There are many factors to why a pet beetle may die suddenly. The following possibilities are listed below
1.Temperature control
2.Infrequent changing of their food source
3. Environment is too dry(mainly for stags)
4. Environment is too wet(mainly for rhinos)
5. Insufficient sticks/bark to flip back to upright position.
6. Flake soil fermentation
7. Underdeveloped internal organs
8. Inbreeding
1.Temperature control
・ A great portion of beetles tend to prefer lower temperatures ranging from 20-25c
- A good amount of species can live outside their optimal temperature range, however life expectancy would drastically decrease. (EXAMPLE: Dorcus antaeus antaeus can live up to 3 years in captivity. if kept in 27-30 c temperature, it is expected to live only about half a year.)
- Even amongst beetles of the same species there are individual characteristics, some may live past their optimal temperature, some may instantly pass away.
・ Some species such as Rhaetus westwoodi may be extremely sensitive to temperature change. In order to successfully raise this species, you must replicate the four seasons. Even after successfully enclosing, if there is a sudden rise in temperature it can end up becoming infertile, die in dormancy, or it can become active but never ends up eating (suddenly dies).
2.Infrequent changing of their food source
・Not frequently changing their food source(jelly/banana) can lead to it fermenting.
-Jellies undergoing fermentation can release toxic gases that can ultimately lead to the suffocation of your beetles.
3.Too dry environment(mainly stags)
・Too dry environments can lead to the death of beetles(mainly stag)
-It is recommended to add substrate that holds enough moisture.
-Make sure the enclosure air hole is not too big in order to trap the moisture in, but big enough to allow necessary airflow.
-If it is too humid, it can lead to the growth of fungi and mold that can cause the death of your beetles
4.Environment is too wet(mainly rhinos)
・When the environment is too wet, molds and other bacteria can grow leading to the death of rhino beetles, it is preferred to keep rhino beetles in a somewhat dry enclosure. When it is too dry, the evaporated water can also end up clogging the air holes suffocating the beetles.
5.Insufficient sticks/bark to flip back to upright position.
・When the beetle unintentionally ends up on their backs, it is extremely hard for them to flip themselves back to an upright position without the use of a stick or bark. If it stays on their back for too long, they would end up using all their energy(dies) in attempt to getting back to an upright position.
6.Flake soil fermentation
・Flake soil fermentation can happen especially when the temperature is high. During fermentation the temperature of the flake soil would be high and smell stagnant due to the gas it releases.
・Similar to the jelly fermenting, the excess gas can suffocate the beetle or larvae. If you notice flake soil going through another fermentation process, it is recommended to finish the fermentation process before using, freeze it, or dry it up completely.
7.Underdeveloped internal organs
・Even when a beetle looks perfectly fine from the out, is is possible the internal organs didn’t harden properly, or it didn’t come with a full set of organs.
-It can be caused by inbreeding
-Just unlucky
-Handling a dormant beetle may cause this issue as their internal organs are still hardening, handling them too much may damage their insides.
8.Inbreeding
・Inbreeding can be an issue as when you selectively breed insects for a specific trait, the specific trait that you are breeding for will get enforced. However, if the beetle has some sort of health issue, this trait would also get passed down and strengthened.
Sources:
https://beetle-shiga.com/blog/%E3%82%AB%E3%83%96%E3%83%88%E3%83%A0%E3%82%B7%E3%80%81%E3%82%AF%E3%83%AF%E3%82%AC%E3%82%BF%E3%83%A0%E3%82%B7%E3%81%8C%E6%AD%BB%E3%81%AC%EF%BC%91%EF%BC%92%E3%81%AE%E5%8E%9F%E5%9B%A0/
https://haru99530.com/kuwagata/sudden-death-causes-and-remedies/#index_id4
BEKUWA 91