73.088X Spodoptera frugiperda (Fall Armyworm)
ws: 32-40mm (Wikipedia); polyphagous, mainly on grasses and grain crops e.g. corn
Native to North and South America it is a long distance migrant. It was found in Africa in 2013 and is now widespread throughout the continent; it has also been found in India, SE Asia and Australasia. Records are increasing in southern Europe as a result of migration, but it is not yet considered to be established. Moth Dissection shows one undated Irish record but at the time of writing the species does not have a RES checklist number. The vernacular name "Armyworm" refers to the invasive behaviour of the larva which is a serious pest of several crops - hence the specific name "frugiperda" which means "lost fruit".
Other scarce migrants trapped at the same site around the same time as this specimen were: 11/11/2025 – Spodoptera cilium (Dark Mottled Willow), 12/11/2025 – Diasemiopsis ramburialis (Migrant Sable); 13/11/2025 – Helicoverpa armigera (Scarce Bordered Straw)
Native to North and South America it is a long distance migrant. It was found in Africa in 2013 and is now widespread throughout the continent; it has also been found in India, SE Asia and Australasia. Records are increasing in southern Europe as a result of migration, but it is not yet considered to be established. Moth Dissection shows one undated Irish record but at the time of writing the species does not have a RES checklist number. The vernacular name "Armyworm" refers to the invasive behaviour of the larva which is a serious pest of several crops - hence the specific name "frugiperda" which means "lost fruit".
Other scarce migrants trapped at the same site around the same time as this specimen were: 11/11/2025 – Spodoptera cilium (Dark Mottled Willow), 12/11/2025 – Diasemiopsis ramburialis (Migrant Sable); 13/11/2025 – Helicoverpa armigera (Scarce Bordered Straw)
Spodoptera frugiperda (Fall Armyworm) §1 female (image provided by Will Scott)
ID: Sexually dimorphic particularly with respect to a broad white wedge at the costal end of the subterminal line and, which is only hinted at in the female; a small white spot in the dorsal portion of the kidney mark, which is not seen in the female; and the oval mark which is brown in the male and variable in the female. The female somewhat resembles an over-sized S.exigua (Small Mottled Willow). The hindwing of both sexes is white with a blackish terminal line extending along the termen from the apex but not reaching the tornus.
Male genitalia:
Female genitalia: The ovipositor and segment 8 have a dense covering of hair scales that need to be removed carefully to avoid damaging the underlying structures. The antrum is well-sclerotised; after a short hyaline gap distal to the antrum the remainder of the ductus bursae is well sclerotised to its junction with the corpus bursae; the corpus bursae is sclerotised in its posterior ⅓, but not in its anterior ⅔, with a sharp line of demarcation; the signum is rounded with longitudinal pleats.
Male genitalia:
Female genitalia: The ovipositor and segment 8 have a dense covering of hair scales that need to be removed carefully to avoid damaging the underlying structures. The antrum is well-sclerotised; after a short hyaline gap distal to the antrum the remainder of the ductus bursae is well sclerotised to its junction with the corpus bursae; the corpus bursae is sclerotised in its posterior ⅓, but not in its anterior ⅔, with a sharp line of demarcation; the signum is rounded with longitudinal pleats.
§1 St Mary's, Isles of Scilly; 12/11/2025; female; fw 17.2mm; to 125W mv light; specimen trapped and provided by Mick and Will Scott;
FIRST RECORD FOR BRITAIN (but possibly second record for the British Isles)
All images © Chris Lewis
FIRST RECORD FOR BRITAIN (but possibly second record for the British Isles)
All images © Chris Lewis
Page published 14/12/2025 (§1)
