jun 2007

The Strength Of Seeds And Their Destruction By Granivorous Insects, Jonathan G. Lundgren, Kurt A. Rosentrater

Kurt A. Rosentrater

The influence of seed structure and strength on their destruction by granivores is central to understanding the dynamics of granivore-plant interactions. For up to nine seed species, the effects of seed size (cm3), mass (mg), density (mg/cm3) and coat strength (MPa) on the damage inflicted by three post-dispersal granivores (Harpalus pensylvanicus, Anisodactylus sanctaecrucis, and Gryllus pennsylvanicus) were evaluated. Seed destruction rates by G. pennsylvanicus were statistically unrelated to the size and toughness of the seeds. Seed densities significantly affected their destruction by A. sanctaecrucis and H. pensylvanicus, as did seed size, mass, and strength in H. pensylvanicus under choice conditions. …


High-Level Resistance To Bacillus Thuringiensis Toxin Cry1ac And Cadherin Genotype In Pink Bollworm, Aaron J. Gassmann, Robert W. Biggs, Jeffrey A. Fabrick, Bruce E. Tabashnick, Timothy J. Dennehy, Yves Carriere, Shai Morin Dec 2006

High-Level Resistance To Bacillus Thuringiensis Toxin Cry1ac And Cadherin Genotype In Pink Bollworm, Aaron J. Gassmann, Robert W. Biggs, Jeffrey A. Fabrick, Bruce E. Tabashnick, Timothy J. Dennehy, Yves Carriere, Shai Morin

Aaron J. Gassmann

Resistance to transgenic cotton, Gossypium hirsutum L., producing Bacillus thuringiensis (Bt) toxin Cry1Ac is linked with three recessive alleles of a cadherin gene in laboratory-selected strains of pink bollworm, Pectinophora gossypiella (Saunders), a major cotton pest. Here, we analyzed a strain (MOV97-R) with a high frequency of cadherin resistance alleles, a high frequency of resistance to 10 μg of Cry1Ac per milliliter of diet, and an intermediate frequency of resistance to 1,000 μg of Cry1Ac per ml of diet. We selected two strains for increased resistance by exposing larvae from MOV97-R to diet with 1,000 μg of Cry1Ac per ml …


Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett Jan 2006

Incorporating Targeted Grazing Into Farming Systems, Andrew W. Lenssen, Patrick Hatfield, Hayes Goosey, Sue Blodgett

Andrew W. Lenssen

When incorporating targeted grazing into farming systems, livestock producers and farm operators need assurance that the benefits from their activities are worth their investments. This chapter will focus on how integrating grazing, particularly with sheep and goats, into farming systems can offer those benefits. The concepts are not new. Cropping systems were once integrated with livestock production: Livestock gained forage value from crop aftermath, crops were grown to sustain livestock, and livestock were used as implements to produce crops. Today, few cropping systems include livestock. Sheep and goats are traditionally produced on rangelands or pasture forages and supplemented during winter …


Seasonal Abundance Of Ground Beetles In Highbush Blueberry (Vaccinium Corymbosum) Fields And Response To A Reduced-Risk Insecticide Program, Matthew E. O'Neal, K. S. Mason, R. Isaacs Apr 2005

Seasonal Abundance Of Ground Beetles In Highbush Blueberry (Vaccinium Corymbosum) Fields And Response To A Reduced-Risk Insecticide Program, Matthew E. O'Neal, K. S. Mason, R. Isaacs

Matthew E. O'Neal

Seasonal patterns of ground beetle activity were examined at six highbush blueberry (Vaccinium corymbosum L.) farms in southwestern Michigan. On each farm, pitfall traps were used to monitor ground beetle activity in two adjacent fields: one managed under a conventional insecticide program (grower standard) and the other with reduced-risk insecticides. Overall, more active ingredient was applied in grower standard than reduced-risk fields, with the greatest amount used in June and July. During the 6-mo sampling period, we collected 11,322 ground beetles comprised of 34 species, with Harpalus pensylvanicus DeGeer representing 70.7% of the total beetles collected. The greatest amount of …


Corn Phenology Influences Diabrotica Virgifera Virgifera Emigration And Visitation To Soybean In, Matthew E. O'Neal, D. A. Landis, J. R. Miller Feb 2004

Corn Phenology Influences Diabrotica Virgifera Virgifera Emigration And Visitation To Soybean In, Matthew E. O'Neal, D. A. Landis, J. R. Miller

Matthew E. O'Neal

We used two types of laboratory apparatus to test whether rotation-resistant and wild-type Diabrotica virgifera virgifera LeConte (Coleoptera: Chrysomelidae) responded differently to corn phenology. Beetles from Nebraska where injury to rotated corn has not been reported were defined as wild type, and beetles from Illinois where injury to rotated corn is common represented “rotation-resistant“ populations. A two-chamber emigration arena assayed propensity of both populations to leave corn during and after anthesis. A side-arm olfactometer tested whether the relative attraction of beetles to soybean versus corn was influenced by corn phenology. Beetle origin did not influence departure from corn of varying …


Does Landscape Diversity Slow The Spread Of Rotation-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae)?, D. W. Onstad, D. W. Crwoder, S. A. Isard, E. Levine, J. L. Spencer, Matthew E. O'Neal, S. T. Ratcliffe, M. E. Gray, L. W. Bledsoe, C. D. Di Fonzo, J. B. Eisley, C. R. Edwards Oct 2003

Does Landscape Diversity Slow The Spread Of Rotation-Resistant Western Corn Rootworm (Coleoptera: Chrysomelidae)?, D. W. Onstad, D. W. Crwoder, S. A. Isard, E. Levine, J. L. Spencer, Matthew E. O'Neal, S. T. Ratcliffe, M. E. Gray, L. W. Bledsoe, C. D. Di Fonzo, J. B. Eisley, C. R. Edwards

Matthew E. O'Neal

A behavioral change in some western corn rootworm (Diabrotica virgifera virgifera LeConte) populations is threatening the effectiveness of crop rotation, a successful management strategy for controlling this pest. We created a set of simple meteorologic and behavioral models that can be used to predict the spread of the beetle infesting soybean (Glycine max (L.)) throughout the midwestern United States. We used data collected in Illinois, IN, MI, and Ohio to create maps of observations to evaluate the model. We displayed data on the maps using detection thresholds for western corn rootworm in soybean fields of 10 or 20 beetles per …


An Inexpensive, Accurate Method For Measuring Leaf Area And Defoliation Through Digital Image Analysis, Matthew E. O'Neal, Douglas A. Landis, Rufus Isaacs Dec 2002

An Inexpensive, Accurate Method For Measuring Leaf Area And Defoliation Through Digital Image Analysis, Matthew E. O'Neal, Douglas A. Landis, Rufus Isaacs

Matthew E. O'Neal

We report a protocol using a common desk-top scanner and public domain software for measuring existing leaf area and leaf area removed as a result of herbivory. We compared the accuracy and precision of this method to that of a standard leaf area meter. Both methods were used to measure metal disks of a known area, the area of soybean (Glycine max L.) leaves, and the area removed by simulating leaf feeding with a hole-punch. We varied the amount of injury across a low, medium, and high degree of simulated feeding. The mean area of 10 cm2 and 50 cm2 …


Recombinant Soluble Epoxide Hydrolase, Bruce D. Hammock, David F. Grant, Jeffrey K. Beetham Aug 1995

Recombinant Soluble Epoxide Hydrolase, Bruce D. Hammock, David F. Grant, Jeffrey K. Beetham

Jeffrey K. Beetham

The present invention relates to nucleic acid sequences and methods useful for producing recombinant human soluble epoxide hydrolase (sEH).


Chivalry In Pholcid Spiders Revisited, Julie A. Blanchong, Michael S. Summerfield, Mary A. Popson, Elizabeth M. Jakob Jan 1995

Chivalry In Pholcid Spiders Revisited, Julie A. Blanchong, Michael S. Summerfield, Mary A. Popson, Elizabeth M. Jakob

Julie A. Blanchong

Cohabiting pairs of adult spiders are likely to interact over prey, and the outcome of these interactions is likely to affect the reproductive success of both individuals. In two species of pholcid spiders, previous workers reported the occurrence of "chivalrous" behavior, in which males cede prey to females. We looked for the occurrence of chivalrous behavior in another pholcid spider, Holocnemus pluchei. Pairs of spiders were placed on a web and left overnight without prey. A housefly was then introduced onto the web equidistant from the spiders, and subsequent interactions were noted on audiotape. We found no evidence of chivalry …


Using Biodiversity Data To Assess Species--Habitat Relationships In Glacier National Park, Montana, Diane M. Debinski, Peter F. Brussard Nov 1994

Using Biodiversity Data To Assess Species--Habitat Relationships In Glacier National Park, Montana, Diane M. Debinski, Peter F. Brussard

Diane M. Debinski

Biodiversity surveys are becoming increasingly popular. However, standard analysis techniques for these data have not yet been developed. This paper explores the use of multivariate ordination techniques for assessing species—habitat relationships using biodiversity data. The research was conducted in Glacier National Park, Montana, and birds and butterflies were chosen as the taxonomic groups of study. Biodiversity assessment sites were established throughout a range of habitats and monitored from 1987 through 1989. Presence/absence sampling over the total number of sampling sites was used to classify species commonness and rarity. Approximately 86% of the historically recorded butterflies and 70% of the historically …


A Nuclear Juvenile Hormone-Binding Protein From Larvae Of Manduca Sexta: A Putative Receptor For The Metamorphic Action Of Juvenile Hormone, Subba R. Palli, Kazushige Touhara, Jean-Philippe Charles, Bryony C. Bonning, Jeffrey K. Atkinson, Stephen C. Trowell, Kiyoshi Hiruma, Walter G. Goodman, Themis Kyriakides, Glenn D. Prestwich, Bruce D. Hammock, Lynn M. Ridiford Jun 1994

A Nuclear Juvenile Hormone-Binding Protein From Larvae Of Manduca Sexta: A Putative Receptor For The Metamorphic Action Of Juvenile Hormone, Subba R. Palli, Kazushige Touhara, Jean-Philippe Charles, Bryony C. Bonning, Jeffrey K. Atkinson, Stephen C. Trowell, Kiyoshi Hiruma, Walter G. Goodman, Themis Kyriakides, Glenn D. Prestwich, Bruce D. Hammock, Lynn M. Ridiford

Bryony C. Bonning

A 29-kDa nuclear juvenile hormone (JH)-binding protein from the epidermis of Manduca sexta larvae was purified by using the photoaffinity analog for JH II ([3H]epoxyhomofarnesyldiazoacetate) and partially sequenced. A 1.1-kb cDNA was isolated by using degenerate oligonucleotide primers for PCR based on these sequences. The cDNA encoded a 262-amino acid protein that showed no similarity with other known proteins, except for short stretches of the interphotoreceptor retinoid-binding protein, rhodopsin, and human nuclear protein p68. Recombinant baculovirus containing this cDNA made a 29-kDa protein that was covalently modified by [3H]epoxyhomofarnesyldiazoacetate and specifically bound the natural enantiomer of JH I (Kd = …


Insect Control By Use Of Recombinant Baculoviruses Expressing Juvenile Hormone Esterase, Bryony C. Bonning, Bruce D. Hammock Jan 1994

Insect Control By Use Of Recombinant Baculoviruses Expressing Juvenile Hormone Esterase, Bryony C. Bonning, Bruce D. Hammock

Bryony C. Bonning

Anti-juvenile hormone activity, and the resulting cessation of feeding, has long been considered by the agricultural chemical industry as a means for insect control. Juvenile hormone esterase (JHE) contributes to the decline in JH titer at certain times during larval development. This chapter reviews the efforts made to develop a fast acting recombinant baculovirus insecticide by creating a virus which will express artificially high levels of JHE in the insect at inappropriate times. The findings are discussed in the light of our current understanding of the regulation of larval development and the role of JHE. Prospects for the newly developed, …


Ligand Binding By A Recombinant Insect Juvenile Hormone Binding Protein, Kazushige Touhara, Keith A. Lerro, Bryony C. Bonning, Bruce D. Hammock, Glenn D. Prestwich Mar 1993

Ligand Binding By A Recombinant Insect Juvenile Hormone Binding Protein, Kazushige Touhara, Keith A. Lerro, Bryony C. Bonning, Bruce D. Hammock, Glenn D. Prestwich

Bryony C. Bonning

A cDNA for the hemolymph juvenile hormone binding protein (JHBP) of larval Manduca sexta has been isolated, sequenced, and expressed in an insect cell line. A recombinant baculovirus, containing the JHBP cDNA fused to the p10 promoter of Autographa californica nuclear polyhedrosis virus, was constructed. Insect cells (Sf9) infected with this virus secreted recombinant JHBP (rJHBP) into the medium (>50 pg/mL), and cotranslational removal of an 18 amino acid leader sequence was observed. rJHBP was cross-reactive with an antiserum prepared to the hemolymph JHBP and was specifically labeled by [3H]EHDA, a photoaffinity analog of JH 11, demonstrating that rJHBP …


Nest Usurpation, Supersedure And Colony Failure Contribute To Africanization Of Commercially Managed European Honey Bees In Venezuela, Robert G. Danka, Richard L. Hellmich, Thomas E. Rinderer Dec 1992

Nest Usurpation, Supersedure And Colony Failure Contribute To Africanization Of Commercially Managed European Honey Bees In Venezuela, Robert G. Danka, Richard L. Hellmich, Thomas E. Rinderer

Richard L Hellmich

The fates of 58 colonies in 4 apiaries managed commercially for honey production in northwest Venezuela were determined during 15 months. All colonies had been previously requeened with marked European queens. Heritage of new queens (European daughter replacements versus Africanized usurpers) was traced by mitochondrial DNA and morphological characteristics of worker progeny. Three usurpations (5% of colony fates, at a rate of 4.7% of colonies per year) occurred. These colonies showed congruent African-derived mitochondrial DNA and Africanized morphology. Supersedures accounted for much of the introgression of African genes into the test apiaries. Twenty-eight colonies (48%) superseded their queens once, three …


Stimulation Of Pheromone Biosynthesis In The Moth Helicoverpa Zea: Action Of A Brain Hormone On Pheromone Glands Involves Ca2+ And Camp As Second Messengers, Russell A. Jurenka, Emmanuelle Jacquin, Wendell L. Roelofs Oct 1991

Stimulation Of Pheromone Biosynthesis In The Moth Helicoverpa Zea: Action Of A Brain Hormone On Pheromone Glands Involves Ca2+ And Camp As Second Messengers, Russell A. Jurenka, Emmanuelle Jacquin, Wendell L. Roelofs

Russell A. Jurenka

Isolated abdomen and pheromone gland bioassays were utilized to determine the physiological action of the pheromone-biosynthesis-activating neuropeptide (PBAN) in the corn earworm moth Helicoverpa (= Heliothis) zea. An isolated pheromone gland bioassay showed that synthetic PBAN was active at 0.02 pmol, with maximal activity occurring at 0.5 pmol and 60 min of incubation. Second-messenger studies demonstrated that extracellular Ca2+ is necessary for PBAN activity on isolated pheromone glands. The Ca2+ ionophore A23187 stimulated pheromone biosynthesis alone, whereas the Ca2+ channel blockers La3+ and Mn2+ inhibited PBAN activity. However, the organic Ca2+ channel blockers verapamil and nifedipine did not inhibit PBAN …


Interaction Of Insecticide Resistance Genes In Field Populations Of Culex Pipiens (Diptera: Culicidae) From Italy In Response To Changing Insecticide Selection Pressure, Bryony C. Bonning, J. Hemingway, R. Romi, G. Majori Mar 1991

Interaction Of Insecticide Resistance Genes In Field Populations Of Culex Pipiens (Diptera: Culicidae) From Italy In Response To Changing Insecticide Selection Pressure, Bryony C. Bonning, J. Hemingway, R. Romi, G. Majori

Bryony C. Bonning

Culex pipiens Linnaeus larvae were collected from various locations in Italy and colonized as separate strains. These were analysed for elevated nonspecific esterase activity and frequency of altered acetylcholinesterase (AChE) mechanisms of insecticide resistance, and bioassayed, to define the cross-resistance spectra conferred by these to organophosphorus and carbamate insecticides. These mechanisms were further characterized by polyacrylamide gel electrophoresis. Elevated esterase A1 (formerly known as Est 3A) which predominated in C. pipiens from Italy in 1985 had been replaced by two esterases, A2 and B2. Altered acetylcholinesterase was still present at high frequencies. Altered and normal acetylcholinesterase were distinguished by differential …


Flight Times Of Africanized And European Honey Bee Drones (Hymenoptera: Apidae), Richard L. Hellmich Ii, Thomas E. Rinderer, Robert G. Danka, Anita M. Collins, D. L. Boykin Jan 1991

Flight Times Of Africanized And European Honey Bee Drones (Hymenoptera: Apidae), Richard L. Hellmich Ii, Thomas E. Rinderer, Robert G. Danka, Anita M. Collins, D. L. Boykin

Richard L Hellmich

Flight activities of Africanized honey bee (Apis mellifera L.) drones were compared with those of two color morphs of European drones in Venezuela. European drones departed from colonies 19 +/- (mean +/- SEM) min earlier, and flight times were more variable than those of Africanized drones. Mean flight time differences decreased as the drones aged and were similar whether drones were flying from Africanized or European colonies. Overlap of their flight distributions was > 70%, which suggests that interbreeding of the two types of bees will be substantial under most natural conditions. Black and yellow European drones flew at similar times …


Response Of Africanized And European Honey Bees To Lactose In Sucrose Syrup, H. Allen Sylvester, Richard L. Hellmich Ii, Anita M. Collins Jan 1991

Response Of Africanized And European Honey Bees To Lactose In Sucrose Syrup, H. Allen Sylvester, Richard L. Hellmich Ii, Anita M. Collins

Richard L Hellmich

Application of biotechnology to control Africanized honey bees may be possible by genetically engineering domestic honey bee stocks to be resistant to some agent which is toxic or debilitating to Africanized bees. The agent could then be made available to forages in an area, and susceptible wild colonies, including Africanized honey bees, would be controlled.


Depression Of Forage Quality Of Alfalfa Leaves And Stems By Acyrthosiphon Kondoi (Homoptera: Aphididae), Andrew W. Lenssen, Edgar L. Sorensen, Gerry L. Posler, Sue L. Blodgett Jan 1991

Depression Of Forage Quality Of Alfalfa Leaves And Stems By Acyrthosiphon Kondoi (Homoptera: Aphididae), Andrew W. Lenssen, Edgar L. Sorensen, Gerry L. Posler, Sue L. Blodgett

Andrew W. Lenssen

ACYTthosiphon kondoi Shinji is a major pest of alfalfa (Medicago sativa L.). Susceptible seedling plants are killed by A. kondoi, and established plants suffer yield loss by stunting. Information is meager on the influence of A. kondoi infestation or host plant resistance on forage quality of alfalfa leaves and stems. In a controlled environment, the forage quality (includingphenolic monomers)of alfalfagermplasmsKSI53P4and KS153BA3P4 (susceptible and resistant to A. kondoi, respectively) with and without A. kondoi infestation was compared. Leaves infested with A. kondoi had lower concentrations of crude protein and true in vitro digestible dry matter (TIVDDM) than uninfested leaves of controls, …