Aspermatophore, fromAncient Greek σπέρμα (spérma), meaning "seed", and -φόρος (-phóros), meaning "bearing", orspermampulla is a capsule or mass containingspermatozoa created by males of various animal species, especiallysalamanders andarthropods, and transferred in entirety to the female'sovipore during reproduction. Spermatophores may additionally contain nourishment for the female, in which case it is called anuptial gift, as in the instance ofbush crickets.[1][2] In the case of the toxic mothUtetheisa ornatrix, the spermatophore includes sperm, nutrients, andpyrrolizidine alkaloids which prevent predation because it is poisonous to most organisms.[3] However, in some species such as theEdith's checkerspot butterfly, the "gift" provides little nutrient value. The weight of the spermatophore transferred at mating has little effect on female reproductive output.[4]
Spermatophores are the norm inarachnids and several soil arthropods. In various insects, such asbush crickets, the spermatophore is often surrounded by a proteinaceousspermatophylax. The function of the spermatophylax is to cause the female to relinquish some of her control over the insemination process allowing full sperm transfer from the spermatophore.[5] Some species of butterflies and moths also deposit a spermatophore into the female during copulation. Examples include thespeckled wood butterfly[6] or theornate moth, where males invest up to 10% of their body mass in creating a single spermatophore.[7]Malaysian stalk-eyed flies also deposit a spermatophore into the female during copulation, but the spermatophore is very small in size and occupies only part of the female's vaginal capacity. This is likely an adaptation to the tendency towards high mating frequency in this species.[8] These butterfly species have been known to usemud-puddling behavior, as demonstrated byDryas iulia, to obtain the minerals needed in spermatophore production.[9]
Most cephalopods use a specialized arm called thehectocotylus to deliver spermatophores to the female. The spermatophores of the giant Pacific octopus are about a meter (or yard) long.[10] A complex hydraulic mechanism releases the sperm from the spermatophore, and it is stored internally by the female.[11]In some cephalopods, like theargonaut octopus, the arm is detachable and capable of autonomous movement and prolonged survival inside the female, to the point that it was mistaken for a parasitic worm byGeorge Cuvier, who gave the hectocotylus (Latin: "hundred" "hollow thing") its name. In some cases, spermatophores from multiple males might be present inside the same female simultaneously.[12]
Males of mostsalamander andnewt species create spermatophores, which the females may choose to take up or not, depending on the success of the male's mating display.[13]
