Small tortoiseshell

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Small tortoiseshell
Aglais urticae LC0310.jpg
Kleine Fuchs, Aglais urticae 6.JPG
Scientific classification OOjs UI icon edit-ltr.svg
Domain: Eukaryota
Kingdom: Animalia
Phylum: Arthropoda
Class: Insecta
Order: Lepidoptera
Family: Nymphalidae
Genus: Aglais
Species:
A. urticae
Binomial name
Aglais urticae
Aglais urticae appearance.png
Synonyms
  • Nymphalis urticae
  • Vanessa urticae

The small tortoiseshell (Aglais urticae) is a colourful Eurasian butterfly in the family Nymphalidae. Adults feed on nectar and may hibernate over winter; in warmer climates they may have two broods in a season. While the dorsal surface of the wings is vividly marked, the ventral surface is drab, providing camouflage. Eggs are laid on the common nettle, on which the larvae feed.

Contents

Description

Wing scales of Aglais urticae. Autumn Leaves (36771486610).jpg
Wing scales of Aglais urticae.

It is a medium-sized butterfly that is mainly reddish orange, with black and yellow markings on the forewings as well as a ring of blue spots around the edge of the wings. It has a wingspan ranging from 4.5 to 6.2 cm. [1]

Technical description

A bright foxy red ground-colour; the forewing with 3 black costal spots, whose interspaces are yellow, there being a larger black spot in the middle of the hindmarginal area and two smaller ones in the disc between the 3 radial and 2 median; hindwing with the basal half black; both wings with black submarginal band bearing blue spots. Underside of the forewing ochreous, with the costal spots as above, the apex and distal margin blackish; hindwing brown, basal half black with dentate edge, the whole surface with darker pencilling; at the distal margin of both wings contiguous dull blue lunules. [2]

The small tortoiseshell is the national butterfly of Denmark. [3]

Range

It is found throughout temperate Europe, Asia Minor, Central Asia, Siberia, China, Nepal, Sikkim Himalayas in India, Mongolia, Korea and Japan, wherever common nettle, which their larvae feed on, is found. There are a few records from New York City which, however, are believed to be of introduced insects.

Subspecies

Aglais urticae, Aberration ex larva MHNT (MHNT) Aglais urticae - Aberration ex larva - Mistrovice Boheme Tchequie - Male dorsal.jpg
Aglais urticae, Aberration ex larva MHNT

The Corsican small tortoiseshell (Aglais ichnusa) looks very similar; whether it is a subspecies or a distinct species is yet to be determined. Nymphalis xanthomelas and Nymphalis l-album are also similar in appearance.

Decline in population

Once among the most common butterflies in Europe and temperate Asia, this butterfly is in very rapid decline, at least in Western Europe. This decline cannot be explained by the decline of its host plant, because the nettle is widespread and even enjoys the general eutrophication of the environment. The chrysalis is sometimes eaten by wasps, but these are also in strong regression. The effect of other phenomena are still poorly understood (environmental degradation, air pollution, contamination by pesticides). Scientific evidence shows that the summer drought is a cause of declining populations, because larvae grow normally on drenched leaves (but hatchlings were even rarer the wet summers of 2007 and 2008). However, before 2000, according to data from an English butterfly monitoring programme, there was a good correlation between reproductive success, the abundance of populations of this species and the host plant moisture stress. From 1976 to 1995, the butterfly had more success in summers that were cool and wet at the beginning of summer than when it was hot and dry. This butterfly may then be sensitive to global warming.

Droughts

The small tortoiseshell butterfly is severely affected by droughts. During periods of drought, the butterfly experiences a vastly reduced reproductive rate. The drought directly affects the Urtica leaves; the higher the nitrogen and water level in the leaves, the more rapid the growth of the larvae. During a drought, both of these levels drop significantly, leaving the tortoiseshell larvae nothing to feed on. The timing of rainfall is also a crucial factor. If there is not adequate rainfall in the early summer, then the plants will not be able to fully develop, leaving the larvae without a suitable source of nutrition. These butterflies actively produce smaller broods under these conditions. [4]

Life cycle

As with several nymphalid butterflies, the caterpillars feed on stinging nettles ( Urtica dioica ) and small nettle ( Urtica urens ). [5] Humulus lupulus has also been recorded as larval food plant. [5] Adults feed on nectar. The species has one of the longest seasons of any Eurasian butterfly, extending from early spring to late autumn. Adults overwinter in hibernation, emerging on the first warm sunny days of the year to mate and breed. In southern parts of the range there may be two broods each year, but northern insects are inhibited by long length of summer days from breeding a second time. [6]

Hatching

Tortoiseshell butterflies usually begin to emerge from their pupa from mid-June into August. They begin hibernation sometime in October and immediately show territorial behaviour after hibernation. [7] The tortoiseshell butterflies that are found in the north usually have one brood a season, whereas further south these butterflies can have two broods. The ability to go through three generations of butterflies in a year is due to the tortoiseshell butterflies' decreased thermal requirement. The larvae of this butterfly are social. [8] These larvae can be found on Urtica dioica, which have a high nitrogen content and much water in the leaves. [9]

Hibernation

The small tortoiseshell butterfly tends to enter hibernation by mid to late September. [7] Typically this butterfly will try to hibernate in dark sheltered locations. Because of this hibernation, they need to accumulate a lot of fat to survive the winter. The tortoiseshell needs at least 20% of its body weight in lipids in order to survive, making them much slower. [10] Towards the end of their foraging for hibernation, they are much more susceptible to attacks by birds because of their low muscle to body mass ratio. During the first few weeks of hibernation, tortoiseshell butterflies are very susceptible to predator attacks. Up to 50% of the population hibernating in any given area can be eaten. The butterflies that hibernate in areas containing more light, and that are accessible to rodents who can climb, are the most susceptible to this type of predation. [11] During hibernation tortoiseshell butterflies are able to supercool in order to keep from freezing. In sheltered areas, these butterflies can stand up to −21 degrees Celsius without freezing. However, they experience rapid weight loss during unusually mild winters. [12]

Developmental stages

Behaviour

Predator defence

The wings of tortoiseshell butterflies help conceal them extremely well from predators. When closed, their wings look like leaves, helping them to hide. On the ground, it may take birds up to 30 minutes to see them. In addition to this, when discovered, tortoiseshell butterflies will flick their wings open to reveal bright colours. While they don't have eyespots like many other butterflies, these bright contrasting colours can often scare a predator, giving the tortoiseshell butterfly ample time to escape. [13] Not only does this colouration tend to frighten birds, it can also act as a warning. The bright red colouration serves as a cautionary sign to the predator about the poor taste of the butterfly. Tortoiseshell butterflies tend to be unpalatable to birds. If a bird sees this bright red colouring, then they will be less likely to eat the butterfly. [14]

The tortoiseshell butterfly is particularly fast. When discovered and attacked by a predator the tortoiseshell butterfly will fly away in a straight line in order to outstrip the predator. [15]

Territorial defence

Most butterflies fail to display any territorial behaviour, probably due to selective environmental pressures. The female tortoiseshell butterflies generally are found in concentrated areas, so it is advantageous for males to stay in that particular area to increase their mating opportunities. Male butterflies usually bask and feed until mid-day and then display territorial behaviour until roosting. Males typically defend a certain territory for up to 90 minutes, unless they attempt to follow a female or are ousted by another male. The next day they find a new territory to defend. These territories tend to be in direct sunlight in areas that females choose to lay their eggs. More often than not, two or more males may end up sharing territory if the cost of defending the territory is greater than the benefit gained from monopolising the females. [7]

Male-male interaction

In order for one male butterfly to gain dominance over the other, he must reach a position slightly above the other butterfly. The non-dominant male will then attempt a series of dives and climbs to escape the pursuer. After a certain distance travelled from the nest, one butterfly will return to the territory while the other flies along in search of another suitable location. [7]

Feeding

For most adult butterflies, including the small tortoiseshell butterfly, nectar is one of the main sources of nutrients. In order to obtain the nectar, the butterfly must be able to recognize distinct floral aromas and colours. The small tortoiseshell butterfly is able to differentiate between various flowers through visual signals. [16] Tortoiseshell butterflies in particular tend to prefer colours at both ends of the visible light spectrum for humans, 400 nm and 600 nm. [17] These correspond to the colours violet and red respectively. This ability comes from their compound eye. The flowers depend on the butterflies for pollination, so it is a mutually beneficial relationship. [16]

Migratory patterns

During migration, tortoiseshell butterflies position themselves in accordance with air currents; they only start migration at certain wind speeds. They are able to do this because of an extra sensory organ in their antennae. These butterflies have a developed Johnston's organ in their second antennae responsible for determining air currents in a number of other insects. [18] Because their host plants, Urtica dioica, grow in widely distributed areas, tortoiseshell butterflies tend to move around more than some other butterflies. These areas tend to be short thickets and shrubs. [15]

Related Research Articles

<i>Vanessa atalanta</i> Species of butterfly

Vanessa atalanta, the red admiral or, previously, the red admirable, is a well-characterized, medium-sized butterfly with black wings, red bands, and white spots. It has a wingspan of about 2 inches (5 cm). It was first described by Carl Linnaeus in his 1758 10th edition of Systema Naturae. The red admiral is widely distributed across temperate regions of North Africa, the Americas, Europe, Asia, and the Caribbean. It resides in warmer areas, but migrates north in spring and sometimes again in autumn. Typically found in moist woodlands, the red admiral caterpillar's primary host plant is the stinging nettle ; it can also be found on the false nettle. The adult butterfly drinks from flowering plants like Buddleia and overripe fruit. Red admirals are territorial; females will only mate with males that hold territory. Males with superior flight abilities are more likely to successfully court females. It is known as an unusually calm butterfly, often allowing observation at a very close distance before flying away, also landing on and using humans as perches.

<i>Aglais io</i> Species of butterfly

Aglais io, the European peacock, or the peacock butterfly, is a colourful butterfly, found in Europe and temperate Asia as far east as Japan. It was formerly classified as the only member of the genus Inachis. It should not be confused or classified with the "American peacocks" in the genus Anartia; while belonging to the same family as the European peacock, Nymphalidae, the American peacocks are not close relatives of the Eurasian species. The peacock butterfly is resident in much of its range, often wintering in buildings or trees. It therefore often appears quite early in spring. The peacock butterfly has figured in research in which the role of eyespots as an anti-predator mechanism has been investigated. The peacock is expanding its range and is not known to be threatened.

<i>Urtica dioica</i> Species of flowering plant in the family Urticaceae

Urtica dioica, often known as common nettle, burn nettle, stinging nettle or nettle leaf, or just a nettle or stinger, is a herbaceous perennial flowering plant in the family Urticaceae. Originally native to Europe, much of temperate Asia and western North Africa, it is now found worldwide. The species is divided into six subspecies, five of which have many hollow stinging hairs called trichomes on the leaves and stems, which act like hypodermic needles, injecting histamine and other chemicals that produce a stinging sensation upon contact.

<i>Pieris brassicae</i> Species of butterfly

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<i>Gonepteryx rhamni</i> Species of butterfly

Gonepteryx rhamni, commonly named the common brimstone, is a butterfly of the family Pieridae. It lives throughout the Palearctic zone and is commonly found across Europe, Asia, and North Africa. Across much of its range, it is the only species of its genus, and is therefore simply known locally as the brimstone. Its wing span size is 60–74 mm (2.4–2.9 in). It should not be confused with the brimstone moth Opisthograptis luteolata.

<i>Polygonia c-album</i> Species of butterfly

Polygonia c-album, the comma, is a food generalist (polyphagous) butterfly species belonging to the family Nymphalidae. The angular notches on the edges of the forewings are characteristic of the genus Polygonia, which is why species in the genus are commonly referred to as anglewing butterflies. Comma butterflies can be identified by their prominent orange and dark brown/black dorsal wings.

<span class="mw-page-title-main">Small blue</span> Species of butterfly

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<span class="mw-page-title-main">Map (butterfly)</span> Butterfly of the family Nymphalidae

The map is a butterfly of the family Nymphalidae.

<span class="mw-page-title-main">New Zealand red admiral</span> Species of butterfly

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<span class="mw-page-title-main">Western pine elfin</span> Species of butterfly

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<i>Polygonia interrogationis</i> Species of butterfly

Polygonia interrogationis, commonly called the question mark butterfly, is a North American nymphalid butterfly. It lives in wooded areas, city parks, generally in areas with a combination of trees and open space. The color and textured appearance of the underside of its wings combine to provide camouflage that resembles a dead leaf. The adult butterfly has a wingspan of 4.5–7.6 cm (1.8–3.0 in). Its flight period is from May to September. "The silver mark on the underside of the hindwing is broken into two parts, a curved line and a dot, creating a ?-shaped mark that gives the species its common name."

<span class="mw-page-title-main">Nymphalini</span> Tribe of butterflies

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<i>Nymphalis</i> Genus of butterflies

Nymphalis, commonly known as the tortoiseshells or anglewing butterflies, is a genus of brush-footed butterflies. The genera Aglais, Inachis, Polygonia and Kaniska, were sometimes included as subgenera of Nymphalis but they may instead be treated as distinct genera. See also anglewing butterflies. For other butterflies named tortoiseshells, see the genus Aglais.

<span class="mw-page-title-main">Yellow admiral</span> Species of butterfly

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<i>Urtica urens</i> Species of flowering plant in the nettle family Urticaceae

Urtica urens, commonly known as annual nettle, dwarf nettle, small nettle, dog nettle, or burning nettle, is a herbaceous annual flowering plant species in the nettle family Urticaceae. It is native to Eurasia, including the Himalayan regions of Kalimpong, Darjeeling and Sikkim in India and can be found in North America, New Zealand and South Africa as an introduced species. It is reputed to sting more strongly than common nettle.

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<i>Polygonia satyrus</i> Species of butterfly

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<i>Dasineura urticae</i> Species of fly

The nettle pouch gall develops in leaf veins, leaf petioles, flower stalks and sometimes the stem of Urtica dioica and Urtica urens. This structure is caused by the gall midge or gnat Dasineura urticae, also spelled Dasyneura urticae. Synonyms are Perrisia urticae and Cecidomyia urticae.

<i>Aglais ichnusa</i> Species of butterfly


Aglais ichnusa is a small butterfly found in the Palearctic that belongs to the browns family. It is endemic to Corsica and Sardinia.

References

  1. "Small tortoiseshell" . Retrieved 30 October 2013.
  2. Seitz. A. in Seitz, A. ed. Band 1: Abt. 1, Die Großschmetterlinge des palaearktischen Faunengebietes, Die palaearktischen Tagfalter, 1909, 379 Seiten, mit 89 kolorierten Tafeln (3470 Figuren)PD-icon.svg This article incorporates text from this source, which is in the public domain .
  3. "Nationalsymboler fra den danske plante- og dyreverden (Danish Ministry of the Environment)". naturstyrelsen.dk. Archived from the original on 15 March 2015. Retrieved 9 May 2015.
  4. Pollard, E., and J. N. Greatorex‐Davies (1997) "Drought reduces breeding success of the butterfly Aglais urticae." Ecological Entomology22 (3) : 315–318.
  5. 1 2 Clarke, Harry E. (14 April 2022). "A provisional checklist of European butterfly larval foodplants". Nota Lepidopterologica. 45. Supplementary material: spreadsheet. doi: 10.3897/nl.45.72017 . Retrieved 22 September 2022.
  6. E. Pollard and T. J. Yates (1993) Monitoring butterflies for ecology and conservation. Chapman & Hall. ISBN   0 412 63460 0
  7. 1 2 3 4 R. R. Baker "Territorial behaviour of the Nymphalid butterflies, Aglais urticae (L.) and Inachis io (L.)" Journal of Animal Ecology, 41 (2) 1972, pp. 453–469
  8. Bryant, S., Thomas, C. and Bale, J. (1997), "Nettle-feeding nymphalid butterflies: temperature, development and distribution." Ecological Entomology, 22: 390–398. doi : 10.1046/j.1365-2311 Pollard, E., Greatorex-Davies, J.N. Thomas.1997.00082.x
  9. Pollard, E., Greatorex-Davies, J.N. and Thomas, J.A. (1997), Drought reduces breeding success of the butterfly Aglais urticae. Ecological Entomology, 22: 315–318.
  10. Almbro M, Kullberg C. (2008). Impaired escape flight ability in butterflies due to low flight muscle ratio prior to hibernation. Journal of Experimental Biology211: 24–48.
  11. Wiklund, Christer, et al. (2008) "Rodent predation on hibernating peacock and small tortoiseshell butterflies." Behavioral Ecology and Sociobiology62 (3): 379–389
  12. Pullin, A. S., and J. S. Bale. "Effects of low temperature on diapausing Aglais urticae and Inachis io (Lepidoptera: Nymphalidae): Cold hardiness and overwintering survival." Journal of Insect Physiology35 (4) (1989): 277–281
  13. Vallin, Sven Jakobsson, and Christer Wiklund, (2006) "Crypsis versus Intimidation—anti-predation Defence in Three Closely Related Butterflies Archived 2019-07-12 at the Wayback Machine ." Behavioral Ecology and Sociobiology59 (3): 455–59
  14. Hagen, S. B., Leinaas, H. P. and Lampe, H. M. (2003), Responses of great tits Parus major to small tortoiseshells Aglais urticae in feeding trials; evidence of aposematism. Ecological Entomology, 28: 503–509
  15. 1 2 Shreeve, T. G. (1981) "Flight Patterns of Butterfly Species in Woodlands." Oecologia51 (2): 289–93 JSTOR   4216536
  16. 1 2 Andersson, Susanna. (2003) "Foraging responses in the butterflies Inachis io, Aglais urticae (Nymphalidae), and Gonepteryx rhamni (Pieridae) to floral scents." Chemoecology13 (1): 1–11
  17. Scherer, Christian, and Gertrud Kolb. (1987) "The influence of color stimuli on visually controlled behavior in Aglais urticae L. and Pararge aegeria L. (Lepidoptera)." Journal of Comparative Physiology A161 (6): 891–98
  18. Gewecke, Michael, and Monika Niehaus, (1981) "Flight and flight control by the antennae in the small tortoiseshell (Aglais urticae L., Lepidoptera)." Journal of Comparative Physiology A145 (2) (1981): 249–56