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- Keyword
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- Wing polymorphism (11)
- Juvenile hormone (8)
- Life history (8)
- Trade-off (6)
- Juvenile hormone esterase (4)
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- Crickets (3)
- Gryllus (3)
- Intermediary metabolism (3)
- JH (3)
- Dispersal (2)
- Hormones (2)
- JHE (2)
- Resource allocation (2)
- wing polymorphism. (1)
- <i>Gryllus assimilis</i> (1)
- <i>Gryllus</i> (1)
- flight-oogenesis syndrome (1)
- wing polymorphism (1)
- Adaptation (1)
- Allocation (1)
- Amino acid (1)
- Biological rhythm (1)
- Biosynthesis (1)
- Circadian rhythm (1)
- Development (1)
- Drosophila (1)
- Ecdysteroid (1)
- Ecdysteroids (1)
- Endocrine regulation (1)
- Energetics (1)
Articles 1 - 30 of 40
Full-Text Articles in Life Sciences
Morph-Associated Jh Titer Diel Rhythm In Gryllus Firmus: Experimental Verification Of Its Circadian Basis And Cycle Characterization In Artificially Selected Lines Raised In The Field, Anthony J. Zera, Zhangwu Zhao
Morph-Associated Jh Titer Diel Rhythm In Gryllus Firmus: Experimental Verification Of Its Circadian Basis And Cycle Characterization In Artificially Selected Lines Raised In The Field, Anthony J. Zera, Zhangwu Zhao
Anthony Zera Publications
Previous studies demonstrated a high-amplitude, diel cycle for the hemolymph JH titer in the wing-polymorphic cricket, Gryllus firmus. The JH titer rose and fell in the flight-capable morph (long-winged, LW(f)) above and below the relatively temporally invariant JH titer in the flightless (short-winged, SW) morph. The morph-specific JH titer cycle appeared to be primarily driven by a morph-specific diel cycle in the rate of JH biosynthesis. In the present study, cycles of the JH titer and rate of JH biosynthesis in the LW(f) morph persisted in the laboratory under constant darkness with an approximate 24 h periodicity. The JH …
Tissue And Stage-Specific Juvenile Hormone Esterase (Jhe) And Epoxide Hydrolase (Jheh) Enzyme Activities And Jhe Transcript Abundance In Lines Of The Cricket Gryllus Assimilis Artificially Selected For Plasma Jhe Activity: Implications For Jhe Microevolution, Anurag Anand, Erica Crone, Anthony J. Zera
Tissue And Stage-Specific Juvenile Hormone Esterase (Jhe) And Epoxide Hydrolase (Jheh) Enzyme Activities And Jhe Transcript Abundance In Lines Of The Cricket Gryllus Assimilis Artificially Selected For Plasma Jhe Activity: Implications For Jhe Microevolution, Anurag Anand, Erica Crone, Anthony J. Zera
Anthony Zera Publications
Fat body and midgut juvenile hormone esterase (JHE) and juvenile hormone epoxide hydrolase (JHEH) specific activities, and plasma JHE activity, were measured throughout the last stadium in two pairs (blocks) of lines of the cricket Gryllus assimilis, each pair of which had been artificially selected for high- or low-plasma JHE activity. Highly significant differences were observed between high- and low-activity lines of each block on most days for fat body JHE, and on one day for midgut JHE activity. In each block, line differences in developmental profiles for fat body JHE activity paralleled line differences in plasma JHE activity …
Jhe In Gryllus Assimilis: Cloning, Sequence-Activity Associations And Phylogeny, E. J. Crone, Anthony J. Zera, A. Anand, J. G. Oakeshott, T. D. Sutherland, R. J. Russell, Lawrence G. Harshman, Federico G. Hoffmann, C. Claudianos
Jhe In Gryllus Assimilis: Cloning, Sequence-Activity Associations And Phylogeny, E. J. Crone, Anthony J. Zera, A. Anand, J. G. Oakeshott, T. D. Sutherland, R. J. Russell, Lawrence G. Harshman, Federico G. Hoffmann, C. Claudianos
Anthony Zera Publications
The 458 amino acid sequence of a mature JHE protein from the cricket Gryllus assimilis was identified after isolating the partial cDNA sequence encoding this protein from a fat body and midgut cDNA library. This hemimetabolan JHE sequence shows over 40% amino acid similarity to the known JHE sequences of several holometabolous insects. It also includes previously determined peptide sequences for G. assimilis JHE as well as two other motifs associated with JHE enzymes in holometabolous insects. The predicted molecular weight of the protein agrees with that of the JHE previously purified from G. assimilis. Partial genomic sequence encoding …
Hormones In The Field: Evolutionary Endocrinology Of Juvenile Hormone And Ecdysteroids In Field Populations Of The Wing-Dimorphic Cricket Gryllus Firmus, Anthony J. Zera, Zangwu Zhao, Katherine Kaliseck
Hormones In The Field: Evolutionary Endocrinology Of Juvenile Hormone And Ecdysteroids In Field Populations Of The Wing-Dimorphic Cricket Gryllus Firmus, Anthony J. Zera, Zangwu Zhao, Katherine Kaliseck
Anthony Zera Publications
Virtually no published information exists on insect endocrine traits in natural populations, which limits our understanding of endocrine microevolution. We characterized the hemolymph titers of juvenile hormone (JH) and ecdysteroids (ECDs), two key insect hormones, in field-collected short-winged, flightless (SW) and long-winged, flight-capable (LW(f)) morphs of the cricket Gryllus firmus. The JH titer exhibited a dramatic circadian rhythm in the LW(f) morph but was temporally constant in the flightless SW morph. This pattern was consistent in each of three years; in young, middle-aged, and older G. firmus; and in three other cricket species. The ECD titer was considerably …
The Cost Of Reproduction: The Devil In The Details, Lawrence G. Harshman, Anthony J. Zera
The Cost Of Reproduction: The Devil In The Details, Lawrence G. Harshman, Anthony J. Zera
Anthony Zera Publications
The cost of reproduction is of fundamental importance in life-history evolution. However, our understanding of its mechanistic basis has been limited by a lack of detailed functional information at all biological levels. Here, we identify, evaluate and integrate recent studies in five areas examining the proximate mechanisms underlying the cost of reproduction. Rather than being alternate explanations, hormonal regulation and intermediary metabolism act in concert and have an overarching influence in shaping the cost of reproduction. Immune function is compromised by reproduction, as is resistance to environmental stress. These studies not only provide new information about mechanisms that comprise “the …
Evolutionary Endocrinology: The Developing Synthesis Between Endocrinology And Evolutionary Genetics, Anthony J. Zera, Lawrence G. Harshman, Tony D. Williams
Evolutionary Endocrinology: The Developing Synthesis Between Endocrinology And Evolutionary Genetics, Anthony J. Zera, Lawrence G. Harshman, Tony D. Williams
Anthony Zera Publications
A productive synthesis of endocrinology and evolutionary genetics has occurred during the past two decades, resulting in the first direct documentation of genetic variation and correlation for endocrine regulators in nondomesticated animals. In a number of insect genetic polymorphisms (dispersal polymorphism in crickets, butterfly wing-pattern polymorphism), blood levels of ecdysteroids and juvenile hormone covary with morphology, development, and life history. Genetic variation in insulin signaling may underlie life history trade-offs in Drosophila. Vertebrate studies identified variation in brain neurohormones, bone-regulating hormones, and hormone receptor gene sequences that underlie ecologically important genetic polymorphisms. Most work to date has focused on genetically …
Evolutionary Genetics Of Juvenile Hormone And Ecdysteroid Regulation In Gryllus: A Case Study In The Microevolution Of Endocrine Regulation, Anthony J. Zera
Evolutionary Genetics Of Juvenile Hormone And Ecdysteroid Regulation In Gryllus: A Case Study In The Microevolution Of Endocrine Regulation, Anthony J. Zera
Anthony Zera Publications
During the past 15 years the first detailed synthesis of endocrinology and population genetics has begun, in which natural genetic variations for endocrine regulators have been characterized, almost exclusively in species of the cricket genus Gryllus. Artificial selection studies have documented that regulators of the juvenile hormone titer can rapidly evolve and exhibit levels of genetic variability similar to other physiological traits. Strong genetic correlations exist between some but not all regulators of the JH titer during the juvenile stage. No genetic correlation exists between regulators functioning in juvenile and adult stages, and thus, endocrine regulation can evolve independently in …
Intermediary Metabolism And Life-History Trade-Offs: Differential Metabolism Of Amino Acids Underlies The Dispersal-Reproduction Trade-Off In A Wing-Polymorphic Cricket, Anthony J. Zera, Zhangwu Zhao
Intermediary Metabolism And Life-History Trade-Offs: Differential Metabolism Of Amino Acids Underlies The Dispersal-Reproduction Trade-Off In A Wing-Polymorphic Cricket, Anthony J. Zera, Zhangwu Zhao
Anthony Zera Publications
Although the differential flow of metabolites through alternate pathways of intermediary metabolism is thought to be an important functional cause of life-history trade-offs, this phenomenon remains understudied. Using a radiolabeled amino acid, we quantified genetic differences in in vivo amino acid metabolism between morphs of the wing-polymorphic cricket Gryllus firmus that trade off early-age reproduction and dispersal capability. Lines selected for the flight-capable morph, which delays reproduction, oxidized a greater proportion of radiolabeled glycine and converted a greater amount into somatic lipid, mainly triglyceride (flight fuel). By contrast, lines selected for the flightless, reproductive morph converted a substantially greater proportion …
Biochemical Basis Of Specialization For Dispersal Vs. Reproduction In A Wing-Polymorphic Cricket: Morph-Specific Metabolism Of Amino Acids, Zhangwu Zhao, Anthony J. Zera
Biochemical Basis Of Specialization For Dispersal Vs. Reproduction In A Wing-Polymorphic Cricket: Morph-Specific Metabolism Of Amino Acids, Zhangwu Zhao, Anthony J. Zera
Anthony Zera Publications
The biochemical basis of specializations for dispersal vs. reproduction is an understudied aspect of dispersal polymorphism in insects. Using a radiolabelled amino acid, we quantified differences in in vivo amino acid metabolism between morphs of the wing-polymorphic cricket, Gryllus firmus, that trade-off early age reproduction and dispersal capability. Studies were conducted in crickets fed a variety of diets expected to influence amino acid and lipid metabolism. On the day of molt to adulthood, prior to the morph-specific trade-off between ovarian growth and biochemical preparation for flight (e.g. biosynthesis of triglyceride flight fuel), morphs did not differ in any aspect of …
Intermediary Metabolism And Life History Trade-Offs: Lipid Metabolism In Lines Of The Wing-Polymorphic Cricket, Gryllus Firmus, Selected For Flight Capability Vs. Early Age Reproduction, Anthony J. Zera
Anthony Zera Publications
The extent to which modifications in intermediary metabolism contribute to life history variation and trade-offs is an important but poorly understood aspect of life history evolution. Artificial selection was used to produce replicate genetic stocks of the wing-polymorphic cricket, Gryllus firmus, that were nearly pure-breeding for either the flight-capable (LW[f]) morph, which delays ovarian growth, or the flightless (SW) morph, which exhibits enhanced early-age fecundity. LW(f) lines accumulated substantially more triglyceride, the main flight fuel in Gryllus, compared with SW-selected lines, and enhanced accumulation of triglyceride was strongly associated with reduced ovarian growth. Increased triglyceride accumulation in LW(f) lines resulted …
A Morph-Specific Daily Cycle In The Rate Of Jh Biosynthesis Underlies A Morph-Specific Daily Cycle In The Hemolymph Jh Titer In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera
A Morph-Specific Daily Cycle In The Rate Of Jh Biosynthesis Underlies A Morph-Specific Daily Cycle In The Hemolymph Jh Titer In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera
Anthony Zera Publications
A previous study documented a high amplitude, morph-specific daily cycle in the hemolymph JH titer in the wing-polymorphic cricket, Gryllus firmus. The JH titer rose and fell 10–20 fold in the flight-capable [LW(f), long-winged] morph during the late-photophase- early scotophase, while it was relatively constant during that time in the flightless (SW, short-winged) morph. In the present study we documented a dramatic morph-specific daily cycle in the in vitro rate of juvenile hormone (JH) biosynthesis that was tightly correlated with the hemolymph JH titer on days 5–7 of adulthood. Biosynthetic rates rose and fell 1–2 fold between the late …
Effect Of A Juvenile Hormone Analogue On Lipid Metabolism In A Wing-Polymorphic Cricket: Implications For The Endocrine-Biochemical Bases Of Life-History Trade-Offs, Anthony J. Zera, Zhangwu Zhao
Effect Of A Juvenile Hormone Analogue On Lipid Metabolism In A Wing-Polymorphic Cricket: Implications For The Endocrine-Biochemical Bases Of Life-History Trade-Offs, Anthony J. Zera, Zhangwu Zhao
Anthony Zera Publications
The wing-polymorphic cricket, Gryllus firmus, has a flight-capable morph (LW[f]: long winged with functional flight muscles) and a flightless morph (SW: short winged with reduced nonfunctional flight muscles) that differ genetically in many aspects of lipid metabolism. To determine whether these differences result from genetically based alterations in endocrine regulation, the juvenile hormone mimic, methoprene, was applied to the LW(f) morph. This hormone manipulation converted the LW(f) morph into a SW phenocopy with respect to all aspects of lipid metabolism studied; that is, methoprene application decreased in vivo biosynthesis of total lipid and triglyceride, increased absolute and relative biosynthesis of …
The Hemolymph Jh Titer Exhibits A Large-Amplitude, Morph-Dependent, Diurnal Cycle In The Wing-Polymorphic Cricket, Gryllus Firmus, Zhangwu Zhao, Anthony J. Zera
The Hemolymph Jh Titer Exhibits A Large-Amplitude, Morph-Dependent, Diurnal Cycle In The Wing-Polymorphic Cricket, Gryllus Firmus, Zhangwu Zhao, Anthony J. Zera
Anthony Zera Publications
The hemolymph juvenile hormone (JH) titer was measured in over 500 flight-capable and flightless, adult female Gryllus firmus at 3–6 h intervals during each of days 2–8 of adulthood. The flight-capable morph exhibited a large-amplitude daily cycle in the hemolymph JH titer, while the flightless morph exhibited a barely perceptible cycle. The JH titer cycle was observed on all days in the flight-capable morph, but the large amplitude cycle (>15–20 fold increase in mean titer; >100-fold increase in some individuals), began on day 5. For both the large and small amplitude cycles, the JH titer peaked near the end …
The Endocrine Regulation Of Wing Polymorphism In Insects: State Of The Art, Recent Surprises, And Future Directions, Anthony J. Zera
The Endocrine Regulation Of Wing Polymorphism In Insects: State Of The Art, Recent Surprises, And Future Directions, Anthony J. Zera
Anthony Zera Publications
The endocrine mechanisms controlling the development and reproduction of flight-capable (long-winged) and flightless (short-winged or wingless) morphs of wing-polymorphic insects have been intensively investigated. The "classical model," put forward in the early 1960s, postulates that morph-specific differences in development and reproduction are caused by variation in the titers of juvenile hormone (JH) and/or ecdysone. Despite decades of study, the importance of these hormones in regulating wing polymorphism in aphids and planthoppers remains uncertain. This uncertainly is largely a consequence of technical and size constraints which have severely limited the types of endocrine approaches that can be used in these insects. …
Morph-Dependent Fatty Acid Oxidation In A Wing-Polymorphic Cricket: Implications For The Trade-Off Between Dispersal And Reproduction, Anthony J. Zera, Zhangwu Zhao
Morph-Dependent Fatty Acid Oxidation In A Wing-Polymorphic Cricket: Implications For The Trade-Off Between Dispersal And Reproduction, Anthony J. Zera, Zhangwu Zhao
Anthony Zera Publications
Although a considerable amount of information is available on the ecology and physiology of wing polymorphism, much less is known about the biochemical–genetic basis of morph specialization for dispersal versus reproduction. Previous studies have shown that the dispersing morph of the wing-polymorphic cricket, Gryllus firmus, prioritizes the accumulation of triglyceride flight fuel over ovarian growth, while the opposite occurs in the flightless morph during the first week of adulthood. In this study, we compared the in vivo rate of lipid oxidation between genetic stocks of flight-capable versus flightless morphs to determine the role of lipid catabolism in morph specialization …
Life-History Evolution And The Microevolution Of Intermediary Metabolism: Activities Of Lipid-Metabolizing Enzymes In Life-History Morphs Of A Wing-Dimorphic Cricket, Anthony J. Zera, Zhangwu Zhao
Life-History Evolution And The Microevolution Of Intermediary Metabolism: Activities Of Lipid-Metabolizing Enzymes In Life-History Morphs Of A Wing-Dimorphic Cricket, Anthony J. Zera, Zhangwu Zhao
Anthony Zera Publications
Although a considerable amount of information is available on the ecology, genetics, and physiology of life-history traits, much more limited data are available on the biochemical and genetic correlates of life-history variation within species. Specific activities of five enzymes of lipid biosynthesis and two enzymes of amino acid catabolism were compared among lines selected for flight-capable (LW[f]) versus flightless (SW) morphs of the cricket Gryllus firmus. These morphs, which exist in natural populations, differ genetically in ovarian growth (100–400% higher in SW) and aspects of flight capability including the size of wings and flight muscles, and the concentration of triglyceride …
Differential Lipid Biosynthesis Underlies A Tradeoff Between Reproduction And Fl Ight Capability In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera
Differential Lipid Biosynthesis Underlies A Tradeoff Between Reproduction And Fl Ight Capability In A Wing-Polymorphic Cricket, Zhangwu Zhao, Anthony J. Zera
Anthony Zera Publications
The biochemical basis of life-history tradeoffs is a poorly studied aspect of life-history evolution. We used radiotracer and endocrine approaches to investigate the extent to which morphs of a wing-polymorphic insect differ in the biosynthesis of lipid classes important for dispersal capability vs. reproduction (ovarian growth). The flightcapable genotype of Gryllus firmus biosynthesized a greater amount of total lipid and triglyceride (main flight fuel), which was preferentially allocated to somatic tissue during early adulthood. By contrast, the fl ightless genotype biosynthesized a significantly greater amount of phospholipid (important in egg development), which was preferentially allocated to ovaries. Topical application of …
Review Of Dispersal. Based On A Conference Held In Roscoff, France, 23 April–1 May 1999., Anthony J. Zera
Review Of Dispersal. Based On A Conference Held In Roscoff, France, 23 April–1 May 1999., Anthony J. Zera
Anthony Zera Publications
Edited by Jean Clobert, Etienne Danchin, André A Dhondt, and James D Nichols. Oxford and New York: Oxford University Press.
Dispersal is a phenomenon of central importance in ecology and evolution. Yet many of its fundamental aspects remain poorly understood or barely investigated. This excellent, broad-ranging volume is a collection of 26 short reviews derived from a Centre National de la Recherche (CNRS)-National Science Foundation (NSF) sponsored workshop held in 1999. As stated by the editors, this book is mainly comprised of “reviews and more theoretical approaches, with a limited number of empirical examples” (p. xx) on dispersal.
I highly …
Purification And Characterization Of Hemolymph Juvenile Hormone Esterase From The Cricket, Gryllus Assimilis, Anthony J. Zera, Travis Sanger, Jeremiah Hanes, Lawrence G. Harshman
Purification And Characterization Of Hemolymph Juvenile Hormone Esterase From The Cricket, Gryllus Assimilis, Anthony J. Zera, Travis Sanger, Jeremiah Hanes, Lawrence G. Harshman
Anthony Zera Publications
Juvenile hormone esterase (JHE) from the serum of the cricket, Gryllus assimilis, was purified to homogeneity in a four-step procedure involving polyethylene glycol precipitation, hydrophobic interaction FPLC, and ion exchange FPLC. This procedure could be completed in 4 days and resulted in a greater than 900-fold purification with greater than 30% recovery. The purified enzyme exhibited a single band on a silver-stained SDS PAGE gel and had an apparent subunit molecular mass of 52 kDa. The native subunit molecular mass, determined by gel permeation FPLC, was 98 kDa, indicating that JHE from Gryllus assimilis is a dimer of two …
Enzymological And Radiotracer Studies Of Lipid Metabolism In The Flight-Capable And Flightless Morphs Of The Wing-Polymorphic Cricket, Gryllus Firmus, Z. Zhao, Anthony J. Zera
Enzymological And Radiotracer Studies Of Lipid Metabolism In The Flight-Capable And Flightless Morphs Of The Wing-Polymorphic Cricket, Gryllus Firmus, Z. Zhao, Anthony J. Zera
Anthony Zera Publications
The flight-capable morph of the wing-polymorphic cricket, Gryllus firmus, exhibited significantly higher activities of each of five lipogenic enzymes compared with the obligately flightless morph on a standard and a high-carbohydrate diet during early adulthood. Similarly, the rate of incorporation of [14C]-acetate into total lipid was higher in the flight-capable morph during this time. By contrast, activities of lipogenic enzymes and rates of lipid biosynthesis, in general, did not differ between morphs on a low nutrient diet during early adulthood. Differences in lipid biosynthesis account for previously documented differences in lipid reserves between morphs on some, but …
The Metabolic Basis Of Life History Variation: Genetic And Phenotypic Differences In Lipid Reserves Among Life History Morphs Of The Wing-Polymorphic Cricket, Gryllus Firmus, Anthony J. Zera, A. Larsen
The Metabolic Basis Of Life History Variation: Genetic And Phenotypic Differences In Lipid Reserves Among Life History Morphs Of The Wing-Polymorphic Cricket, Gryllus Firmus, Anthony J. Zera, A. Larsen
Anthony Zera Publications
The flight-capable morph of the wing-polymorphic cricket, Gryllus firmus, accumulated a substantially greater quantity of total lipid and triglyceride, compared with the obligately flightless morph, during the first five days of adulthood. Increased lipid accumulation in the flight-capable morph was genetically based, and was produced when ovarian growth is substantially reduced in that morph. Temporal changes in lipid levels suggest that the higher triglyceride reserves in the flight-capable morph fed a high-nutrient diet were produced by elevated lipid biosynthesis. By contrast, on a low-nutrient or high carbohydrate diet, increased lipid levels in the flight-capable morph appeared to result primarily …
The Physiology Of Life History Trade-Offs In Animals, Anthony J. Zera, Lawrence G. Harshman
The Physiology Of Life History Trade-Offs In Animals, Anthony J. Zera, Lawrence G. Harshman
Anthony Zera Publications
The functional causes of life history trade-offs have been a topic of interest to evolutionary biologists for over six decades. Our review of life history trade-offs discusses conceptual issues associated with physiological aspects of trade-offs, and it describes recent advances on this topic. We focus on studies of four model systems: wing polymorphic insects, Drosophila, lizards, and birds. The most significant recent advances have been: (a) incorporation of genetics in physiological studies of trade-offs, (b) integration of investigations of nutrient input with nutrient allocation, (c) development of more sophisticated models of resource acquisition and allocation, (d) a shift to more …
Genetic And Diurnal Variation In The Juvenile Hormone Titer In A Wing-Polymorphic Cricket: Implications For The Evolution Of Life Histories And Dispersal, Anthony J. Zera, Gretchen Cisper
Genetic And Diurnal Variation In The Juvenile Hormone Titer In A Wing-Polymorphic Cricket: Implications For The Evolution Of Life Histories And Dispersal, Anthony J. Zera, Gretchen Cisper
Anthony Zera Publications
The wing-polymorphic cricket, Gryllus firmus, contains (1) a flight-capable morph (LWf) with long wings and functional flight muscles, (2) a flightless morph with reduced wings and underdeveloped flight muscles (SW), and (3) a flightless morph with histolyzed flight muscles but with fully developed wings (LWh). The LWf morph differed genetically from the SW morph and phenotypically from the LWh morph in the size of flight muscles, ovarian growth during the first week of adulthood, and the hemolymph titer of juvenile hormone (JH). This is the first study to document that phenotypes that differ …
The Endocrine-Genetic Basis Of Life-History Variation: The Relationship Between The Ecdysteroid Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket Gryllus Firmus, Anthony J. Zera, Justin Bottsford
The Endocrine-Genetic Basis Of Life-History Variation: The Relationship Between The Ecdysteroid Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket Gryllus Firmus, Anthony J. Zera, Justin Bottsford
Anthony Zera Publications
The hormonal basis of variation in life-history traits is a poorly studied topic in life-history evolution. An important step in identifying the endocrine-genetic causes of life-history variation is documenting statistical and functional associations between hormone titers and genotypes/phenotypes that vary in life-history traits. To this end, we compared the blood ecdysteroid titer and the mass of the ovaries during the first week of adulthood among a flight-capable morph and two fl ightless morphs of the wing-polymorphic cricket Gryllus firmus. Ecdysteroids are a group of structurally related hormones that regulate many important aspects of reproduction in insects. Both the ecdysteroid …
Nutrient Absorption And Utilization By Wing And Flight Muscle Morphs Of The Cricket Gryllus Firmus: Implications For The Trade-Off Between Flight Capability And Early Reproduction, Anthony J. Zera, Tammy Brink
Nutrient Absorption And Utilization By Wing And Flight Muscle Morphs Of The Cricket Gryllus Firmus: Implications For The Trade-Off Between Flight Capability And Early Reproduction, Anthony J. Zera, Tammy Brink
Anthony Zera Publications
Absorption efficiency (AD, approximate digestibility, assimilation efficiency) of various macronutrients and conversion of absorbed nutrients to biomass (ECD) were compared among the two types of flightless morph and the flight-capable morph of the cricket, Gryllus firmus. No biologically significant phenotypic or genetic difference in AD for carbohydrate, protein or lipid was observed among morphs fed either a high-nutrient (100%) or a low-nutrient (25%) diet. Thus, previously-documented differences among adult morphs in carbohydrate and lipid content must be caused by processes other than variation in nutrient absorption by morphs during adulthood. Relative absorption efficiency of total dry mass of food …
Juvenile Hormone Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket, Gryllus Firmus, Gretchen Cisper, Anthony J. Zera, David W. Borst
Juvenile Hormone Titer And Morph-Specific Reproduction In The Wing-Polymorphic Cricket, Gryllus Firmus, Gretchen Cisper, Anthony J. Zera, David W. Borst
Anthony Zera Publications
Juvenile hormone titers and reproductive characteristics were measured in adult wing and flight-muscle morphs of the wing-polymorphic cricket, Gryllus firmus, during the first week of adulthood. This species has three morphs: one flight capable morph with fully-developed wings and fully-developed flight muscles [LW(F)], one flightless morph with fully-developed wings and histolyzed (non-functional) flight muscles [LW(H)], and another flightless morph with underdeveloped (short) wings and underdeveloped flight muscles (SW). Both flightless morphs [LW(H) and SW] had larger ovaries which contained a greater number of postvitellogenic eggs compared with the flight capable [LW(F)] morph. The juvenile hormone titer was significantly higher …
Evolutionary Endocrinology Of Juvenile Hormone Esterase: Functional Relationship With Wing Polymorphism In The Cricket, Gryllus Firmus, Anthony J. Zera, Yuan Huang
Evolutionary Endocrinology Of Juvenile Hormone Esterase: Functional Relationship With Wing Polymorphism In The Cricket, Gryllus Firmus, Anthony J. Zera, Yuan Huang
Anthony Zera Publications
The existence, nature, and physiological consequences of genetic variation for juvenile hormone esterase (JHE) activity was studied in the wing-polymorphic cricket, Gryllus firmus. Hemolymph (blood) JHE activity was sixfold lower in nascent short-winged (SW) females, relative to nascent long-winged (LW) females, during the last juvenile stadium (stage). Morph-associated genetic variation for JHE activity had two causes, variation in loci: (1) regulating whole-organism enzyme activity; and (2) controlling the degree to which JHE is secreted into the blood. Reduced JHE activity in nascent SW-selected individuals was associated with reduced in vivo juvenile hormone catabolism. This suggests that variation in JHE …
The Endocrine Genetics Of Wing Polymorphism In Gryllus: Critique Of Recent Studies And State Of The Art, Anthony J. Zera
The Endocrine Genetics Of Wing Polymorphism In Gryllus: Critique Of Recent Studies And State Of The Art, Anthony J. Zera
Anthony Zera Publications
In a series of papers, the most recent of which was published in Evolution, quantitative-genetic experiments were undertaken on reproductive and physiological correlates of wing polymorphism in the sand cricket, Gryllus firmus (Fairbairn 1994; Fairbairn and Yadlowski 1997; Roff et al. 1997). A goal of these studies was to determine the physiological causes underlying: (1) genetic variation for an ecologically important threshold trait (wing polymorphism); and (2) genetic correlations between wing morph and other reproductive and migratory features, such as fecundity and flight muscle histolysis. These authors concluded that genetic variation for the activity of the endocrine regulator, juvenile hormone …
The Physiology Of Life-History Trade-Offs: Experimental Analysis Of A Hormonally Induced Life-History Trade-Off In Gryllus Assimilis, Anthony J. Zera, Jason Potts, Kari Kobus
The Physiology Of Life-History Trade-Offs: Experimental Analysis Of A Hormonally Induced Life-History Trade-Off In Gryllus Assimilis, Anthony J. Zera, Jason Potts, Kari Kobus
Anthony Zera Publications
Adult Gryllus assimilis given an analog of juvenile hormone exhibited reduced flight muscles and enlarged ovaries similar to those found in naturally occurring flightless individuals of species that are polymorphic for dispersal capability. Control and hormone-treated (flightless) G. assimilis did not differ in the amount of food consumed or assimilated on any of three diets that differed in nutrient quantity. Thus, enhanced ovarian growth of flightless individuals resulted from increased allocation of internal nutrients to reproduction (i.e., a trade-off) rather than from increased acquisition of nutrients. Compared with flight-capable controls, flightless G. assimilis also had reduced whole-organism respiration, reduced respiration …
Physiology And Ecology Of Dispersal Polymorphism In Insects, Anthony J. Zera, Robert F. Denno
Physiology And Ecology Of Dispersal Polymorphism In Insects, Anthony J. Zera, Robert F. Denno
Anthony Zera Publications
Studies of dispersal polymorphism in insects have played a pivotal role in advancing our understanding of population dynamics, life history evolution, and the physiological basis of adaptation. Comparative data on wing-dimorphic insects provide the most definitive evidence to date that habitat persistence selects for reduced dispersal capability. The increased fecundity of flightless females documents that a fitness tradeoff exists between flight capability and reproduction. However, only recently have studies of nutrient consumption and allocation provided unequivocal evidence that this fitness trade-off results from a trade-off of internal resources. Recent studies involving wing-dimorphic insects document that flight capability imposes reproductive penalties …