Black Spot Disease
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About this condition
Black spots or patches appearing on the surface of adult beetles or pupae, potentially caused by bacterial or fungal infection following physical injury to the exoskeleton. When observed during the pupal stage, there is a risk of associated eclosion failure.
Common symptoms
- Black spots or patches appear on the elytra, pronotum, or head
- Part of the pupa turns black with suspected tissue necrosis
- The affected area appears sunken or is clearly different in color from surrounding cuticle
- In adults, a lymph-like secretion may be observed near the affected area
Common causes
- Damage to the exoskeleton from fighting, falls, or abrasion inside the enclosure
- Bacterial or fungal infection entering through wounds
- Physical damage sustained before the exoskeleton hardened immediately after eclosion
- Unsanitary enclosure conditions due to old substrate or accumulation of waste
Prevention (husbandry & daily care)
House beetles individually rather than together to prevent fighting. Provide climbing aids such as bark and branches to minimize falls and damage to the exoskeleton. Regularly clean the enclosure and promptly remove decayed substrate and waste.
Related species guide
→ Browse the species guide for this animalWhen to see a vet
Consider consulting a specialist store within a few daysWhat can a specialist store do?
Consulting an insect specialty shop or breeder provides guidance on assessing the progression of black spots and improving husbandry. For affected pupae, specialist knowledge regarding the need to transfer to an artificial pupal chamber is particularly valuable.
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