scholarly journals Variation in wing characteristics of monarch butterflies during migration: Earlier migrants have redder and more elongated wings

2014 ◽  
Vol 2 (1) ◽  
Author(s):  
Dara A. Satterfield ◽  
Andrew K. Davis
Keyword(s):  
North America ◽  
Bird Migration ◽  
Danaus Plexippus ◽  
Flight Performance ◽  
Wing Morphology ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Significant Tendency ◽  
Length Width ◽  
Ultimate Fate

AbstractThe migration of monarch butterflies (Danaus plexippus) in North America has a number of parallels with long-distance bird migration, including the fact that migratory populations of monarchs have larger and more elongated forewings than residents. These characteristics likely serve to optimize flight performance in monarchs, as they also do with birds. A question that has rarely been addressed thus far in birds or monarchs is if and how wing characteristics vary within a migration season. Individuals with superior flight performance should migrate quickly, and/or with minimal stopovers, and these individuals should be at the forefront of the migratory cohort. Conversely, individuals with poor flight performance and/or low endurance would be more likely to fall behind, and these would comprise the latest migrants. Here we examined how the wing morphology of migrating monarchs varies to determine if wing characteristics of early migrants differ from late migrants. We measured forewing area, elongation (length/width), and redness, which has been shown to predict flight endurance in monarchs. Based on a collection of 75 monarchs made one entire season (fall 2010), results showed that the earliest migrants (n = 20) in this cohort had significantly redder and more elongated forewings than the latest migrants (n = 17). There was also a non-significant tendency for early migrants to have larger forewing areas. These results suggest that the pace of migration in monarchs is at least partly dependent on the properties of their wings. Moreover, these data also raise a number of questions about the ultimate fate of monarchs that fall behind

scholarly journals Estimating the annual distribution of monarch butterflies in Canada over 16 years using citizen science data

FACETS ◽  
2019 ◽  
Vol 4 (1) ◽  
pp. 238-253
Author(s):  
D. T. Tyler Flockhart ◽  
Maxim Larrivée ◽  
Kathleen L. Prudic ◽  
D. Ryan Norris
Keyword(s):  
North America ◽  
Citizen Science ◽  
Habitat Restoration ◽  
Danaus Plexippus ◽  
The United States ◽  
Science Data ◽  
Eastern Canada ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Breeding Distribution

Monarch butterflies ( Danaus plexippus, Linnaeus, 1758) are comprised of two migratory populations separated by the Rocky Mountains and are renowned for their long-distance movements among the United States, Canada, and Mexico. Both populations have declined over several decades across North America prompting all three countries to evaluate conservation efforts. Monitoring monarch distribution and abundance is a necessary aspect of ongoing management in Canada where they are a species at risk. We used presence-only data from two citizen science data sets to estimate the annual breeding distribution of monarch butterflies in Canada between 2000 and 2015. Monarch breeding distribution in Canada varied widely among years owing to natural variation, and when considering the upper 95% of the probability of occurrence, the annual mean breeding distribution in Canada was 484 943 km2 (min: 173 449 km2; max: 1 425 835 km2). The area of occurrence was approximately an order of magnitude larger in eastern Canada than in western Canada. Habitat restoration for monarch butterflies in Canada should prioritize productive habitats in southern Ontario where monarchs occur annually and, therefore, likely contribute most to the long-term viability of monarchs in eastern North America. Overall, our assessment sets the geographic context to develop successful management strategies for monarchs in Canada.

scholarly journals Tracking multi-generational colonization of the breeding grounds by monarch butterflies in eastern North America

2013 ◽  
Vol 280 (1768) ◽  
pp. 20131087 ◽  
Author(s):  
D. T. Tyler Flockhart ◽  
Leonard I. Wassenaar ◽  
Tara G. Martin ◽  
Keith A. Hobson ◽  
Michael B. Wunder ◽  
...  
Keyword(s):  
North America ◽  
Danaus Plexippus ◽  
Late Summer ◽  
Breeding Habitat ◽  
Eastern North America ◽  
Distribution Models ◽  
Monarch Butterflies ◽  
Breeding Distribution ◽  
Breeding Grounds ◽  
Isotope Measurements

Insect migration may involve movements over multiple breeding generations at continental scales, resulting in formidable challenges to their conservation and management. Using distribution models generated from citizen scientist occurrence data and stable-carbon and -hydrogen isotope measurements, we tracked multi-generational colonization of the breeding grounds of monarch butterflies ( Danaus plexippus ) in eastern North America. We found that monarch breeding occurrence was best modelled with geographical and climatic variables resulting in an annual breeding distribution of greater than 12 million km 2 that encompassed 99% occurrence probability. Combining occurrence models with stable isotope measurements to estimate natal origin, we show that butterflies which overwintered in Mexico came from a wide breeding distribution, including southern portions of the range. There was a clear northward progression of monarchs over successive generations from May until August when reproductive butterflies began to change direction and moved south. Fifth-generation individuals breeding in Texas in the late summer/autumn tended to originate from northern breeding areas rather than regions further south. Although the Midwest was the most productive area during the breeding season, monarchs that re-colonized the Midwest were produced largely in Texas, suggesting that conserving breeding habitat in the Midwest alone is insufficient to ensure long-term persistence of the monarch butterfly population in eastern North America.

Developmental and reproductive effects of clothianidin exposure in monarch butterflies (Lepidoptera: Nymphalidae)

2021 ◽  
pp. 1-16
Author(s):  
Alana A.E. Wilcox ◽  
Amy E.M. Newman ◽  
D. Ryan Norris
Keyword(s):  
Egg Size ◽  
Insect Pests ◽  
Danaus Plexippus ◽  
Crop Damage ◽  
High Dose ◽  
Monarch Butterflies ◽  
Insecticide Treatment ◽  
Late Instar ◽  
Length Width ◽  
The Impact

Abstract Neonicotinoid insecticides are used to reduce crop damage caused by insect pests, but sublethal levels could affect development and reproduction in nontarget insects, such as monarch butterflies (Danaus plexippus) (Lepidoptera: Nymphalidae). To investigate the impact of field-realistic concentrations of the neonicotinoid clothianidin on monarch butterflies, we grew swamp milkweed (Asclepias incarnata) (Apocynaceae) in either low (15 ng/g of soil) or high (25 ng/g of soil) levels of clothianidin, or in a control (0 ng/g), then raised monarchs on the milkweed. Morphological traits of monarch caterpillars were measured during development and, once they eclosed, were mated as adults to quantify egg size and mass and the number of eggs laid. Although the effects of the treatment had complex effects on caterpillar length, width and volume of late-instar caterpillars were negatively affected. Fifth-instar caterpillars from the high-dose insecticide treatment had lower mass than other groups. Adult monarch butterflies raised on treated milkweed were larger than controls, but clothianidin exposure did not affect the number of eggs laid or egg size. Although the magnitude of the effect depends on clothianidin concentration, our results suggest that exposure to clothianidin during early life can impact monarch caterpillar development but is unlikely to reduce female reproductive output.

scholarly journals A poor substitute for the real thing: captive-reared monarch butterflies are weaker, paler and have less elongated wings than wild migrants

2020 ◽  
Vol 16 (4) ◽  
pp. 20190922 ◽  
Author(s):  
Andrew K. Davis ◽  
Farran M. Smith ◽  
Ashley M. Ballew
Keyword(s):  
Danaus Plexippus ◽  
Late Summer ◽  
Population Declines ◽  
Average Strength ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Real Thing ◽  
In The Wild ◽  
Wild Group ◽  
Migration Propensity

For many animals and insects that are experiencing dramatic population declines, the only recourse for conservationists is captive rearing. To ensure success, reared individuals should be biologically indistinct from those in the wild. We tested if this is true with monarch butterflies, Danaus plexippus , which are increasingly being reared for release by citizens and commercial breeders. Since late-summer monarchs should be as migration capable as possible for surviving the arduous long-distance migration, we evaluated four migration-relevant traits across two groups of captive-reared monarchs ( n = 41 and 42) and one group of wild-caught migrants ( n = 41). Monarchs (descendants of wild individuals) were reared from eggs to adulthood either in a warm indoor room next to a window, or in an incubator that mimicked late-summer conditions. Using an apparatus consisting of a perch mounted to an electronic force gauge, we assessed ‘grip strength' of all groups, then used image analysis to measure forewing size, pigmentation and elongation. In three of the four traits, reared monarchs underperformed compared to wild ones, even those reared under conditions that should have produced migration-ready individuals. The average strength of reared monarchs combined was 56% less than the wild group, even when accounting for size. Their orange wing colour was paler (an indicator of poor condition and flight ability) and their forewings were less elongated (elongation is associated with migration propensity) than wild monarchs. The reason(s) behind these effects is unknown but could stem from the frequent disturbance and/or handling of reared monarchs, or the fact that rearing removes the element of natural selection from all stages. Regardless, these results explain prior tagging studies that showed reared monarchs have lower migratory success compared to wild.

scholarly journals Wing Color of Monarch Butterflies (Danaus plexippus) in Eastern North America across Life Stages: Migrants Are “Redder” than Breeding and Overwintering Stages

2009 ◽  
Vol 2009 ◽  
pp. 1-5 ◽  
Author(s):  
Andrew K. Davis
Keyword(s):  
North America ◽  
Southeastern United States ◽  
Danaus Plexippus ◽  
Color Difference ◽  
Color Variation ◽  
Eastern North America ◽  
Life Stages ◽  
Monarch Butterflies ◽  
Bright Orange ◽  
The Many

Monarch butterflies are famous among insects for their unique migration in eastern North America to overwinter sites in Mexico and their bright orange wing color, which has an aposematic function. While capturing migrating monarchs in northeast Georgia, USA, I noticed that many appeared to have unusually deep orange wings. I initiated the current study to compare wing hues (obtained using image analysis of scanned wings) of migrants (captured in 2005 and 2008) to samples of breeding and overwintering monarchs. Consistent with initial observations, migrants had significantly lower orange hues (reflecting deeper, redder orange colors) than breeding and overwintering monarchs. There was also a difference in hue between sexes and a relationship with wing size, such that larger monarchs had deeper, redder hues. The reasons for the color difference of migrants are not apparent, but one possibility is that the longer-lived migrant generation has denser scalation to allow for scale loss over their lifespan. Alternatively, this effect could be confined to the subpopulation of monarchs in the Southeastern United States, which may not be well represented at the Mexican overwintering sites. In any case, this discovery highlights the many questions emerging on the significance of wing color variation in this species.

scholarly journals Long-distance dispersal of the beach strawberry, Fragaria chiloensis, from North America to Chile and Hawaii

2020 ◽  
Author(s):  
James F Hancock ◽  
Harold H Prince
Keyword(s):  
North America ◽  
Bird Migration ◽  
Aleutian Islands ◽  
South American ◽  
Rocky Shores ◽  
Long Distance Dispersal ◽  
Feeding Preferences ◽  
Long Distance ◽  
Central California ◽  
Fragaria Chiloensis

Abstract Background and Aims The beach strawberry, Fragaria chiloensis, is found in a narrow coastal band from the Aleutian Islands to central California and then jumps thousands of kilometres all the way to Hawaii and Chile. As it probably had a North American origin, it must have been introduced to the other locations by long-distance dispersal. The aim of this study was to determine which agent carried the beach strawberry to its Pacific and South American locations. Methods A deductive framework was constructed to separate between the possible modes of long-distance dispersal involving animals, wind and ocean currents. Bird migration was subsequently identified as the most likely scenario, and then the routes, habitats, feeding preferences and flight distances of all the shorebird species were evaluated to determine the most likely carrier. Key Results Six species migrate between North America and Chile and feed on the beaches and rocky shores where F. chiloensis grows naturally: Black-bellied Plovers, Greater Yellowlegs, Ruddy Turnstones, Sanderlings, Whimbrels and Willets. Of these, only two eat fruit and migrate in long continuous flight: Ruddy Turnstones and Whimbrels. Two species travel between North America and Hawaii, eat fruit and forage on the beaches and rocky shores where F. chiloensis grows naturally: Pacific Golden-plovers and Ruddy Turnstones. Ruddy Turnstones eat far less fruit than Pacific Golden-plovers and Whimbrels, making them less likely to have introduced the beach strawberry to either location. Conclusions We provide evidence that F. chiloesis seeds were probably dispersed to Hawaii by Pacific Golden-plovers and to Chile by Whimbrels.

scholarly journals Monarch butterflies cross the Appalachians from the west to recolonize the east coast of North America

2010 ◽  
Vol 7 (1) ◽  
pp. 43-46 ◽  
Author(s):  
Nathan G. Miller ◽  
Leonard I. Wassenaar ◽  
Keith A. Hobson ◽  
D. Ryan Norris
Keyword(s):  
North America ◽  
Direct Evidence ◽  
East Coast ◽  
Gulf Coast ◽  
Danaus Plexippus ◽  
Early Spring ◽  
Eastern United States ◽  
The West ◽  
Monarch Butterflies ◽  
The Usa

Each spring, millions of monarch butterflies ( Danaus plexippus ) migrate from overwintering sites in Mexico to recolonize eastern North America. However, few monarchs are found along the east coast of the USA until mid-summer. Brower (Brower, L. P. 1996 J. Exp. Biol. 199, 93–103.) proposed that east coast recolonization is accomplished by individuals migrating from the west over the Appalachians, but to date no evidence exists to support this hypothesis. We used hydrogen ( δ D) and carbon ( δ 13 C) stable isotope measurements to estimate natal origins of 90 monarchs sampled from 17 sites along the eastern United States coast. We found the majority of monarchs (88%) originated in the mid-west and Great Lakes regions, providing, to our knowledge, the first direct evidence that second generation monarchs born in June complete a ( trans -) longitudinal migration across the Appalachian mountains. The remaining individuals (12%) originated from parents that migrated directly from the Gulf coast during early spring. Our results provide evidence of a west to east longitudinal migration and provide additional rationale for conserving east coast populations by identifying breeding sources.

scholarly journals No broad decline of breeding monarch butterflies in North America: implications for conservation efforts

2021 ◽  
Author(s):  
Andrew K Davis ◽  
Michael S Crossley ◽  
Matthew K Moran ◽  
Jeffrey Glassberg ◽  
William E Snyder
Keyword(s):  
North America ◽  
Habitat Restoration ◽  
Danaus Plexippus ◽  
Geographic Range ◽  
Breeding Habitat ◽  
Flagship Species ◽  
Monarch Butterflies ◽  
Breeding Populations ◽  
First Time

Many insects are in clear decline, with monarch butterflies (Danaus plexippus) drawing particular attention as a flagship species. Falling numbers of overwintering monarchs are well documented, but there has been debate regarding population trends of summer breeding populations. Here, we compile a series of long-term monarch monitoring datasets, some which are analyzed here for the first time, that reveal highly variable responses across the migratory geographic range, but no broad net decline in numbers of breeding monarchs. We also did not find evidence that sampling biased towards natural sites was masking declines at disturbed sites. Overall, our results suggest a robust resiliency in summer populations that thus far has allowed recovery from losses during the winter. Thus, monarchs may not require as much breeding habitat restoration as once thought, and focus should be on conserving the fall and spring migration.

scholarly journals Monarchs Reared in Winter in California Are Not Large Enough to Be Migrants. Comment on James et al. First Population Study on Winter Breeding Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) in the Urban South Bay of San Francisco, California. Insects 2021, 12, 946

Insects ◽  
2022 ◽  
Vol 13 (1) ◽  
pp. 63 ◽  
Author(s):  
Andrew K. Davis
Keyword(s):  
North America ◽  
San Francisco ◽  
Population Study ◽  
Danaus Plexippus ◽  
Monarch Butterflies ◽  
Urban South ◽  
Winter Breeding

A recent study in this journal aimed to understand certain changes in the wintering behavior of monarch butterflies, specifically in the western subpopulation of North America [...]

scholarly journals Effects of early-life exposure to sublethal levels of a common neonicotinoid insecticide on the orientation and migration of monarch butterflies (Danaus plexippus)

2020 ◽  
Vol 224 (4) ◽  
pp. jeb230870
Author(s):  
Alana A. E. Wilcox ◽  
Amy E. M. Newman ◽  
Nigel E. Raine ◽  
Greg W. Mitchell ◽  
D. Ryan Norris
Keyword(s):  
Danaus Plexippus ◽  
Monarch Butterfly ◽  
Flight Simulator ◽  
Testing Time ◽  
Long Distance ◽  
Monarch Butterflies ◽  
Early Life Exposure ◽  
Neonicotinoid Insecticide ◽  
In The Wild ◽  
And Migration

ABSTRACTMigratory insects use a variety of innate mechanisms to determine their orientation and maintain correct bearing. For long-distance migrants, such as the monarch butterfly (Danaus plexippus), these journeys could be affected by exposure to environmental contaminants. Neonicotinoids are synthetic insecticides that work by affecting the nervous system of insects, resulting in impairment of their mobility, cognitive performance, and other physiological and behavioural functions. To examine how neonicotinoids might affect the ability of monarch butterflies to maintain a proper directional orientation on their ∼4000 km migration, we grew swamp milkweed (Asclepias incarnata) in soil that was either untreated (0 ng g−1: control) or mixed with low (15 ng g−1 of soil) or high (25 ng g−1 of soil) levels of the neonicotinoid clothianidin. Monarch caterpillars were raised on control or clothianidin-treated milkweed and, after pupation, either tested for orientation in a static flight simulator or radio-tracked in the wild during the autumn migration period. Despite clothianidin being detectable in milkweed tissue consumed by caterpillars, there was no evidence that clothianidin influenced the orientation, vector strength (i.e. concentration of direction data around the mean) or rate of travel of adult butterflies, nor was there evidence that morphological traits (i.e. mass and forewing length), testing time, wind speed or temperature impacted directionality. Although sample sizes for both flight simulator and radio-tracking tests were limited, our preliminary results suggest that clothianidin exposure during early caterpillar development does not affect the directed flight of adult migratory monarch butterflies or influence their orientation at the beginning of migration.

Sign in / Sign up

Export Citation Format

Share Document