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Selective Response (selective + response)
Selected AbstractsTemporal Shifts in Conspicuousness: Mate Attraction Displays of the Texas Field Cricket, Gryllus texensisETHOLOGY, Issue 12 2004Susan M. Bertram Conspicuous mate attraction displays can simultaneously draw the attention of potential mates and predators, placing the signaller in peril of becoming prey. The balance between these countervailing forms of selection has the potential to shape mate attraction displays. Male Texas field crickets (Gryllus texensis; Orthoptera) signal acoustically to attract mates. Mating signals also attract acoustically orienting parasitoid flies (Ormia ochracea; Tachinidae). Both the abundance of female crickets and parasitoid flies fluctuates throughout the night. We show mate attraction displays exhibit diel shifts that correlate positively with expected female cricket presence and negatively with expected parasitoid fly activity. During early evening, when parasitoids are most common and mating is scarce, crickets signal less often and with reduced conspicuousness. During the second half of the evening, when sexually receptive females are abundant and parasitoids are scarce, crickets signal more often and with enhanced conspicuousness. These diel shifts in mate attraction displays do not appear to result from male crickets detecting parasitoid flies or female crickets and altering their behaviour accordingly. Males in close proximity to parasitoid flies or female crickets do not signal differently than lone males. Instead, diel pattern shifts in mate attraction displays appear to be a selective response to trade-offs between natural selection via parasitism and sexual selection via mate choice. [source] Butterfly life history and temperature adaptations; dry open habitats select for increased fecundity and longevityJOURNAL OF ANIMAL ECOLOGY, Issue 1 2005BENGT KARLSSON Summary 1Evidence suggests that changes of temperature-related performance curves can trigger a selective response in life-history traits. Hence, it should be expected that insects adapted to different temperature regimes should exhibit optimal performance at the temperature to which they are adapted. 2To test this idea we investigated how fecundity and longevity are influenced by ambient temperatures in a set of satyrine butterflies adapted to live in dry open landscapes or in closed forest landscapes, respectively, by keeping egg-laying adult females at five different constant temperatures ranging between 20 and 40 °C. 3We studied four species, two of which are confined to dry and hot open habitats, namely the grayling (Hipparchia semele) and the small heath (Coenonympha pamphilus), and two of which are shade dwelling, namely the ringlet (Aphantopus hyperantus) and the speckled wood butterfly (Pararge aegeria). 4As predicted, the results showed that lifetime fecundity exhibited bell-shaped curves in relation to temperature with the open landscape group peaking at a higher temperature, 30 °C, compared with the shade-dwelling group that peaked at 25 °C. Longevity decreased with increasing temperatures among all species, but the open landscape living species survived better at higher temperatures. Moreover, although the magnitude of reproductive effort measured as lifetime egg mass did not differ between the two ecological groups, lifetime fecundity did with open landscape species laying more and smaller eggs than the shade-dwelling species. 5This difference in life-history character traits suggests either that dry and relatively warm open habitats open life-history opportunities in terms of higher fecundity and longevity that remain closed to butterflies adapted to cooler temperatures, or that life in dry open habitats actively selects for higher fecundity and survival as a result of increased offspring mortality. [source] Competing Rationales for Corporate Governance in France: Institutional Complementarities between Financial Markets and Innovation SystemsCORPORATE GOVERNANCE, Issue 2 2008Soo H. Lee ABSTRACT Manuscript Type: Conceptual Research Question/Issue: This paper identifies the causes and consequences of corporate governance reform with reference to the French case. By disaggregating institutional complementarities into global and domestic dimensions, we analyze the path of institutional change compelled by financial efficiency and cooperative innovation. Research Findings/Results: Our analysis of the French case shows that both converging and diverging forces of institutional change coexist, shaping selective responses to globalization. While the adoption of the shareholder model is necessary for resource acquirement from the global capital markets, resource allocation in the cooperative innovation systems reinforces the stakeholder model. The French case confirms the sustainability of distinctive institutional complementarities, albeit with selective adaptation based on a sense-making social compromise. Theoretical Implications: The French case reminds us of the importance of distinctive institutional traditions and dominant social rationalities to understand the underlying logic of governance reform. The comparative research on corporate governance needs to address not just the cross-country variations in institutional arrangements and practices, but also the clash of competing rationales for reform explicitly in comparative terms within a single country context. Practical Implications: For foreign investors, it is vital to understand the unique institutional environment of state-centred stakeholder economies if they are to negotiate the best terms of return and to avoid unnecessary conflicts. French managers are expected to devise strategic choices responding to the competing rationales of governance. Managerial sense-making is essential for achieving sound long-term performance, upon which the legitimacy and sustainability of the constellation of selective governance rests. [source] Role of differential changes in sympathetic nerve activity in the preparatory adjustments of cardiovascular functions during freezing behaviour in ratsEXPERIMENTAL PHYSIOLOGY, Issue 1 2010Kenju Miki Freezing behaviour is associated with a distinct pattern of changes in cardiovascular function, which has been considered as a preparatory reflex for ,fight or flight' behaviour. However, the detailed mechanisms underlying preparatory cardiovascular adjustments and their physiological implications have received less attention. We studied responses in renal and lumbar sympathetic nerve activity and cardiovascular function during freezing behaviour in conscious rats, which was induced by exposure to loud white noise. Freezing behaviour was associated with regionally specific alterations in sympathetic nerve activity, in that renal sympathetic nerve activity increased while lumbar sympathetic nerve activity did not change. Moreover, freezing behaviour was associated with differential shifts in baroreflex control of sympathetic outflows, which could help to explain the selective responses in renal and lumbar sympathetic nerve activity during freezing behaviour. These differential changes in sympathetic outflows would result in a visceral vasoconstriction without having any impact on the skeletal muscle vasculature. These cardiovascular adjustments during freezing behaviour may help to explain the immediate and massive increase in muscular blood flow that occurs at the onset of fight or flight behaviour. It is hypothesized that central command originating from the defence area could somehow modulate separate baroreflex pathways, causing differential changes in sympathetic nerve activity to generate the preparatory cardiovascular adjustments during the freezing behaviour. [source] | ||||||||||