Variable checkerspot
Variable checkerspot | |
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In the William O. Douglas Wilderness | |
Scientific classification | |
Domain: | Eukaryota |
Kingdom: | Animalia |
Phylum: | Arthropoda |
Class: | Insecta |
Order: | Lepidoptera |
Family: | Nymphalidae |
Genus: | Euphydryas |
Species: | E. chalcedona
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Binomial name | |
Euphydryas chalcedona (Doubleday, 1847)
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The variable checkerspot or Chalcedon checkerspot (Euphydryas chalcedona) is a
During the breeding period, males congregate around larval host plants to encounter females.[3] Males court female butterflies via physical displays.[4] Successful courtship leads to copulation, when the male deposits a nutrient-rich spermatophore in the female. In addition, males also secrete a mating plug during copulation that hinders the ability of females to mate with other males.[5]
Pregnant females look for host plants like
The variable checkerspot is a potential food source for many avian predators.[9] Due to a larval diet rich in catalpol, this butterfly has developed a strategy of unpalatability to deter avian predation.[10][11] In addition, coloring plays a part in the defense strategy of the butterfly; intense red coloration deters predators from attacking them.[12]
Taxonomy
The variable checkerspot is a member of the
Description
The variable checkerspot is usually brown-black with extensive yellow, red and white spots on the dorsal wing. Their underside usually contains yellow and orange bands. However, as its name suggests, the butterfly is highly variable in appearance.
Distribution and habitat
The variable checkerspot is found across western North America, ranging from Alaska in the north to Baja California and Mexico in the south. Its habitat is bounded to the west by the Pacific Ocean and it extends east past the Rocky Mountains into Montana, Wyoming, Colorado and New Mexico.[2]
The butterfly's habitat encompasses a large variety of environments, including sagebrush flats, desert hills, prairies, open forests and alpine tundra.[2]
Life cycle
The variable checkerspot lays its eggs in clusters. Pre-
During diapause, some larvae are able to wake up and feed before re-entering dormancy. The larvae emerge from diapause between late January and mid-March.
Breeding
Mate location
Male mate-location strategies in the variable checkerspot are primarily determined by female distribution in an area. For species like E. chalcedona that
Courtship
To start courtship, the male arrives in the vicinity of a fertilizable female, who quickly moves to the ground or to vegetation.[4] The male follows and attempts to copulate with the female by curling his abdomen forward along the side of his body and inserting it between the female's hindwings. At this point, the female may stay still or flutter her wings and move away. If the female moves away, the male follows her and repeats his attempts to copulate. Only when the female stops and remains motionless can the male successfully copulate with her.[4] In unsuccessful courtships, the female either flies away or rapidly flutters her wings until the male departs.[4] Courtship in the variable checkerspot lacks an obvious male display such as the release of chemical signals by the male. Successful courtship in E. chalcedona lasts about a minute.[4]
Copulation
Once a male has successfully courted a female, the pair begins to copulate. Copulations typically last around an hour, although prolonged copulations as long as six hours have been observed in the wild. During copulation, the male fills the female's bursa copulatrix with material that forms the spermatophore, a nutrient-rich complex that delivers the sperm to the female. On average, the spermatophore represents 7% of the male’s body weight.[4]
This weight proportion is similar to that of other butterflies whose
Paternal investment via the spermatophore in E. chalcedona may be less important than in other butterfly species due to the severe time constraints on female variable checkerspot butterflies to lay their eggs quickly. Because of these constraints, female butterflies emerge with all
Harassment
Female availability is an important factor in determining mating systems. Because the
However, this potential for harassment does not influence egg distribution by mated females in E. chalcedona. Variable checkerspot eggs are always distributed around good larval food sources, regardless of the level of male harassment at those sites.[19]
Mating plugs
Female butterflies regularly
Remating behavior by a female harms her most previous mate, who could lose his paternity if another male's sperm fertilizes the female. Thus, after males produce the spermatophore, they pass an additional gland secretion that spills out of the female's copulatory opening, forming a
Group behavior
During the flight season, large groups of variable checkerspot butterflies can be found across western North America. Individual butterflies are capable of recognizing suitable areas rich in larval food plants and do not usually linger in other parts of the landscape. This leads to populations of butterflies that are small, isolated and clearly separated from other populations.[20] Females do not fly as much as males, who frequently fly around their habitats and perch in open areas while searching for female mates.[21]
Flight times for the variable checkerspot vary regionally. Usually, the flight season lasts from April to June in California and Oregon, while it normally takes place from June to July farther north and in higher elevations.[2]
Diet
The diet of the variable checkerspot changes dramatically with development: the larva has an
Larval diet
The principal food source for variable checkerspot larvae are the leaves of the flowering
Another factor in D. aurantiacus plants that impacts larval growth is leaf nitrogen content. Unlike resin levels, heightened nitrogen levels are correlated with increased larval growth and survivorship. In a controlled experiment, larva that were fed a diet of fertilized D. aurantiacus plants, which contained 50% more nitrogen than unfertilized plants, experienced higher survival rates and growth than larvae that fed on unfertilized plants.[22] While leaves with increased nitrogen content are the most attractive for the larvae, they are also the most valuable carbon-gainers for the plant. This leads to the activity patterns of larvae and D. aurantiacus plants synchronizing. Larvae emerge from diapause as D. aurantiacus plants start flowering. This is when the plants need the most carbon. The plants then concentrate their resin in their youngest leaves, which contain the largest amount of nitrogen; this resin deterrent forces larvae to feed on less valuable older leaves whose nitrogen content is lower.[23] To maximize their own nutritional benefits, larvae selectively eat leaves with the highest available nitrogen:resin ratio.[24] In addition, larvae exhibit a strong preference for feeding on host plant leaves that have been in the sun compared to leaves that have been in the shade.[11]
Another less common host plant for variable checkerspot larvae is Scrophularia californica, which lacks the resin defense system found in D. aurantiacus and is thus easier for larvae to digest. Larvae that feed on S. californica grow faster and larger than those that feed on D. aurantiacus. While D. aurantiacus may not be the most nutritious food for the larvae, it is the most reliable and widespread host available to the variable checkerspot and is often the plant closest to nectar sources, leading to its role as principal host plant and food source for the larvae.[25]
Adult diet
In contrast to the herbivorous diet of the larva, the adult variable checkerspot's main food source is the nectar it obtains from flowers. In Jasper Ridge Biological Preserve in California, an extremely well studied site, the nectar source most frequently used by adult butterflies is Eriodictyon californicum.[6]
Diet and oviposition
The diet of the adult butterfly has a large impact on the choice of D. aurantiacus as the
Predation and defense
The variable checkerspot's main predators are
One study analyzed the evidence of avian predation on the butterflies by the presence of a large number of detached variable checkerspot wings at a butterfly population center. These detached wings exhibited beak marks and characteristic triangular tears indicating that birds attacked the butterflies and detached their wings before eating the body. In addition to the remains of this successful predation, photographs of variable checkerspot butterflies show some individuals that exhibit beak marks and tears, indicating unsuccessful avian predation attempts.[12]
Analysis of the avian predation on the variable checkerspot population has found that predators disproportionately attack female butterflies. This is because attacks are concentrated on butterflies that contain less intense red coloration. The male butterfly exhibits more variation in its coloration than the female, and can be more intensely red colored. This means that on average, females face more attacks than males do. Red serves as a warning color in many species of butterfly, so it is possible that diminished avian predation is linked to this warning signal. Indeed, the pressure exerted on the variable checkerspot by visually hunting avian predators may play an important role in the evolution of its wing coloration and pattern.[12]
Defense strategy
The variable checkerspot, like many other butterflies, has developed a defense strategy of
Iridoid glycosides
The main
See also
- Euphydryas editha
References
- ^ "Butterflies of Orange County, California". http://nathistoc.bio.uci.edu/lepidopt/nymph/chalcedo.htm
- ^ a b c d e f g Sommer, Stefan; Denise Knight; Stephanie McDowell; Stephen Burton; Ean Harker. "Euphydryas chalcedona". Digital Atlas of Idaho. Archived from the original on 2007-11-17. Retrieved 2008-06-22.
- ^ a b c Rutowski, Ronald L., George W. Gilchrist, and Barbara Terkanian. "Male Mate-locating Behavior in Euphydryas Chalcedona (Lepidoptera: Nymphalidae) Related to Pupation Site Preferences." Journal of Insect Behavior 1.3 (1988): 277-89.
- ^ a b c d e f Rutowski, Ronald L., and George W. Gilchrist. "Courtship, Copulation and Oviposition in the Chalcedon Checkerspot,(Lepidoptera: Nymphalidae)." Journal of Natural History 21.5 (1987): 1109-117.
- ^ a b c d e f Dickinson, Janis L., and Ronald L. Rutowski. "The Function of the Mating Plug in the Chalcedon Checkerspot Butterfly." Animal Behaviour 38.1 (1989): 154-62.
- ^ a b c Murphy, Dennis D., Marian S. Menninger, and Paul R. Ehrlich. "Nectar Source Distribution as a Determinant of Oviposition Host Species in Euphydryas Chalcedona." Oecologia 62.2 (1984): 269-71.
- ^ a b Han, Kaiping, and David Lincoln. "The Evolution of Carbon Allocation to Plant Secondary Metabolites: A Genetic Analysis of Cost in Diplacus Aurantiacus." Evolution 48.5 (1994): 1550-563.
- ^ a b c d e f O'Brien, Diane M., Carol L. Boggs, and Marilyn L. Fogel. "Making Eggs from Nectar: The Role of Life History and Dietary Carbon Turnover in Butterfly Reproductive Resource Allocation." Oikos 105.2 (2004): 279-91.
- ^ a b Bowers, M. D. "Unpalatability as a Defense Strategy of Western Checkerspot Butterflies (Euphydryas Scudder, Nymphalidae)." Evolution 35.2 (1981): 367-75.
- ^ a b Stermitz, Frank R., Maged S. Abdel-Kader, Tommaso A. Foderaro, and Marc Pomeroy. "Iridoid Glycosides from Some Butterflies and Their Larval Food Plants." Phytochemistry 37.4 (1994): 997-99.
- ^ a b Lincoln, David E., and Harold A. Mooney. "Herbivory on Diplacus Aurantiacus Shrubs in Sun and Shade." Oecologia 64.2 (1984): 173-76.
- ^ a b c d Bowers, M. D., Irene L. Brown, and Darryl Wheye. "Bird Predation as a Selective Agent in a Butterfly Population." Evolution 39.1 (1985): 93-103.
- ^ "Euphydryas chalcedona (E. Doubleday, 1847)". The Integrated Taxonomic Information System (ITIS). Retrieved 22 November 2013.
- ^ "Euphydryas chalcedona". The Global Biodiversity Information Facility: GBIF Backbone Taxonomy. Retrieved 22 November 2013.
- ^ Opler, Paul A. "Attributes of Euphydryas chalcedona". Butterflies and Moths of North America.
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(help) - ^ a b c Rutowski, Ronald L. "The Evolution of Male Mate-Locating Behavior in Butterflies." The American Naturalist 138.5 (1991): 1121-139.
- ^ Rutowski, Ronald R., Mark Newton, and John Schaeffer. "Interspecific Variation in the Size of the Nutrient Investment Made by Male Butterflies During Copulation." Evolution 37.4 (1983): 708-13.
- ^ a b Jones, Kristina M., Francois J. Odendaal, and Paul R. Ehrlich. "Evidence against the Spermatophore as Paternal Investment in Checkerspot Butterflies (Euphydryas: Nymphalidae)." American Midland Naturalist 116.1 (1986): 1-6.
- ^ a b Odendaal, F. J., Y. Iwasa, and P. R. Ehrlich. "Duration of Female Availability and Its Effect on Butterfly Mating Systems." The American Naturalist 125.5 (1985): 673-78.
- ^ Ehrlich, P. R., D. D. Murphy, M. C. Singer, C. B. Sherwood, R. R. White, and I. L. Brown. "Extinction, Reduction, Stability and Increase: The Responses of Checkerspot Butterfly (Euphydryas) Populations to the California Drought." Oecologia 46.1 (1980): 101-05.
- ^ Brown, Irene L., and Paul R. Ehrlich. "Population Biology of the Checkerspot Butterfly, Euphydryas Chalcedona Structure of the Jasper Ridge Colony." Oecologia 47.2 (1980): 239-51.
- ^ Johnson, Nelson D., Kathy S. Williams, and Paul R. Ehrlich. "Effects of Chemical Fertilization of Diplacus Aurantiacus on the Development and Persistence of the Postdiapause Larvae of Its Lepidopteran Herbivore Euphydryas Chalcedona." American Midland Naturalist 117.2 (1987): 435-38.
- ^ Mooney, H. A., K. S. Williams, D. E. Lincoln, and P. R. Ehrlich. "Temporal and Spatial Variability in the Interaction between the Checkerspot Butterfly, Euphydryas Chalcedona and Its Principal Food Source, the Californian Shrub, Diplacus Aurantiacus." Oecologia 50.2 (1981): 195-98.
- ^ Williams, K. S., D. E. Lincoln, and P. R. Ehrlich. "The Coevolution of Euphydryas Chalcedona Butterflies and Their Larval Host Plants I. Larval Feeding Behavior and Host Plant Chemistry." Oecologia 56.2-3 (1983): 323-29.
- ^ Williams, K. S., D. E. Lincoln, and P. R. Ehrlich. "The Coevolution of Euphydryas Chalcedona Butterflies and Their Larval Host Plants II. Maternal and Host Plant Effects on Larval Growth, Development, and Food-Use Efficiency." Oecologia 56.2-3 (1983): 330-35.
- ^ a b Bowers, M. Deane. "The Role of Iridoid Glycosides in Host-plant Specificity of Checkerspot Butterflies." Journal of Chemical Ecology 9.4 (1983): 475-93.
External links
- Media related to Euphydryas chalcedona at Wikimedia Commons
- Variable checkerspot, Butterflies of Canada