Scientists love to group things. We also like to name things. We also like to plot data on bivariate graphs. On really crazy nights, we let our hair down, well not me per se but other scientists with hair, and do all three. 90% of science is grouping, naming, and plotting.
If you don’t know already know, hermaphrodites have lady bits and man bits. Or in dryer language an individual with both male and reproductive organs. Hermaphrodites can be either synchronous or sequential, i.e. both sexes occur at the same time or the individual changes sex during their lifespan. More dude was a lady than dude looks like lady.
Again because we like to name and group, sequential hermaphrodites are further divided into protogynous and protandrous. The former for when the female comes first in the sequence and the later for when the male comes first. This requires a full transformation of the gonads. The sequential hermaphrodite possesses the genetic blueprint to produce both sexual bits. Environment cues trigger which genes express themselves. Express yourself, [you’ve got to make him], Express himself, Hey, hey, hey, hey, So if you want it right now, make him show you how, Express what hes got, oh baby ready or not
Hermaphrodiitism is rare in mammals and birds and probably explains why they are really boring. In fish and invertebrates on the other hand, hermaphroditism ccurs in high frequency. Clown fish, those cute little fish promoted by Disney…protandrous hermaphrodites. Does the conservative right know Disney is promoting hermaphroditism?
A recent study adds another species to the list. Work by Tyler et al. finds that Idas washingtonia, a deep-sea clam, is a protandric hermaphrodite. Idas is a small clam found inhabiting dead whale carcasses on the deep-sea floor. So what triggers the switch from male to female? 6mm.
At ~6mm males, males lose the man bits and gain some lady bits. Then begins formation of unfertilized eggs. Apparently, not many males make 6mm and become female. That’s reserved for a lucky 12%.
Tyler, P., Marsh, L., Baco-Taylor, A., & Smith, C. (2009). Protandric hermaphroditism in the whale-fall bivalve mollusc Idas washingtonia Deep Sea Research Part II: Topical Studies in Oceanography, 56 (19-20), 1689-1699 DOI: 10.1016/j.dsr2.2009.05.014