Has homosexual behavior ever been observed in invertebrates?

I know there are gay penguins, and that homosexual behavior has been observed in many other species, but always vertebrate AFAIK. Are there such things as gay insects, arachnids, mollusks, etc.?

A lot of invertebrates are simultaneous hermaphrodites, like the banana slug, and thus I suppose could be considered bisexual.

Some male insects and spiders will attempt to mate with other males, but this is almost certainly due to lack of discrimination rather than same-sex attraction.

Bugs not gay, just confused.

1964 article Studies on the mating behavior of the house fly, Musca domestica L." bears this out:

Of all the papers I read last year, my favorite was the one that showed that if you pull the front legs off of male fruit flies, they can no longer tell the difference between males and females, and so begin attempting to hump every fly they come across. They also lose some ability to distinguish between closely-related fly species, so they will attempt to mate with other species as well. Amputee bisexual flies into bestiality -> best band name ever.

(It goes on to show that there’s a specific neuron in the legs that expresses a specific receptor protein that allows the fly to detect specific pheromones that it uses to make these determinations)

I can’t find the video now (but boy, googling “octopi mating” gets some interesting results) but there is footage of two male ocotupuses attempting to mate. Even better, they were of different species. It was interspecies gay octopus humping.

One of my exes was rather spineless . . . . . . . . .

Amputee Bisexual Flies = Band Name
Into Bestiality = Their first album

Oh, and many invertebrates, such as a lot of the gastropods, are hermaphroditic. So they either change sex roles from one mating event to another or mate in both sex roles simultaneously. :eek: :cool:

I’m not sure the concept of a sexual “orientation” is meaningful for invertebrate brains.

During the cuttlefish mating season, some smaller males will use their camoflage ability to impersonate females so they can sneak past the large and dominant males that have the real females cornered. I don’t recall hearing of any instances of the larger males trying to mate with the impersonators, so this is just crossdressing, not homosexuality.

Did anyone else hear that in the voice of Mongo?

And then there’s penis fencing, practiced by some flatworms. The worms are hermaphroditic, but in any given mating, one will take on the female role, while the other takes on the male role. Both get the same benefit from this, offspring, but it costs the mother a lot more than it does the father. So how do they decide who gets to be the dad? By penis fencing. The flatworm penis has a sharp point, and they jab at each other until one penetrates the other’s skin and inseminates it.

Different species of nematode are various combinations of hermaphrodite, male, or female. C. elegans are primarily hermaphrodites but there are some males. Their mating behavior is basically to rub their tail on absolutely everything until they find a vulva. Large groups of males will form writhing clusters. If you can excuse the anthropomorphism, they’re probably all thinking “there must be a vulva in here somewhere!”

Better than a band name, this needs to be a new Olympic sport.:stuck_out_tongue:

Or a cartoon. Now on sale at Home Depot!

Only bugs??? My dog will try and hump my leg when he gets randy.

Except that cock fights are banned in some countries.

You mean Mango?

I think he meant Mongo rather than Mango.

Mongo like candy.

Since at least the mid-1980s male fruit flies have been shown to court other male fruit flies when carrying certain mutations. Genes that lead to some form of sterility in fruit flies are often given some version of the name “Fruitless”, since they can not bear any offspring.

The researcher wanted to name this gene “Fruity”, since males courting males lead to no offspring. :rolleyes: (this rollyeyes does NOT convey how I feel about that name)

Not surprisingly, the name was rejected by the drosophila community. Yes, this man was my genetics professor and had the lab next door to the lab I was in as an undergrad.