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- Almbro, Maria, 1979-
(författare)
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Escape flight in butterflies
- 2009
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- Flight is considered to be the overarching reason for the enormous diversity and world-wide abundance of insects. Not only does flight enable great distances to be covered and new areas to be colonised, flying has also evolved to be important in most adult life-history characteristics from reproduction to anti-predator strategies. However, despite its advantages, the costs of flight are high, particularly with regard to building a flight apparatus and staying in the air. Winged insects are popular prey for various predators from which they rely on flight to escape. However, because of their nutrient poor adult diet, butterflies are especially sensitive to the trade-off between flight and reproduction. Theory therefore predicts costs of physiological changes such as weight gain to be visible through altered aerial performance. Whereas insect flight has been extensively studied with regard to biomechanics, aerodynamics, dispersal and force production, little effort has been made to empirically study the relationship between escape strategies and weight loading, despite its value for survival and fitness. In this thesis a novel three-dimensional flight-recording set-up was used to study free flight ability in relation to natural weight loads in male and female Aglais urticae and Pieris napi butterflies. Weight loads consisted of ingested food, mate-carrying and reproductive mass, affecting wing loading and flight muscle ratio, key determinants of flight ability. Moreover, butterfly escape strategies were investigated through the use of model predators. The results showed that perceived predation risk affected butterfly flight behaviour, with greater speed being observed in attacked butterflies. Decreased flight muscle ratio after feeding resulted in slower escape flights in A. urticae, and impaired flight during mate-carrying in P. napi. Increased wing loading during reproduction in P. napi negatively affected male flight speed and female take-off angles. In summary, this thesis demonstrates that flight effort is context dependant and shows a trade-off between flight ability and longevity- and fitness related weight gain that may ultimately affect survival, mating success and energy expenditure.
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- Almbro, Maria, et al.
(författare)
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Season, sex and flight muscle investment affect take-off performance in the hibernating small tortoiseshell butterfly Agalis urticae (Lepidoptera: Nymphalidae)
- 2011
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Ingår i: The Journal of Research on the Lepidoptera. - 0022-4324. ; 44, s. 77-84
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Tidskriftsartikel (refereegranskat)abstract
- Flight ability is generally expected to increase with relative flight muscle mass. Changes in weight can therefore be expected to influence the capacity to rapidly take-off, which can determine mating success and predator avoidance. This study examined the influence of relative flight muscle mass, sex, and season on free take-off flight ability in a butterfly model (Aglais urticae) that undergoes adult winter hibernation. Mass change and take-off flight ability (velocity and take-off angle), was predicted to fluctuate with season (before, during and after hibernation) and sex (due to reproductive investment). Our results indeed showed changes in take-off ability in relation to both parameters. Females maintained velocity across seasons but reduced take-off angles during and after hibernation. Male flight speed increased during and after hibernation, whereas take-off angles were significantly reduced during hibernation. Finally, we showed that investment in relative flight muscle mass increased velocity in female, but not in male butterflies.
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- Almbro, Maria, et al.
(författare)
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Weight Loading and Reproductive Status Affect the Flight Performance of Pieris napi Butterflies
- 2012
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Ingår i: Journal of insect behavior. - : Springer Science and Business Media LLC. - 0892-7553 .- 1572-8889. ; 25:5, s. 441-452
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Tidskriftsartikel (refereegranskat)abstract
- Weight-induced mobility reductions can have dramatic fitness consequences and winged animals are especially sensitive to the trade-off between mass and locomotion. Data on how natural weight fluctuations influence a flying insect's ability to take off are scarce. We therefore quantified take-off flight ability in Pieris napi butterflies in relation to reproductive status. Take-off flight ability (velocity and take-off angle) under suboptimal temperature conditions was recorded with a 3D-tracking camera system and was predicted to decrease with relatively larger weight loads. Our results show that relatively larger weight loads generally reduce flight speed in male butterflies and lower take-off angles in females. However, despite having a lower wing loading, mated male butterflies flew slower than unmated males. Our study suggests that retention of weight loads associated with reproduction impairs insect flight performance.
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| 6. |
- André, Alann, et al.
(författare)
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Re-use of wind turbine blade for construction and infrastructure applications
- 2020
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Ingår i: IOP Conference Series. - : IOP Publishing Ltd.
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Konferensbidrag (refereegranskat)abstract
- To achieve a more resource-efficient society with a future with reduced carbon dioxide emissions, new technological challenges must be dealt. One way to reach a more sustainable world is to start re-using end-of-life structures and waste and give them a Second Life"with a new function in the society. As composite structures are lightweight, strong, stiff and durable materials, there is great potential to re-use decommissioned composite for new resource-efficient solutions in the building and infrastructure sector. The present paper investigates innovative solutions in re-using wind turbine blades as elements in new bicycle and pedestrian bridge designs. Several conceptual bridge designs where wind blades utilized as load bearing elements were developed and studied. The main design requirements for pedestrian bridges were considered and assumptions regarding wind blades quality and their mechanical properties addressed based on interviews with industries working with wind turbine blades repair and recycling. The aim of this paper is to contribute to a sustainable use of fibre reinforced polymer (FRP) waste and at the same time provide a more cost-effective FRP bridges. In a larger perspective, the authors would like to highlight the economically profitable potential of recovering and reusing / re-manufacturing end-of-life glass FRP composites.
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| 7. |
- Barboutis, Christos, et al.
(författare)
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Fuelling in front of the barrier-are there age based behavioral differences in Garden Warblers Sylvia borin?
- 2014
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Ingår i: PeerJ. - San Fransisco and London : PeerJ. - 2167-8359. ; 2
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Tidskriftsartikel (refereegranskat)abstract
- Garden Warblers Sylvia borin were studied during autumn stopover in Crete before crossing the barrier of the Mediterranean Sea and the Sahara Desert. Birds followed with transmitters show extensive stopover periods, which were longer in first-year birds, 16 days, compared with adult birds, 14 days. The distribution of body masses from birds trapped in fig trees were used to estimate the departure body mass and the results found indicate that both age categories on average depart with a fuel load close to 100% of lean body mass. The movement of transmitter birds shows differences between first-year and adult birds. Adult birds move further away from the release site and many also left the study area. Several were found settled outside the study area, up to 17 km away, indicating that they regularly make longer stopover movements. It is suggested that this might be a result of that they return to a place where they stayed during an earlier migration. It was shown that stopover site fidelity exists and nine garden warblers were recaptured in the area during a following autumn. The results found highlights the importance of stopover areas close to the Sahara Desert.
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| 8. |
- Benson, Scott A., et al.
(författare)
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Graded-risk sensitivity in northern European mixed-species flocks of tit and nuthatch species
- 2022
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Ingår i: Ethology. - : Wiley. - 0179-1613 .- 1439-0310. ; 128:5, s. 437-442
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Tidskriftsartikel (refereegranskat)abstract
- Avian species often use anti-predator calls such that the costs and benefits of vigilance are distributed within the group. Some species respond differentially to graded risk by attending to relevant predator cues, such as head orientation and gaze direction. One benefit of graded-risk sensitivity is fewer missed foraging opportunities. It is not known how the makeup of risk response behaviors in mixed-species flocks may relate to the relative nuclearity of each species in the flock. In the current study, predator models were presented to two nuclear and two satellite species of passerines that frequently occur in natural mixed flocks. Predator models either faced toward or away from a nearby stocked feeder to simulate high and low risk of predation, and calling and seed-taking rates of the present flock were recorded. The nuclear species, great tits (Parus major) and crested tits (Lophophanes cristatus), took more seeds when the predator faced away from the feeder than toward it. The satellite species, Eurasian nuthatches (Sitta europaea) and willow tits (Poecile montanus), did not show an effect of predator orientation. No species showed consistent differences in calling behavior relative to predator orientation, although insufficient calling data for great tits prevented analysis for this species. The results of this study suggest that one aspect of nuclearity in mixed-species flocks is a tendency for graded-risk sensitivity, or alternatively, that satellite species are more sensitive to mere predator presence rather than to predator orientation cues.
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| 10. |
- Boström, Jannika, et al.
(författare)
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Autumn migratory fuelling : a response to simulated magnetic displacement in juvenile wheatears, Oenathe oenathe
- 2010
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Ingår i: Behavioral Ecology and Sociobiology. - : Springer Science and Business Media LLC. - 0340-5443 .- 1432-0762. ; 64:11, s. 1725-1732
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Tidskriftsartikel (refereegranskat)abstract
- Recent experiments exposing migratory birds to altered magnetic fields simulating geographical displacements have shown that the geomagnetic field acts as an external cue affecting migratory fuelling behaviour. This is the first study investigating fuel deposition in relation to geomagnetic cues in long-distance migrants using the western passage of the Mediterranean region. Juvenile wheatears (Oenanthe oenanthe) were exposed to a magnetically simulated autumn migration from southern Sweden to West Africa. Birds displaced parallel to the west of their natural migration route, simulating an unnatural flight over the Atlantic Ocean, increased their fuel deposition compared to birds experiencing a simulated migration along the natural route. These birds, on the other hand, showed relatively low fuel loads in agreement with earlier data on wheatears trapped during stopover. The experimental displacement to the west, corresponding to novel sites in the Atlantic Ocean, led to a simulated longer distance to the wintering area, probably explaining the observed larger fuel loads. Our data verify previous results suggesting that migratory birds use geomagnetic cues for fuelling decisions and, for the first time, show that birds, on their first migration, can use geomagnetic cues to compensate for a displacement outside their normal migratory route, by adjusting fuel deposition.
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