Colias eurytheme
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Colias eurytheme |
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| ( Boisduval , 1852) |
Colias eurytheme , also known as Alfalfa Butterfly , is a butterfly from the family of the white flies (Pieridae).
features
butterfly
Colia's eurytheme has a wingspan of 35 to 60 millimeters, sometimes up to 75 millimeters, and a basic color that goes from bright yellow to orange. Yellow color variants are more common in spring. There are also creamy white color variants, but these are very rare. These are more common in their northern range and almost only affect the female moths. The wing edges are dark brown in males and females, although this is interrupted in females by the yellowish basic color. There are also dark, lined up spots on the outer edges of the wings. On the upper side of the forewing there is a black point in the middle that shines through pale underneath. On the top of the hind wing there is an orange spot that serves as an important identifier. This is only faintly visible on the underside, which shimmers yellowish-green. Female moths are larger than the males. The first and second generation adults in spring are generally smaller than those of the summer generation. The colder the winters are during the pupal stage, the darker the generation affected, the spring generation, is colored. They are darker on the underside of the hind wings and more yellow on the upper side of the forewings on the outer edge.
egg
The eggs have a reddish or greenish cream color and darken to a deeper red over time. They are filed individually.
Caterpillar
The caterpillars are dark green with white, black and pink side stripes. The species overwinters in its third or fourth instar. If the caterpillars are exposed to little sunlight, they develop darker, black lateral stripes.
Doll
The pupa is apple green with a rosy shimmer, or yellowish-white and black marbling and a yellow side band.
distribution and habitat
The species is distributed throughout North America from southern Canada to central Mexico and inhabits open fields, farmland, meadows and grass plains. It is more common in the south of its range. The species does not occur in Florida .
Behavior and way of life
Male moths fly forays into their territory to look for females. These are recognized by optical stimuli based on the color of the underside of the hind wing. Males repel each other through UV reflection from their wings. Females appear to be attracted by the males' UV reflection. This reduces hybridization with Colias philodice . The lighter the color variation of the female moths, the faster they are in their development and can lay more eggs earlier, which gives them an enormous reproductive advantage in their northern range. These females are also preferred by the male butterflies for mating. Adult moths prefer a temperature of 35 to 39 ° C .
In the northern part of their range they fly in two to three generations from June to October, in the south there are four to five generations from March to November.
The moths suck nectar from a variety of different plant species such as dandelions ( Taraxacum , Leontodon ), silk plants ( Asclepias ), goldenrods ( Solidago ), asters ( aster ), lesser brown elk ( Prunella vulgaris ), teasel ( Dipsacus sylvestris ), peppermint ( Mentha piperita) ), Canadian fleabane ( Erigeron canadensis ), coneflower ( Echinacea purpurea ) and sunflower ( Helianthus hirsutus ). They also suck water on puddles. At night the moths are found in small groups near the ground. The lifespan of the moths is up to 39 days. In a study in the wild in Virginia , females had a lifespan of 14 days and males 25 days. In captivity, butterflies were around 1 year old.
Up to 700 eggs are deposited in the middle of the leaves of the host plant. Under laboratory conditions it took 31 days from hatching of the caterpillars to the moth.
The caterpillars mostly feed on alfalfa ( Medicago sativa ), white sweet clover ( Melilotus albus ), white clover ( Trifolium repens ) and legumes ( Fabaceae ) such as the tragacanth genus ( Astragalus ) at night . Young caterpillars eat holes in the leaf tips, while older caterpillars eat the leaves from the edge of the leaf tip. When half of the leaf is eaten, switch to the next leaf. When the temperature is too hot or too cold, the caterpillars withdraw deeper into the foliage of the host plant. They prefer temperatures 23-29 ° C .
status
In some areas, the caterpillars are considered a pest, as they sometimes cause major damage in alfalfa fields.
literature
- Elizabeth Balmer: Butterflies: Recognizing and Identifying. Parragon Books Ltd., 2007, ISBN 978-1-4075-1203-7 , p. 54.
Individual evidence
- ↑ a b c d e f g h i j James A. Scott: The Butterflies of North America: A Natural History and Field Guide. Stanford, California: Stanford University Press, 1986, ISBN 0-8047-2013-4 , pp. 196-198.
- ↑ a b c d Art Shapiro's Butterfly Site , accessed August 17, 2014.
- ↑ a b Animal Diversity Web , accessed August 17, 2014.
Web links
- Butterflies and Moths of North America , accessed August 17, 2014
- Art Shapiro's Butterfly Site , accessed August 17, 2014
- Animal Diversity Web , accessed August 17, 2014