Fish Queue Here

One of my favourite science lobbying stories is about how a team of conservation biologists managed to extract support for funding to save a rare bird from a usually anti-environmental US Senator. Realizing that his conservative sexual politics trumped his hostility to the environment they explained that the species in question was unusually monogamous. They explained to him it’s exemplary family values and argued “We cannot afford to lose this moral archetype.” They got the money. Unfortunately for the senator, later research showed the birds are not as faithful as previously thought.[1]

I was reminded of this on reading this account of dissension resulting from a video using sexual diversity in animals to teach acceptance amongst school children. (Hat tip the marvelous Scarleteen.) In this case the program was directed towards gender identity, rather than sexuality, but the two issues are intimately linked.

The ultimate text on animal sexual diversity is Bruce Bageihl’s Nature’s Exuberance, 700 plus pages of detailed accounts of homosexuality in animals, discrediting forever the old cry of “it’s not natural”. But there’s much more to animal sexual diversity than same-sex coupling.

One of the few times I got to publish a story that years later became big news was on the discovery of transvestite cuttlefish in Spencer Gulf. The larger males aggressively scare others away from “their” mates. Smaller males however, have learned to change their colouring and hide two of their legs (the females have fewer) so that the larger male thinks the female has a girlfriend over, while he is in fact being cuckolded. Perhaps the strangest part of this is that the smaller males who do this are often young, and grow up to be larger males. Yet they seem to forget their own behaviour and let some young whipper snapper do the same thing to them.

Just in my time at Australasian Science I’ve written more than a dozen articles on animals from dung beetles to monkeys behaving in ways that would appall social conservatives, and not just through promiscuity. If I ever get post anything about the antechinus I’ll probably have to declare the blog X-rated. However, I think the most relevant piece of Australian research I’ve encountered as far as the Oakland project goes is the case of a particular species of coral reef fish.

Sex changes are common on the reefs, a point alluded to with the reference to transgender clownfish (and of course studiously ignored in Finding Nemo). However, the way the fish do it varies. Some change from male to female, others the other way. Some change only once in their lives, others can shift in each direction. In the species I am thinking of[2] the males have a harem of females. From an evolutionary point of view being male is better – males in this scenario get to mate with many females, while females mate with only one male. In some animals such a system leads to multiple left out males, but the fish deal with this by all being born female.

When a male dies, the largest female in his harem will fairly quickly turn male and take over his mates. The system is quite rigid. It’s always the largest female who gets the gig. Consequently, it’s not desirable for a female to be too far back in the queue. Young small females know they have to wait their turn, but sometimes those of greater size get sick of being stuck too far back. They’ll impatiently defect to a different harem where they may be the largest female, or at least closer to the front. If you think about this it takes quite sophisticated numerical skills. “Hmm, I’m fourth in line here, but if I jump I’ll be in second spot”. Perhaps the Redwood Heights Elementary School could re-enforce their message while also teaching maths by having the children play games where they pretend to be reef fish working out the best strategy to get them to an elusive sex-change. Now that would really drive Fox News crazy.

[1] I forgot to note the species of bird involved when I read this tale. If anyone knows I’d be grateful.

[2] I have the species’ name in my files at work, but can’t check from home. Will update.

Update: The species the study I wrote about was on the crimson-banded wrasse. However, many related and unrelated species do something similar. The sand perch is another species that changes from female to male. A seperate study on sand perches found that once they have transitioned they start looking for females to form a harem. In this process their otoliths (bones in their ears) start to grow. The more females a male acquires for his harem the more his otoliths grow. The researchers theorised that since otoliths are crucial for balance and direction finding the male, who often leads a literal queue of females needs better ones to be able to work out tricky paths through complex reef mazes.


About Stephen Luntz

I am a science journalist, specialising in Australian and New Zealand research across all fields of science. My book, Forensics, Fossils and Fruitbats: A Field Guide to Australian Scientists is out now through CSIRO Publishing. I am also a professional returning officer for non-government organisations. I'm very politically active, but generally try to restrict this blog to scientific matters.
This entry was posted in Australasian Science, Behavioural Zoology, Research funding, Self Promotion. Bookmark the permalink.

4 Responses to Fish Queue Here

  1. Charlie Goodman says:

    I think the fish you have in mind would be the various Anthias species Stephen?

  2. Carina says:

    Thanks for sharing this! I’d love to blog about it after you’ve been able to confirm the species name.

  3. Somebody needs to figure out if these fish could successfully manage picking the right supermarket checkout, it seems to be the same problem! If they’ve got it licked, I have a job for them 😉

    (I know it’s not actually solvable because you’d need the “how long will this person take?” information and you don’t know whose trolley has unlabelled items and their cheque book hidden under the 4 visible bits… but it sounds good :)).

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