scholarly journals Lipid reserves and immune defense in healthy and diseased migrating monarchs Danaus plexippus

2013 ◽  
Vol 59 (3) ◽  
pp. 393-402 ◽  
Author(s):  
Dara A. Satterfield ◽  
Amy E. Wright ◽  
Sonia Altizer
Keyword(s):  
Danaus Plexippus ◽  
Protozoan Parasite ◽  
Parasite Load ◽  
Immune Defense ◽  
Eastern North America ◽  
Energy Reserves ◽  
Long Distance ◽  
Phenoloxidase Activity ◽  
Weak Support ◽  
Ophryocystis Elektroscirrha

Abstract Recent studies suggest that the energetic demands of long-distance migration might lower the pool of resources available for costly immune defenses. Moreover, migration could amplify the costs of parasitism if animals suffering from parasite-induced damage or depleted energy reserves are less able to migrate long distances. We investigated relationships between long-distance migration, infection, and immunity in wild fall-migrating monarch butterflies Danaus plexippus. Monarchs migrate annually from eastern North America to central Mexico, accumulating lipids essential for migration and winter survival as they travel southward. Monarchs are commonly infected by the debilitating protozoan parasite Ophryocystis elektroscirrha (OE). We collected data on lipid reserves, parasite loads, and two immune measures (hemocyte concentration and phenoloxidase activity) from wild monarchs migrating through north GA (USA) to ask whether (1) parasite infection negatively affects lipid reserves, and (2) greater investment in lipid reserves is associated with lower immune measures. Results showed that monarchs sampled later in the fall migration had lower but not significantly different immune measures and significantly higher lipid reserves than those sampled earlier. Lipid measures correlated negatively but only nearly significantly with one measure of immune defense (phenoloxidase activity) in both healthy and infected monarchs, but did not depend on monarch infection status or parasite load. These results provide weak support for a trade-off between energy reserves and immune defense in migrants, and suggest that previously-demonstrated costs of OE infection for monarch migration are not caused by depleted lipid reserves.

scholarly journals Further Insights on the Migration Biology of Monarch Butterflies, Danaus plexippus (Lepidoptera: Nymphalidae) from the Pacific Northwest

Insects ◽  
2021 ◽  
Vol 12 (2) ◽  
pp. 161
Author(s):  
David G. James ◽  
Linda Kappen
Keyword(s):  
Pacific Northwest ◽  
Danaus Plexippus ◽  
Protozoan Parasite ◽  
Poor Quality ◽  
Santa Barbara ◽  
Monarch Butterflies ◽  
Ophryocystis Elektroscirrha ◽  
Straight Line ◽  
The Pacific ◽  
Travel Rate

The fall migration of monarch butterflies, Danaus plexippus (L.), in the Pacific Northwest was studied during 2017–2019 by tagging 14,040 captive-reared and 450 wild monarchs. One hundred and twenty-two captive-reared monarchs (0.87%) were recovered at distances averaging 899.9 ± 98.6 km for Washington-released and 630.5 ± 19.9 km for Oregon-released monarchs. The greatest straight-line release to recovery distance was 1392.1 km. A mean travel rate of 20.7 ± 2.2 km/day and maximum travel of 46.1 km/day were recorded. Recovery rates were greater for Oregon-released monarchs (0.92%) than Washington-released (0.34%) or Idaho-released monarchs (0.30%). Most monarchs (106/122) were recovered SSW-S-SSE in California, with 82 at 18 coastal overwintering sites. Two migrants from Oregon were recovered just weeks after release ovipositing in Santa Barbara and Palo Alto, CA. Two migrants released in central Washington recovered up to 360.0 km to the SE, and recoveries from Idaho releases to the S and SE suggests that some Pacific Northwest migrants fly to an alternative overwintering destination. Monarchs released in southern Oregon into smoky, poor quality air appeared to be as successful at reaching overwintering sites and apparently lived just as long as monarchs released into non-smoky, good quality air. Migration and lifespan for monarchs infected with the protozoan parasite, Ophryocystis elektroscirrha (McLaughlin and Myers), appeared to be similar to the migration and survival of uninfected monarchs, although data are limited. Our data improve our understanding of western monarch migration, serving as a basis for further studies and providing information for conservation planning.

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.

Low prevalence of the parasite Ophryocystis elektroscirrha at the range edge of the eastern North American monarch (Danaus plexippus) butterfly population

2021 ◽  
Author(s):  
Felipe Dargent ◽  
Sydney M Gilmour ◽  
Emma A Brown ◽  
Rees Kassen ◽  
Heather M Kharouba
Keyword(s):  
North American ◽  
Population Distribution ◽  
Danaus Plexippus ◽  
Range Limits ◽  
North American Population ◽  
Ophryocystis Elektroscirrha ◽  
Range Edge ◽  
Relative Contribution ◽  
Northern Edge ◽  
Butterfly Population

Every year monarch butterflies (Danaus plexippus Linnaeus, 1758) from the eastern North American population migrate from Mexico to Southern Canada in the spring. This northward migration has been shown to reduce monarch infection with the host-specific parasite Ophryocystis elektroscirrha (OE) (McLaughlin and Myers, 1970); yet, the prevalence of OE at their range limits, and the mechanism(s) responsible, is unknown. We assessed OE infection levels of monarchs at the northern edge of the eastern population distribution around Ottawa, Canada, and found extremely low levels of infection (~1% with upper confidence intervals close to 3%). Low OE infection levels are likely due to low densities of monarchs in this region and/or migratory escape effects, where migrating individuals leave behind areas with high density of conspecifics and high potential for parasite accumulation and transmission. Future work should aim to disentangle the relative contribution of these two mechanisms for governing the decrease in parasitism at the range limits of migratory populations.

scholarly journals Differential Regulation of β-Defensin Gene Expression during Cryptosporidium parvum Infection

2004 ◽  
Vol 72 (5) ◽  
pp. 2772-2779 ◽  
Author(s):  
Tarek K. Zaalouk ◽  
Mona Bajaj-Elliott ◽  
John T. George ◽  
Vincent McDonald
Keyword(s):  
Gene Expression ◽  
Cryptosporidium Parvum ◽  
Protozoan Parasite ◽  
Immune Defense ◽  
Microbial Pathogens ◽  
In Vivo Models ◽  
Defensin Gene ◽  
Intestinal Epithelia

ABSTRACT Invasion of enterocytes by pathogenic microbes evokes both innate and adaptive immune responses, and microbial pathogens have developed strategies to overcome the initial host immune defense. β-Defensins are potentially important endogenous antibiotic-like effectors of innate immunity expressed by intestinal epithelia. In this study, the interplay between the enteric protozoan parasite Cryptosporidium parvum and host epithelial β-defensin expression was investigated. Using human and murine models of infection, we demonstrated that C. parvum infection differentially regulates β-defensin gene expression. Downregulation of murine β-defensin-1 mRNA and protein was observed in both in vitro and in vivo models of infection. Infection of the human colonic HT29 cell line with the parasite resulted in differential effects on various members of the defensin gene family. Partial reduction in human β-defensin-1 (hBD-1), induction of hBD-2, and no effect on hBD-3 gene expression was observed. Recombinant hBD-1 and hBD-2 peptides exhibited significant antimicrobial activity against C. parvum sporozoites in vitro. These findings demonstrate that C. parvum infection of enterocytes may affect the expression of various defensins in different ways and suggest that the overall outcome of the effect of antimicrobial peptides on early survival of the parasite may be complex.

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.

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