Phenology of Epilachna quadricollis (Dieke) (Coccinellidae: Epilachnini) in Korea
Background : Epilachna quadricollis (Dieke) (Coccinellidae: Epilachnini) is the only known species in Korea that hibernates as a 4th instar larva, unlike most phytophagous coccinellids, which overwinter as adults. This study was conducted to understand its distribution, seasonal phenology, developme...
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| Format: | Article |
| Language: | English |
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The Ecological Society of Korea
2025-07-01
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| Series: | Journal of Ecology and Environment |
| Subjects: | |
| Online Access: | http://www.e-jecoenv.org/journal/view.html?doi=10.5141/jee.25.039 |
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| Summary: | Background : Epilachna quadricollis (Dieke) (Coccinellidae: Epilachnini) is the only known species in Korea that hibernates as a 4th instar larva, unlike most phytophagous coccinellids, which overwinter as adults. This study was conducted to understand its distribution, seasonal phenology, developmental patterns, and reproductive traits through field surveys across Korea and laboratory observations, providing baseline data for future studies on its ecological adaptations. Results : Epilachna quadricollis undergoes four larval instars and overwinters as a mature 4th instar larva. Except for slight variation observed in the 2nd instar, head capsule width was a reliable indicator for distinguishing larval developmental stages. The mean duration of the development from oviposition to the new 4th instar was 43.1 days. Females laid a mean of 51.5 ± 2.8 (SE) eggs per cluster on the underside of leaves from June to mid-August, with a mean fecundity of 338.4 ± 93.2 (SE) eggs. Pupation began in late April, with adult emergence from mid-May. Oviposition began approximately 39 days after adult emergence and lasted for 19 days. The phenology of E. quadricollis was estimated by reorganizing multi-year field collection and observation records, and its feeding and development were closely linked to the phenology of Fraxinus spp. Conclusion : s: This study provides detailed insight into the life history, seasonal development, and reproductive traits of E. quadricollis. Its univoltine cycle, closely synchronized with the phenology of Fraxinus spp., highlights the species’ dependence on host plant availability. Larval stages can be reliably distinguished based on morphological characteristics, especially head capsule dimensions. The extended preoviposition period suggests that reproduction is regulated by photoperiod. Its confirmed distribution across several offshore islands–including Deachungdo Island, Jejudo Island, and Ulleungdo Island–highlights the need to investigate potential dispersal mechanisms and population connectivity. |
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| ISSN: | 2287-8327 2288-1220 |