gemmule

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June 29, 2026

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A gemmule is a reproductive bud produced by some freshwater and marine sponges. It is a form of asexual reproduction, serving as a survival mechanism during unfavorable environmental conditions such as drought or extreme temperatures.12

Gemmules begin as aggregates of cells, primarily archaeocytes, that become laden with food reserves. These aggregates are then surrounded by a protective outer covering. In freshwater sponges, this covering is reinforced by spicules, which vary in shape and aid in classification.2

When conditions become favorable again, the gemmule germinates. The cells emerge through an opening called a micropyle, differentiate into various cell types, and develop into a new sponge. This process allows the species to persist through harsh periods, with gemmules sometimes described as hibernating in cold regions or estivating in warm regions.2

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sponge
Asexual reproduction
These so-called “gemmules” are expelled from the adult sponge and, in some marine species, serve as a normal reproductive process or, sometimes, as a means to carry the sponges over periods of unfavourable conditions when the adults degenerate; e.g., drought, temperature extremes.
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These so-called “gemmules” are expelled from the adult sponge and, in some marine species, serve as a normal reproductive process or, sometimes, as a means to carry the sponges over periods of unfavourable conditions when the adults degenerate; e.g., drought, temperature extremes.
Read More

dormancy
Invertebrates
…cold or drought by forming gemmules within the body of the adult sponge. These structures, which are surrounded by a resistant covering, are released when the sponge dies and disintegrates. When conditions are appropriate, the cell mass escapes from the covering and forms a new sponge.
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…cold or drought by forming gemmules within the body of the adult sponge. These structures, which are surrounded by a resistant covering, are released when the sponge dies and disintegrates. When conditions are appropriate, the cell mass escapes from the covering and forms a new sponge.
Read More