scholarly journals Simple rules guide dragonfly migration

2006 ◽  
Vol 2 (3) ◽  
pp. 325-329 ◽  
Author(s):  
Martin Wikelski ◽  
David Moskowitz ◽  
James S Adelman ◽  
Jim Cochran ◽  
David S Wilcove ◽  
...  
Keyword(s):  
Decision Rules ◽  
Population Level ◽  
Long Distance ◽  
Migration Strategy ◽  
Anax Junius ◽  
Wind Speeds ◽  
Radio Transmitters ◽  
Migratory Patterns ◽  
And Migration ◽  
Made In

Every year billions of butterflies, dragonflies, moths and other insects migrate across continents, and considerable progress has been made in understanding population-level migratory phenomena. However, little is known about destinations and strategies of individual insects. We attached miniaturized radio transmitters ( ca 300 mg) to the thoraxes of 14 individual dragonflies (common green darners, Anax junius ) and followed them during their autumn migration for up to 12 days, using receiver-equipped Cessna airplanes and ground teams. Green darners exhibited distinct stopover and migration days. On average, they migrated every 2.9±0.3 days, and their average net advance was 58±11 km in 6.1±0.9 days (11.9±2.8 km d −1 ) in a generally southward direction (186±52°). They migrated exclusively during the daytime, when wind speeds were less than 25 km h −1 , regardless of wind direction, but only after two nights of successively lower temperatures (decrease of 2.1±0.6 °C in minimum temperature). The migratory patterns and apparent decision rules of green darners are strikingly similar to those proposed for songbirds, and may represent a general migration strategy for long-distance migration of organisms with high self-propelled flight speeds.

scholarly journals Multidimensional natal isotopic niches reflect migratory patterns in birds

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
A. Franzoi ◽  
S. Larsen ◽  
P. Franceschi ◽  
K. A. Hobson ◽  
P. Pedrini ◽  
...  
Keyword(s):  
Large Scale ◽  
Trophic Position ◽  
Bird Species ◽  
Ecological Niches ◽  
Type I ◽  
Long Distance ◽  
Migration Strategy ◽  
Stopover Site ◽  
Migratory Patterns

AbstractNaturally occurring stable isotope ratios in animal tissues allow estimation of species trophic position and ecological niche. Measuring multiple isotopes of migratory species along flyway bottlenecks offers the opportunity to sample multiple populations and species whose tissues carry information at continental scales. We measured δ2H, δ18O, δ13C, δ15N in juvenile feathers of 21 bird species captured at a migratory bottleneck in the Italian Alps. We examined if trends in individual isotopes reflected known migratory strategies and whether dietary (δ13C–δ15N) and spatially-explicit breeding origin (δ2H–δ18O) niche breadth (NB) differed among long-distance trans-Saharan (TS), short-distance (IP) and irruptive (IR) intra-Palearctic migrants, and whether they correlated with reported populations long-term trends. In both TS and IP groups, species δ2H declined with capture date, indicating that northern populations reached the stopover site later in the season, following a Type-I migration strategy. Values of δ2H indicated that breeding range of TS migrants extended farther north than IP and IR migrants. The breeding season was longer for IP migrants whose δ13C and δ15N values declined and increased, respectively, with time of capture. Average species dietary NB did not differ among migratory groups, but TS migrants displayed wider breeding origin niches, suggesting that long-distant migration is linked to broader ecological niches. Isotope origin NB well reflected species geographic range extent, while dietary NB did not correlate with literature accounts of species’ diet. We found no relationship between species breeding NB and population trends in Europe, suggesting that conditions in the breeding grounds, as inferred by stable isotopes, are not the only determinant of species’ long-term persistence. We demonstrate that ringing activities and isotopic measurements of passerines migrating through a bottleneck represents a unique opportunity to investigate large-scale life-history phenomena relevant to conservation.

scholarly journals Mechanistic movement models identify continuously updated autumn migration cues in Arctic caribou

2021 ◽  
Vol 9 (1) ◽  
Author(s):  
Matthew D. Cameron ◽  
Joseph M. Eisaguirre ◽  
Greg A. Breed ◽  
Kyle Joly ◽  
Knut Kielland
Keyword(s):  
Environmental Conditions ◽  
Rangifer Tarandus ◽  
Continuous Process ◽  
Population Level ◽  
Spring Migration ◽  
The Arctic ◽  
Autumn Migration ◽  
Long Distance ◽  
Movement Model ◽  
Migratory Patterns

Abstract Background Migrations in temperate systems typically have two migratory phases, spring and autumn, and many migratory ungulates track the pulse of spring vegetation growth during a synchronized spring migration. In contrast, autumn migrations are generally less synchronous and the cues driving them remain understudied. Our goal was to identify the cues that migrants use in deciding when to initiate migration and how this is updated while en route. Methods We analyzed autumn migrations of Arctic barren-ground caribou (Rangifer tarandus) as a series of persistent and directional movements and assessed the influence of a suite of environmental factors. We fitted a dynamic-parameter movement model at the individual-level and estimated annual population-level parameters for weather covariates on 389 individual-seasons across 9 years. Results Our results revealed strong, consistent effects of decreasing temperature and increasing snow depth on migratory movements, indicating that caribou continuously update their migratory decision based on dynamic environmental conditions. This suggests that individuals pace migration along gradients of these environmental variables. Whereas temperature and snow appeared to be the most consistent cues for migration, we also found interannual variability in the effect of wind, NDVI, and barometric pressure. The dispersed distribution of individuals in autumn resulted in diverse environmental conditions experienced by individual caribou and thus pronounced variability in migratory patterns. Conclusions By analyzing autumn migration as a continuous process across the entire migration period, we found that caribou migration was largely related to temperature and snow conditions experienced throughout the journey. This mechanism of pacing autumn migration based on indicators of the approaching winter is analogous to the more widely researched mechanism of spring migration, when many migrants pace migration with a resource wave. Such a similarity in mechanisms highlights the different environmental stimuli to which migrants have adapted their movements throughout their annual cycle. These insights have implications for how long-distance migratory patterns may change as the Arctic climate continues to warm.

scholarly journals Morphology of migration: Associations between wing shape, bill morphology, and migration in kingbirds (Tyrannus)

2021 ◽  
Author(s):  
Maggie MacPherson ◽  
Alex Jahn ◽  
Nicholas A Mason
Keyword(s):  
Energy Expenditure ◽  
Long Distance ◽  
Migration Strategy ◽  
Dietary Specialization ◽  
Seasonal Movements ◽  
Bill Morphology ◽  
Pan American ◽  
Migratory Status ◽  
And Migration ◽  
Intraspecific Morphological Variation

Morphology is closely linked to locomotion and diet in animals. In animals that undertake long-distance migrations, limb-morphology is under selection to maximize mobility and minimize energy expenditure. Migratory behaviors also interact with diet, such that migratory animals tend to be dietary generalists, while sedentary taxa tend to be dietary specialists. Despite a hypothesized link between migration status and morphology, phylogenetic comparative studies have yielded conflicting findings. In this study, we tested for evolutionary associations between migratory status and limb and bill morphology across kingbirds, a pan-American genus of birds with migratory, partially migratory, and sedentary taxa. We found that migratory kingbirds had longer and more pointed wings, in agreement with expectations if selection favors improved aerodynamics for long-distance migration. We also found an association between migratory status and bill shape, such that more migratory taxa had wider and deeper bills and sedentary taxa had longer bills. However, there was no difference in levels of intraspecific morphological variation among migrants, partial migrants, and residents, suggesting that dietary specialization has evolved independently of migration strategy. Evolutionary links between migration, diet, and morphology in kingbirds further strengthen ecomorphological associations that underlie long-distance seasonal movements in animals.

scholarly journals Variability and repeatability of noctule bat migration in Central Europe: evidence for partial and differential migration

2018 ◽  
Vol 285 (1893) ◽  
pp. 20182174 ◽  
Author(s):  
Linn S. Lehnert ◽  
Stephanie Kramer-Schadt ◽  
Tobias Teige ◽  
Uwe Hoffmeister ◽  
Ana Popa-Lisseanu ◽  
...  
Keyword(s):  
Central Europe ◽  
Migratory Behaviour ◽  
Natal Philopatry ◽  
Differential Migration ◽  
Long Distance ◽  
Migration Strategy ◽  
Migration Patterns ◽  
Bat Migration ◽  
Source Populations ◽  
And Migration

Each year, large numbers of bats move across Europe between their summer and winter areas, yet even though many of them are endangered and legally protected, we are unaware about many aspects of their migratory behaviour. Here, taking Nyctalus noctula as a model species, we used stable hydrogen isotopic values in fur ( δ 2 H f ) as an endogenous marker to shed light on the migratory behaviour of more than 1000 bats from hibernacula across Central Europe. Specifically, we asked the following questions: how flexible is migration in temperate zone bats? Which general migration pattern do noctule bats follow? How repeatable and thus predictable is the migratory behaviour of individuals? Do morphological correlates of migration occur in bats? Our study confirmed that noctule bats engage in partial and female-biased migration across Europe, suggesting the strongest migration pressures for northern populations. Further, we revealed a combination of partial and differential migration patterns with highly variable migration distances which lead to a pronounced mixing of different source populations in hibernacula where mating occurs. Most individuals were consistent in their migration strategy over time, i.e. 86% could be repeatedly assigned to either long-distance or regional origin across years. This is consistent with our finding that the between-individual component explained 84% of the variation in δ 2 H f values, suggesting specialized individual migratory behaviours and a strong natal philopatry. We discovered a positive correlation between forearm length and migration distance and support for sex-specific effects of migration on body condition. Our study elucidated migration patterns over large geographical scales, demonstrating that considerable numbers of migratory bats originating from distant populations depend on hibernacula across Central Europe, calling for international conservation management.

scholarly journals Multidimensional natal isotopic niches reflect migratory patterns in birds

2021 ◽  
Author(s):  
A. Franzoi ◽  
S. Larsen ◽  
P. Franceschi ◽  
K.A. Hobson ◽  
P. Pedrini ◽  
...  
Keyword(s):  
Large Scale ◽  
Trophic Position ◽  
Bird Species ◽  
Ecological Niches ◽  
Type I ◽  
Long Distance ◽  
Migration Strategy ◽  
Stopover Site ◽  
Migratory Patterns

AbstractNaturally occurring stable isotope ratios in animal tissues allow estimation of species trophic position and ecological niche. Measuring multiple isotopes of migratory species along flyway bottlenecks offers the opportunity to sample multiple populations and species whose tissues carry information at continental scales.We measured δ2H, δ18O, δ13C, δ15N in juvenile feathers of 21 bird species captured at a migratory bottleneck in the Italian Alps.We examined if trends in individual isotopes reflected known migratory strategies and whether dietary (δ13C-δ15N) and spatially-explicit breeding origin (δ2H-δ18O) niche breadth (NB) differed among long-distance trans-Saharan (TS), short-distance (IP) and irruptive (IR) intra-Palearctic migrants, and whether they correlated with reported populations long-term trends.In both TS and IP groups, species δ2H declined with capture date, indicating that northern populations reached the stopover site later in the season, following a Type-I migration strategy. Values of δ2H indicated that breeding range of TS migrants extended farther north than IP and IR migrants. The breeding season was longer for IP migrants whose δ13C and δ15N values declined and increased, respectively, with time of capture.Average species dietary NB did not differ among migratory groups, but TS migrants displayed wider breeding origin niches, suggesting that long-distant migration is linked to broader ecological niches. Isotope origin NB well reflected species geographic range extent, while dietary NB did not correlate with literature accounts of species’ diet. We found no relationship between species breeding NB and population trends in Europe, implying that conditions in the wintering grounds could be more important for the long-term persistence of species.We demonstrate that isotopic measurements of passerines migrating through a bottleneck represents a unique opportunity to investigate large-scale life-history phenomena relevant to conservation.

scholarly journals Adaptations to migration in birds: behavioural strategies, morphology and scaling effects

2007 ◽  
Vol 363 (1490) ◽  
pp. 287-299 ◽  
Author(s):  
Anders Hedenström
Keyword(s):  
Fuel Load ◽  
Scaling Effects ◽  
Annual Life Cycle ◽  
Long Distance ◽  
Migration Strategy ◽  
Stopover Site ◽  
Optimal Migration ◽  
Migration Theory ◽  
Time Minimization ◽  
And Migration

The annual life cycle of many birds includes breeding, moult and migration. All these processes are time and energy consuming and the extent of investment in any one may compromise the others. The output from breeding is of course the ultimate goal for all birds, while the investment in moult and migration should be selected so that lifetime fitness is maximized. In particular, long-distance migrants breeding at high latitudes face severe time pressures, which is a probable reason why natural selection has evolved efficient behaviours, physiological and morphological adaptations allowing the maximum possible migration speed. Optimal migration theory commonly assumes time minimization as an overall strategy, but the minimization of energy cost and predation risk may also be involved. Based on these assumptions, it is possible to derive adaptive behaviours such as when and at which fuel load a stopover site should be abandoned. I review some core components of optimal migration theory together with some key predictions. A review of accumulated empirical tests of the departure rule indicates that time minimization is an important component of the overall migration strategy, and hence gives support to the assumption about time-selected migration. I also briefly discuss how the optimal policy may be implemented by the bird by applying a set of simple rules. The time constraints on migrants increase with increasing body size. Some consequences of this are discussed.

Systematics, Biogeography, and Morphological Character Evolution of the Hemiepiphytic Subfamily Monsteroideae (Araceae)

2019 ◽  
Vol 104 (1) ◽  
pp. 33-48 ◽  
Author(s):  
Alejandro Zuluaga ◽  
Martin Llano ◽  
Ken Cameron
Keyword(s):  
Dna Sequences ◽  
Pacific Islands ◽  
R Package ◽  
Morphological Characters ◽  
Ancestral State ◽  
Seed Shape ◽  
Long Distance ◽  
The Pacific ◽  
And Migration ◽  
The Tropics

The subfamily Monsteroideae (Araceae) is the third richest clade in the family, with ca. 369 described species and ca. 700 estimated. It comprises mostly hemiepiphytic or epiphytic plants restricted to the tropics, with three intercontinental disjunctions. Using a dataset representing all 12 genera in Monsteroideae (126 taxa), and five plastid and two nuclear markers, we studied the systematics and historical biogeography of the group. We found high support for the monophyly of the three major clades (Spathiphylleae sister to Heteropsis Kunth and Rhaphidophora Hassk. clades), and for six of the genera within Monsteroideae. However, we found low rates of variation in the DNA sequences used and a lack of molecular markers suitable for species-level phylogenies in the group. We also performed ancestral state reconstruction of some morphological characters traditionally used for genera delimitation. Only seed shape and size, number of seeds, number of locules, and presence of endosperm showed utility in the classification of genera in Monsteroideae. We estimated ancestral ranges using a dispersal-extinction-cladogenesis model as implemented in the R package BioGeoBEARS and found evidence for a Gondwanan origin of the clade. One tropical disjunction (Monstera Adans. sister to Amydrium Schott–Epipremnum Schott) was found to be the product of a previous Boreotropical distribution. Two other disjunctions are more recent and likely due to long-distance dispersal: Spathiphyllum Schott (with Holochlamys Engl. nested within) represents a dispersal from South America to the Pacific Islands in Southeast Asia, and Rhaphidophora represents a dispersal from Asia to Africa. Future studies based on stronger phylogenetic reconstructions and complete morphological datasets are needed to explore the details of speciation and migration within and among areas in Asia.

scholarly journals Prevalence and genetic diversity of avian haemosporidian parasites in wild bird species of the order Columbiformes

2021 ◽  
Author(s):  
Yvonne R. Schumm ◽  
Dimitris Bakaloudis ◽  
Christos Barboutis ◽  
Jacopo G. Cecere ◽  
Cyril Eraud ◽  
...  
Keyword(s):  
Host Species ◽  
Large Scale ◽  
Phylogenetic Reconstruction ◽  
Bird Species ◽  
Avian Species ◽  
Blood Parasites ◽  
Migration Strategy ◽  
Haemosporidian Parasites ◽  
Multiplex Pcr Assay ◽  
And Migration

AbstractDiseases can play a role in species decline. Among them, haemosporidian parasites, vector-transmitted protozoan parasites, are known to constitute a risk for different avian species. However, the magnitude of haemosporidian infection in wild columbiform birds, including strongly decreasing European turtle doves, is largely unknown. We examined the prevalence and diversity of haemosporidian parasites Plasmodium, Leucocytozoon and subgenera Haemoproteus and Parahaemoproteus in six species of the order Columbiformes during breeding season and migration by applying nested PCR, one-step multiplex PCR assay and microscopy. We detected infections in 109 of the 259 screened individuals (42%), including 15 distinct haemosporidian mitochondrial cytochrome b lineages, representing five H. (Haemoproteus), two H. (Parahaemoproteus), five Leucocytozoon and three Plasmodium lineages. Five of these lineages have never been described before. We discriminated between single and mixed infections and determined host species-specific prevalence for each parasite genus. Observed differences among sampled host species are discussed with reference to behavioural characteristics, including nesting and migration strategy. Our results support previous suggestions that migratory birds have a higher prevalence and diversity of blood parasites than resident or short-distance migratory species. A phylogenetic reconstruction provided evidence for H. (Haemoproteus) as well as H. (Parahaemoproteus) infections in columbiform birds. Based on microscopic examination, we quantified parasitemia, indicating the probability of negative effects on the host. This study provides a large-scale baseline description of haemosporidian infections of wild birds belonging to the order Columbiformes sampled in the northern hemisphere. The results enable the monitoring of future changes in parasite transmission areas, distribution and diversity associated with global change, posing a potential risk for declining avian species as the European turtle dove.

War Captives, Left-Behind Wives, and Buddhist Nuns: Female Migrants in Early Medieval China (4th–6th Century CE)

2021 ◽  
pp. 1-18
Author(s):  
Wen-Yi Huang
Keyword(s):  
Fourth Century ◽  
Early Medieval ◽  
Long Distance ◽  
Textual Representations ◽  
Medieval China ◽  
Gender And Migration ◽  
Early Medieval China ◽  
And Migration ◽  
Northern Wei ◽  
Distance Travel

Abstract Using received texts and excavated funerary epitaphs, this article examines the intricacies of gender and migration in early medieval China by exploring women's long-distance mobility from the fourth century to the sixth century, when what is now known as China was divided by the Northern Wei and a succession of four southern states—the Eastern Jin, Liu-Song, Southern Qi, and Liang. I focus on three types of migration in which women participated during this period: war-induced migration, family reunification, and religious journeys. Based on this analysis, I propose answers to two important questions: the connection between migration and the state, and textual representations of migrants. Though the texts under consideration are usually written in an anecdotal manner, the references to women, I argue, both reveals nuances in perceptions of womanhood at the time and elucidates the contexts within—and through—which long-distance travel became possible for women.

scholarly journals Advancement in long-distance bird migration through individual plasticity in departure

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Jesse R. Conklin ◽  
Simeon Lisovski ◽  
Phil F. Battley
Keyword(s):  
Bird Migration ◽  
Population Level ◽  
Breeding Site ◽  
Environmental Constraints ◽  
Adaptive Responses ◽  
Long Distance ◽  
Direct Observations ◽  
Breeding Resources ◽  
Plastic Responses

AbstractGlobally, bird migration is occurring earlier in the year, consistent with climate-related changes in breeding resources. Although often attributed to phenotypic plasticity, there is no clear demonstration of long-term population advancement in avian migration through individual plasticity. Using direct observations of bar-tailed godwits (Limosa lapponica) departing New Zealand on a 16,000-km journey to Alaska, we show that migration advanced by six days during 2008–2020, and that within-individual advancement was sufficient to explain this population-level change. However, in individuals tracked for the entire migration (50 total tracks of 36 individuals), earlier departure did not lead to earlier arrival or breeding in Alaska, due to prolonged stopovers in Asia. Moreover, changes in breeding-site phenology varied across Alaska, but were not reflected in within-population differences in advancement of migratory departure. We demonstrate that plastic responses can drive population-level changes in timing of long-distance migration, but also that behavioral and environmental constraints en route may yet limit adaptive responses to global change.

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