Spoladea recurvalis

(Fabricius, 1775)

Beet Webworm Moth, Hawaiian Beet Webworm Moth, Amaranth Leaf-Webber

Spoladea recurvalis is a small crambid with a global tropical and subtropical distribution. The is a documented agricultural pest, with feeding primarily on Amaranthus species (amaranth) as well as spinach, beet, and other . require nectar feeding for survival and exhibit temperature-dependent activity. The species has been to temperate regions including Europe and North America, where it continues to expand its range. It serves as for the larval Apanteles hemara, which has been studied for potential.

Spoladea recurvalis by (c) Hsu Hong Lin, some rights reserved (CC BY). Used under a CC-BY license.

Spoladea recurvalis (4463513027) by LiCheng Shih. Used under a CC BY-SA 2.0 license.

Spoladea recurvalis 1 by Jacy Lucier. Used under a CC BY-SA 4.0 license.

Pronunciation

How to pronounce Spoladea recurvalis: /spoˈlade.a reˈkur.valɪs/

These audio files are automatically generated. While they are not always 100% accurate, they are a good starting point.

Identification

Distinguished from similar crambid by the characteristic markings on the (the source of the specific epithet 'recurvalis'). The banded pattern with contrasting and white is distinctive. In Europe, distinguished from by its tropical origin and association with cultivated amaranth and beet . Molecular identification supported by transcriptome data showing highest sequence similarity to among reference databases.

Images

Habitat

Agricultural and horticultural environments, particularly where plants (Amaranthus spp., Beta vulgaris, Spinacia oleracea) are cultivated. In tropical and subtropical range, occurs in diverse agricultural settings. In expanded temperate range, associated with protected and urban gardens where host plants persist.

Distribution

to tropical and subtropical regions worldwide. Documented from Africa, Asia, Australasia, Pacific Islands, and the Americas. Expanded distribution into Europe (first records in Italy with subsequent spread to multiple regions; also recorded in Belgium). In North America, established in southeastern USA (Florida, South Carolina, Virginia, New Jersey). Present on oceanic islands including Hawaii, Galápagos, and Atlantic islands. Range expansion ongoing, facilitated by human transport of plants and climate change.

Seasonality

period varies geographically: May to September in temperate regions, year-round activity in tropics. In laboratory conditions, females exhibit pre- period of 3 days and continue -laying for up to 20 days post-. Temperature strongly influences activity: optimal flight temperature 17–23°C, with some individuals capable of flight at 12°C.

Diet

are feeding on leaves of Amaranthus (primary ), spinach (Spinacia oleracea), beet/sugar beet (Beta vulgaris), cotton (Gossypium), maize (Zea mays), and soybean (Glycine max). require nectar feeding ( solution in laboratory; natural nectar sources in field) for survival; even one day without nectar significantly depresses subsequent activity.

Host Associations

Amaranthus spp. - primary larval Main in Africa and Asia; causes complete foliage loss under severe
Beta vulgaris - larval Includes sugar beet and beetroot; 'Beet ' derives from this association
Spinacia oleracea - larval Documented
Gossypium - larval Cotton
Zea mays - larval Maize
Glycine max - larval Soybean
Apanteles hemara - larval Most important ; solitary that parasitizes young (1–4 days old preferred)

Life Cycle

with , , , and stages. Larval development includes web-building on foliage. site not explicitly described in sources but presumably within or near larval shelters. Adult longevity and reproductive period documented in laboratory: females have 3-day pre- period, lay eggs for up to 20 days. Developmental timing temperature-dependent.

Behavior

construct webs on foliage and feed within these shelters, hence '' . exhibit temperature-dependent activity with optimal range 17–23°C; 10% of females capable of continuous long-duration flight even at 12°C. Females more actively during pre- period. Flight activity not clearly separated from reproductive period. Mating status has no clear effect on flight activity. Adults require frequent nectar feeding to maintain flight capability.

Ecological Role

and agricultural pest; can cause complete of amaranth . Serves as for including Apanteles hemara, supporting parasitoid . Expansion into new regions may disrupt local and compete with herbivores.

Human Relevance

Significant agricultural pest of amaranth, spinach, beet, and other in tropics and subtropics; has become established in temperate regions through human-mediated transport. Subject of research for including (certain amaranth accessions show strong ) and using Apanteles hemara. Transcriptome sequencing has been performed to develop molecular tools for pest management. Monitored through citizen science platforms (iNaturalist, observation.org) for tracking range expansion.

Similar Taxa

Other Spilomelinae crambidsSimilar size and general appearance; distinguished by specific pattern with markings and association with amaranth/beet
Other 'webworm' mothsLarval web-building shared with many Crambidae; distinguished by specificity and pattern

More Details

Molecular resources

Transcriptome assembly available with 120,435 contigs; 58,225 sequences with BLASTX annotations. of DH- ( biosynthesis-activating neuropeptide) characterized at 4,295 with six exons. Forty putative genes related to pheromone production and reception identified, with potential for pheromone-based pest management.

Biological control research

Apanteles hemara, the primary larval , exhibits II to . success highest on 1–2 day old ; does not parasitize larvae 7 days or older. Temperature requirements for development (10.3–35.0°C threshold) may limit effectiveness in some climates.

Host plant resistance

Accession VI036227 of Amaranthus shows complete (100% larval mortality within 36 hours) without deterring , offering promising breeding material.