Hemileuca

from Wikipedia, the free encyclopedia
Hemileuca
Hemileuca eglanterina

Hemileuca eglanterina

Systematics
Class : Insects (Insecta)
Order : Butterflies (Lepidoptera)
Family : Peacock moth (Saturniidae)
Subfamily : Hemileucinae
Genre : Hemileuca
Scientific name
Hemileuca
Walker , 1855
Hemileuca hera from above and from the side
Hemileuca eglanterina laying eggs

Hemileuca is a genus of butterflies from the family of peacock moth (Saturniidae). "The Global Lepidoptera Names Index" of the Natural History Museum lists 27 species of the genus that are distributed in North America. The moths arevery popular with butterfly collectorsdue to their variable coloring and wing pattern and their unusual way of life, which adapt to the hot and dry habitats. Most moths fly in summer and autumn. The eggs are laid in ring-shaped clutchesattached to stems or branches of host plants and overwintered, which is unusual for peacock moths. However, this is the caterpillars, up to before the hot summer of the following year pupation develop hatch so that the butterflies in the cooler late summer and autumn. The stinging hairs of the caterpillars cause a rash that lasts from a day to more than a week when touched . In favorable years the caterpillars can appear en masse.

features

The moths are brightly colored, in shades of white, black, yellow and red, and are very variable in their appearance even within a species. In many species, the end of the abdomen is colored red, which may serve as a warning to predators. In other species it is ringed yellow and black. The antennae of the males are simply pinnate. In all other species within the subfamily, they are double-pinnate, as is the case with most species of the peacock moth family. The genitals look similar to those of the genus Coloradia .

The caterpillars are black, dark red or dark brown in color, but develop a species-specific pattern with increasing age. The processes (scoli) on the back of the abdomen consist of short tufts or groups of spines that do not have a central shaft. This distinguishes them from the caterpillars of the closely related genus Automeris . Stinging hairs are formed in all species.

Occurrence

The moths come from southern Canada , across the western and southwestern United States, including the Great Basin, to Mexico . The desert, chaparral and mountain areas form the core of the distribution there . While some species are rare, they can be common locally. In general, the populations of those species that inhabit the vast and open habitats of the Great Basin and the deserts of the southwestern United States are widely dispersed, but are densely populated .

Way of life

The moths of most species fly around quickly in unpredictable uneven flight. If the animals are disturbed in their rest while sitting, they raise their wings over their backs and curve their abdomen down. Species with the abdomen ringed in yellow and black also pulsate with this part of the body, which creates a resemblance to defensive hymenoptera such as wasps ( Müller's mimicry ).

Flight and caterpillar times

The adults of most species fly in summer or autumn. At high altitudes they tend to fly earlier in the year and are diurnal. The few nocturnal species are found mainly in the desert areas, where they fly in early autumn when the evening temperatures are still high enough. In most species, the eggs overwinter and the caterpillars hatch in March or April. In a few species, the caterpillars hatch at the onset of winter rains in southern California or at the onset of summer rains in southeastern Arizona . The moths of the new generation hatch in most species a few months after pupation, but some of the animals can overwinter as pupae. In the case of desert species in particular, it has been documented when rearing in captivity that the pupae can linger for two to four years before the moths hatch. The species of the eglanterina group have a two-year life cycle in the habitats they inhabit in high mountain areas with only a short vegetation period. The eggs hibernate in the first year, the pupae in the second. The same species develop much faster if they are raised under more favorable conditions. The diapause , however, is induced by the duration of daylight and the correlated hormone level .

The development cycle in which the eggs overwinter is probably an adaptation to the short growing season in the populated dry habitats. The caterpillars that hatch in the spring can immediately find food of ideal quality. They finish their development before the hot and dry summer and spend it in the pupal stage before the moths hatch in autumn or late summer with milder temperatures again. The daytime activity of the moths bypasses the cold night temperatures, which in turn are necessary to interrupt the development of the eggs.

Food of the caterpillars

The main food plants of the caterpillars are Rose family (Rosaceae), Buckthorn family (Rhamnaceae), pasture plants (Salicaceae), daisy family (Asteraceae), honeysuckle (Caprifoliaceae), Sumac (Anacardiaceae), legumes (Fabaceae), grasses (Poaceae) and Knotweed (Polygonaceae) Depending on the species or species group, only certain plant families are eaten. The species that colonize dry habitats develop on the shrubby plants that dominate there.

development

The females of all species lay their eggs in ring-shaped clutches around a branch or a flower stalk of the food plants. For species living in deserts, whose food plants are small, the clutches contain fewer than 24 eggs; for species that eat shrubs, trees and herbaceous herbivores, the clutches contain 50 to 200 eggs.

At first, the caterpillars eat gregariously sitting close together. Because of their dark color, they absorb solar radiation efficiently, and the resulting increase in body temperature accelerates physiological development, especially in higher mountain regions. The caterpillars go through at least five stages, depending on the species and food plant it can be six or seven. After the fourth stage, they live as loners. If these animals are disturbed, they curl up and fall to the ground. The caterpillars are severely decimated by parasitoid flies or hymenoptera. Sometimes up to 90% of the caterpillar population is parasitized. Pupation occurs in all species between parts of the plant on the ground or in tufts of grass. However, if the caterpillars find loose soil, most of them bury themselves to a depth of 10 to 20 centimeters.

Taxonomy and systematics

The great variability of the moths, especially within the eglanterina group, led to the description of many subspecies, which are, however, taxonomically not tenable when taking into account the high variability, the distribution areas and their overlap.

The genus has been divided into four sub-genera by some authors, to which the division of the species is problematic. For this reason, Tuskes and Collins define the species groups tricolor , maia , electra , burnsi , chinatiensis and eglanterina , which are supposed to better reflect the phylogenetic relationship.

"The Global Lepidoptera Names Index" of the Natural History Museum lists the following species of the genus:

supporting documents

Individual evidence

  1. ↑ a b The Global Lepidoptera Names Index - Hemileuca  ( page no longer available , search in web archives )  Info: The link was automatically marked as defective. Please check the link according to the instructions and then remove this notice.@1@ 2Template: Dead Link / www.nhm.ac.uk  
  2. ↑ a b c d e f g h i j k P. M. Tuskes, JP Tuttle, MM Collins: The Wild Silkmoths of North America. A Natural History of the Saturniidae of the United States and Canada . Ed .: George C. Eickwort. 1st edition. Cornell University Press, Ithaca / London 1996, ISBN 0-8014-3130-1 , pp. 103 ff . (English).
  3. ^ A b P. M. Tuskes, JP Tuttle, MM Collins: The Wild Silkmoths of North America. A Natural History of the Saturniidae of the United States and Canada . Ed .: George C. Eickwort. 1st edition. Cornell University Press, Ithaca / London 1996, ISBN 0-8014-3130-1 (English).

literature

  • PM Tuskes, JP Tuttle, MM Collins: The Wild Silkmoths of North America. A Natural History of the Saturniidae of the United States and Canada . Ed .: George C. Eickwort. 1st edition. Cornell University Press, Ithaca / London 1996, ISBN 0-8014-3130-1 (English).

Web links

Commons : Hemileuca  - collection of images, videos and audio files
This version was added to the list of articles worth reading on June 15, 2012 .