Breeding Report for Brahmaea tancrei - Siberian Owl Moth, (Austaut, 1896)
Manuel Andreas Staggl1,2
1 Department of Palaeontology, Faculty of Earth Sciences, Geography and Astronomy, Josef-Holaubek-Platz 2, 1090 Vienna, Austria
2 Vienna Doctoral School of Ecology and Evolution (VDSEE), University of Vienna, Djerassiplatz 1, 1030 Vienna
Abstract:
Brahmaea tancrei, commonly known as the Siberian owl moth, is a fascinating species of moth found in Russia, Korea, China, and Indonesia. This captivating insect exhibits unique characteristics throughout its life cycle. The larvae, with their iconic whip-like appendages, feed on plants from the olive family, primarily Ligustrum species. The breeding process involves careful attention to temperature, ventilation, and food sources. The pupae undergo diapause. The adult moths, although possessing a functioning proboscis, are considered non-feeding, relying on moisture for hydration. Understanding the life cycle and requirements of Brahmaea tancrei can contribute to successful breeding and appreciation of this remarkable species.
General Information:
Brahmaea tancrei, commonly known as the Siberian owl moth, is a captivating species belonging to the family Brahmaeidae. This moth species is distributed from Russia (Amur, Siberia, and Russian Far East) to Korea, China, and Indonesia. It was first described by Austaut in 1896. Breeding Brahmaea tancrei can be a rewarding and fascinating experience, but it requires careful attention to some specific conditions and stages of development.
Suitable Food Plants:
Brahmaea tancrei larvae primarily feed from my experience on some plants from the family Oleaceae, with Ligustrum ovalifolium (Privet) and Syringa vulgaris (Lilac) being the preferred host plant. Ligustrum has proven to be the most suitable food plant for their development based on experience and observations. Offering fresh and healthy food plants is crucial for the successful rearing of the larvae.

Fig. 1: Netting cage (60x40x40cm) with about 30 caterpillars in L4 and L5, on the .left with fresh food in the evening, on the right the next morning, caterpillars on .the ground in the migration phase looking for a place to pupate.
Egg Stage:
The eggs of Brahmaea tancrei are round, the lower side is flattened and pale white. Fertilized eggs undergo a colour change, turning dark to completely black just a few days before hatching. The duration of the egg stage is approximately 8 to 15 days, depending on the temperature, most caterpillars hatched between 10-12 days after oviposition. Room temperature is suitable for egg incubation, and a light misting can assist in hatching. After emerging from the eggs, the tiny caterpillars exhibit their iconic whip-like appendages. It is recommended to provide individual space for the caterpillars, as they are highly active and spin silk threads during this stage.

Fig. 2: f.l.t.r., eggs, some already with dark discolouration; Hatch; L1;
Larval Stages (L1-L5):
Brahmaea tancrei larvae progress through several instars, each lasting between 5 to 8 days. The duration of each instar increases as the larvae mature. The first instar caterpillars are mainly black, with four whip-like appendages on the thoracic segments, one on the second last segment and two shirt ones on the anal segment. They prefer feeding on the edge of the leaves and can be raised in plastic containers. The container should be ventilated at least twice a day to prevent condensation. Second instar caterpillars are dark purple with longer appendages and can also be raised in plastic tubs. If provided with optimal conditions, the larvae quickly advance to the third instar, characterized by vibrant colours and two bright red colour patterns. Ventilation becomes crucial from the third instar onwards, and the larvae are best kept in netting cages or sleeves to ensure adequate air circulation.

Fig. 3: f.l.t.r, L2; L3 on Ligustrum ovalifolium;
When disturbed, Brahmaea tancrei caterpillars exhibit a defensive behaviour from the third instar on by striking their thorax and using their whip-like appendages to fend off predators like parasitic wasps.

Fig. 4: f.l.t.r., L4 in the group at privet; L4 shortly before moulting to L5; L4 in resting .position
Brahmaea tancrei keeps its long tentacle-like appendages during the fourth instar. At this stage, the caterpillar displays a pale pink colouration with black and yellow markings along its side. However, in the fifth instar, the caterpillar sheds all its appendages and takes on a sand-coloured yellow/brownish appearance adorned with pale white speckles. Especially when getting towards the end of the last instar, the colour pattern is especially beautiful from close.

Fig. 5: f.l.t.r., L4 in molting dormancy vs. L5 shortly after molting; L5 in resting position total + detail;
Pupation:
When the larvae are ready to pupate, they become active, descend from the food plants and start running around in search of a suitable spot to burrow themselves. In nature, they would typically burrow into soil, but in captivity, ripped toilet paper or similar paper material can be provided in a clear plastic box. The larvae burrow almost instantly, and pupation occurs approximately one week later. The use of paper material has proven effective, with almost no losses or deformities observed.

Fig. 6: f.l.t.r.,L5 in migration phase; pupation box with substrate; L5 in pupation dormancy at the bottom of the box;
Pupal Stage:
The pupae of Brahmaea tancrei have first a polished appearance, appearing glossy and shiny and become matt and almost seem to be covered in talcum powder as soon as they have hardened. They are dark grey/blackish in colour and exhibit slight wiggling movements when touched. The pupae generally undergo diapause, lasting 8 to 10 months. Apparently, they can also emerge as a secondary generation about one month later, but to me they never did. Proper overwintering is essential for their development. To facilitate this, the pupae can be stored on kitchen paper placed on moist perlite in the vegetable compartment of a refrigerator. The optimal temperature range for overwintering is between 1 and 9 degrees Celsius. It has been noted that males and females tend to emerge simultaneously. In some cases, certain pupae may experience an extended diapause and emerge after an additional year of storage.

Fig. 7: f.l.t.r, pupae, darker pupa in the middle still with typical gloss when not fully hardened; pupation box with pupation .substrate; pupae in storage box, brown-green pupae pupated just a few hours earlier;
Mating and Imago:
The adult moths of Brahmaea tancrei have a functioning proboscis but are considered to not feed. One says that they suck up moisture such as raindrops. So, I tried to provide water, meaning I sprayed them, but I could never observe them drinking. Mating Brahmaea tancrei can be a challenging task, and determining the key conditions for successful pairings is not yet certain to me. However, providing ample air flow and maintaining cool to cold temperatures have shown to be advantageous factors for achieving acceptable success rates. Netting cages can be used for mating, ensuring a darkened environment. Males and females can be placed together in the cage, and mating usually occurs within the first few nights. Females lay eggs all over the cage.

Fig. 8: Male of Brahmaea tancrei for size comparison on the hand
In conclusion, rearing Brahmaea tancrei is a rewarding experience with the right approach and conditions. Breeding this species is relatively easy, with the larvae progressing quickly and exhibiting straightforward rearing requirements. Maintaining dry conditions in netting cages during the later instars, offering fresh food plants, and providing suitable storage conditions for pupae are key factors for successful breeding. Although challenges may arise during mating, adjusting temperature and air flow can increase the chances of successful pairings. By following these guidelines, enthusiasts can enjoy the enchanting life cycle of Brahmaea tancrei.
Please note that this breeding report is based mainly on personal experiences. If one has any additional details or specific observations you would like to share, please feel free to contact me.
Fig. 9: Male of Brahmaea tancrei