Browsing by Subject "FLEXIBILITY"

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  • Quesada, J.; Chavez-Zichinelli, Carlos A.; Garcia-Arroyo, Michelle; Yeh, Pamela J.; Guevara, R.; Izquierdo-Palma, J.; MacGregor-Fors, I. (2022)
    Bold or shy? Examining the risk-taking behavior and neophobia of invasive and non-invasive house sparrows. Behavior provides a useful framework for understanding specialization, with animal personality aiding our understanding of the invasiveness of birds. Invasions imply dispersion into unknown areas and could require changes in behavior or spatial clustering based on personality. Reduced neophobia and increased exploring behavior could allow individuals to colonize new areas as they test and use non-familiar resources. Here, we hypothesized that house sparrow (Passer domesticus) individuals from invasive populations would exhibit bolder behavior than in non-invasive populations. We assessed risk taking and neophobia in male house sparrows in Barcelona (where it is considered native) and in Mexico City (where it has become widely invasive), captured in two different habitats, urban and non-urban. We assessed latency to enter an experimental cage and to explore it, and latency to feed and feeding time in the presence of a novel object. We found that sparrows from Mexico City, both from urban and non-urban areas, were quicker to enter the experimental cage than the sparrows from Barcelona. The time it took the birds to start exploring the cage gave a similar result. We found no differences between cities or habitats in the latency to feed and feeding time while exposed to a novel object. Our results partially support the view that the invader populations from Mexico City are bolder than those from Barcelona. Behavior is an important component of plasticity and its variability may have an important effect on adaptation to local situations. Future studies should disentangle the underlying mechanisms that explain the different personalities found in populations of different regions, contrasting populations of different densities, and taking different food availability scenarios into account.
  • Joki, Anu; Mäkelä, Johanna; Fogelholm, Mikael (2017)
    Maintaining normal weight in the current obesogenic environment is a challenge. However, some people can do it. More insight is needed to understand how and why some people succeed in long-term weight maintenance. This study uses a rare, qualitative approach by describing the thoughts of successful weight management and self-perceived requirements for success in weight maintenance. We interviewed 39 individuals who have maintained normal weight for their entire lives (men and women). The content analysis revealed a main theme: flexible, permissive and conscious self-regulation, which was divided into two subthemes (eating-related behavior and weight-related behavior). The informants reported certain routines that supported their weight management: regular eating, sufficient meal sizes, eating in response to hunger, healthy and vegetable-rich diet along with moderate feasting and flexible eating restriction. Flexibility in routines allowed freedom in their eating behavior. In addition, informants regarded themselves as physically active, and they enjoyed regular exercise. Regular weighing was generally considered unnecessary. Normal weight was regarded as a valuable and worthwhile issue, and most of the informants worked to keep their weight stable. Although the perceived workload varied among informants, the weight management strategies were similar. It was crucial to be conscious of the balance between eating and energy consumption. Further, flexibility characterized their behavior and was the basis of successful weight management. Women were more aware of weight control practices and knowledge than men, but otherwise, women and men reported similar weight management methods and attitudes. In conclusion, the interviewees who have maintained the normal weight had created a personal weight-management support environment where weight management was a lifestyle. (C) 2017 Elsevier Ltd. All rights reserved.
  • Tolman, Deryk; Campobello, Daniela; Rönkä, Katja; Kluen, Edward; Thorogood, Rose (2021)
    Hosts of brood parasitic cuckoos often employ mobbing attacks to defend their nests and, when mobbing is costly, hosts are predicted to adjust their mobbing to match parasitism risk. While evidence exists for fine-tuned plasticity, it remains unclear why mobbing does not track larger seasonal changes in parasitism risk. Here we test a possible explanation from parental investment theory: parents should defend their current brood more intensively as the opportunity to replace it declines (re-nesting potential), and therefore "counteract" any apparent seasonal decline to match parasitism risk. We take advantage of mobbing experiments conducted at two sites where reed warblers (Acrocephalus scirpaceus) experience (in Italy), or do not experience (in Finland), brood parasitism. We predicted that mobbing of cuckoos should be higher overall in Italy, but remain constant over the season as in other parasitised sites, whereas in Finland where cuckoos do not pose a local threat, we predicted that mobbing should be low at the beginning of the season but increase as re-nesting potential declined. However, while cuckoos were more likely to be mobbed in Italy, we found little evidence that mobbing changed over the season at either the parasitized or non-parasitized sites. This suggests that re-nesting potential has either little influence on mobbing behavior, or that its effects are obscured by other seasonal differences in ecology or experience of hosts.
  • Saraheimo, Satu; Hepojoki, Jussi; Nurmi, Visa; Lahtinen, Anne; Hemmila, Ilkka; Vaheri, Antti; Vapalahti, Olli; Hedman, Klaus (2013)
  • Salazar-Ciudad, Isaac (2021)
    The concept of developmental constraints has been central to understand the role of development in morphological evolution. Developmental constraints are classically defined as biases imposed by development on the distribution of morphological variation. This opinion article argues that the concepts of developmental constraints and developmental biases do not accurately represent the role of development in evolution. The concept of developmental constraints was coined to oppose the view that natural selection is all-capable and to highlight the importance of development for understanding evolution. In the modern synthesis, natural selection was seen as the main factor determining the direction of morphological evolution. For that to be the case, morphological variation needs to be isotropic (i.e. equally possible in all directions). The proponents of the developmental constraint concept argued that development makes that some morphological variation is more likely than other (i.e. variation is not isotropic), and that, thus, development constraints evolution by precluding natural selection from being all-capable. This article adds to the idea that development is not compatible with the isotropic expectation by arguing that, in fact, it could not be otherwise: there is no actual reason to expect that development could lead to isotropic morphological variation. It is then argued that, since the isotropic expectation is untenable, the role of development in evolution should not be understood as a departure from such an expectation. The role of development in evolution should be described in an exclusively positive way, as the process determining which directions of morphological variation are possible, instead of negatively, as a process precluding the existence of morphological variation we have no actual reason to expect. This article discusses that this change of perspective is not a mere question of semantics: it leads to a different interpretation of the studies on developmental constraints and to a different research program in evolution and development. This program does not ask whether development constrains evolution. Instead it asks questions such as, for example, how different types of development lead to different types of morphological variation and, together with natural selection, determine the directions in which different lineages evolve.