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Dynastes neptunus
Rare large beetle from South American highlands. Second largest after Hercules. Jet-black body with long horn is stunning.
Dynastes neptunus, the Neptune beetle, inhabits high-altitude cloud forests of the Andes in Colombia, Ecuador, and Peru, at elevations roughly between 1,000 and 2,500 meters. It is one of the largest rhinoceros beetles, with males reaching total lengths of 80–150 mm, ranking second only to the Hercules beetle in maximum size. Males bear a long thoracic horn and shorter cephalic horn, with a striking glossy jet-black body coloration. The larval stage spans 2–3 years—exceptionally long for a rhinoceros beetle—and demands large quantities of high-quality fermented substrate. Females lay eggs in fermented substrate, and breeding is moderately challenging. Adults live 6–12 months. While requiring experienced husbandry, the Neptune beetle's jet-black form and impressive proportions make it one of the most revered species in the collecting world.
The Neptune Beetle lives Adult 6-12 months, larva 2-3 years.
The Neptune Beetle grows to Up to 150mm.
As a highland species, it requires strict low-temperature management at 17–22°C; warmer conditions are detrimental to both adults and larvae.
Origin
high-altitude Andean cloud forests of Colombia, Ecuador, and Peru
Lifespan
Adult 6-12 months, larva 2-3 years
Size
Captive record (♂)
157.3 mm
Record source: BE-KUWA 2025 edition (Neptune - Captive 157.3mm Motomi Takizawa 2018, total length = including horns)
Notable localities
An Andes-origin large rhinoceros beetle with slender, elongated thoracic and head horns. Records include total length with horns. Captive breeding records are updated annually through BE-KUWA (Mushi-sha) competitions. Individual value varies significantly depending on locality, generation (CBF/WF/WD), and size.
Generation codes
Sources: BE-KUWA Certified Breeding Records (Mushi-sha, FY2025 edition, JA)
Edited & verified by: BreederDirect editorial team
The taxonomic, regulatory, and husbandry data on this page are compiled and verified against the authoritative primary sources below.
Accepted name: Dynastes neptunus (Quensel, 1805)
Synonyms: Dynastes neptunus rouchei Nagai, 2005, Geotrupes neptunus Quensel, 1805, Scarabaeus jupiter Buquet, 1840
Authority databases: GBIF
Nomenclature follows global taxonomic authority databases.
Plant Protection Act: When importing live specimens of Scarabaeoidea (including rhinoceros beetles, stag beetles, flower beetles, etc.), a species identification certificate issued by the exporting country government agency or equivalent must be attached in accordance with the Invasive Species Act (import ports are limited to Narita, Chubu, Kansai, Fukuoka, and Kagoshima airports). This species itself is not a designated invasive species, and import is possible upon submission of the certificate.
Sources: Ministry of the Environment, Invasive Species Act: "Guidance for Those Importing Live Insects in Scarabaeoidea" / CITES Appendix (checklist.cites.org)
Regulations may change. Always verify the latest information with the relevant authorities.
Find listings for this species
Up to 150mm
Temperature
20〜28℃
Humidity
60〜80%
Beetle jelly (adult), fermented substrate (larva)
17-22°C (cool temperature essential)
2-3 years — very long
Rare in trade and expensive
Wine cooler temperature management essential
Highland species — Japanese summer is biggest threat
Advanced. This is an advanced-level species. It requires specialized equipment and advanced husbandry skills with precise environmental control.
The average lifespan of Neptune Beetle is Adult 6-12 months, larva 2-3 years. With proper care and nutrition, they can live a long and healthy life.
Neptune Beetle typically reaches Up to 150mm as an adult. Size may vary depending on care conditions and individual genetics.
Neptune Beetle feeds on: Beetle jelly (adult), fermented substrate (larva). Aim for a balanced diet with appropriate feeding frequency.
The price of Neptune Beetle varies significantly depending on bloodline, size, captive-bred generation, and sex. Check our market price page for the latest pricing information.
Last updated: August 31, 2026