Spermatophore

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Mating of the leaf insect Phyllium siccifolium; the white ball near the bottom of the picture is a spermatophore.

A spermatophore or sperm ampulla is a capsule or mass created by males of various animal species, containing spermatozoa and transferred in entirety to the female's ovipore during copulation. It may contain nourishment for the female, in which case it is called a nuptial gift, as in the instance of bush crickets. [1][2] In the case of the toxic moth Utetheisa ornatrix, the spermatophore includes sperm, nutrients, and pyrrolizidine alkaloids (PA). PA plays an important role in preventing predation in Utetheisa ornatrix because it is poisonous to most organisms.[3] However, in some species such as the Edith's Checkerspot butterfly, the "gift" provides little nutrient value. The spermatophore transferred at mating has little effect on female reproductive output.[4] The alternative hypothesis of its usefulness is that the process of eating the spermatophore prevents the female from subsequent copulation, thereby giving the male's sperm more time to fertilize.

Giant squid spermatophores

Invertebrates[edit]

Spermatophores are the norm in arachnids. In various insects, such as bush crickets, the spermatophore is often surrounded by a proteinaceous spermatophylax. 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 the Speckled Wood butterfly [6]or the Ornate Moth, where males invest up to 10% of their body mass in creating a single spermatophore. [7]

Vertebrates[edit]

Some vertebrates also reproduce via spermatophores. Males of many salamander and newt species create spermatophores, which the females may choose to take up or not, depending on the success of the male's mating display.

References[edit]

  1. ^ Nina Wedell, Tom Tregenza & Leigh W. Simmons (2008), Nuptial gifts fail to resolve a sexual conflict in an insect, BMC Evolutionary Biology 8: 204, doi:10.1186/1471-2148-8-204, PMC 2491630, PMID 18627603 
  2. ^ Peter D. Sozou & Robert M. Seymour (2005), Costly but worthless gifts facilitate courtship, Proceedings of the Royal Society B 272 (1575): 1877–1884, doi:10.1098/rspb.2005.3152, PMC 1559891, PMID 16191592 
  3. ^ Gonzalez, Andres, Carmen Rossini, and Thomas Eisner. "Sexually Transmitted Chemical Defense in a Moth (Utetheisa Ornatrix)." PNAS 96.10 (1999): n. pag. Print.
  4. ^ Jones; Odendaal, Ehrlich (1 1986). "Evidence Against the Spermatophore as Paternal Investment in Checkerspot Butterflies (Euphydras: Nymphalidae)". Midland Naturalist 116 (1): 1–6. doi:10.2307/2425932.  Check date values in: |date= (help)
  5. ^ K. Vahed (1998), The function of nuptial feeding in insects: review of empirical studies (PDF), Biological Reviews 73: 43–78, doi:10.1017/S0006323197005112 
  6. ^ Svard, L. (1985). "Paternal Investment in a Monandrous Butterfly, Pararge Aegeria". Nordic Society Oikos 45 (1): 66–70. doi:10.2307/3565223. 
  7. ^ Iyengar, Vikram K.; Thomas Eisner (1999). "Female Choice Increases Offspring Fitness in an Arctiid Moth (Utetheisa Ornatrix)". Proceedings of the National Academy of Sciences 96 (26): 15013–15016. doi:10.1073/pnas.96.26.15013.