17 research outputs found

    The Invisible Power of MacHines Revisiting the Proposed Flash Order Ban in the Wake of the Flash Crash

    Get PDF
    Technological innovation continues to make trading and markets more efficient, generally benefitting market participants and the investing public. But flash trading, a practice that evolved from high-frequency trading, benefits only a select few sophisticated traders and institutions with the resources necessary to view and respond to flashed orders. This practice undermines the basic principles of fairness and transparency in securities regulation, exacerbates information asymmetries and harms investor confidence. This iBrief revisits the Securities and Exchange Commission\u27s proposed ban on the controversial practice of flash trading and urges the Securities and Exchange Commission and the Commodity Futures Trading Commission to implement the ban across the securities and futures markets. Banning flash trading will not impact high-frequency trading or other advantageous innovative trading practices, and will benefit all market participants by making prices and liquidity more transparent. In the wake of the May 6, 2010 flash crash and the passage of the Dodd-Frank Wall Street Reform and Consumer Protection Act, now is an opportune time for the Securities and Exchange Commission and Commodity Futures Trading Commission to implement the ban

    Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community

    Get PDF
    Social information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds.</p

    Intra- and interspecific social information use in nest site selection of a cavity-nesting bird community

    No full text
    Abstract Animals need information about local conditions to make optimal fitness-enhancing decisions such as where to breed. Information can be acquired by personal sampling of the environment, but it can also be acquired from other individuals. The latter is termed social information use. Social information use has gained a lot of attention in modern ecology because it affects principal ecological phenomena such as animal distribution and resource use. Social information use is not restricted to obviously cognitive mammals and birds but is also found in e.g. reptiles, fish and insects. Social information use studies have thus far been concentrated on situations with one social information user and one (often the same) source species. The community-wide consequences of social information use have almost exclusively been considered in theoretical studies. In this thesis, I studied empirically social information use in the nest site selection within and between species in a cavity-nesting bird community consisting of the collared flycatcher (Ficedula albicollis), the great tit (Parus major) and the blue tit (P. caeruleus). I studied social information use on two time scales: social information gathered just before a breeding attempt, and social information gathered already during the previous breeding season for the following year’s breeding attempt. I used experiments in which different white geometric symbols represented nest site choices of earlier settled tutors and empty nest boxes, and I observed the symbol choices of later-breeding individuals. The symbol approach eradicates bias from innate and learned preferences enabling strong inference. My results demonstrate that collared flycatchers use social information from both con- and heterospecific tutors in different situations in a flexible manner. Hence, social information use seems to be context-dependent. Furthermore, I show that great tits avoid choosing nest site characteristics which were associated with either con- or heterospecifics nests the previous year and prefer symbols which depicted an empty nest box the previous year, probably to avoid nest ectoparasites. I also show that in great tits the male has greater influence on nest site selection than previously assumed even though the female builds the nest. My thesis deepens our understanding about the complexity of social information use and highlights its significance in future ecological research.TiivistelmĂ€ ElĂ€imet tarvitsevat informaatiota paikallisista olosuhteista tehdĂ€kseen edullisia pÀÀtöksiĂ€ esimerkiksi siitĂ€, missĂ€ lisÀÀntyĂ€. Informaatiota voidaan hankkia tutkimalla ympĂ€ristöÀ itse, mutta sitĂ€ voidaan hankkia myös muilta yksilöiltĂ€. JĂ€lkimmĂ€istĂ€ kutsutaan sosiaaliseksi informaatioksi. ElĂ€inten sosiaalisen informaation kĂ€yttö on saavuttanut viime aikoina paljon huomiota ekologisessa tutkimuksessa, koska se vaikuttaa tĂ€rkeisiin ekologisiin ilmiöihin, kuten elĂ€inten levinneisyyteen ja resurssien kĂ€yttöön. Sosiaalinen informaation kĂ€yttö ei rajoitu vain nisĂ€kkĂ€isiin ja lintuihin, vaan sitĂ€ on havaittu myös esimerkiksi matelijoilla, kaloilla ja hyönteisillĂ€. Sosiaalisen informaation kĂ€yttöÀ on tutkittu lĂ€hes yksinomaan lajien sisĂ€llĂ€ tai kĂ€yttĂ€en ainoastaan yhtĂ€ sosiaalisen informaation lĂ€hdelajia. Yhteisötason vaikutuksia on pohdittu miltei pelkĂ€stÀÀn teoreettisissa tutkimuksissa. TĂ€ssĂ€ vĂ€itöskirjatyössĂ€ tutkin kokeellisesti sosiaalisen informaation kĂ€yttöÀ pesĂ€paikan valinnassa lajin sisĂ€llĂ€ ja lajien vĂ€lillĂ€ kolopesivien lintujen yhteisössĂ€ sepelsiepolla (Ficedula albicollis), talitiaisella (Parus major) ja sinitiaisella (P. caeruleus). Otin tutkimuksissani huomioon kaksi aikatasoa: tutkin juuri ennen pesimisyritystĂ€ kerĂ€tyn sekĂ€ jo edellisen lisÀÀntymiskauden aikana seuraavan vuoden pesintÀÀ varten hankitun sosiaalisen informaation kĂ€yttöÀ. Kokeissani kĂ€ytin linnunpönttöihin kiinnitettyjĂ€ erilaisia valkoisia geometrisia symboleita, jotka edustivat aiemmin pesinnĂ€n aloittaneiden lintujen eli tuutoreiden pesĂ€paikanvalintoja. Seurasin tĂ€mĂ€n jĂ€lkeen myöhemmin pesimÀÀn saapuvien parien symbolivalintoja. Tulosteni perusteella sepelsiepot hankkivat sosiaalista informaatiota sekĂ€ lajitovereiltaan ettĂ€ tiaisilta joustavasti eri tilanteissa. LisĂ€ksi osoitan, ettĂ€ talitiaiset vĂ€lttĂ€vĂ€t valitsemasta pesĂ€paikkoja, jotka olivat asuttuina edellisenĂ€ vuonna, ja suosivat sellaisia pesĂ€paikkoja, joissa ei pesitty edellisenĂ€ vuonna - todennĂ€köisesti vĂ€lttÀÀkseen kirppuja ja muita pesĂ€loisia. Osoitan myös, ettĂ€ talitiaiskoirailla on suurempi vaikutus pesĂ€paikan valintaan kuin aikaisemmin on oletettu, vaikka naaraat rakentavat pesĂ€n. VĂ€itöskirjatyöni syventÀÀ kĂ€sitystĂ€mme sosiaalisen informaation kĂ€ytön monitahoisuudesta elĂ€inkunnassa ja korostaa sen merkitystĂ€ ekologisessa tutkimuksessa

    Flycatchers copy conspecifics in nest-site selection but neither personal experience nor frequency of tutors have an effect

    Get PDF
    Abstract Using the behavior of others in guiding one’s own behavior is a common strategy in animals. The prevailing theory predicts that young age and the inexperience of an individual are expected to increase the probability of adopting the behaviors of others. Also, the most common behavior in the population should be copied. Here, we tested the above predictions by examining social information use in the selection of nest-site features with a field experiment using a wild cavity nesting bird, the collared flycatcher (Ficedula albicollis). We used an experimental design in which geometric symbols depict nestsite features. By manipulating the apparent symbol choices of early settled individuals and monitoring the choices of later arriving birds, we can study social information use without bias from learned or innate preferences. Flycatchers were found to use social information in the selection of nest-site features, with about 60% of the population preferring the manipulated conspecific choices. However, age and experience as explanatory factors suggested by the social information use theory did not explain the choices. The present result, in concert with earlier similar experiments, implies that flycatchers may in some situations rely more on interspecific information in the selection of nest-site characteristics

    Flycatchers Copy Conspecifics in Nest-Site Selection but Neither Personal Experience nor Frequency of Tutors Have an Effect

    No full text
    Abstract Using the behavior of others in guiding one&apos;s own behavior is a common strategy in animals. The prevailing theory predicts that young age and the inexperience of an individual are expected to increase the probability of adopting the behaviors of others. Also, the most common behavior in the population should be copied. Here, we tested the above predictions by examining social information use in the selection of nest-site features with a field experiment using a wild cavity nesting bird, the collared flycatcher (Ficedula albicollis). We used an experimental design in which geometric symbols depict nestsite features. By manipulating the apparent symbol choices of early settled individuals and monitoring the choices of later arriving birds, we can study social information use without bias from learned or innate preferences. Flycatchers were found to use social information in the selection of nest-site features, with about 60% of the population preferring the manipulated conspecific choices. However, age and experience as explanatory factors suggested by the social information use theory did not explain the choices. The present result, in concert with earlier similar experiments, implies that flycatchers may in some situations rely more on interspecific information in the selection of nest-site characteristics

    The best generalized linear mixed-effects models (GLMMs).

    No full text
    <p>A) In 'lme4' syntax: match/mismatch of choice ∌ experience + (tutor number −1 | area)</p><p>B) In 'lme4' syntax: match/mismatch of choice ∌ experience + (tutor number | area)</p>*<p>P value from permutation test, see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0060395#s2" target="_blank">Methods</a> for details</p><p>Estimated fixed effects for experience variable of the two best GLMMs explaining the probability of flycatchers to copy the tutors' symbol choice. The models were fitted with Laplace approximation (R function ‘glmer’), binomial error distribution and a logistic link function. Only area-specific random slopes in relation to the number of tutors at the time of choice were included in model 1, whereas both area-specific random slopes and intercepts in relation to the number of tutors at the time of choice were included in model 2.</p

    Flycatcher choices.

    No full text
    <p>The percentage of flycatcher females choosing matching (black bar) or opposite (white bar) symbol of the tutoring flycatchers in the three cohorts. Yearlings are individuals born the previous year, and are all immigrants (63.2% matching choices, n = 19). Older immigrants are older individuals which are new to the area (60.3.% matching choices, n = 58). Older site-faithfuls are older individuals, which bred on the same area the year before (58.5% matching choices, n = 41).</p

    Experimental set-up.

    No full text
    <p>The first two flycatcher pairs were assigned to breed in a symbol that portrays the apparent choice of all conspecifics on the area (here a triangle) with an adjacent empty box with the other symbol (here a circle). Later arriving birds had to make a choice in an empty box-pair portraying apparent preferred and rejected symbols. Each later pair was also assigned the same manipulation symbol, thus increasing the amount of tutors for subsequent birds.</p

    Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community

    No full text
    Abstract. Background: Social information use is usually considered to lead to ecological convergence among involved con- or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds. Results: Of the examined species, resident great tits ( Parus major ) preferred the symbol that had been associated with unoccupied nest boxes in the previous year, i.e., their preference shifted towards niche space previously unused by putative competitors and conspecifics. Conclusions: Our results show that animals can remember the earlier resource use of conspecifics and other guild members and adjust own decisions accordingly one year after. Our experiment cannot reveal the ultimate mechanism(s) behind the observed behaviour but avoiding costs of intra- or interspecific competition or ectoparasite load in old nests are plausible reasons. O ur findings imply that interspecific social information use can affect resource sharing and realized niches in ecological time-scale through active avoidance of observed decisions and behavior of potentially competing species.peerReviewe

    Avoiding perceived past resource use of potential competitors affects niche dynamics in a bird community

    No full text
    Background: Social information use is usually considered to lead to ecological convergence among involved con-or heterospecific individuals. However, recent results demonstrate that observers can also actively avoid behaving as those individuals being observed, leading to ecological divergence. This phenomenon has been little explored so far, yet it can have significant impact on resource use, realized niches and species co-existence. In particular, the time-scale and the ecological context over which such shifts can occur are unknown. We examined with a long-term (four years) field experiment whether experimentally manipulated, species-specific, nest-site feature preferences (symbols on nest boxes) are transmitted across breeding seasons and affect future nest-site preferences in a guild of three cavity-nesting birds. Results: Of the examined species, resident great tits (Parus major) preferred the symbol that had been associated with unoccupied nest boxes in the previous year, i.e., their preference shifted towards niche space previously unused by putative competitors and conspecifics. Conclusions: Our results show that animals can remember the earlier resource use of conspecifics and other guild members and adjust own decisions accordingly one year after. Our experiment cannot reveal the ultimate mechanism(s) behind the observed behaviour but avoiding costs of intra-or interspecific competition or ectoparasite load in old nests are plausible reasons. Our findings imply that interspecific social information use can affect resource sharing and realized niches in ecological time-scale through active avoidance of observed decisions and behavior of potentially competing species
    corecore