spermatheka

The spermatheca, also known as a bursa copulatrix or spermathecal sac, is a specialized organ found in many invertebrates, particularly arthropods, that stores sperm following mating. Its primary function is to retain sperm from one or more males until fertilization is required. This allows the female to control when and which sperm fertilizes her eggs, potentially influencing the genetic makeup of her offspring. The morphology and structure of the spermatheca can vary greatly among different species, reflecting diverse mating systems and reproductive strategies. In some cases, it is a simple sac, while in others it can be a complex series of ducts and chambers. The lining of the spermatheca often secretes substances that maintain sperm viability and can even influence sperm competition. The stored sperm can be used for multiple batches of eggs over an extended period, which is particularly advantageous for species with infrequent mating opportunities or long breeding seasons. In some species, the spermatheca may also play a role in sperm selection, where only certain sperm are viable or allowed to fertilize eggs. The presence and characteristics of the spermatheca are often important taxonomic features used in the identification and classification of invertebrate groups.