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Our understanding of the evolutionary significance of ectoparasites in natural communities is limited by a paucity of information concerning the mechanisms and heritability of resistance to this ubiquitous and diverse assemblage of organisms. Here, we report the results of artificial selection for increasing ectoparasite resistance in replicate lines ofDrosophila melanogasterderived from a field-fresh population. Resistance, as ability to avoid infestation by naturally occurringGamasodes queenslandicusmites, increased significantly in response to selection, and realized heritability (s.e.) was estimated to be 0.11 (0.0090). Ability to deploy energetically expensive bursts of flight from the substrate was a main mechanism of resistance that responded to selection, aligning with previously documented metabolic costs of fly behavioral defenses. Host body size, which affects parasitism rate in some fly-mite systems, was not shifted by selection. In contrast, resistant lines expressed significant reductions in larva-to-adult survivorship with increasing toxic (ammonia) stress, identifying an environmentally modulated pre-adult cost of resistance. Flies resistant toG. queenslandicuswere also more resistant to a different mite,Macrocheles subbadius, suggesting that we documented genetic variation and a pleiotropic cost of broad-spectrum behavioral immunity against ectoparasites. This study demonstrates significant evolutionary potential of an ecologically important trait.

Summary Traits that increase reproductive success in males can have negative fitness consequences in females. A new study shows that natural selection by a predator that targets males with larger secondary sexual traits drives an evolutionary increase in female fitness.

Traumatic insemination (TI) is a rare reproductive behaviour characterized by the transfer of sperm to the female via puncture wounds inflicted across her body wall. Here, we challenge the claim made by Kamimura (Kamimura 2007

Článek představuje teoretický pohled na buněčné základy procesů na úrovni sítě, které se podílejí na vytváření našich vědomých zkušeností. Vstupy do apikálních synapsí ve vrstvě 1 velké podskupiny neokortikálních buněk se sčítají v integrační zóně poblíž vrcholu jejich apikálního kmene. Tyto vstupy pocházejí z různých zdrojů a poskytují kontext, v němž lze případně zesílit přenos informací získaných ze senzorického vstupu do jejich bazálních a perisomatických synapsí. Tvrdíme, že apikální amplifikace umožňuje vědomý vjemový prožitek a činí ho pružnějším, a tedy přizpůsobivějším, tím, že je citlivý na kontext. Apikální amplifikace poskytuje možný mechanismus teorie rekurentního zpracování, která se vyhýbá silným smyčkám. Je možným mechanismem globální distribuce signálu, jak je postulována teoriemi globálního neuronálního pracovního prostoru a zároveň zachovává odlišné příspěvky jednotlivých buněk přijímajících signál. Poskytuje také mechanismy, které přispívají k holistickým aspektům teorie integrované informace. Jelikož je apikální amplifikace vysoce závislá na cholinergních, aminergních a dalších neuromodulátorech, dává do souvislosti konkrétní obsah vědomých zkušeností s globálními mentálními stavy a s fluktuacemi arousalu v bdělém stavu. Došli jsme k závěru, že apikální dendrity poskytují buněčný mechanismus kontextově citlivé selektivní amplifikace, která je základním předpokladem vědomého vnímání. The paper presents a theoretical view of the cellular foundations for network-level processes involved in producing our conscious experience. Inputs to apical synapses in layer 1 of a large subset of neocortical cells are summed at an integration zone near the top of their apical trunk. These inputs come from diverse sources and provide a context within which the transmission of information abstracted from sensory input to their basal and perisomatic synapses can be amplified when relevant. We argue that apical amplification enables conscious perceptual experience and makes it more flexible, and thus more adaptive, by being sensitive to context. Apical amplification provides a possible mechanism for recurrent processing theory that avoids strong loops. It makes the broadcasting hypothesized by global neuronal workspace theories feasible while preserving the distinct contributions of the individual cells receiving the broadcast. It also provides mechanisms that contribute to the holistic aspects of integrated information theory. As apical amplification is highly dependent on cholinergic, aminergic, and other neuromodulators, it relates the specific contents of conscious experience to global mental states and to fluctuations in arousal when awake. We conclude that apical dendrites provide a cellular mechanism for the context-sensitive selective amplification that is a cardinal prerequisite of conscious perception.

Traumatic insemination (TI) is a rare reproductive behaviour characterized by the transfer of sperm to the female via puncture wounds inflicted across her body wall. Here, we challenge the claim made by Kamimura (2007) that males of species of the Drosophila bipectinata complex utilize a pair of claw-like processes (“claws”) to traumatically inseminate females: the claws are purported to puncture the female body wall and genital tract, and to inject sperm through the wounds into the genital tract, bypassing the vaginal opening, the route of sperm transfer occurring in other Drosophila. This supposed case of TI is widely cited and featured in prominent subject reviews. We examined high-resolution scanning electron micrographs of the claws and failed to discover any obvious “groove” for sperm transport. We demonstrated that sperm occurred in the female reproductive tract as a single integrated unit when mating flies were experimentally separated, inconsistent with the claim that sperm are injected via paired processes. The aedeagus in the bipectinata complex was imaged, and shown to deliver sperm through the vaginal opening. Laser ablation of the sharp terminal ends of the claws failed to inhibit insemination. The results refute the claim of TI in the Drosophila bipectinata species complex.

The estimation of plant growth is a challenging but key issue that may help us to understand crop vs. environment interactions. To perform precise and high-throughput analysis of plant growth in field conditions, remote sensing using LiDAR and unmanned aerial vehicles (UAV) has been developed, in addition to other approaches. Although there are software tools for the processing of LiDAR data in general, there are no specialized tools for the automatic extraction of experimental field blocks with crops that represent specific “points of interest”. Our tool aims to detect precisely individual field plots, small experimental plots (in our case 10 m2) which in agricultural research represent the treatment of a single plant or one genotype in a breeding trial. Cutting out points belonging to the specific field plots allows the user to measure automatically their growth characteristics, such as plant height or plot biomass. For this purpose, new method of edge detection was combined with Fourier transformation to find individual field plots. In our case study with winter wheat, two UAV flight levels (20 and 40 m above ground) and two canopy surface modelling methods (raw points and B-spline) were tested. At a flight level of 20 m, our algorithm reached a 0.78 to 0.79 correlation with LiDAR measurement with manual validation (RMSE = 0.19) for both methods. The algorithm, in the Python 3 programming language, is designed as open-source and is freely available publicly, including the latest updates.

Argumentace Tomáše Hříbka proti fenomenálnímu charakteru se opírá především o Dennettova stanoviska. Dennettem dlouhodobě preferovaná strategie při vypořádání se s tímto problémem je metodologický naturalismus. Tato strategie jistě přinesla své ovoce, zejména je-li řeč o otevření skutečně kritické diskuse na téma kválií. Problém vědomí je však v současnosti traktován spíše v rámci materialistické metafyziky, než z pohledu Dennettova metodologického naturalismu. Tato preference má své empirické, ale i filosofické důvody, o nichž jsme hovořili s Tomášem Marvanem v knize Vědomí a jeho teorie. Protože Hříbkova monografie reaguje na některé názory z této knihy, komentuji Hříbkovy reakce a upřesňuji naše postoje. Zároveň se vyjadřuji k zařazení naší pozice v rámci materialistické metafyziky k materialismu typu B. V druhé části statě se zabývám problémem fenomenálního charakteru vědomé zkušenosti a snažím se argumentovat, že tento těžký problém nelze odstranit pouze tím, že se prokáže neudržitelnost tradičního chápání kválií.

Our understanding of coevolution between male genitalia and female traits remains incomplete. This is perhaps especially true for genital traits that cause internal injuries in females, such as the spiny genitalia of seed beetles where males with relatively long spines enjoy a high relative fertilization success. We report on a new set of experiments, based on extant selection lines, aimed at assessing the effects of long male spines on females in Callosobruchus maculatus . We first draw on an earlier study using microscale laser surgery, and demonstrate that genital spines have a direct negative (sexually antagonistic) effect on female fecundity. We then ask whether artificial selection for long versus short spines resulted in direct or indirect effects on female lifetime offspring production. Reference females mating with males from long-spine lines had higher offspring production, presumably due to an elevated allocation in males to those ejaculate components that are beneficial to females. Remarkably, selection for long male genital spines also resulted in an evolutionary increase in female offspring production as a correlated response. Our findings thus suggest that female traits that affect their response to male spines are both under direct selection to minimize harm but are also under indirect selection (a good genes effect), consistent with the evolution of mating and fertilization biases being affected by several simultaneous processes.

The present paper was written as a contribution to ongoing methodological debates within the NCC project. We focus on the neural correlates of conscious perceptual episodes. Our claim is that the NCC notion, as applied to conscious perceptual episodes, needs to be reconceptualized. It mixes together the processing related to the perceived contents and the neural substrate of consciousness proper, i.e. mechanisms making the perceptual contents conscious. We thus propose that the perceptual NCC be divided into two constitutive subnotions. The paper elaborates the distinction, marshals some initial arguments in its favour, and sketches advantages of the proposed reconceptualization.

Parasites cause harm to their hosts and represent pervasive causal agents of natural selection. Understanding host proximate responses during interactions with parasites can help predict which genes and molecular pathways are targets of this selection. In the current study, we examined transcriptional changes arising from interactions betweenDrosophila melanogasterand their naturally occurring ectoparasitic mite,Gamasodes queenslandicus. Shifts in host transcript levels associated with behavioural avoidance revealed the involvement of genes underlying nutrient metabolism. These genetic responses were reflected in altered body lipid and glycogen levels in the flies. Mite infestation triggered a striking immune response, while male accessory gland protein transcript levels were simultaneously reduced, suggesting a trade-off between host immune responses to parasite challenge and reproduction. Comparison of transcriptional analyses during mite infestation to those during nematode and parasitoid attack identified host genes similarly expressed in flies during these interactions. Validation of the involvement of specific genes with RNA interference lines revealed candidates that may directly mediate fly–ectoparasite interactions. Our physiological and molecular characterization of theDrosophila–Gamasodesinterface reveals new proximate mechanisms underlying host–parasite interactions, specifically host transcriptional shifts associated with behavioural avoidance and infestation. The results identify potential general mechanisms underlying host resistance and evolutionarily relevant trade-offs.

In this paper, we propose the following hypothesis: the hard problem of consciousness is in part an artifact of what we call the unitary approach to phenomenal consciousness. The defining mark of the unitary approach is that it views consciousness and phenomenality as inseparable. Giving up this conceptual commitment redefines, in a productive way, the explanatory tasks of the theory of consciousness. Adopting a non-unitary conception of experience does not make the hard problem of consciousness go away completely but it shifts the locus of where the explanation of experience gets difficult, and cuts down the mystery of consciousness to size. Other advantages of the non-unitary account of consciousness are sketched as well.

Optimal life-history strategies are those that best allocate finite environmental resources to competing traits. We used the geometric framework for nutrition to evaluate life-history strategies followed by Drosophila melanogaster by measuring the condition-dependent performance of life-history traits, including the morphology of male secondary sexual characters, sex combs. We found that depending on their rearing environment flies faced different forms of trait trade-offs and accordingly followed different life-history strategies. High-energy, high-carbohydrate, low-protein diets supported development of the largest and most symmetrical sex combs, however, consistent with handicap models of sexual selection these foods were associated with reduced fly survival and developmental rate. Expressing the highest quality sex combs may have required secondary sexual trait quality to be traded-off with developmental rate, and our results indicated that flies unable to slow development died. As larval nutritional environments are predominantly determined by female oviposition substrate choice, we tested where mated female flies laid the most eggs. Mothers chose high-energy, high-protein foods associated with rapid larval development. Mothers avoided high-carbohydrate foods associated with maximal sex comb expression, showing they may avoid producing fewer ‘sexy’ sons in favour of producing offspring that develop rapidly.

Positive genetic covariance between male sexual display traits and fertilizing capacity can arise through different mechanisms and has important implications for sexual trait evolution. Evidence for such genetic covariance is rare, and when it has been found, specific physiological traits underlying variation in fertilization success linked to trait expression have not been identified. A previous study of correlated responses to bidirectional artificial selection on the male sex comb, a secondary sexual trait, in Drosophila bipectinata Duda documented a positive genetic correlation between sexual trait size and competitive fertilization success, and found that transcript levels of multiple seminal fluid proteins (SFPs) were significantly increased in the large sex comb (high) genetic lines. These results suggest that changes in SFP activity may be a causal factor underlying the increased fertilizing capacity of high line males. Here, we tested for correlated responses to this selection in a suite of additional reproductive traits, measured in the context of variation in male age and exposure to rivals. Whereas several traits including sperm length, number and viability, and accessory gland size, increased with age, only sperm viability was influenced by selection treatment, but in complex fashion. Sperm viability of high line males surpassed that of their smaller-combed counterparts when they had been housed with rivals and were 5–6 days old or older. Interestingly, this interaction effect was evident for sperm sampled from the female seminal receptacle, but not from the male seminal vesicles (where sperm have yet to be combined with accessory gland products), consistent with the differential SFP activity between the lines previously found. Our results suggest that differences in sperm quality (as viability) may be a contributing factor to the positive genetic correlation between sexual trait size and competitive fertilization capacity in D. bipectinata.

Summary Postcopulatory sexual selection results from variation in competitive fertilization success among males and comprises powerful evolutionary forces that operate after the onset of mating. 1 , 2 Theoretical advances in the field of sexual selection addressing the buildup and coevolutionary consequences of genetic coupling 3 , 4 , 5 motivate the hypothesis that indirect postcopulatory sexual selection may promote evolution of male secondary sexual traits—those traits traditionally ascribed to mate choice and male fighting. 6 , 7 A crucial prediction of this hypothesis is genetic covariance between trait expression and competitive fertilization success, which has been predicted to arise, for example, when traits subject to pre- and postcopulatory sexual selection are under positive correlational selection. 8 We imposed bidirectional artificial selection on male ornament (sex comb) size in Drosophila bipectinata and demonstrated increased competitive fertilization success as a correlated evolutionary response to increasing ornament size. Transcriptional analyses revealed that levels of specific seminal fluid proteins repeatedly shifted in response to this selection, suggesting that properties of the ejaculate, rather than the enlarged sex comb itself, contributed fertilizing capacity. We used ultraprecise laser surgery to reduce ornament size of high-line males and found that their fertilizing superiority persisted despite the size reduction, reinforcing the transcriptional results. The data support the existence of positive genetic covariance between a male secondary sexual trait and competitive fertilization success, and suggest the possibility that indirect postcopulatory sexual selection may, under certain conditions, magnify net selection on ornamental trait expression.

Male genital traits exhibit extraordinary interspecific phenotypic variation. This remarkable and general evolutionary trend is widely considered to be the result of sexual selection. However, we still do not have a good understanding of whether or how individual genital traits function in different competitive arenas (episodes of sexual selection), or how different genital traits may interact to influence competitive outcomes. Here, we use an experimental approach based on high-precision laser phenotypic engineering to address these outstanding questions, focusing on three distinct sets of micron-scale external (nonintromittent) genital spines in male Drosophila kikkawai Burla (Diptera: Drosophilidae). Elimination of the large pair of spines on the male secondary claspers sharply reduced male ability to copulate, yet elimination of the other sets of spines on the primary and secondary claspers had no significant effects on copulation probability. Intriguingly, both the large spines on the secondary claspers and the cluster of spines on the primary claspers were found to independently promote male competitive fertilization success. Moreover, when large and small secondary clasper spines were simultaneously shortened in individual males, these males suffered greater reductions in fertilization success relative to males whose traits were altered individually, providing evidence for synergistic effects of external genital traits on fertilization success. Overall, the results are significant in demonstrating that a given genital trait (the large spines on the secondary claspers) can function in different episodes of sexual selection, and distinct genital traits may interact in sexual selection. The results offer an important contribution to evolutionary biology by demonstrating an understudied selective mechanism, operating via subtle trait interactions in a post-insemination context, by which genital traits may be co-evolving.

Indicator models of sexual selection predict that females mating with the most ornamented males should produce offspring with enhanced expression of fitness-related traits, such as overall vigor and viability. Empirical support for this prediction, however, is limited. We quantified the effects of a heritable and condition-dependent secondary sexual trait on offspring performance traits in Drosophila bipectinata Duda (Diptera: Drosophilidae). Forty-eight genetic (isofemale) lines were extracted from a natural population, reared in a common environment, and characterized in terms of sex comb size. We measured pupal viability and adult mating success among the progeny of the 5 lines with the largest combs (high line category) and the 5 lines with the smallest combs (low line category). The high line category produced offspring that were significantly more viable than the low line category, and this advantage held across 2 developmental temperatures. In contrast, there was no effect of line category on male mating success, although at the individual-level, comb size was significantly positively correlated with mating success. Our results indicate that the relative size of the D. bipectinata sex comb taps genotypic properties that enhance offspring fitness in a trait-specific manner. Thus, distinct proximate mechanisms likely underlie relationships between secondary sexual trait expression and different performance traits in offspring, offering a possible explanation for inconsistent support for the existence of indirect benefits in sexual selection.

One of the greatest challenges of consciousness research is to understand the relationship between consciousness and its implementing substrate. Current research into the neural correlates of consciousness regards the biological brain as being this substrate, but largely fails to clarify the nature of the brain-consciousness connection. A popular approach within this research is to construe brain-consciousness correlations in causal terms: the neural correlates of consciousness are the causes of states of consciousness. After introducing the notion of the neural correlate of consciousness, we argue (see Against Causal Accounts of NCCs) that this causal strategy is misguided. It implicitly involves an undesirable dualism of matter and mind and should thus be avoided. A non-causal account of the brain-mind correlations is to be preferred. We favor the theory of the identity of mind and brain, according to which states of phenomenal consciousness are identical with their neural correlates. Research into the neural correlates of consciousness and the theory of identity (in the philosophy of mind) are two major research paradigms that hitherto have had very little mutual contact. We aim to demonstrate that they can enrich each other. This is the task of the third part of the paper in which we show that the identity theory must work with a suitably defined concept of type. Surprisingly, neither philosophers nor neuroscientists have taken much care in defining this central concept; more often than not, the term is used only implicitly and vaguely. We attempt to open a debate on this subject and remedy this unhappy state of affairs, proposing a tentative hierarchical classification of phenomenal and neurophysiological types, spanning multiple levels of varying degrees of generality. The fourth part of the paper compares the theory of identity with other prominent conceptions of the mind-body connection. We conclude by stressing that scientists working on consciousness should engage more with metaphysical issues concerning the relation of brain processes and states of consciousness. Without this, the ultimate goals of consciousness research can hardly be fulfilled.

The relationship between morphological symmetry and mating success in animals varies dramatically across species and populations. The reasons for this heterogeneity in effect size are poorly understood, which has lead to intense debate among evolutionary biologists. I will evaluate the general hypothesis that differences in the level of developmental instability (DI) across populations accounts for heterogeneity in the effect of symmetry on sexual selection. According to this hypothesis, most populations have levels of DI insufficient to propel adaptive processes such as mate selection; only when DI levels surpass a critical threshold will selection operate and be detectable. I will test this hypothesis using results of our work with Drosophila bipectinata Duda (Diptera: Drosophilidae), focusing on fluctuating asymmetry (FA) and size of the male sex comb, a model secondary sexual trait for animal studies. The following key predictions will be tested: (1) Intensity of sexual selection depends on the level of DI in the population. Data from nine distinct populations sampled throughout Australasia and the South Pacific will be evaluated for this test; (2) the level of DI in a population, in turn, is the result of the particular history of directional selection for trait size experienced by that population. This prediction will be evaluated using comparative data as well as the results of artificial selection for increasing trait size under laboratory conditions. This study will provide a framework for understanding the dramatic variation in effect size across FA-sexual selection studies.

Genitalia are one of the most rapidly diverging morphological features in animals. The evolution of genital morphology is proposed to be driven by sexual selection via cryptic female choice, whereby a female selectively uptakes and uses a particular male's sperm on the basis of male genital morphology. The resulting shifts in genital morphology within a species can lead to divergence in genitalia between species, and consequently to reproductive isolation and speciation. Although this conceptual framework is supported by correlative data, there is little direct empirical evidence. Here, we used a microdissection laser to alter the morphology of the external male genitalia in Drosophila, a widely used genetic model for both genital shape and cryptic female choice. We evaluate the effect of precision alterations to lobe morphology on both interspecific and intraspecific mating, and demonstrate experimentally that the male genital lobes do not affect copulation duration or cryptic female choice, contrary to long-standing assumptions regarding the role of the lobes in this model system. Rather, we demonstrate that the lobes are essential for copulation to occur. Moreover, slight alterations to the lobes significantly reduced copulatory success only in competitive environments, identifying precopulatory sexual selection as a potential contributing force behind genital diversification.

The developmental instability (DI)-sexual selection hypothesis proposes that large size and symmetry in secondary sexual traits are favored by sexual selection because they reveal genetic quality. A critical prediction of this hypothesis is that there should exist negative correlations between trait fluctuating asymmetry (FA) and size of condition dependent sexual traits, condition dependent traits should reveal an organism’s overall health and vigor, and be influenced by a multitude of genetic loci. Here, we tested for the predicted negative FA-size correlations in the male sex comb of Drosophila bipectinata. Among field-caught males from five widely separated geographic localities, FA-size correlations were consistently positive, despite evidence that sex comb size is condition dependent. After controlling for trait size, FA was significantly negatively correlated with body size within several populations, indicating that developmental instability in the comb may reveal individual genetic quality. We suggest the possibility that condition dependent traits in some cases tap into independent units of the genome (a restricted set of genes), rather than signaling overall genetic properties of the organism. There were pronounced among-population differences in both comb FA and size, and these traits were positively correlated across populations, recapitulating the within-population patterns. We conclude that the results are inconsistent with the DI-sexual selection hypothesis, and discuss potential reasons for positive FA-size co-variation in sexual traits.

1. Dispersal is essential for locating mates, new resources, and to escape unfavourable conditions. Parasitism can impact a host's ability to perform energetically demanding activities such as long-distance flight, with important consequences for gene flow and meta-population dynamics. 2. Ectoparasites, in particular, can adversely affect host flight performance by diminishing flight aerodynamics and/or by inflicting physiological damage while feeding on host tissue. 3. Experimental flight assays were conducted using two fruit fly-mite systems: Drosophila nigrospiracula (Patterson and Wheeler) – Macrocheles subbadius (Berlese) and D. hydei (Sturtevan) – M. muscaedomesticae (Scopoli). Flies that are burdened by mites are expected to exhibit lower flight endurance compared to uninfected flies. 4. The results show that the presence of mites (attached) significantly decreased flight endurance by 57% and 78% compared to uninfected D. nigrospiracula and D. hydei, respectively. The physiological damage caused by M. subbadius was revealed through a 53% decline in flight time among previously infected flies (mites removed just prior to flight assay). Surprisingly, the presumably phoretic M. muscaedomesticae also caused a 62% reduction in flight endurance among previously infected D. hydei. 5. These results suggest a strong deleterious effect of ectoparasitic mites on host flight performance, mediated by a reduction in flight aerodynamics and damage to host physiology. Adverse effects on host flight and/or dispersal may have broad implications for gene flow, population genetic structure, and local adaptation in both host and parasite meta-populations.

The contemporary explanation for the rapid evolutionary diversification of animal genitalia is that such traits evolve by post-copulatory sexual selection. Here, we test the hypothesis that the male genital spines of Drosophila ananassae play an adaptive role in post-copulatory sexual selection. Whereas previous work on two Drosophila species shows that these spines function in precopulatory sexual selection to initiate genital coupling and promote male competitive copulation success, further research is needed to evaluate the potential for Drosophila genital spines to have a post-copulatory function. Using a precision micron-scale laser surgery technique, we test the effect of spine length reduction on copulation duration, male competitive fertilization success, female fecundity and female remating behaviour. We find no evidence that male genital spines in this species have a post-copulatory adaptive function. Instead, females mated to males with surgically reduced/blunted genital spines exhibited comparatively greater short-term fecundity relative to those mated by control males, indicating that the natural (i.e. unaltered) form of the trait may be harmful to females. In the absence of an effect of genital spine reduction on measured components of post-copulatory fitness, the harm seems to be a pleiotropic side effect rather than adaptive. Results are discussed in the context of sexual conflict mediating the evolution of male genital spines in this species and likely other Drosophila.

Male secondary sexual traits of animals are richly diversified in form and complexity, yet there are many species in which their precise function remains unknown. Within the genus Drosophila, species belonging to the melanogaster and obscura species groups have evolved a remarkable variety of sex combs, male-limited secondary sexual traits located on the tarsi of both front legs. Information concerning sex comb function is minimal or absent, except for D. melanogaster, where previous studies indicate that the sex combs are used for grasping the female prior to copulation. These studies, however, do not unambiguously demonstrate comb function, because it has not been possible to ascribe observed behavioral outcomes of the various comb manipulations to changes in the combs per se. We used microscale laser surgery to manipulate comb size in D. melanogaster and D. bipectinata, and tested the hypothesis that the sex combs function as grasping devices in courtship, making them essential for copulation to ensue. Results of high-resolution behavioral analysis in small observation arenas demonstrated that in both species in which sex combs were surgically eliminated, males were unable to grasp, mount or copulate. The combless foretarsi of these altered males slipped off the end (D. melanogaster) and sides (D. bipectinata) of the female abdomen when courting males attempted to grasp. In most cases, males whose sex combs were reduced but not completely removed exhibited similar copulation probabilities as surgical control males, a result we demonstrated in observation chambers as well as under more ecologically realistic conditions inside population cages where males and females interacted on the surface of fruit substrates. Thus, the sex combs in D. melanogaster and D. bipectinata are grasping devices, essential for mounting and copulation.

The presented article is focused on a theoretical dynamic analysis of the footbridge across the Opatovicka street in Prague, which acts as a simply supported beam. The structure was loaded by an ordinary pedestrian traffic, synchronous runners and vandals. The ordinary traffic was simulated by the Monte Carlo method as a stream of moving periodic forces with stochastic parameters. The synchronous runners and vandals were modeled as a combination of biomechanical models of human body, which influenced the structure vibration only passively, and driving forces, which loaded the structure in the contact points between the human body models and the structure. The driving force was the time – dependent function based on decomposition to the Fourier’s Series and periodic triangle function. The obtained theoretical results are compared with experimental data.

This paper is focused on cement specimen testing by impact excitation non-destructive technique. The impulse excitation method was used for measuring of the natural frequencies and modes of longitudinal, transversal and torsional vibration of the specimens. The objective was to find dynamic properties of the specimens without a crack, with a crack and with a healed crack by cement paste and based on their comparison detect and localize the crack.

There is almost unanimous consensus among the theorists of consciousness that the phenomenal character of a mental state cannot exist without consciousness. We argue for a reappraisal of this consensus. We distinguish two models of phenomenal consciousness: unitary and dual. Unitary model takes the production of a phenomenal quality and it's becoming conscious to be one and the same thing. The dual model, which we advocate in this paper, distinguishes the process in which the phenomenal quality is formed from the process that makes this quality conscious. We put forward a conceptual, methodological, neuropsychological and neural argument for the dual model. These arguments are independent but provide mutual support to each other. Together, they strongly support the dual model of phenomenal consciousness and the concomitant idea of unconscious mental qualities. The dual view is thus, we submit, a hypothesis worthy of further probing and development.

Non-destructive methods for testing mechanical properties of materials spreads to many fields of investigation at present. A typical example of the use of non-destructive testing can be determination of the effect of freeze-thaw cycles on the mechanical properties of porous building materials. The great advantage of non-destructive testing, compared to destructive, is that still the same sample is tested and it excludes various negative effects such as technological indiscipline in the production of samples, different environment storage of samples prior to testing, recognition of cracks in the sample prior to testing, etc. The paper presents the development of modulus of elasticity on samples of hardened plaster according to the number of freeze-thaw cycles. Elastic moduli were determined using an impulse excitation method. For cyclic loading, the samples were saturated with water at 20 °C and tested in 8-hour cycles. Samples were removed from the water bath and placed in a freezer with a temperature lower than - 20 °C and after 8 hours they were placed again in the water bath for a period of eight hours. The temperature in the freezer was measured using platinum thermometers during the freeze-thaw cycles. The difference from 'dry' frost resistance was that the samples of hardened plaster were exposed to "wet" frost resistance, i.e. to the extreme load of the samples with the external climatic conditions.

SummaryThe rapidly evolving and often extraordinarily complex appearance of male genital morphology of internally fertilizing animals has been recognized for centuries [1]. Postcopulatory sexual selection is regarded as the likely evolutionary engine of this diversity [2], but direct support for this hypothesis is limited. We used two complementary approaches, evolution through artificial selection and microscale laser surgery, to experimentally manipulate genital morphology in an insect model system. We then assessed the competitive fertilization success of these phenotypically manipulated males and studied the fate of their ejaculate in females using high-resolution radioisotopic labeling of ejaculates. Males with longer genital spines were more successful in gaining fertilizations, providing experimental evidence that male genital morphology influences success in postcopulatory reproductive competition. Furthermore, a larger proportion of the ejaculate moved from the reproductive tract into the female body following mating with males with longer spines, suggesting that genital spines increase the rate at which seminal fluid passes into the female hemolymph. Our results show that genital morphology affects male competitive fertilization success and imply that sexual selection on genital morphology may be mediated in part through seminal fluid [3].

We test for effects of thermal stress applied to pupal flies from Noumea (New Caledonia) and Taipei (Taiwan) on developmental instability (DI) in the male sex comb of Drosophila bipectinata, as well as on pre-adult survivorship and adult body size. The temperature treatments were Low (25 °C), High (29 °C) and Variable (18 h at 29 °C, 6 h at 34 °C). Although the Variable treatment reduced survivorship and body size, absolute comb size and fluctuating asymmetry generally were invariant across treatments. In contrast, comb phenodeviance increased with stress in both populations. Phenodeviance in one comb segment (C2) increased sharply with stress, whereas phenodeviance in a second major segment (C1) also increased with stress but only in Noumea flies. A major conclusion is that phenodeviations induced in a secondary sexual trait reflect the developmental environment that also damages fitness components, a foundation stone of the hypothesis that expressions of DI reveal phenotypic quality in sexual selection.

Secondary sexual traits that are condition-dependent are expected to reveal the physiological state and/or genetic quality of individuals, and therefore, should more often be found to be under sexual selection than (1) secondary sexual traits not currently condition-dependent, and (2) nonsecondary sexual traits. In the present study, we contrasted the degree of condition dependence in three morphological traits of male Drosophila bipectinata: two secondary sexual traits (distinct components of the sex comb), one of which significantly predicts mating success in nature (segment 2), whereas the other does not (segment 1), and a nonsecondary sexual trait (sternopleural bristle number). As predicted, comb segment 2 decreased significantly in size, in response to increasing temperature during development, whereas comb segment 1 and sternopleural bristle number either did not change significantly, or increased with increasing temperature. These results support the hypothesis that condition-dependence, inferred from stress-induced reductions in trait expression, engenders a trait to sexual selection. Small-combed genotypes did not exhibit disproportionate reductions in larva-to-adult survivorship and adult body size compared to large-combed genotypes, suggesting that comb size does not reveal genotypic quality, at least as revealed by sensitivity in body size and juvenile survivorship to thermal stress.

Male Polistes canadensis and P. carnifex aggregate along crests of prominent ridges in Santa Rosa National Park, Costa Rica. At these sites males of both species defend territories (trees and shrubs) by chasing conspecific rivals. Territories do not contain nests or resources that are collected by females. Chasing by territorial males reduces the amount of time spent by intruders in a territory. I describe and contrast male territorial behavior of both species. Some male P. canadensis are territorial while others in the same area exhibit patrolling behavior, flying from one occupied territory to another. Males of P. carnifex exhibit territoriality only. Patrolling in P. canadensis is an outcome of relatively high male density along the ridge, rendering territories in short supply, as shown by the observation that experimentally vacated territories are seized rapidly by formerly patrolling males. Due to a high intraspecific intrusion rate, territorial male P. canadensis spend less time perching and more time flying and chasing intruders from their territories than do male P. carnifex. Males of these two species also differ in the placement of their territories along the ridgeline; P. canadensis occupy territories in saddles while P. carnifex occupy those at peaktops. I show that this divergent spatial pattern is not maintained by competitive exclusion of either species by the other, and I discuss alternative explanations for their separate spatial distributions. Comparative data suggest that males are territorial because females restrict matings to within territories, and I discuss alternative hypotheses to explain this bias in female behavior.

Well-established causal links exist between maternal nutritional deficits and embryo health and viability. By contrast, environmental effects operating through the father that could influence embryo mortality have seldom been examined. Yet, ejaculates can require non-trivial resource allocation, and seminal plasma components are increasingly recognized to exert wide-ranging effects on females and offspring, so paternal dietary effects on the embryo should be expected. We test for effects of varying levels of protein (P), carbohydrate (C) and caloric load in adult male diet on embryo mortality inDrosophila melanogaster. We demonstrate that macronutrient balance and caloric restriction exert significant effects, and that nutritional effects are more impactful when a prior mating has occurred. Once-mated males produced embryos with marginally elevated mortality under high-caloric densities and a 1 : 8 P : C ratio. In contrast, embryos produced by twice-mated males were significantly more likely to die under male caloric restriction, an outcome that may have resulted from shifts in ejaculate quality and/or epigenetic paternal effects. Body nutrient reserves were strongly and predictably altered by diet, and body condition, in turn, was negatively related to embryo mortality. Thus, sire nutritional history and resultant shifts in metabolic state predict embryo viability and post-fertilization fitness outcomes.

Males developing relatively large, costly sexually selected traits may be of superior body condition compared to small-ornamented males. Thus, males developing the largest secondary sexual trait in a given environment may also be able to augment their investment into ejaculate quality, and fertilize a larger proportion of a female's eggs. We tested the prediction that the degree of expression of a condition-dependent secondary sexual trait, the male sex comb, in a Cape Tribulation (northeastern Australia) population of Drosophila bipectinata Duda, reveals male ability to fertilize eggs in the absence of sperm competition. This test permitted us also to evaluate whether pre-copulatory sexual selection and fertilization efficiency might act additively to influence male reproductive success because a previous study of the same population demonstrated a positive association between comb size and copulation probability. The results obtained indicate that, although genotypes developing smaller sex combs collectively had a significantly higher rate of insemination failure compared to larger comb genotypes, the hatch rate and the number of eggs laid by females inseminated by the two genotypic categories were not statistically different. The results fail to support the prediction that comb size reveals noncompetitive fertilization efficiency of males in this Australian population. © 2009 The Linnean Society of London, Biological Journal of the Linnean Society, 2009, 98, 406–413.

Stress placed on individuals in a population from natural and anthropogenic disturbances can elevate developmental instability. We studied the result of a natural disaster when one-third of a forested nature preserve was destroyed by an F3 tornado. Populations of two abundant species of small mammals, Peromyscus maniculatus and P. leucopus, were monitored in both disturbed and undisturbed habitats. We used an X-ray technique to measure developmental instability as indicated by fluctuating asymmetry (FA) in cranial and skeletal features of live animals. FA in femur length was higher in disturbed habitat for P. leucopus but was higher in undisturbed habitat for P. maniculatus. This difference in developmental instability mirrors differences in habitat preference between these species: P. leucopus prefers forest habitat and P. maniculatus prefers open, herbaceous habitat. These results were not explained by either food availability or body condition, both of which were higher in the disturbed habitat suggesting higher quality for this habitat. Thus, the FA response may be related to other indicators of habitat quality, e.g., vertical stratification, coarse-woody debris, or population density, which may differ between undisturbed and disturbed habitats.

Animals subject to environmental stress often exhibit higher levels of developmental instability, frequently measured as Fluctuating Asymmetry (FA), small, random deviations from perfect left-right symmetry in bilaterally symmetrical animals. We used FA measurement as a means of determining the impact of a catastrophic ecosystem disturbance (a major Class F3 tornado) on populations of Schizocosa ocreata, a common forest-dwelling wolf spider. As FA in sexually selected ornamental traits in males has been shown in some (but not all) species studied to be a sensitive indicator of environmental stress, we measured FA of foreleg tufts in male S. ocreata. Spiders from the first post-disturbance generation were collected by pitfall trapping in the spring of 2000, and preserved specimens were photographed and measured using digital imaging. Spiders from disturbed and undisturbed areas within the forest did not differ significantly in body size parameters, although body condition varied significantly bet...

The evolution of male secondary sexual traits traditionally has been ascribed to precopulatory sexual selection. In contrast, the importance of postcopulatory sexual selection for the evolution of secondary sexual traits is uncertain, and what little evidence exists for this process to contribute to the evolution of such traits is mixed. Here we test the hypothesis in Drosophila bipectinata Duda that the male sex comb, a rapidly evolving secondary sexual trait, is under positive postcopulatory sexual selection. We extracted replicate genetic lines exhibiting relatively large and small sex comb size from a natural population. Males from these lines were subjected to an assay of competitive fertilization ability, measured as P2, the proportion of a female’s clutch of eggs fertilized by the second male to mate. Males with the largest sex combs sired more offspring than less ornamented individuals, demonstrating for the first time in any Drosophila species that postcopulatory sexual selection favors increasing sex comb size. This study identifies a postcopulatory selective mechanism that may be contributing to the evolutionary diversification of a secondary sexual trait. Key words: competitive fertilization success, Drosophila bipectinata, ejaculate quality, P2, postcopulatory sexual selection, sex comb size. [Behav Ecol]

We test for fitness costs of resistance in a natural host-parasite system, involving Drosophila nigrospiracula and ectoparasitic mites, Macrocheles subbadius. We contrasted rates of mortality at embryonic and pupal stages of host ontogeny between replicate-resistant and -susceptible (control) lines at different temperatures (24, 28, and 34°C). Evidence for a cost of resistance was shown as a 17% overall reduction in egg hatch rate in replicate-resistant lines, although this effect was heterogeneous across replicate selection experiments. This cost of resistance was not magnified under thermal stress. Pupa survivorship was statistically invariant between resistant and control lines, at either temperature. Embryo and pupa mortalities were significantly elevated at the high temperature, confirming that the thermal treatment was physiologically stressful. The results suggest differential sensitivity of life history traits to the pleiotropic effects of genetic resistance against ectoparasitic mites.

Developmental instability results from small, random perturbations to developmental processes of individual traits. Phenotypic outcomes of developmental instability include fluctuating asymmetry (FA, subtle deviations from perfect bilateral symmetry) and phenodeviance (minor morphological abnormalities). A great deal of research over the past 18 years has focused on the role of developmental instability in sexual selection. A driving force behind this research has been the developmental instability-sexual selection hypothesis, which posits that symmetry and lack of phenodeviance in secondary sexual traits are assessed by mates and rivals because they provide a reliable cue of individual genetic quality. The present article tests this hypothesis by evaluating its five main predictions using published results: expressions of developmental instability in secondary sexual traits should be (1) negatively correlated with mating success; (2) directly assessed by mates and sexual rivals; (3) heritable; (4) condition-dependent; and (5) negatively correlated with ornament size. The first two predictions receive considerable, though not ubiquitous, support from a range of animal species. However, FA in secondary sexual traits is generally not significantly heritable, indicating that FA is unlikely to reveal genetic quality that can be transmitted to offspring. Similarly, there is little evidence to support the predictions that FA is condition dependent, and that it is negatively phenotypically or genetically correlated with sexual trait size. Based on an evaluation of the evidence overall, it is concluded that this hypothesis is unlikely to be viable; it appears unlikely that mate choice for symmetry evolves by “good genes” sexual selection. Hypotheses that do not require asymmetry and phenodeviance to reveal heritable genetic quality may explain observed links between FA/phenodeviance and mating success. Results of a case study of Drosophila bipectinata are summarized, which reinforce this general conclusion. It is suggested that nonadditive genetic variation arising from an interaction between trait-specific developmental genes and genetic background may drive sexual selection for reducing developmental instability in some cases. Levels of developmental instability variation in a population may need to surpass a critical threshold for sexual selection to operate, possibly explaining some of the pronounced heterogeneity in the effect of developmental instability on sexual selection reported in the literature.

In evolutionary biology, fluctuating asymmetry (FA) is thought to reveal developmental instability (DI, inability to buffer development against perturbations), but its adaptive and genetic bases are being debated. In other fields, such as human clinical genetics, DI is being assessed as incidence of minor morphological abnormalities (MMAs) and used to predict certain fitness outcomes. Here, for the first time, we combine these complementary measures of DI in sexual selection and quantitative genetic studies of a natural population. Comprehensive multivariate analyses demonstrate that FA and MMAs in a condition-dependent sexual ornament, the male Drosophila bipectinata sex comb used in courtship, are sole significant targets of selection favouring their reduced expression in New Caledonia. Comb FA and MMAs are positively correlated, confirming that each are linked to a common buffering system. Ornament size and DI (as FA and MMAs) are positively correlated, genetically and phenotypically, contrary to theoretical expectation of negative size-FA scaling under the assumption that FA reveals overall genetic quality. There exists significant additive genetic variance for MMAs, demonstrating their evolutionary potential. Ornament DI in New Caledonia is markedly elevated compared with populations where such selection was not detected, suggesting that the increased population-level DI is capacitating adaptive evolution.

Research on the role of parasites in sexual selection has focused mainly on host mate choice favoring relatively unparasitized males. But parasites can also generate variance in host reproductive success by influencing the ability of individual hosts to directly compete among themselves for mates or fertilizations, a subject area that has received far less attention. We demonstrate experimentally that parasitism by mites can drive sexual selection by way of a novel mechanism involving male competition: physical inhibition of host copulation. Mite resistance in natural populations is heritable, emphasizing the evolutionary potential of parasite-mediated sexual selection in this system and indicating that females should be receiving indirect fitness benefits as a result of this process. We show that parasitism by mites, Macrocheles subbadius, reduces mating success of male Drosophila nigrospiracula. Smaller males were more strongly compromised, identifying host body size as a tolerance trait. As parasite load increased, the rate at which males attempted to copulate but failed because of obstruction by mites increased. When mites were removed from infested males, host mating success was restored. Thus, the physical presence of the mites per se generates differential mating success, in this case by interrupting the normal flow of mating behaviors. This study elucidates a potent mechanism of parasite-mediated sexual selection in a system wherein parasite resistance is demonstrably heritable, and as such expands our understanding of the evolutionary potential of sexual selection. Copyright 2007, Oxford University Press.

Genitalia are one of the most rapidly diverging morphological features in animals. The evolution of genital morphology is proposed to be driven by sexual selection via cryptic female choice, whereby a female selectively uptakes and uses a particular male's sperm on the basis of male genital morphology. The resulting shifts in genital morphology within a species can lead to divergence in genitalia between species, and consequently to reproductive isolation and speciation. Although this conceptual framework is supported by correlative data, there is little direct empirical evidence. Here, we used a microdissection laser to alter the morphology of the external male genitalia in Drosophila, a widely used genetic model for both genital shape and cryptic female choice. We evaluate the effect of precision alterations to lobe morphology on both interspecific and intraspecific mating, and demonstrate experimentally that the male genital lobes do not affect copulation duration or cryptic female choice, contrary to long-standing assumptions regarding the role of the lobes in this model system. Rather, we demonstrate that the lobes are essential for copulation to occur. Moreover, slight alterations to the lobes significantly reduced copulatory success only in competitive environments, identifying precopulatory sexual selection as a potential contributing force behind genital diversification.

Identifying sources of phenotypic variability in secondary sexual traits is critical for understanding their signaling properties, role in sexual selection, and for predicting their evolutionary dynamics. The present study tests for the effects of genotype, developmental temperature, and their interaction, on size and fluctuating asymmetry of the male sex comb, a secondary sexual character, in Drosophila bipectinata Duda. Both the size and symmetry of elements of the sex comb have been shown previously to be under sexual selection in a natural population in northeastern Australia. Two independent reciprocal crosses were conducted at 25° and 29°C between genetic lines extracted from this population that differed in the size of the first (TC1) and third (TC3) comb segments. These temperatures are within the documented range experienced by the species in nature. Additive and dominance genetic effects were detected for TC1, whereas additive genetic, and Y-chromosomal effects were detected for TC3. TC...