Small Tortoiseshell

Aglais urticae (ag-LAR-iss ur-TY-see)

Small Tortoiseshell, Wiggonholt (31 August 2011)
Photo © Mark Colvin
 

Wingspan
Male: 45 - 55mm
Female: 52 - 62mm

Checklist Number
59.027

Family:NymphalidaeRafinesque, 1815
Subfamily:NymphalinaeRafinesque, 1815
Tribe:NymphaliniRafinesque, 1815
Genus:AglaisDalman, 1816
Subgenus:  
Species:urticae(Linnaeus, 1758)

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Introduction

The Small Tortoiseshell is one of our most-familiar butterflies, appearing in gardens throughout the British Isles. Unfortunately, this butterfly has suffered a worrying decline, especially in the south, over the last few years. This butterfly has always fluctuated in numbers, but the cause of a recent decline is not yet known, although various theories have been proposed. One is the increasing presence of a particular parasitic fly, Sturmia bella, due to global warming - this species being common on the continent. The fly lays its eggs on leaves of the foodplant, close to where larvae are feeding. The tiny eggs are then eaten whole by the larvae and the grubs that emerge feed on the insides of their host, avoiding the vital organs. A fly grub eventually kills its host and emerges from either the fully-grown larva or pupa before itself pupating. Although the fly attacks related species, such as the Peacock and Red Admiral, it is believed that the lifecycle of the Small Tortoiseshell is better-synchronised with that of the fly and it is therefore more prone to parasitism. This is one of our most widespread butterflies, occurring throughout the British Isles, including Orkney and Shetland.

Aglais urticae

This species was first defined in Linnaeus (1758) as shown here (type locality: Sweden).

Small Tortoiseshell -  Cornwall Coast Path 12-Sept-2013

Male
Photo © Neil Hulme

Small Tortoiseshell - Chaldon, Surrey 14-June-09

Male Underside
Photo © Vince Massimo

Small Tortoiseshell - Ferring Rife, Sussex 22-April-2013

Female
Photo © Neil Hulme

Small Tortoiseshell ovipositing - Coulsdon, Surrey 14-July-2013

Female Underside
Photo © Vince Massimo

Photo Album ...


History

The table below shows a chronology of vernacular names attributed to this species. Any qualification of the name (e.g. male, female) is shown in brackets after the name.

YearNameReference
1699Lesser or Common Tortoise-shell ButterflyPetiver (1695-1703)
1742Small TortoiseshellWilkes (1742)
1766Tortoise-shellHarris (1766)
1795Nettle TortoiseshellLewin (1795)

Conservation Status

Despite being a widespread and common species in certain areas, the declining fortunes of this butterfly, especially in the south, mean that this butterfly is a species of conservation concern.

UK BAP StatusOccurrence Change
1976-2014 (%)
Abundance Change
1976-2014 (%)
Occurrence Change
2005-2014 (%)
Abundance Change
2005-2014 (%)
Not Listed
Decrease-15
Large Decrease-73
Increase+13
Large Increase+146

The table above shows the occurrence (distribution) and abundance (population) trends, using information from The State of the UK's Butterflies 2015 (Fox, 2015). Any UK BAP status is taken from the UK Biodiversity Action Plan (UK BAP) (2007 review).

Habitat

This butterfly can turn up almost anywhere, from city centres to mountain tops. As such, it is one of our most successful butterflies. It is most-often seen, however, where nettles grow in abundance, such as field margins. This butterfly is often encountered while hibernating in an outbuilding, such as a garage, shed or barn, where they may be found in the company of other individuals. Other hibernation sites include hollow trees and wood piles.

Distribution

 

Click here to see the distribution of this species or here to see the distribution of this species together with specific site information overlaid.

Life Cycle

The adult butterflies can be seen at any time of the year, even on the last days of December or first days of January if the temperature is high enough to wake them from hibernation. However, adults normally emerge from hibernation at the end of March and start of April. There are typically 2 broods each year, except in the north, where there is usually only a single brood. Whether single or double-brooded, the butterfly is a familiar sight in late summer as it takes nectar to build up essential fats in preparation for hibernation.

The chart(s) above have been correlated with the phenology plot below, taken from the UK Butterfly Monitoring Scheme. The blue line gives average counts over the full data set from 1976 to date, and the red line gives the average for the last year.

Imago

The two sexes are almost identical in appearance, with the distinctive yellow and orange uppersides providing a contrast with the drab undersides that provide the butterfly a good deal of camouflage when hibernating.

In the afternoon, males set up territories, usually close to a nettle patch, where they rest of the foodplant or ground with their wings open, waiting for a passing female. When a female enters the territory, a most curious courtship begins. The male approaches the female from behind and starts to "drum" his antennae on the hindwings of the female, making a feint sound that is audible to the human ear. The female may fly a little distance, with the male following, where the process repeats. This can go on for several hours with the couple spending a good amount of time basking together. Eventually, usually in early evening, the female will lead the male into vegetation, often a nettle patch, and crawl between stems with the male following, where they eventually mate. They remain coupled until the following morning.

Adults feed primarily on Betony (Stachys officinalis), Bramble (Rubus fruticosus), Carline Thistle (Carlina vulgaris), Dandelion (Taraxacum agg.), Devil's-bit Scabious (Succisa pratensis), Field Scabious (Knautia arvensis), Greater Stitchwort (Stellaria holostea), Hawkweeds (Hieracium/Hypochoeris), Heather (Calluna vulgaris / Erica spp.), Hemp Agrimony (Eupatorium cannabinum), Ivy (Hedera helix), Knapweeds (Centaurea spp.), Marjoram (Origanum vulgare), Primrose (Primula vulgaris), Privet (Ligustrum vulgare), Ragwort (Senecio jacobaea), Thistles (Cirsium spp. and Carduus spp.), Thyme (Thymus polytrichus) and Water Mint (Mentha aquatica).

Aglais urticae

Small Tortoiseshell - Ferring Rife, Sussex 22-April-2013

Photo © Neil Hulme
22-Apr-2013

Female Small Tortoiseshell and Male Meadow Brown pairing - Brentwood, Essex 14-July-2013

Photo © Essex Bertie
14-Jul-2013

small tortoiseshell, stockbridge down 09

Photo © geniculata
09-Aug-2009

Small Tortoiseshell ovapositing. Littlington, Sussex. 5/7/2013

Photo © badgerbob
05-Jul-2013

Small Tortoiseshell - Pewsey Vale School - 10-09-2015

Photo © Wurzel

Small Tortoiseshell - Addington, Surrey 15-March-12

Photo © Vince Massimo
15-Mar-2012

Small Tortoiseshell - Steep Down, Sompting, Sussex  3-April-2014

Photo © Neil Hulme
03-Apr-2014

Small Tortoiseshell ovipositing - Coulsdon, Surrey 9-July-2013

Photo © Vince Massimo
09-Jul-2013

Small Tortoiseshell - imago - Bridport - 07-Jun-09 [Jules Cross]

Photo © Jules Cross
07-Jun-2009

Small Tortoiseshell - Somerset - 31/03/14

Photo © William
30-Mar-2014

Small Tortoiseshell underside - Five Rivers - 26 August 2012

Photo © Wurzel

Small Tortoiseshell (Female) Pairing with Meadow Brown (Male) - Collard Hill - Somerset - 23/06/14

Photo © William
23-Jun-2014

Small Tortoiseshell and Peacock ovipositing - Hylands Park, nr Chelmsford 9-April-2014

Photo © essexbuzzard

Small Tortoiseshell. 7/7/2013. Seaford, East Sussex.

Photo © badgerbob
07-Jul-2013

Small Tortoiseshell - Ferring Rife, Sussex 6-Mar-2014

Photo © Neil Hulme
06-Mar-2014

Small Tortoiseshell - Somerset - 07/08/13

Photo © William
07-Aug-2013

Small Tortoiseshell - Larkhill - 06-07-2016

Photo © Wurzel

3 Female Small Tortoiseshell laying eggs together. Arlington. E.Sussex. 9/4/2014.

Photo © badgerbob
09-Apr-2014

Small Tortoiseshell - male - Greenham Common - 17-Aug-13-3

Photo © Pete Eeles
17-Aug-2013

Small Tortoiseshell - imago - Stockbridge Down - 28-Jun-04

Photo © Pete Eeles
28-Jun-2004

Photo Album (59 photos) ...


Ovum

The female is quite choosy about where she lays, which is not surprising since she lays her green eggs in large batches and needs to ensure that the location is just right for the developing larvae. Typical sites are nettle patches containing relatively-new growth, and that receive full sun. Eggs are laid on the underside of a nettle leaf, usually one near the top of the stem and at the edge of the nettle patch. The eggs are not laid in neat rows, but piled on top of one another. Egg batches can contain up to 80 eggs which take some time to lay - typically between 20 and 90 minutes. The egg stage lasts between 1 and 3 weeks, depending on the weather.

"On May 4th, 1890, the author found (at Benfleet, Essex) a large batch of eggs just deposited; the butterfly was hanging helpless on the leaf with outspread wings. The eggs were in a dense heap, piled up many deep; in one view of the external layer about 200 were visible; the entire batch contained about 1,000 eggs, apparently the full complement of this species; these eggs hatched on May 18th, remaining fourteen days in the egg state. On May 25th, 1907, the author watched a female depositing between and 1.30 p.m. (at Rayleigh, Essex), during sunshine; she hung with expanded wings on the first leaf below the apical cluster of young leaves and deposited on the under side of the leaf a small batch of eggs, closely packed together and heaped up, about eighty in the top layer. On May 14th, 1910, a female was observed depositing a small batch of eggs, about fifty; these were also in a heap on the under side of a terminal nettle leaf. They hatched on May 23rd, being only nine days in the egg state owing to the warm weather during a few days previous to hatching. Another batch of eggs was laid on June 1st, 1910, followed by a spell of very warm weather, with a shade temperature of 79 degrees Fahr. They hatched very early on June 9th, being only eight and a half days in the egg stage. The egg stage lasts about ten days in normal weather. The egg is of an oblong shape, but fullest near the base, which is rounded and smooth; there are nine prominent longitudinal keels; these are fluted, white and glassy, very elevated where they commence round the micropyle, and gradually diminish in height as they descend the side, and finally disappear on reaching the base; the spaces between the keels are strongly ribbed transversely. The micropyle is finely pitted. The colour is a clear green, which becomes changed on the eighth day to paler ochreous, zoned at the middle with translucent green; and on the ninth day the dark head of the larva begins to mature, and rapidly develops during very warm weather in a temperature between 76 degrees and 80 degrees Fahr." - Frohawk (1924)

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-8

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell - ovum - Coulsdon, Surrey - 09-May-13

Photo © Pete Eeles

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-10

Photo © Pete Eeles
25-Apr-2014

Small Tortiseshell ovum, East Lothian

Photo © NickMorgan

Small Tortoiseshell egg batches - Coulsdon, Surrey 14-July-2013

Photo © Vince Massimo
14-Jul-2013

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-9

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell - Ova being parasitized - 18-April-2015 - Bishopstone, East Sussex

Photo © Butterflysaurus rex

Small Tortoiseshell ova - Steep Down, Sompting, Sussex  3-April-2014

Photo © Neil Hulme
03-Apr-2014

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-14

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell - Ova - 18-April-2015 - Bishopstone, East Sussex

Photo © Butterflysaurus rex

Small Tortoiseshell ova - Coulsdon, Surrey 2-May-2013

Photo © Vince Massimo
02-May-2013

Small Tortoiseshell - Ova being parasitized - 16-April-2015 - Bishopstone, East Sussex

Photo © Butterflysaurus rex

Small Tortoiseshell ova. Littlington, Sussex. 5/7/2013

Photo © badgerbob
05-Jul-2013

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-13

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-11

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell ova - Coulsdon, Surrey 2-May-2013

Photo © Vince Massimo
02-May-2013

Small Tortoiseshell ova - Coulsdon, Surrey 9-July-2013

Photo © Vince Massimo
09-Jul-2013

Small Tortoiseshell - ovum - Cumnor, Oxford - 25-Apr-14-12

Photo © Pete Eeles
25-Apr-2014

Small Tortoiseshell ova (1 day before hatching) - Coulsdon, Surrey 20-July-2013

Photo © Vince Massimo
20-Jul-2013

Small Tortoiseshell eggs, Alice Holt, 14/07/2016

Photo © Pauline
14-Jul-2016

Photo Album (25 photos) ...


Larva

On emerging from their eggs, the larvae build a communal web, usually at the top of the nettle, from which they emerge to bask and feed. As the larvae grow, they move to new plants, building new webs along the way. This leaves a trail of webs, decorated with shed larval skins and droppings, that show the passing of time, and allows the patient observer to trace the larvae all the way back to the plant where the eggs were laid. The first experience that some people have of a Small Tortoiseshell is seeing these webs as they extend over stretches of nettle, with the larvae resting communally and quite visibly on the surface of the web, or feeding from nearby leaves.

Larvae have several techniques to avoid predation. When disturbed, a group of larvae will often jerk their bodies from side to side in unison, which must be a formidable sight to any predator. The larvae will also regurgitate green fluid and will, if necessary, curl up in a ball and drop to the ground. Larvae feed by both day and night and there are 5 instars in total.

The primary larval foodplants are Common Nettle (Urtica dioica) and Small Nettle (Urtica urens).

Small Tortoiseshell - larva - Ashford Hill NNR - Uknown date [Tim Norriss]

Photo © Tim Norriss

parasitic wasp infesting Small Tortoiseshell lavae,Harlow,Essex July 2013

Photo © essexbuzzard
Parasitic wasp infesting Small Tortoiseshell larvae
28-Jul-2013

Parasitic Fly (Phryxe vulgaris or Phryxe nemea) - Caterham, Surrey 8-July-2013

Photo © Vince Massimo
08-Jul-2013

Parasitic Fly (Phryxe vulgaris or Phryxe nemea) - Caterham, Surrey 8-July-2013

Photo © Vince Massimo
08-Jul-2013

Pupa of Parasitic Fly (Phryxe vulgaris or Phryxe nemea) - Caterham, Surrey 27-June-2013

Photo © Vince Massimo
27-Jun-2013

Pupa of parasitic fly (likely Sturmia bella) - Caterham, Surrey 18-June-2013

Photo © Vince Massimo
18-Jun-2013

Pupa of parasitic fly (likely Sturmia bella) - Caterham, Surrey 18-June-2013

Photo © Vince Massimo
18-Jun-2013

Photo Album (7 photos) ...


1st Instar

"Shortly after emergence the larva is very small, measuring only 1.25 mm. long; the anterior end of the body is stoutest; the head is large, black and shining and sparsely beset with fine black hairs. The body is a translucent ochreous-green and has ten (five on each side) longitudinal series of small tubercles, each bearing a long, simple, fine black hair slightly curved forwards, three above the spiracle, one immediately behind it, and one below, also two more simple hairs on base of claspers and others on the ventral surface; the legs and spiracles are black. The whole surface is covered with minute dusky granulations. Soon after feeding they assume a greenish hue. Upon emerging they quickly commence feeding on the young terminal leaves, perforating them and spinning a web all over the portion which they live upon. They are gregarious. When all the terminal leaves are consumed, they move off in a body to the topmost leaves of a neighbouring plant. If a large brood they break up into separate companies, from three to five, as soon as hatched." - Frohawk (1924)

Small Tortoiseshell larva on hatching, East Lothian

Photo © NickMorgan

Small Tortoiseshell Larvae - First Instar - Somerset - 08/06/13

Photo © William
08-Jun-2013

Small Tortoiseshell larvae hatching - Coulsdon, Surrey 16-July-2103

Photo © Vince Massimo
16-Jul-2013

Small Tortoiseshell larvae (newly emerged) - Caterham, Surrey 20-May-2013

Photo © Vince Massimo
20-May-2013

Small Tortoiseshell larvae (3 days old) - Caterham, Surrey 22-May-2013

Photo © Vince Massimo
22-May-2013

Small Tortoiseshell larvae (8 days old) - Caterham, Surrey 27-May-2013

Photo © Vince Massimo
27-May-2013

Photo Album (6 photos) ...


2nd Instar

"The first moult occurred on May 31st, 1910, the first stage lasting nine days. Before the second moult it measures 4.8 mm. long. The ground colour is a pale primrose-yellow, mottled with dark olive-brown, forming a checkered, broad sub-dorsal band, a speckled spiracular line and a broken-up medio-dorsal line. There are seven rows of short, blunt, dull olive-green tubercles, each terminating in a long, serrated black bristle and shorter ones springing round the base. The medio-dorsal row is composed of one on each segment, from the fourth to eleventh inclusive; the three other rows on each side are sub-dorsal, super-spiracular and sub-spiracular; numerous other black bristles, varying in size, are scattered over the whole surface. The entire body is densely covered with very minute black points. The head is shining black and bristle-bearing like the body. When undergoing the moult they remain in a mass within a web." - Frohawk (1924)

Small Tortoiseshell Larvae - Somerset - 09/08/13

Photo © William
09-Aug-2013

Small Tortoiseshell larvae (19 day old 2nd instar) - Caterham, Surrey 6-June-2013

Photo © Vince Massimo
06-Jun-2013

Photo Album (2 photos) ...


3rd Instar

"The second moult on June 5th, the second stage lasting only five days. Before third moult, sixteen days old, it measures 8.5 mm. long. In general structure and colouring it is almost similar to the previous stage, but all the tubercles are more highly developed and the colouring is darker, it being more densely mottled with blackish, and the medio-dorsal line more continuous; the black spiracles are surrounded by whitish, and placed on a blackish wavy band bordered on either side by a lemon-yellow line; the whitish hairs sprinkled over the body have pale bulbous bases, giving the body a speckled appearance. The habits are also similar, and when moulting they rest in a heap one above the other." - Frohawk (1924)

Small Tortoiseshell Larval Web - Outwood, Surrey 31-May-09

Photo © Vince Massimo

Small Tortoiseshell - larva - Bucklebury - 13-Aug-06 (0680)

Photo © Pete Eeles
13-Aug-2006

Small Tortoiseshell - larva - Thatcham - 22-Jul-07

Photo © Pete Eeles
22-Jul-2007

Small Tortoiseshell larvae (3rd instar) - Coulsdon, Surrey 4-June-2013

Photo © Vince Massimo
04-Jun-2013

Small Tortoiseshell larvae (3rd instar) - Coulsdon, Surrey 31-May-2013

Photo © Vince Massimo
31-May-2013

Small Tortoiseshell larvae (3rd instar) - Coulsdon, Surrey 31-May-2013

Photo © Vince Massimo
31-May-2013

Small Tortoiseshell larvae (3rd instar) - Coulsdon, Surrey 31-May-2012

Photo © Vince Massimo
31-May-2012

Small Tortoiseshell Larvae - Bishopstone - East Sussex - 29th-April-2014

Photo © Butterflysaurus rex

Photo Album (8 photos) ...


4th Instar

"The third moult took place early morning June 10th, the third stage occupying only between four and five days. Shortly before fourth moult, it is 19 mm. in length. It is similar to the previous stage excepting being darker, the tubercles more fully developed, and the lateral series and claspers olive-green. They still remain gregarious and are similar in habits. The fourth moult occurred on June 13th, the fourth stage lasting just over three days." - Frohawk (1924)

Small Tortoiseshell Larvae - Danebury Ring - 31-7-09

Photo © Gwenhwyfar
31-Jul-2009

Small Tortoiseshell - larva - Noar Hill - 30-Jul-04

Photo © Pete Eeles
30-Jul-2004

Small Tortoiseshell larvae - East Lothian, Scotland 7-June-2012

Photo © NickMorgan

Small Tortoiseshell larvae - East Lothian, Scotland 7-June-2012

Photo © NickMorgan

Small Tortoiseshell larvae (4th instar) - Caterham, Surrey 5-June-2013

Photo © Vince Massimo
05-Jun-2013

Small Tortoiseshell larva (4th instar) - Caterham, Surrey 6-June-2013

Photo © Vince Massimo
06-Jun-2013

Small Tortoiseshell (4th instar larval tent) - Caterham, Surrey 8-June-2012

Photo © Vince Massimo
08-Jun-2012

Small Tortoiseshell (4th instar moulting tents) - Coulsdon, Surrey 9-June-2013

Photo © Vince Massimo
09-Jun-2013

Small Tortoiseshell (pre-moult larva) - Caterham, Surrey 8-June-2013

Photo © Vince Massimo
08-Jun-2013

Small Tortoiseshell (pre-moult larva) - Caterham, Surrey 8-June-2013

Photo © Vince Massimo
08-Jun-2013

Small Tortoiseshell Larva - Somerset - 23/07/13

Photo © William
23-Jul-2013

Small Tortoiseshell Larvae - Somerset - 24/07/13

Photo © William
24-Jul-2013

Small Tortoiseshell larvae - Solihull West Midlands 10.05.2014

Photo © Neil Freeman
10-May-2014

Small Tortoiseshell larva (4th instar) - Caterham, Surrey 6-June-2013

Photo © Vince Massimo
06-Jun-2013

Photo Album (14 photos) ...


5th Instar

"After the fourth and last moult, fully grown, twenty-six days old, it measures 22.2 mm. long. The body tapers at both ends, mostly so anteriorly; the first segment is small; the head is shining black and notched on the crown, and covered with greenish tubercles, each emitting a black serrated bristle; they vary in length. On the body are seven longitudinal rows of branching tubercles, stout at the base and somewhat abruptly tapering, the apex and each branch terminating in a moderately long, sharply pointed, simple black spine. The tubercles are of varying depths of olive-green, the sub-dorsal series usually black, but all are shining; the medio-dorsal series commences on the fourth segment and ends on the eleventh segment; the super-and sub-spiracular rows are palest in colour; the second, third and anal segments have each four tubercles. The body is rather thickly speckled with white and yellow warts, each bearing a spinous hair, all varying greatly in length; the longest are white and very finely serrated, and encircle the posterior sub-divisions of the segments, and similar white hairs are on the ventral surface and on the base of each clasper. The larva vary much in colour, some being almost wholly black, while others are variegated with a preponderance of yellow; every gradation of colouring exists between the two extremes. The normal form has the ground colour black on the dorsal surface, and more or less olivaceous below the spiracular line, spreading over the ventral surface, checkered with pale yellow and wavy yellow super-and sub-spiracular markings, forming a checkered, chain-like, lateral band enclosing the spiracles, which are black outlined with pale yellow; the legs and hind pair of claspers are black, the remaining claspers are green. After the fourth moult the larva separate, and frequently fold up a nettle leaf by dragging the edges together by silk, and therein live and feed in solitude; others disperse over the plants. When fully fed they wander away in search of suitable places for pupation; frequently thcy suspend themselves on palings or under coping stones, or other suitable ledges, often a considerable distance. from their food plant. During very warm weather the larva hangs suspended during the period of pupation for only about fourteen or sixteen hours; the actual act of transforming from the larva to pupa occupies four and a half minutes. At the last stage of casting the larval skin the pupa contrives, by curving the apex of the abdomen, to reach the pad of silk with the hooks of the cremaster while still adhering to the shrivelled larval skin, but immediately the hooks. touch the silk the pupa most vigorously twists to and fro and becomes securely anchored, and the larval skin usually becomes detached and falls. Within one hour the pupa is fully developed in form; at first it is more or less. uniformly green." - Frohawk (1924)

Small Tortoiseshell - larva - Bucklebury - 13-Aug-06 (0828)

Photo © Pete Eeles
15-Aug-2006

Small Tortoiseshell - larva - Thatcham - 11-Aug-09 (1) {REARED}

Photo © Pete Eeles
11-Aug-2009

Small Tortoiseshell pre-pupa and Pteromalus.

Photo © Mikhail
The Pteromalus wasp is waiting for the larva to shed its skin, when it will pump its eggs into the newly formed pupa before it hardens.

Small Tortoiseshell (post-moult larva) - Caterham, Surrey 9-June-2013

Photo © Vince Massimo
09-Jun-2013

Small Tortoiseshell (post-moult larva) - Caterham, Surrey 9-June-2013

Photo © Vince Massimo
09-Jun-2013

Small Tortoiseshell larva - Coulsdon, Surrey 9-June-2013

Photo © Vince Massimo
09-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva pupating - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell larva preparing to pupate - Caterham, Surrey 12-June-2013

Photo © Vince Massimo
12-Jun-2013

Small Tortoiseshell larva preparing to pupate - Caterham, Surrey 12-June-2013

Photo © Vince Massimo
12-Jun-2013

Photo Album (14 photos) ...


Pupa

The larvae disperse as they become fully grown, and eventually wander off to find a suitable pupation site. The pupa is formed head down, attached to a stem or leaf by the cremaster. The colour of the pupa is quite variable, often having a beautiful metallic sheen. This stage lasts between 2 and 4 weeks, depending on temperature.

"The pupa measures from 20 mm. to 22 mm. long; it is rather slender in proportion. Lateral view: The head is sharply pointed in front; thorax rising to a central triangular point; sunken at the meta-thorax and first abdominal segment; the abdomen then swelling and curving to the anal segment, which terminates in a well developed cremastral process, which is grooved above and below and furnished with a dense mass of hooks; the ventral surface forms a gentle waved outline. The tongue sheath all but reaches the fifth abdominal segment. Dorsal view: The head is strongly bilobed, having a pair of well developed lateral conical points; thorax sharply pointed at the base of the wing; the inner margin is somewhat keeled and angular; the middle of wing is slightly sunken, the abdomen tapering. On the dorsal surface are three rows of conical points representing the dorsal tubercles of the larva; the medio-dorsal row is composed of a series of very small points, one on each segment from the second to seventh inclusive; the sub-dorsal rows commence on the meso-thorax and extend to the eighth segment, on which they are barely discernible; the lateral rows are represented by minute points only. The colouring is very various, even in the same brood, all reared together and pupated side by side under precisely similar conditions. For instance, a brood which pupated within a large glass cylinder with gauze covering the top, containing nettles, produced different forms; most of them were of a very beautifully gilded form, while others were of the dull smoky-brown type, and others were intermediate between these two extremes. This brood was from one batch of eggs, laid by a wild female on May 14th, 1910. The gilded form has the ground colour of the abdomen only a flesh colour, the rest of the pupa being wholly washed with very beautiful gold, reflecting coppery and green lustre; the entire surface is very finely reticulated and speckled with buff, brown and black; the black is chiefly on the head and dorsal points. Some have the ground colour delicate lilac-pink, washed with metallic copper over the thorax and opalescent at the base of the first few dorsal points. The most dusky form has the ground colour much duller and all the dark markings heavier. A dusky-olive wavy band passes obliquely over the centre of the wing, and a blotch of the same colour spreads over the apex; also oblique markings run from the dorsal points across the abdomen, and a spiracular longitudinal band formed of oblique markings, which become broken up on each segment, gives the pupa a somewhat checkered pattern. The ventral edge of the cremaster is black, from which the spiracular band originates. There is also a medio-ventral longitudinal band; the dorsal points are black with orange tips. Shortly before emergence the gilded form becomes metallic bronze-green and gold. The first imago emerged on July 2nd, 1910." - Frohawk (1924)

Small Tortoiseshell pupa - Caterham, Surrey 16-June-2013

Photo © Vince Massimo
16-Jun-2013

Small Tortoiseshell Pupa - Somerset - 03/08/13

Photo © William
03-Aug-2013

Small Tortoiseshell pupa (1 hour old) - Caterham, Surrey 13-June-2013

Photo © Vince Massimo
13-Jun-2013

Small Tortoiseshell pupa (with emerging parasitic wasps) - Essex 19-Aug-2013

Photo © roundwood123
19-Aug-2013

Small Tortoiseshell pupa (21 hours before hatching) - Caterham, Surrey 2-July-2013

Photo © Vince Massimo
02-Jul-2013

Small Tortoiseshell pupa - Caterham, Surrey 22-June-2013

Photo © Vince Massimo
22-Jun-2013

Small Tortoiseshell hatching - Caterham, Surrey 3-July-2013

Photo © Vince Massimo
03-Jul-2013

Small Tortoiseshell hatching - Caterham, Surrey 3-July-2013

Photo © Vince Massimo

Small Tortoiseshell pupa (20 hours before hatching) - Caterham, Surrey 2-July-2013

Photo © Vince Massimo
02-Jul-2013

Small Tortoiseshell hatching - Caterham, Surrey 3-July-2013

Photo © Vince Massimo
03-Jul-2013

Small Tortoiseshell - pupa - Unknown location - 30-May-05 [REARED] [Matt Berry]

Photo © Matt Berry

Small Tortoiseshell - pupa - Thatcham - 30-May-09 (1) {REARED}

Photo © Pete Eeles
30-May-2009

Small Tortoiseshell pupa - Caterham, Surrey 22-June-2013

Photo © Vince Massimo
22-Jun-2013

Small Tortoiseshell pupa - Caterham, Surrey 22-June-2013

Photo © Vince Massimo
20-Jun-2013

Small Tortoiseshell pupa - Caterham, Surrey 16-June-2013

Photo © Vince Massimo
16-Jun-2013

Small Tortoiseshell pupa - Caterham, Surrey 22-June-2013

Photo © Vince Massimo
22-Jun-2013

Small Tortoiseshell Pupa (about a day before emergence) - Somerset - 08/08/13

Photo © William
08-Aug-2013

Small Tortoiseshell hatching - Caterham, Surrey 3-July-2013

Photo © Vince Massimo
03-Jul-2013

Small Tortoiseshell pupa - Caterham, Surrey 16-June-2013

Photo © Vince Massimo
16-Jun-2013

Small Tortoiseshell pupa (parasitised) - Essex 20-Aug-2013

Photo © roundwood123
20-Aug-2013

Photo Album (27 photos) ...


Aberrations

This species displays considerable variation in both the upperside ground colour and the familiar upperside pattern and markings.

Much work has been carried out in this species to discover how temperature shock in the late larval/ early pupal stage can affect the development of pigments in the imago. These experiments have assisted our understanding of how and when the pigments are 'mapped' in the Vanessid butterflies. The Small Tortoiseshell appears to be particularly sensitive to temperature shock, and this species has been widely bred in the past in the hope of producing extreme environmentally controlled aberrations such as ab. semi-ichnusoides.

Extreme shocks of either heat or cold during the last 24 hours of the larval stage and the first 48 hours of the pupal stage can disrupt the natural process of metamorphosis and inhibit the normal processes in which organic chemicals create the colouration of the wing scales.

The expression of aberration through temperature shock is a graduated process; one level of exposure creates ab. semi-ichnusoides, a little more fuses all three black blotches along the costa of the forewing to create ab. conjuncta, and the most extreme exposure produces an almost entirely melanic form known as ab. osborni. The conditions required to produce the latter forms are thought to be so extreme that they lie right on the very cusp of extremes of temperature that would be fatal to the larva or pupa. Consequently these forms are rare in captivity and extremely unlikely to be met with in the wild.

It is difficult to ascertain how frequently any of these aberration occur in the wild, however it is a rare event that exposes the newly formed pupa or transitional larva to the necessary conditions for metamorphosis to be disrupted in this way, and this is supported by the paucity of historical sightings of the extreme aberrations in the wild. That is not to say that the lesser of the aberrations do not occur however, and an ab. semi-ichnusoides presents a particularly striking sight when nectaring on a garden buddleia amongst typical individuals.

It has been speculated that severe late frosts could possibly cause instances of these aberrant forms, as well as a larva/pupa being exposed to particularly strong sunlight after having the normally sheltered pupation site disturbed in some manner.

Environmental influences are not the sole cause of aberration in this species however, and there are many genetic aberrations which the observer could encounter at any time. Occasionally the orange ground colour is replaced entirely by a pale whitish buff (ab. lutea), as well as various transitional shades leading to this. Similarly, sometimes the orange colour is replaced by a brownish-purple hue and this is known as ab. brunneoviolacea.

There are in excess of 105 named aberrations known to occur in Britain.

Click here to see the aberration descriptions and images for this species.

Similar Species

Large Tortoiseshell

Description to be completed.

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The following links provide additional information on this butterfly.

References

The species description provided here references the following publications:

ReferenceDetails
Dalman (1816) Dalman, J.W. (1816) Kongl. Svenska Vetenskaps akademiens Handlingar.
Frohawk (1924) Frohawk, F.W. (1924) The Natural History of British Butterflies.
Harris (1766) Harris, M. (1766) The Aurelian. Edition 1.
Lewin (1795) Lewin, W. (1795) The Papilios of Great Britain.
Linnaeus (1758) Linnaeus, C. (1758) Systema Naturae. Edition 10.
Petiver (1695-1703) Petiver, J. (1695-1703) Musei Petiveriani centuria prima-decima, rariora naturae continens.
Rafinesque (1815) Rafinesque, C.S. (1815) Analyse de la nature ou Tableau de l'univers et des corps organisés.
Wilkes (1742) Wilkes, B. (1742) Twelve New Designs of English Butterflies.