Sample records for narnia konservatiivne unelm

  1. Marx in Narnia.

    ERIC Educational Resources Information Center

    Wade, Barrie; Sheppard, John

    1989-01-01

    Argues that teachers must understand the different values found in children's literature. Examines four aspects of values present in C. S. Lewis's "Chronicles of Narnia." Asserts that teachers must take responsibility for how such texts are received by young readers in the current multicultural, sexually equal society. (MM)

  2. New species of Narnia (Hemiptera: Heteroptera: Coreidae: Coreinae: Anisoscelini) from Mexico and key to the known species of the genus.

    PubMed

    Brailovsky, Harry; Barrera, Ernesto

    2013-11-13

    One new species of Narnia is described from Mexico, N. anaticula sp. nov. A key to the species is provided together with dorsal view photograph of each known species of Narnia. The genus is divided in two groups according the color of the dorsal abdominal segments.

  3. Oral Interpretation of C.S. Lewis'"Narnia Tales": A Refracting of "Pictures."

    ERIC Educational Resources Information Center

    Keefe, Carolyn

    "The Chronicles of Narnia" are a series of seven fairy tales written by C.S. Lewis that have become popular with both children and adults. Lewis points to five aspects of the fairy tale form that made the form suitable for expressing the images he saw. The aspects are: (1) no love interest; (2) no close psychology; (3) severe restraints…

  4. Lion king or Aslan: a tale from Narnia!

    PubMed

    Battista, Renaldo

    2011-01-01

    In the Chronicles of Narnia series by C.S. Lewis, Aslan the all-powerful but benevolent lion does not need to have his tail twisted; rather, he twists tails to create convergence and harmony in his dream world. In this issue's lead article, "Twisting the Lion's Tail: Collaborative Health Policy Making in British Columbia," the authors discuss the problems regarding better coordination of health services research, knowledge translation and policy making. The roles of academia, health authorities and government are presently unclear, with leadership differences, power discrepancies, conflicting agendas, lag times and systemic structural complexity. Exploring these issues in British Columbia, Lindstrom, MacLeod and Levy advocate a change in perspective from practice gaps to bridging knowledge boundaries. Recommendations include networking of academia, action research and strengthening of relationships between stakeholders. However, a key cohesive element seems missing. Health technology assessment (HTA) is a formidable, dynamic driving force. With over 20 years' experience in HTA, Canada has a number of world-class innovative agencies federally and provincially that actively involve academia to generate evidence for informed policy making. Increased use of evidence-based medicine in research and the clinic may be achieved by augmenting HTA's scientific capacity through the creation of pan-Canadian exchange forums and by boosting the demand for knowledge translation.

  5. Seasonal resource value and male size influence male aggressive interactions in the leaf footed cactus bug, Narnia femorata.

    PubMed

    Nolen, Zachary J; Allen, Pablo E; Miller, Christine W

    2017-05-01

    In animal contests, resource value (the quality of a given resource) and resource holding potential (a male's absolute fighting ability) are two important factors determining the level of engagement and outcome of contests. Few studies have tested these factors simultaneously. Here, we investigated whether natural, seasonal differences in cactus phenology (fruit quality) influence interactions between males in the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae). We also considered whether males were more likely to interact when they were similar in size, as predicted by theory. Finally, we examined if male size relative to the size of an opponent predicted competitive success. We found that males have more interactions on cactus with high value ripe fruit, as we predicted. Further, we found that males that were closer in size were more likely to interact, and larger males were more likely to become dominant. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Seasonal Effects on the Population, Morphology and Reproductive Behavior of Narnia femorata (Hemiptera: Coreidae)

    PubMed Central

    Cirino, Lauren A.; Miller, Christine W.

    2017-01-01

    Many insects are influenced by the phenology of their host plants. In North Central Florida, Narnia femorata (Hemiptera: Coreidae) spends its entire life cycle living and feeding on Opuntia mesacantha ssp. lata. This cactus begins producing flower buds in April that lead to unripe green fruit in June that ripen into red fruit through December. Many morphological and behavioral characteristics of N. femorata are known to be affected by cactus phenology in a controlled laboratory setting, including the degree of sexual dimorphism and mating behavior. Our goal with this study was to determine if similar phenotypic changes of N. femorata occurred over time in the wild, and the extent to which these changes were concordant with phenological changes in its host plant. Further, we investigate the length of the insect mouthparts (beak) over time. Ongoing work has suggested that beak length may change across cohorts of developing insects in response to feeding deep within cactus fruit where seed and pulp depth decrease as the fruit ripens. Our results revealed a drop in cactus fruit abundance between the months of July through October 2015 as cactus fruits turned red and ripened. Simultaneously, the average body size of both males and females of N. femorata declined at two sampled sites. Male hind femora (a sexually-selected weapon) decreased disproportionately in size over time so that males later in the year had relatively smaller hind femora for their body size. The sex-specific patterns of morphological change led to increased sexual-size dimorphism and decreased sexual dimorphism for hind femora later in the year. Further, we found that beak length decreased across cohorts of insects as cactus fruit ripened, suggesting phenotypic plasticity in mouthpart length. Behavioral studies revealed that female readiness to mate increased as the season progressed. In sum, we found pronounced changes in the phenotypes of these insects in the field. Although this study is far from

  7. Seasonal Effects on the Population, Morphology and Reproductive Behavior of Narnia femorata (Hemiptera: Coreidae).

    PubMed

    Cirino, Lauren A; Miller, Christine W

    2017-01-17

    Many insects are influenced by the phenology of their host plants. In North Central Florida, Narnia femorata (Hemiptera: Coreidae) spends its entire life cycle living and feeding on Opuntia mesacantha ssp. lata . This cactus begins producing flower buds in April that lead to unripe green fruit in June that ripen into red fruit through December. Many morphological and behavioral characteristics of N. femorata are known to be affected by cactus phenology in a controlled laboratory setting, including the degree of sexual dimorphism and mating behavior. Our goal with this study was to determine if similar phenotypic changes of N. femorata occurred over time in the wild, and the extent to which these changes were concordant with phenological changes in its host plant. Further, we investigate the length of the insect mouthparts (beak) over time. Ongoing work has suggested that beak length may change across cohorts of developing insects in response to feeding deep within cactus fruit where seed and pulp depth decrease as the fruit ripens. Our results revealed a drop in cactus fruit abundance between the months of July through October 2015 as cactus fruits turned red and ripened. Simultaneously, the average body size of both males and females of N. femorata declined at two sampled sites. Male hind femora (a sexually-selected weapon) decreased disproportionately in size over time so that males later in the year had relatively smaller hind femora for their body size. The sex-specific patterns of morphological change led to increased sexual-size dimorphism and decreased sexual dimorphism for hind femora later in the year. Further, we found that beak length decreased across cohorts of insects as cactus fruit ripened, suggesting phenotypic plasticity in mouthpart length. Behavioral studies revealed that female readiness to mate increased as the season progressed. In sum, we found pronounced changes in the phenotypes of these insects in the field. Although this study is far from

  8. Adult nutrition, but not inbreeding, affects male primary sexual traits in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae).

    PubMed

    Joseph, Paul N; Sasson, Daniel A; Allen, Pablo E; Somjee, Ummat; Miller, Christine W

    2016-07-01

    Adverse conditions may be the norm rather than the exception in natural populations. Many populations experience poor nutrition on a seasonal basis. Further, brief interludes of inbreeding can be common as population density fluctuates and because of habitat fragmentation. Here, we investigated the effects of poor nutrition and inbreeding on traits that can be very important to reproductive success and fitness in males: testes mass, sperm concentration, and sperm viability. Our study species was Narnia femorata, a species introduced to north-central Florida in the 1950s. This species encounters regular, seasonal changes in diet that can have profound phenotypic effects on morphology and behavior. We generated inbred and outbred individuals through a single generation of full-sibling mating or outcrossing, respectively. All juveniles were provided a natural, high-quality diet of Opuntia humifusa cactus cladode with fruit until they reached adulthood. New adult males were put on a high- or low-quality diet for at least 21 days before measurements were taken. As expected, the low-quality diet led to significantly decreased testes mass in both inbred and outbred males, although there were surprisingly no detectable effects on sperm traits. We did not find evidence that inbreeding affected testes mass, sperm concentration, and sperm viability. Our results highlight the immediate and overwhelming effects of nutrition on testes mass, while suggesting that a single generation of inbreeding might not be detrimental for primary sexual traits in this particular population.

  9. Resource quality affects weapon and testis size and the ability of these traits to respond to selection in the leaf-footed cactus bug, Narnia femorata.

    PubMed

    Sasson, Daniel A; Munoz, Patricio R; Gezan, Salvador A; Miller, Christine W

    2016-04-01

    The size of weapons and testes can be central to male reproductive success. Yet, the expression of these traits is often extremely variable. Studies are needed that take a more complete organism perspective, investigating the sources of variation in both traits simultaneously and using developmental conditions that mimic those in nature. In this study, we investigated the components of variation in weapon and testis sizes using the leaf-footed cactus bug, Narnia femorata (Hemiptera: Coreidae) on three natural developmental diets. We show that the developmental diet has profound effects on both weapon and testis expression and scaling. Intriguingly, males in the medium-quality diet express large weapons but have relatively tiny testes, suggesting complex allocation decisions. We also find that heritability, evolvability, and additive genetic variation are highest in the high-quality diet for testis and body mass. This result suggests that these traits may have an enhanced ability to respond to selection during a small window of time each year when this diet is available. Taken together, these results illustrate that normal, seasonal fluctuations in the nutritional environment may play a large role in the expression of sexually selected traits and the ability of these traits to respond to selection.

  10. See you in Narnia

    NASA Astrophysics Data System (ADS)

    Wright, Peter

    2010-02-01

    Having read James Gillies' Lateral Thoughts article on "The perilous world of the wardrobe" (January p52), I could not appreciate his comparison of the experiments at the Large Hadron Collider (LHC) with the opening of a wardrobe door, albeit tongue in cheek. It is absolutely understandable that scientists should wish to support and justify their work, but however much scorn Gillies pours on those with opposing views, the fact is that, as scientists, we have a duty to carry out our work responsibly.

  11. The fairy tale as paradigm of the separation-individuation crisis: implications for treatment of the borderline adolescent.

    PubMed

    Brandt, L M

    1983-01-01

    This chapter is an attempt to offer a model for therapeutic work with borderline patients that is based on the structure and content of the fairy tale. It views the fairy tale as both descriptive in its echoing of developmental struggles of childhood and integrative in providing a model for resolution of these conflicts. Clare's use of the fairy tale offers confirmation of theoretical notions which place the etiology of borderline pathology in early developmental failures and a clue to the therapeutic work with borderline patients. While the childhood route of the fairy tale may no longer be available to most, its subtle mirroring of the separation-individuation crisis and gradual, growthful steps toward integration of both the external and the internal worlds offer an exquisite model for the work of psychotherapy. "Once a king in Narnia , always a king in Narnia . But don't go trying to use the same route twice. . ." (Lewis 1950, p. 186).

  12. Paradise Lost and Found: Obedience, Disobedience, and Storytelling in C.S. Lewis and Philip Pullman.

    ERIC Educational Resources Information Center

    Wood, Naomi

    2001-01-01

    Considers how in the fantasy series "The Chronicles of Narnia" and "His Dark Materials," by C.S. Lewis and Philip Pullman respectively, the authors use symbols and themes from "Paradise Lost." Notes that each author's narrative choice uses his view of cosmic order to persuade readers that obedience should be…

  13. Ransom, Religion, and Red Giants: C.S. Lewis and Fred Hoyle

    NASA Astrophysics Data System (ADS)

    Larsen, Kristine

    2010-01-01

    Famed fantasy writer C.S. Lewis (1898-1963) was known to friends as a well-read astronomy aficionado. However, this medieval scholar and Christian apologist embraced a pre-Copernican universe (with its astrological overtones) in his Chronicles of Narnia series and defended the beauty and relevance of the geocentric model in his final academic work, "The Discarded Image". In the "Ransom Trilogy” ("Out of the Silent Planet", "Perelandra", and "That Hideous Strength") philologist Ransom (loosely based on Lewis's close friend J.R.R. Tolkien) travels to Lewis's visions of Mars and Venus, where he interacts with intelligent extraterrestrials, battles with evil scientists, and aids in the continuation of extraterrestrial Christian values. In the final book, Ransom is joined by a handful of colleagues in open warfare against the satanic N.I.C.E. (National Institute for Coordinated Experiments). Geneticist and evolutionary biologist J.B.S. Haldane criticized Lewis for his scientifically inaccurate descriptions of the planets, and his disdain for the scientific establishment. Lewis responded to the criticism in essays of his own. Another of Lewis's favorite scientific targets was atheist Fred Hoyle, whom he openly criticized for anti-Christian statements in Hoyle's BBC radio series. Writer and Lewis friend Dorothy L. Sayers voiced her own criticism of Hoyle. In a letter, Lewis dismissed Hoyle as "not a great philosopher (and none of my scientific colleagues think much of him as a scientist.” Given Lewis's lack of respect for Hoyle, and use of creative license in describing the planets, and the flat-earth, "geocentric” Narnia, it is surprising that Lewis very carefully includes an astronomically correct description of red giants in two novels in the Narnia series ("The Magician's Nephew" and "The Last Battle"). This inclusion is even more curious given that Fred Hoyle is well-known as one of the pioneers in the field of stellar death and the properties of red giants.

  14. Hobbits, Hogwarts, and the Heavens: The use of fantasy literature and film in astronomy outreach and education

    NASA Astrophysics Data System (ADS)

    Larsen, Kristine

    2011-06-01

    Due in part to recent (and ongoing) film adaptations, the fantasy series of C.S. Lewis (The Chronicles of Narnia), J.K. Rowling (Harry Potter), Philip Pullman (His Dark Materials), and J.R.R. Tolkien (The Silmarillion, The Hobbit, and The Lord of the Rings) are being introduced to a new audience. Many astronomers and astronomy educators are unaware of the wide variety of astronomical references contained in each series, and the myriad possible uses of these works in astronomy education and outreach. This paper highlights activities which educators, planetariums, and science centers have already developed to utilise these works in their education and outreach programs.

  15. Illustrated key for identification of the species included in the genus Leptoglossus (Hemiptera: Heteroptera: Coreidae: Coreinae: Anisoscelini), and descriptions of five new species and new synonyms.

    PubMed

    Brailovsky, Harry

    2014-05-05

    Five new species of Leptoglossus are described: L.caicosensis from Turks and Caicos Island, L. egeri and L. impensus from Bolivia, L. franckei from Costa Rica, and L. polychromus from Ecuador, Cooperative Republic of Guiana (British Guiana), and French Guiana. Leptoglossus argentinus Bergroth is synonymized under L. chilensis chilensis (Spinola) and Narnia anaticula Brailovsky & Barrera under Leptoglossus occidentalis Heidemann. Dorsal view drawings and key to the 61 known species and 1 subspecies are included; a complete checklist, and the position of each species within the species-group defined herein, are given except for two species L. macrophylus Stål and L. polychromus sp.nov., that are insertae-sedis. The pronotal disk, hind legs, and male genital capsule of the new species here described are illustrated.

  16. Into the wardrobe of Narnia: beyond HIV infection a world of cardiovascular risk

    PubMed Central

    Colotto, Marco; Renzi, Alessandra; Durante, Cosimo

    2012-01-01

    A 38-years-old HIV-hepatitis C virus (HCV) coinfected woman presented to us for dyslipidemia. Clinical, familial and laboratory data were consistent with the diagnosis of familial heterozygous hypercholesterolaemia. History, clinical examination and laboratory findings also supported suspected acromegaly. A pituitary MRI showed a sellar macroadenoma that was removed by transphenoidal surgery without complications. MRI carried out 6 months after surgery showed almost complete removal of the adenoma. This case report describes an uncommon association of diseases, very different for aetiology—genetic for FH, infectious for HIV and HCV, caused by excessive hormone secretion for acromegaly-clinical features and therapy, but all sharing a significant impact on cardiovascular risk as a common feature. PMID:22805737

  17. Into the wardrobe of Narnia: beyond HIV infection a world of cardiovascular risk.

    PubMed

    Colotto, Marco; Renzi, Alessandra; Durante, Cosimo

    2012-07-17

    A 38-years-old HIV-hepatitis C virus (HCV) coinfected woman presented to us for dyslipidemia. Clinical, familial and laboratory data were consistent with the diagnosis of familial heterozygous hypercholesterolaemia. History, clinical examination and laboratory findings also supported suspected acromegaly. A pituitary MRI showed a sellar macroadenoma that was removed by transphenoidal surgery without complications. MRI carried out 6 months after surgery showed almost complete removal of the adenoma. This case report describes an uncommon association of diseases, very different for aetiology--genetic for FH, infectious for HIV and HCV, caused by excessive hormone secretion for acromegaly--clinical features and therapy, but all sharing a significant impact on cardiovascular risk as a common feature.

  18. Muggles, Meteoritic Armor, and Menelmacar: Using Fantasy Series in Astronomy Education and Outreach

    NASA Astrophysics Data System (ADS)

    Larsen, Kristine; Bednarski, M.

    2008-05-01

    Due in part to recent (and ongoing) film adaptations, the fantasy series of C.S. Lewis (The Chronicles of Narnia), J.K. Rowling (Harry Potter), Philip Pullman (His Dark Materials), and J.R.R. Tolkien (The Lord of the Rings) are being introduced to a new audience of young (and not so young) readers. Many astronomers and astronomy educators are unaware of the wide variety of astronomical references contained in each series. The first portion of this workshop will introduce participants to these references, and highlight activities which educators, planetariums, and science centers have already developed to utilize these works in their education and outreach programs. In the second segment of the workshop, participants will develop ideas for activities and materials relevant to their individual circumstances, including standards-based education materials (in concert with an on-hand specialist in curriculum development).

  19. Muggles, Meteoritic Armor, and Menelmacar: Using Fantasy Series in Astronomy Education and Outreach

    NASA Astrophysics Data System (ADS)

    Larsen, K.; Bednarski, M.

    2008-11-01

    Due in part to recent (and ongoing) film adaptations, the fantasy series of C.S. Lewis (The Chronicles of Narnia), J.K. Rowling (Harry Potter), Philip Pullman (His Dark Materials), and J.R.R. Tolkien (The Silmarillion, The Hobbit, and The Lord of the Rings) are being introduced to a new audience of young (and not so young) readers. Many astronomers and astronomy educators are unaware of the wide variety of astronomical references contained in each series. The first portion of this workshop will introduce participants to these references, and highlight activities which educators, planetariums, and science centers have already developed to utilize these works in their education and outreach programs. In the second segment of the workshop, participants will develop ideas for activities and materials relevant to their individual circumstances, including standards-based education materials.

  20. Conspecific and Heterospecific Cues Override Resource Quality to Influence Offspring Production

    PubMed Central

    Miller, Christine W.; Fletcher, Robert J.; Gillespie, Stephanie R.

    2013-01-01

    Animals live in an uncertain world. To reduce uncertainty, animals use cues that can encode diverse information regarding habitat quality, including both non-social and social cues. While it is increasingly appreciated that the sources of potential information are vast, our understanding of how individuals integrate different types of cues to guide decision-making remains limited. We experimentally manipulated both resource quality (presence/absence of cactus fruit) and social cues (conspecific juveniles, heterospecific juveniles, no juveniles) for a cactus-feeding insect, Narnia femorata (Hemiptera: Coreidae), to ask how individuals responded to resource quality in the presence or absence of social cues. Cactus with fruit is a high-quality environment for juvenile development, and indeed we found that females laid 56% more eggs when cactus fruit was present versus when it was absent. However, when conspecific or heterospecific juveniles were present, the effects of resource quality on egg numbers vanished. Overall, N . femorata laid approximately twice as many eggs in the presence of heterospecifics than alone or in the presence of conspecifics. Our results suggest that the presence of both conspecific and heterospecific social cues can disrupt responses of individuals to environmental gradients in resource quality. PMID:23861984

  1. Automatic detection of artifacts in converted S3D video

    NASA Astrophysics Data System (ADS)

    Bokov, Alexander; Vatolin, Dmitriy; Zachesov, Anton; Belous, Alexander; Erofeev, Mikhail

    2014-03-01

    In this paper we present algorithms for automatically detecting issues specific to converted S3D content. When a depth-image-based rendering approach produces a stereoscopic image, the quality of the result depends on both the depth maps and the warping algorithms. The most common problem with converted S3D video is edge-sharpness mismatch. This artifact may appear owing to depth-map blurriness at semitransparent edges: after warping, the object boundary becomes sharper in one view and blurrier in the other, yielding binocular rivalry. To detect this problem we estimate the disparity map, extract boundaries with noticeable differences, and analyze edge-sharpness correspondence between views. We pay additional attention to cases involving a complex background and large occlusions. Another problem is detection of scenes that lack depth volume: we present algorithms for detecting at scenes and scenes with at foreground objects. To identify these problems we analyze the features of the RGB image as well as uniform areas in the depth map. Testing of our algorithms involved examining 10 Blu-ray 3D releases with converted S3D content, including Clash of the Titans, The Avengers, and The Chronicles of Narnia: The Voyage of the Dawn Treader. The algorithms we present enable improved automatic quality assessment during the production stage.

  2. Herbivore-mediated ecological costs of reproduction shape the life history of an iteroparous plant.

    PubMed

    Miller, Tom E X; Tenhumberg, Brigitte; Louda, Svata M

    2008-02-01

    Plant reproduction yields immediate fitness benefits but can be costly in terms of survival, growth, and future fecundity. Life-history theory posits that reproductive strategies are shaped by trade-offs between current and future fitness that result from these direct costs of reproduction. Plant reproduction may also incur indirect ecological costs if it increases susceptibility to herbivores. Yet ecological costs of reproduction have received little empirical attention and remain poorly integrated into life-history theory. Here, we provide evidence for herbivore-mediated ecological costs of reproduction, and we develop theory to examine how these costs influence plant life-history strategies. Field experiments with an iteroparous cactus (Opuntia imbricata) indicated that greater reproductive effort (proportion of meristems allocated to reproduction) led to greater attack by a cactus-feeding insect (Narnia pallidicornis) and that damage by this herbivore reduced reproductive success. A dynamic programming model predicted strongly divergent optimal reproductive strategies when ecological costs were included, compared with when these costs were ignored. Meristem allocation by cacti in the field matched the optimal strategy expected under ecological costs of reproduction. The results indicate that plant reproductive allocation can strongly influence the intensity of interactions with herbivores and that associated ecological costs can play an important selective role in the evolution of plant life histories.

  3. Plant reproductive allocation predicts herbivore dynamics across spatial and temporal scales.

    PubMed

    Miller, Tom E X; Tyre, Andrew J; Louda, Svata M

    2006-11-01

    Life-history theory suggests that iteroparous plants should be flexible in their allocation of resources toward growth and reproduction. Such plasticity could have consequences for herbivores that prefer or specialize on vegetative versus reproductive structures. To test this prediction, we studied the response of the cactus bug (Narnia pallidicornis) to meristem allocation by tree cholla cactus (Opuntia imbricata). We evaluated the explanatory power of demographic models that incorporated variation in cactus relative reproductive effort (RRE; the proportion of meristems allocated toward reproduction). Field data provided strong support for a single model that defined herbivore fecundity as a time-varying, increasing function of host RRE. High-RRE plants were predicted to support larger insect populations, and this effect was strongest late in the season. Independent field data provided strong support for these qualitative predictions and suggested that plant allocation effects extend across temporal and spatial scales. Specifically, late-season insect abundance was positively associated with interannual changes in cactus RRE over 3 years. Spatial variation in insect abundance was correlated with variation in RRE among five cactus populations across New Mexico. We conclude that plant allocation can be a critical component of resource quality for insect herbivores and, thus, an important mechanism underlying variation in herbivore abundance across time and space.

  4. Cut your losses: self-amputation of injured limbs increases survival.

    PubMed

    Emberts, Zachary; Miller, Christine W; Kiehl, Daniel; St Mary, Colette M

    2017-01-01

    Autotomy, self-induced limb loss, is an extreme trait observed throughout the animal kingdom; lizards drop their tails, crickets release their legs, and crabs drop their claws. These repeated evolutionary origins suggest that autotomy is adaptive. Yet, we do not have a firm understanding of the selective pressures that promote and maintain this extreme trait. Although multiple adaptive hypotheses exist, research has generally focused on autotomy's adaptive value as a form of predator escape. However, autotomy could also be selected to reduce the cost of an injured limb, which we investigate here. Previously, this alternative hypothesis has been challenging to directly test because when an injury occurs on an autotomizable limb, that limb is almost always dropped (i.e., autotomy is behaviorally fixed within populations). Recently, however, we have identified a species, Narnia femorata (Insecta: Hemiptera: Coreidae), where some individuals autotomize limbs in response to injury, but some do not. This natural variation allowed us to investigate both the survival costs of retaining an injured limb and the benefits of autotomizing it. In this study, we find a positive association between autotomizing injured limbs and survival, thereby quantifying a new and likely widespread benefit of autotomy-reducing the cost of injury.

  5. Cut your losses: self-amputation of injured limbs increases survival

    PubMed Central

    Miller, Christine W; Kiehl, Daniel; St. Mary, Colette M

    2017-01-01

    Abstract Autotomy, self-induced limb loss, is an extreme trait observed throughout the animal kingdom; lizards drop their tails, crickets release their legs, and crabs drop their claws. These repeated evolutionary origins suggest that autotomy is adaptive. Yet, we do not have a firm understanding of the selective pressures that promote and maintain this extreme trait. Although multiple adaptive hypotheses exist, research has generally focused on autotomy’s adaptive value as a form of predator escape. However, autotomy could also be selected to reduce the cost of an injured limb, which we investigate here. Previously, this alternative hypothesis has been challenging to directly test because when an injury occurs on an autotomizable limb, that limb is almost always dropped (i.e., autotomy is behaviorally fixed within populations). Recently, however, we have identified a species, Narnia femorata (Insecta: Hemiptera: Coreidae), where some individuals autotomize limbs in response to injury, but some do not. This natural variation allowed us to investigate both the survival costs of retaining an injured limb and the benefits of autotomizing it. In this study, we find a positive association between autotomizing injured limbs and survival, thereby quantifying a new and likely widespread benefit of autotomy—reducing the cost of injury. PMID:29622925

  6. Demographic models reveal the shape of density dependence for a specialist insect herbivore on variable host plants.

    PubMed

    Miller, Tom E X

    2007-07-01

    1. It is widely accepted that density-dependent processes play an important role in most natural populations. However, persistent challenges in our understanding of density-dependent population dynamics include evaluating the shape of the relationship between density and demographic rates (linear, concave, convex), and identifying extrinsic factors that can mediate this relationship. 2. I studied the population dynamics of the cactus bug Narnia pallidicornis on host plants (Opuntia imbricata) that varied naturally in relative reproductive effort (RRE, the proportion of meristems allocated to reproduction), an important plant quality trait. I manipulated per-plant cactus bug densities, quantified subsequent dynamics, and fit stage-structured models to the experimental data to ask if and how density influences demographic parameters. 3. In the field experiment, I found that populations with variable starting densities quickly converged upon similar growth trajectories. In the model-fitting analyses, the data strongly supported a model that defined the juvenile cactus bug retention parameter (joint probability of surviving and not dispersing) as a nonlinear decreasing function of density. The estimated shape of this relationship shifted from concave to convex with increasing host-plant RRE. 4. The results demonstrate that host-plant traits are critical sources of variation in the strength and shape of density dependence in insects, and highlight the utility of integrated experimental-theoretical approaches for identifying processes underlying patterns of change in natural populations.

  7. Novel host plant leads to the loss of sexual dimorphism in a sexually selected male weapon.

    PubMed

    Allen, Pablo E; Miller, Christine W

    2017-08-16

    In this time of massive global change, species are now frequently interacting with novel players. Greater insight into the impact of these novel interactions on traits linked to fitness is essential, because effects on these traits can hinder population existence or promote rapid adaptation. Sexually selected weapons and ornaments frequently influence fitness and often have heightened condition-dependence in response to nutrition. Condition-dependence in response to different ecological conditions, a form of developmental plasticity, may be responsible for much of the intraspecific variation in sexually selected ornaments and weapons in wild populations. Here we examined the consequences of developing on a novel plant for the expression of size and shape in the leaf-footed cactus bug Narnia femorata (Hemiptera: Coreidae). The males of this species possess enlarged, sexually dimorphic femurs on their hind legs. These legs are used as weapons in male-male contests. Females are typically larger in overall body size. Our study revealed that developing upon a novel host can lead to pronounced phenotypically plastic change in sexually dimorphic traits. Male hind femurs were greatly impacted by the novel diet to the extent that the sexual dimorphism in hind femurs was lost. Further, dimorphism in body size increased, as males became tiny adults while females better maintained their body size. These patterns underscore the complex effects that novel species interactions may have on sexual phenotypes. © 2017 The Author(s).

  8. Males that drop a sexually selected weapon grow larger testes.

    PubMed

    Joseph, Paul N; Emberts, Zachary; Sasson, Daniel A; Miller, Christine W

    2018-01-01

    Costly sexually selected weapons are predicted to trade off with postcopulatory traits, such as testes. Although weapons can be important for achieving access to females, individuals of some species can permanently drop (i.e. autotomize) their weapons, without regeneration, to escape danger. We capitalized on this natural behavior to experimentally address whether the loss of a sexually selected weapon leads to increased testes investment in the leaf-footed cactus bug, Narnia femorata Stål (Hemiptera: Coreidae). In a second experiment, we measured offspring production for males that lost a weapon during development. As predicted, males that dropped a hind limb during development grew significantly larger testes than the control treatments. Hind-limb autotomy did not result in the enlargement of other nearby traits. Our results are the first to experimentally demonstrate that males compensate for natural weapon loss by investing more in testes. In a second experiment we found that females paired with males that lost a hind limb had 40% lower egg hatching success than females paired with intact males, perhaps because of lower mating receptivity to males with a lost limb. Importantly, in those cases where viable offspring were produced, males missing a hind limb produced 42% more offspring than males with intact limbs. These results suggest that the loss of a hind-limb weapon can, in some cases, lead to greater fertilization success. © 2017 The Author(s). Evolution © 2017 The Society for the Study of Evolution.

  9. The form of sexual selection arising from male-male competition depends on the presence of females in the social environment.

    PubMed

    Procter, D S; Moore, A J; Miller, C W

    2012-05-01

    Sexual selection arises from social interactions, and if social environments vary so too should sexual selection. For example, male-male competition often occurs either in the presence or in the absence of females, and such changes in the social environment could affect the form and strength of sexual selection. Here we examine how the presence of a female influences selection arising from male-male competition in a leaf-footed cactus bug, Narnia femorata, which has a resource defence mating system. Males compete for territories on cacti because females lay eggs on the cactus plants. Females are not always present when this competition first occurs; however, the presence or absence of the female matters. We found that both the form and strength of selection on male traits, those traits that influenced success in intrasexual competition, depended on the social context. When a female was not present, male size and the area of the sexually dimorphic hind legs was only marginally important to winning a contest. However, males with larger overall size and leg area were more likely to win in the presence of a female. There was also positive quadratic selection on these traits when a female was present with both the largest and the smallest males winning. The implication is unexpected alternative strategies when females are present. Our results support the notion that sexual selection should be studied under all relevant social contexts. © 2012 The Authors. Journal of Evolutionary Biology © 2012 European Society For Evolutionary Biology.

  10. The tale of the shrinking weapon: seasonal changes in nutrition affect weapon size and sexual dimorphism, but not contemporary evolution.

    PubMed

    Miller, C W; McDonald, G C; Moore, A J

    2016-11-01

    Sexually selected traits are often highly variable in size within populations due to their close link with the physical condition of individuals. Nutrition has a large impact on physical condition, and thus, any seasonal changes in nutritional quality are predicted to alter the average size of sexually selected traits as well as the degree of sexual dimorphism in populations. However, although traits affected by mate choice are well studied, we have a surprising lack of knowledge of how natural variation in nutrition affects the expression of sexually selected weapons and sexual dimorphism. Further, few studies explicitly test for differences in the heritability and mean-scaled evolvability of sexually selected traits across conditions. We studied Narnia femorata (Hemiptera: Coreidae), an insect where males use their hind legs as weapons and the femurs are enlarged, to understand the extent to which weapon expression, sexual dimorphism and evolvability change across the actual range of nutrition available in the wild. We found that insects raised on a poor diet (cactus without fruit) are nearly monomorphic, whereas those raised on a high-quality diet (cactus with ripe fruit) are distinctly sexually dimorphic via the expression of large hind leg weapons in males. Contrary to our expectations, we found little evidence of a potential for evolutionary change for any trait measured. Thus, although we show weapons are highly condition dependent, and changes in weapon expression and dimorphism could alter evolutionary dynamics, our populations are unlikely to experience further evolutionary changes under current conditions. © 2016 European Society For Evolutionary Biology. Journal of Evolutionary Biology © 2016 European Society For Evolutionary Biology.

  11. Sexual selection is influenced by both developmental and adult environments.

    PubMed

    Gillespie, Stephanie R; Scarlett Tudor, M; Moore, Allen J; Miller, Christine W

    2014-12-01

    Sexual selection is often assumed to be strong and consistent, yet increasing research shows it can fluctuate over space and time. Few experimental studies have examined changes in sexual selection in response to natural environmental variation. Here, we use a difference in resource quality to test for the influence of past environmental conditions and current environmental conditions on male and female mate choice and resulting selection gradients for leaf-footed cactus bugs, Narnia femorata. We raised juveniles on natural high- and low-quality diets, cactus pads with and without ripe cactus fruits. New adults were again assigned a cactus pad with or without fruit, paired with a potential mate, and observed for mating behaviors. We found developmental and adult encounter environments affected mating decisions and the resulting patterns of sexual selection for both males and females. Males were not choosy in the low-quality encounter environment, cactus without fruit, but they avoided mating with small females in the high-quality encounter environment. Females were choosy in both encounter environments, avoiding mating with small males. However, they were the choosiest when they were in the low-quality encounter environment. Female mate choice was also context dependent by male developmental environment. Females were more likely to mate with males that had developed on cactus with fruit when they were currently in the cactus with fruit environment. This pattern disappeared when females were in the cactus without fruit environment. Altogether, these results experimentally demonstrate context-dependent mate choice by both males and females. Furthermore, we demonstrate that simple, seasonal changes in resources can lead to fluctuations in sexual selection. © 2014 The Author(s). Evolution © 2014 The Society for the Study of Evolution.

  12. Absolute dating and palaeoenvironmental evolution in Palaeolithic Mani, SW Peloponnesus

    NASA Astrophysics Data System (ADS)

    Christodoulakis, John; Bassiakos, Yannis; Athanassas, Constantin

    2013-04-01

    the chronological framework of human-palaeoenvironment interactions over the later part of the Pleistocene with higher resolution than that attained formerly by ESR, A report about the progress of this effort is here presented. This study is funded by the NARNIA/FP7 Marie Curie Initial Training Network project.