Eurema hecabe

{{Speciesbox

| image = Eurema hecabe Linnaeus, 1758 – Common Grass Yellow.jpg

| image_caption = Bangalore, India

| image2 = Common grass yellow (Eurema hecabe solifera) 2.jpg

| image2_caption = E. h. solifera Ghana

| taxon = Eurema hecabe

| authority = (Linnaeus, 1758)

| synonyms =

Papilio hecabe Linnaeus, 1758
Terias hecabe
Terias solifera Butler, 1875
Terias bisinuata Butler, 1876
Terias chalcomiaeta Butler, 1879
Terias dentilimbata Butler, 1879
Terias bewsheri Butler, 1879
Terias orientis Butler, 1888
Terias aethiopica Trimen & Bowker, 1889
Terias butleri Trimen & Bowker, 1889
Terias floricola f. parva Rothschild, 1921
Terias brenda ab. alba Dufrane, 1945
Terias brenda ab. subalba Dufrane, 1945
Terias floricola ab. alba Dufrane, 1945
Terias brenda ab. maureli Dufrane, 1947
Terias hecabe senegalensis f. continua Storace, 1949
Terias hecabe f. napia Stoneham, 1957
Terias hecabe f. neria Stoneham, 1957
Terias maroensis Butler, 1883
Terias biformis Butler, 1884
Terias latilimbata Butler, 1886
Terias hecabe borneensis Fruhstorfer, 1910
Terias amplexa Butler, 1887
Terias mandarina de l'Orza, 1869
Terias photophila Butler, 1884
Terias diversa Wallace, 1867
Terias hecabe oeta Fruhstorfer, 1910
Terias phoebus Butler, 1886
Eurema hecabe var. kerawara Ribbe, 1898
Eurema hecabe var. magna Ribbe, 1898
Terias contubernalis Moore, 1886

}}

Eurema hecabe, the common grass yellow, is a small pierid butterfly species found in Asia, Africa and Australia.{{Cite book|title=A Synoptic Catalogue of the Butterflies of India |last1=Varshney |first1=R.K. |last2=Smetacek|first2=Peter|publisher=Butterfly Research Centre, Bhimtal & Indinov Publishing, New Delhi|year=2015|isbn=978-81-929826-4-9|location=New Delhi|pages=69|doi=10.13140/RG.2.1.3966.2164}}{{cite web |last=Savela |first=Markku |url=http://www.nic.funet.fi/pub/sci/bio/life/insecta/lepidoptera/ditrysia/papilionoidea/pieridae/coliadinae/eurema/#hecabe |title=Eurema hecabe (Linnaeus, 1758) |website=Lepidoptera and Some Other Life Forms |access-date=July 1, 2018}}{{cite book|last=Woodhall |first=Steve |title=Field Guide to Butterflies of South Africa |year=2005 |location=Cape Town, South Africa |publisher=Struik |isbn=978-1-86872-724-7}} They are found flying close to the ground and are found in open grass and scrub habitats. It is simply known as "the grass yellow" in parts of its range; the general term otherwise refers to the entire genus Eurema.

Description

The common grass yellow exhibits seasonal polyphenism. The lepidopteran has a darker summer morph, triggered by a long day exceeding 13 hours in duration, while the shorter diurnal period of 12 hours or less induces a fairer morph in the post-monsoon period.Gullan, P.J. & Cranston P.S. (2005). E.blanda is almost always larger and a faster flier than this species. "The insects: an outline of entomology" (5th Ed). Wiley-Blackwell, {{ISBN|1-4051-1113-5}}, {{ISBN|978-1-4051-1113-3}}. [https://books.google.com/books?id=ZZaVjVWUaXIC Ltd preview] in Google Books. Accessed on 12 Jan 2010.{{rp|164}}

= Male =

Upperside (dorsal surface): yellow, variable in tint from sulphur to rich lemon yellow according to season and locality. Forewing: apex and termen deep black, this colour continued narrowly along the costal margin to base of wing, near which it often becomes diffuse; the inner margin of the black area from costa to vein 4 very oblique and irregular, between veins 2 and 4 excavate on the inner side, this excavation outwardly rounded between the veins and inwardly toothed on vein 3; below vein 2 the black area is suddenly dilated into a square spot which occupies the whole of the tornal angle; the inner margin of this dilatation is variable, in the typical form slightly concave. Hindwing: terminal margin with a narrow black band which is attenuated anteriorly and posteriorly; dorsal margin broadly paler than the ground colour.

The region of dorsal surface that appears visibly yellow to humans also reflects brightly in the ultraviolet (320-400 nm) owing to the presence of multilayer cuticular nanostructures.{{Cite journal|last1=White|first1=Thomas E.|last2=Macedonia|first2=Joseph|last3=Birch|first3=Debra|last4=Dawes|first4=Judith|last5=Kemp|first5=Darrell J.|date=2012|title=The nanoanatomical basis of sexual dimorphism in iridescent butterfly colouration|url=http://www.publish.csiro.au/?paper=ZO12045|journal=Australian Journal of Zoology|language=en|volume=60|issue=2|pages=101|doi=10.1071/ZO12045|s2cid=4847428|issn=0004-959X|url-access=subscription}}

Underside (ventral surface): yellow, generally a slightly paler shade than that of the upperside, with the following reddish-brown markings. Forewing: two small spots or specks in basal half of cell and a reniform (kidney-shaped) spot or ring on the discocellulars. Hindwing: a slightly curved subbasal series of three small spots, an irregular slender ring or spot on the discocellulars, followed by a highly irregular, curved, transverse, discal series of spots or specks, some or all of which are often obsolescent. On both the forewings and hindwings, the veins that attain the costal and terminal margins end in minute reddish-brown specks. Antenna are greyish yellow, the club black; head, thorax and abdomen are yellow, shaded with fuscous scales; beneath: the palpi, thorax and abdomen are yellowish white. The sex-mark seen from above appears as a thickening of the basal half of the median vein on the forewing.

= Female =

Upperside: Very similar to that of the male but without the sex-mark; the black areas on both forewings and hindwings slightly broader, with the inner edge of the black terminal band on the hindwing often diffuse.

Females also have a reduced patch of ultraviolet-reflecting scales located in the proximate region of the dorsal forewing. The mechanism responsible for this colouration is the same as in males but the reflectance is less bright.{{Cite journal|last=Kemp|first=Darrell J.|title=Resource-Mediated Condition Dependence in Sexually Dichromatic Butterfly Wing Coloration|date=September 2008|journal=Evolution|language=en|volume=62|issue=9|pages=2346–2358|doi=10.1111/j.1558-5646.2008.00461.x|pmid=18637962|s2cid=205781790|doi-access=free}}

Underside: ground colour and markings as in the male. Antennae, head, thorax and abdomen similarly coloured.

= Dry-season form =

Upperside: ground colour and markings much as in wet-season specimens, the emargination on the inner side of the black area and the tornal dilatation on the forewing similar. On the hindwing, in the great majority of individuals, the black terminal band is also similar; in a few it is narrower and diffuse inwardly in both sexes.

Underside: ground colour similar to that in wet-season specimens, but very many have a greater or less irroration of black scales over the yellow parts of the wing; the reddish-brown markings on both forewings and hindwings are also similar, but the spots are larger, more clearly defined, darker, and therefore far more conspicuous. In addition, on the forewing there is a preapical, very prominent, transverse, elongate spot or short bar or reddish brown extended downwards from the costa. This spot is irregular in shape and of variable width, but does not seem to ever spread outwards to the actual edge of the termen. In a few specimens there is also a small reddish-brown spot in interspace near the tornus. Antennae, head, thorax and abdomen, and in the male, the sex-mark, as in wet-season specimens.{{Source-attribution|sentence=yes|{{cite book |last1=Bingham |first1=C.T. |author-link=Charles Thomas Bingham |title=The Fauna of British India, Including Ceylon and Burma |url=https://archive.org/stream/butterflies02bingiala#page/250/mode/2up/ |volume=II |edition=1st |publisher= Taylor and Francis, Ltd. |location=London |year=1907|pages=250–254}}}}{{Cite book|url=https://www.biodiversitylibrary.org/item/103631#page/64/mode/1up|title=Lepidoptera Indica. Vol. VII |last=Swinhoe|first=Charles|author-link=Charles Swinhoe|publisher=Lovell Reeve and Co.|year=1905–1910|location=London|pages=50–56}}

Life cycle

Eggs are laid on Abrus precatorius, Falcataria moluccana, Acacia sp., Aeschynomene species and numerous other Leguminosae, Euphorbiaceae and Cucurbitaceae sp..{{cite web |author1=Gaden S. Robinson |author2=Phillip R. Ackery |author3=Ian J. Kitching |author4=George W. Beccaloni |author5=Luis M. Hernández |title=HOSTS - a Database of the World's Lepidopteran Hostplants |publisher=Natural History Museum |url=http://www.nhm.ac.uk/research-curation/projects/hostplants/ }}

Studies suggest that the females can discriminate colours when choosing host plants for oviposition.{{cite journal |doi=10.1303/aez.2004.229 |author1=Tadao Hirota |author2=Yoshiomi Kato |year=2004 |title=Color discrimination on orientation of female Eurema hecabe (Lepidoptera: Pieridae) |journal=Applied Entomology and Zoology |volume=39 |pages=229–233 |issue=2 |doi-access=free |bibcode=2004AppEZ..39..229H }}

Larva: "Long, green, rough, cylindrical, or slightly depressed, with a large head."

Pupa: "Suspended by the tail and by a moderately long band; the abdominal segments are round, but the thorax is much compressed, the wing-cases uniting to form a deep sharp keel. The head-case terminates in a short pointed snout. Ordinarily the pupa is solitary and green, but sometimes on a twig in large numbers. Many Pierine and other larvae seek each others company at that time. Having selected a dead branch of some neighbouring bush, they acquired the colour of their surroundings as nearly all Pierine and Papilionine pupae do to a greater or less extent."

This species has been found to be parasitised by multiple strains of Wolbachia. These bacteria can alter the sex ratios of the species.{{cite journal |doi=10.1098/rspb.2004.2769 |author1=Masato Hiroki |author2=Yohsuke Tagami |author3=Kazuki Miura |author4=Yoshiomi Kato |year=2004 |title=Multiple infection with Wolbachia inducing different reproductive manipulations in the butterfly Eurema hecabe |journal=Proceedings of the Royal Society B |volume=271 |pages=1751–1755 |issue=1549 |pmid=15306297 |pmc=1691781 }}

File:Common grass yellows (Eurema hecabe solifera) mating Nyamebe Bepo.jpg|E. h. solifera mating

file:Eurema hecabe egg sec.jpg|Egg

file:Eurema hecabe cat sec.jpg|Larva (caterpillar)

file:Eurema hecabe pupa sec.jpg|Pupa