Aspermia

Definition

The complete absence of sperm or seminal fluid in the ejaculate, resulting in functional infertility despite potentially normal copulatory behavior and genital morphology. In arthropods, aspermia may stem from developmental defects in testes or accessory glands, senescence, nutritional deficiency, parasitic castration, or environmental stressors such as heat or pesticides.

Etymology

Greek a- (without) + sperma (seed, sperm)

Example

Laboratory colonies of Mediterranean fruit flies (Ceratitis capitata) sometimes exhibit aspermia in males reared at suboptimal temperatures, where the testes develop normally but accessory glands fail to produce seminal fluid, rendering males behaviorally active but reproductively sterile.

Related Terms

• azoospermia
• Spermatogenesis
• accessory gland
• reproductive senescence
• Parasitic castration
• mating plug
• sterility

Usage Notes

Distinguish from azoospermia (presence of seminal fluid lacking sperm cells) and from behavioral sterility (failure to mate). Aspermia is an absolute finding—any detectable semen excludes the diagnosis. In insects, the term is sometimes used more broadly to describe males that produce no viable sperm, though strict usage reserves it for the absence of ejaculate entirely. Field diagnosis in small arthropods is difficult without dissection or molecular assay.