Changes in butterfly movements along a gradient of land use in farmlands of Transylvania (Romania)

Diffusion, which approximates a correlated random walk, has been used by ecologists to describe movement, and forms the basis for many theoretical models. However, it is often criticized as too simple a model to describe animal movement in real populations. We test a key prediction of diffusion models, namely, that animals should be more abundant in land cover classes through which they move more slowly. This relationship between density and diffusion has rarely been tested across multiple species within a given landscape. We estimated diffusion rates and corresponding densities of 25 Israeli butterfly species from flight path data and visual surveys. The data were collected across 19 sites in heterogeneous landscapes with four land cover classes: semi-natural habitat, olive groves, wheat fields and field margins. As expected from theory, species tended to have higher densities in land cover classes through which they moved more slowly and lower densities in land cover classes through which they moved more quickly. Two components of movement (move length and turning angle) were not associated with density, nor was expected net squared displacement. Move time, however, was associated with density, and animals spent more time per move step in areas with higher density. The broad association we document between movement behaviour and density suggests that diffusion is a good first approximation of movement in butterflies. Moreover, our analyses demonstrate that dispersal is not a species-invariant trait, but rather one that depends on landscape context. Thus, land cover classes with high diffusion rates are likely to have low densities and be effective conduits for movement.

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“…; Loos et al . ). In our study, the diffusion‐density relationship is based mostly on variation within species, among land cover classes (e.g.…”

Section: Discussionmentioning

confidence: 97%

“…; Loos et al . ), for example, based on mark‐recapture, or radio or satellite telemetry data, such as in Frair et al . .…”

Section: Introductionmentioning

confidence: 99%

Does movement behaviour predict population densities? A test with 25 butterfly species

Schultz

Pe'er

Damiani³

et al. 2017

Journal of Animal Ecology

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“…Other factors may also play a role in this context (e.g. population age, sex and species; [22][23][24]). …”

Section: Introductionmentioning

confidence: 99%

Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes

2016

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Flight is an essential biological ability of many insects, but is energetically costly. Environments under rapid human-induced change are characterized by habitat fragmentation and may impose constraints on the energy income budget of organisms. This may, in turn, affect locomotor performance and willingness to fly. We tested flight performance and metabolic rates in meadow brown butterflies (Maniola jurtina) of two contrasted agricultural landscapes: intensively managed, nectar-poor (IL) versus extensively managed, nectar-rich landscapes (EL). Young female adults were submitted to four nectar treatments (i.e. nectar quality and quantity) in outdoor flight cages. IL individuals had better flight capacities in a flight mill and had lower resting metabolic rates (RMR) than EL individuals, except under the severest treatment. Under this treatment, RMR increased in IL individuals, but decreased in EL individuals; flight performance was maintained by IL individuals, but dropped by a factor 2.5 in EL individuals. IL individuals had more canalized (i.e. less plastic) responses relative to the nectar treatments than EL individuals. Our results show significant intraspecific variation in the locomotor and metabolic response of a butterfly to different energy income regimes relative to the landscape of origin. Ecophysiological studies help to improve our mechanistic understanding of the eco-evolutionary impact of anthropogenic environments on rare and widespread species.

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“…Next, the butterfly was tracked for a maximum of 10 min from a distance of c . 1 m to avoid interference by the observer (Loos et al ., ). The trajectory was recorded by a hand‐held GPS (Pathfinder Data logger SiRf Star III, GPS‐DL R8; relative spatial accuracy: ±0.1 m).…”

Section: Methodsmentioning

confidence: 97%

“…After marking, the butterfly was returned to the net and released after a 1-min recovery period (Cormont et al, 2010). Next, the butterfly was tracked for a maximum of 10 min from a distance of c. 1 m to avoid interference by the observer (Loos et al, 2015). The trajectory was recorded by a hand-held GPS (Pathfinder Data logger SiRf Star III, GPS-DL R8; relative spatial accuracy: AE0.1 m).…”

Section: Behavioural Trackingmentioning

confidence: 99%

Flower use of the butterfly Maniola jurtina in nectar‐rich and nectar‐poor grasslands: a nectar generalist with a strong preference?

Lebeau

Wesselingh

Dyck

2017

Insect Conserv Diversity

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Butterflies are often considered as opportunistic nectar consumers that visit a range of flower species. The degree of specialisation in foraging behaviour and flower choice may, however, vary considerably at the inter‐specific level, from highly specialised to generalist species. In generalist nectar use, there can be intra‐specific variation in the availability and use of floral resources (diversity and abundance) among different populations. Knowing the preferences of nectar‐feeding butterflies can increase the understanding of ecological relationships and resource use and help in developing better strategies for butterfly conservation. By means of behavioural tracking, we identified foraging patterns of Maniola jurtina butterflies in nectar‐rich and nectar‐poor grasslands. For both males and females, we showed significant preference for the brown knapweed Centaurea jacea and thistles (Cirsium sp.) in nectar‐rich, extensively managed grasslands. In the absence of these preferred species, as is typically the case in nectar‐poor intensively managed sites, M. jurtina nectared on Trifolium pratense and Leucanthemum vulgare. Flower visits were on average shorter on T. pratense compared to C. jacea. These observational results were confirmed by a field experiment in which a wild flower nectar array with C. jacea and T. pratense was introduced. In extensively managed grasslands, foraging bouts were generally confined to patches of flowering plants and did not involve long flights between flower visits. In intensively managed meadows, butterflies performed longer flights, and ignored more flowers between two consecutive visits. Despite the variety of flower species visited, M. jurtina showed a significant preference for a few nectar sources in a context‐dependent way.

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Changes in butterfly movements along a gradient of land use in farmlands of Transylvania (Romania)

Cited by 25 publications

References 48 publications

Does movement behaviour predict population densities? A test with 25 butterfly species

Does movement behaviour predict population densities? A test with 25 butterfly species

Nectar resource limitation affects butterfly flight performance and metabolism differently in intensive and extensive agricultural landscapes

Flower use of the butterfly Maniola jurtina in nectar‐rich and nectar‐poor grasslands: a nectar generalist with a strong preference?

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