The Relationship Between Beetles/Stag Beetles and Mites
When raising beetles or stag beetles, you may discover small white or reddish-brown particles moving around in large numbers inside the case. These are "mites." In insect breeding using feeding mats or leaf mold, mite infestation is one of the common problems, but depending on the species, it can have serious effects on the health of both adults and larvae, so proper knowledge and countermeasures are necessary.
Types of Mites in Insect Breeding
False Semar Hyoudan Mites (White Mites)
This is a small, whitish mite most commonly seen in breeding cases. It can attach to adult beetles and stag beetles in large numbers. While normally a "saprophagous mite" that feeds on humus and decomposing organic matter, when it multiplies in large numbers, it accumulates around the mouth and spiracles of adults, negatively affecting feeding and respiration.
Flour Mites and Hairy Flour Mites
These are extremely small mites that appear like white powder. They tend to proliferate in large numbers in dried mats, grains, and fungal substrate bottles, sometimes causing damage to the fungal bed. Since they can become allergens, attention must also be paid to potential health effects on humans.
Beetle Mites and Tick Species
These are relatively large mites ranging from reddish-brown to brown (approximately 1-3mm). They may be attached to beetles and stag beetles collected in the wild. They are "predatory mites" that feed on the body fluids of larvae and adults, and when heavily parasitized, they can cause exhaustion and death.
Smooth Mites (a type of detritivore mite)
These are detritivore mites commonly found in the intestines and around the feces of larvae. In small numbers they cause no particular harm, but a large outbreak is a sign of deteriorating mat conditions.
Causes of Large-Scale Mite Outbreaks
Excessively Moist Mat
Proper humidity is necessary for breeding beetles and stag beetles, but if the mat becomes too wet, it creates an ideal environment for mite reproduction. Special care must be taken during the hot, humid summer to fall period.
The proper moisture level is when you squeeze the mat and it holds its shape but does not drip water (45-55% moisture content). A mat so wet that water drips out becomes a breeding ground for mites and fungi.
Mat Degradation and Feces Accumulation
In larval cases, as larvae feces accumulate, ammonia concentration in the mat increases, making certain mites more likely to multiply. In fungal substrate bottles, as they age, the fungal threads degrade and attract flour mites.
Unsterilized or Low-Quality Mat
Inexpensive leaf mold or unheated mats may contain mite eggs and larvae. The basic rule is to use heat-treated feeding mats.
Introduction of Wild-Collected Specimens
Beetles and stag beetles collected in the wild often carry various mites. Placing collected specimens directly into existing breeding cases will spread mites throughout.
Practical Mite Control: 5 Approaches
Measure 1: Removing Mites from Adults
Water Washing (Most Effective):
Gently wash beetles and stag beetles under running water using a soft toothbrush or cotton swabs to remove mites. Carefully remove mites hiding in the joints, between the legs, and around the mouth. After this, replace all the feeding mat with fresh new material.
Method of Moving on Newspaper:
Place the adult on newspaper, and mites will fall onto the paper over time. Repeat this process several times to remove a significant number of mites.
Measure 2: Heat Treatment of Mat
Even new feeding mats can be heat-treated as a precaution (heat in a microwave for 2-3 minutes or in a heat-resistant bag at 70°C or higher for 1 hour) to kill mite eggs and larvae. However, after heating, allow the mat to cool thoroughly and release gases before use.
Commercially available "mite removal mats" and "hinoki chip mats" also have mite-repelling effects.
Measure 3: Review of Breeding Environment
- Improved Ventilation: Use cases with multiple ventilation holes in the lid. Since fruit fly sheets may impede airflow, temporarily prioritize ventilation during periods of high mite activity.
- Proper Humidity Management: Maintain mat moisture so it holds shape when squeezed. Check approximately twice per month.
- Case Cleaning: Cases with large mite infestations should be disinfected with hot water or cleaned with bleach before reuse.
Measure 4: Use of Mite Removal Sheets
Apply commercially available "mite removal sheets (such as Danitori Robot)" to the outer wall of the case. While it does not provide complete eradication, it is effective in preventing mite spread outside the case.
Measure 5: Regular Mat Replacement
Larval case: Replace mat when feces accumulate to one-third or more.
Adult case: Replace all mat once every 1-2 months.
When replacing, do not add fresh mat directly; confirm moisture content before use.
Effects of Mites on Larvae and Response
This is how to handle cases where mites have proliferated in larval breeding containers.
- Remove larvae: Dig larvae out of the mat and gently wipe off mites attached to their bodies with a damp tissue.
- Discard all mat: Dispose of all mat where mites have proliferated heavily, then wash and dry the container.
- Transfer to fresh mat: Move larvae back to heat-treated fresh mat.
- Improve environment: Review ventilation and humidity.
Note: Health Effects on Humans
Flour mites can become allergens causing human allergies (dust mite allergies and asthma). Wearing a mask is recommended when replacing mats with large mite infestations. Consider also keeping the breeding area separate from living spaces.
To Maintain a Healthy Breeding Environment Free of Mites
Regular observation is key to early detection and management of mites. Make it a habit to inspect the case monthly by removing the lid to check the mat condition, adult surface appearance, and larval status.
| Check Frequency | Items to Confirm |
|---|
| Daily (during feeding) | Are mites not heavily attached to adult bodies? |
| 1-2 times per month | Mat moisture, color, odor, and mite outbreak status |
| During mat replacement | Larval condition and mite confirmation in mat |
Summary
Mite problems in beetle and stag beetle breeding can be greatly reduced through proper maintenance of the breeding environment and regular care. Following just three points—"mat moisture management," "regular replacement," and "isolation of wild-collected specimens"—can prevent most large-scale mite outbreaks. Even if a large outbreak occurs, it can be managed with water washing and complete mat replacement. Understand mites correctly and create an environment for beetles and stag beetles to grow healthily.
