Close up of the swamp metalmark showing markings on the dorsal side of its wingsSwamp thistle (Cirsium muticum)Carolina thistle (C. Carolinianum)Tall thistle (C. altissimum)
Calephelis muticum, the swamp metalmark, is a butterfly species in the family Riodinidae.[1]
The swamp metalmark is a small butterfly with red-brown and orange colored wings that have silver and black markings.[2]
Scattered across ten states, this species is rare and has a conservation status ranging from vulnerable to possibly extinct. Swamp metalmark colonies are small and mostly concentrated in wet environments. Their habitat has decreased in size due to invasive species and human interference, such as the use of pesticides and the conversion of wetlands for commercial use. Swamp metalmarks are herbivores, feeding mostly on swamp thistles.[3] Conservationists hope that a greater abundance of swamp thistles may lead to an increase in the swamp metalmark population.[2]
Taxonomy
The swamp metalmark was formerly considered the same species as the northern metalmark until 1937, when William S. McAlpine determined that the swamp metalmark is a distinct species. Some major differences between the two include their habitat, their wings, and their diet. The swamp metalmark prefers low, grassy, and moist habitations, while the northern metalmark prefers open and dry spaces. The swamp metalmark has darker undersides on its wings and eats swamp thistle, while the northern metalmark primarily eats round-leaved groundsel. Both populations, however, are small and isolated.[4]
Genetics and Adaptations
The caterpillar form of the swamp metalmark is green with black dots, covered in long white hairs. They look similar to a tiger moth caterpillar.[5]
The swamp metalmark can be distinguished by its red-brown coloring and rows of small, metallic spots and lines on the insect's hind wings. It's abdomen is orange and gray to enable camouflage, and the species sometimes has checkered marks on its wing fringes.[2] Males have pointed forewings while the females' forewings tend to be slightly more rounded. Both sexes have bright red-brown wings which are lightly checkered. Wingspan is 2.4 to 3 cm.[6]
Metalmarks with reddish-brown coloring on their forewings and hindwings, a yellowish ventral side, and metallic silver bands have been identified with the genus Calephelis. In 2017, a study of the metalmark family completed the first complete genome sequencing of two unfamiliar metalmark species and bridged the gap in scientists' understanding of the metalmark genome. Even though research on the genetics of the swamp metalmark is recent and developing, it was discovered that the Calephelis butterflies have a distinctive expansion of specific genes that help caterpillars leave behind their old exoskeletons as they mature. Additionally, the genomic data confirmed the closely related Riodinidae family to Lepidoptera, suggesting that Riodinidae is a subgroup of Lepidoptera. Among the multitude of species within the genus Calephelis, C. multicum is classified as critically endangered, especially without the initiation of conservation efforts.[7]
Habitat and Distribution
Swamp metalmarks tend to reside in wetlands that contain lots of vegetation.[3] The distribution of the swamp metalmark includes wetlands from the upper Midwest, including the Ohio Valley, through the Ozark Mountain range and into parts of Arizona.[8] The species is endangered in Illinois.[9] Additionally, the distribution of these butterflies can be linked to certain vegetation including the Cirsium muticum, C. Carolinianum, and C. altissimum, also known as the swamp thistle, Carolina thistle, and tall thistle, respectively.[2]
Life cycle
Swamp metalmark eggs are found on the bottom side of host leaves. During the later stages of their development as caterpillars, they overwinter. Adult butterflies reproduce twice before the end of their life cycle, but northern butterflies reproduce only once.[6]
Conservation Status and Threats
Calephelis muticum is threatened by ongoing loss and degradation of habitat, invasive species, and pesticides.[3]
The swamp metalmark currently resides within the G3 rank of conservation status, indicating that it is a globally vulnerable population.[10]
Present and potential threats to this population and their habitat include:
Fire suppression: The use of fire to regulate vegetation growth can directly harm swamp metalmark larvae, but it also proves necessary in habitat maintenance. [10]
Grazing: Livestock trample larvae and pupae, as well as deplete their food sources.[10]
Pasture development: The spraying of pesticides destroys swamp metalmark habitats.[10]
Competition from introduced species: species of garlic mustard, Japanese and bush honeysuckles, Japanese stilt grass, non-native buckthorns, and native raspberries pose dangers to the swamp metalmark habitat.[10]
Overutilization: Illegal collection of the swamp metalmark continues to deplete the population.[10]
Predation and human interference: gypsy moth populations defoliate the swamp metalmark's habitat. Chemical attempts to eradicate the gypsy moth populations increase the mortality rate among swamp metalmark larvae populations.[10]
A past example of human interference is peat mining, which destroyed the habitats of swamp metalmarks in the 19th and early 20th centuries.[10]
Residential development: The clearing of sites, use of herbicides and insecticides, and fertilizer and pesticide runoff all contribute to habitat deterioration.[10]
Conservation efforts must emphasize habitat preservation and land management since most threats to the swamp metalmark population are due to a direct impact on its habitat.[10]
This page is based on this Wikipedia article Text is available under the CC BY-SA 4.0 license; additional terms may apply. Images, videos and audio are available under their respective licenses.
