A mycetome is a specialized organ in a variety of animal species which houses that animal's symbionts, isolating them from the animal's natural cellular defense mechanisms and allowing sustained controlled symbiotic growth. In several species, such as bed bugs and certain families of

leech Leeches are segmented parasitism, parasitic or Predation, predatory worms that comprise the Class (biology), subclass Hirudinea within the phylum Annelida. They are closely related to the Oligochaeta, oligochaetes, which include the earthwor ...

, these symbionts are attached to the gut and aid in the production of

vitamin B B vitamins are a class of water-soluble vitamins that play important roles in cell metabolism and synthesis of red blood cells. They are a chemically diverse class of compounds. Dietary supplements containing all eight are referred to as a vita ...

from ingested meals of blood. In insects, the organisms that inhabit these structures are either bacteria or yeasts. In bed bugs, it has been found that heat stress can cause damage to the mycetome, preventing the symbionts from being successfully passed from the adult female to her eggs at the time of

oogenesis Oogenesis () or ovogenesis is the differentiation of the ovum (egg cell) into a cell competent to further develop when fertilized. It is developed from the primary oocyte by maturation. Oogenesis is initiated before birth during embryonic devel ...

, causing the resulting nymphs to develop abnormally or to die prematurely.

References

{{reflist Insect biology Symbiosis Animal anatomy