Weird Fishes

Have you ever stopped to consider how awesome parasites are? While it’s not cool to be the host, per se, the absurd creatures that fall into this category are certainly worth our awe. I wanted to share with you not a bizarre mating story, though there are a fair share of parasites yielded from those. No, this is a story about a bond much greater than that formed between mates.

Our subject: the tongue-eating louse, Cymothoa exigua. This is a bit of a misnomer – more like, tongue-eroding-by-cutting-off-the-blood-supply-and-eventually-replacing-its-host’s-tongue-entirely!! But that’s a mouthful.

This terrifying crustacean enters a fish’s gills as a larva and attaches to the base of its tongue, where it starts to leech its host’s blood supply. Over time, it develops into a nasty, overgrown lice, engorging on the fish’s blood at the expense of the tongue. The tongue withers, and who else to take its place but the lice? Not only does it continue to feed off the fish’s blood supply, it also devours anything the fish attempts to eat. Check out this hijacked fish tongue!

Cymothoa exigua (Photo Credit: Dr. Nico Smit)

Cymothoa exigua (Photo Credit: Dr. Nico Smit)

Nom nom nom. How would you like to find that in your sushi?

Oddly enough, the fish survives despite the malnourishment, and they live happily ever after. True story. Why this didn’t make it into The Little Mermaid or Finding Nemo, I’ll never know.

From an evolutionary perspective, it is often a bad thing for a parasite to kill its host. If it is sustaining itself off of the life of another individual, shouldn’t it do everything in its power to make sure that individual remains alive? This isn’t true for all parasites, particularly ones with multiple hosts and complicated life cycles. Seems like this parasite’s a keeper though, so cuddle up!


Like a Virgin? No, Love One!

In a recent post, I mentioned the theory of sexual selection, which involves males competing against one another for females and said females being choosy in deciding who to mate with. But this isn’t the entirety of the story. What if I told you that males can also be choosy?

Indeed, there have been a number of studies that have demonstrated male preference for certain females. In seahorses, for example, the males are the ones who provide all the care for the offspring in their brood pouch.

Pregnant Male Seahorse (Credit: Rudie Kuiter)

Pregnant Male Seahorse (Credit: Rudie Kuiter)

Do you think they take eggs from just any female? Pshaw! Remember, caring for offspring is a HUGE investment of time and energy. In short, the answer is no. Especially when you consider the oh-so-busy lives of the male seahorse (cue David Attenborough voice here).

So what kind of traits does a male seahorse look for in a partner? Experiments have shown that males base their preferences on body size – and they like their ladies large! What can larger ladies provide? It’s often the case that larger females tend to produce more eggs (or sometimes bigger eggs), so he may reap the benefits of having more offspring, bigger offspring, or both!

Another interesting male preference that was recently discovered in black widow spiders is a preference for – you guessed it – virgins!

Black Widow Female   (above) and Male (below) (Credit: Don R. Simons)

Black Widow Female (above) and Male (below) (Credit: Don R. Simons)

Why might this be the case?

Males may be ensuring their paternity by mating only with females who have never mated before (and so avoid any sperm competition whatsoever). Or perhaps females in this species tend to have most of their eggs fertilized by the first male to mate, so you really win the lottery by being that male. Or maybe these males just really took Madonna literally.

If you were a black widow male, how would you tell the mating status of a potential partner? Through pheromones the females emit for advertisement. “Come here you, I’ve never mated.” “No, pick me, I’m a virgin AND I’m well-fed.” “Oh my, a talking spider.”

Charlie Darwin

Happy Charlie Darwin day!

This amazing evolutionary biologist was born on this very date in 1809 (thanks Wikipedia!), and so I share with you some fun facts about Charles Darwin that I’ve learned since coming to graduate school.

Darwin in color

First, let’s talk about some things you should know about C.D.

At  the tender age of 22, he boarded the H.M.S. Beagle as a self-financed naturalist meant to survey the lands reached on the expedition as well as provide company for the captain. Some company he must have been with all of that journal writing he was doing. Good thing he did though, as his notes, observations, and collections over those five years resulted in the beginnings of his theory of natural selection and descent with modification as an agent of evolution. It was not until 1858 that he began writing up this theory, when lo and behold a competitor named Alfred Russell Wallace was also meant to be publishing soon on the same theory. What to do?!

I found this on my computer and have no idea where it came from.

Click on the photo to read the tiny writing

Well, based on the fact that you probably have at least heard of Darwin and not Wallace, you can probably guess that Darwin’s work got more support. As it should have, given the amount of time that he poured into it by comparison. The Origin of Species was published in 1859.

In 1871 he published another fascinating tale called The Descent of Man, and Selection in Relation to Sex. It was here that he outlined the theory of sexual selection. The basic premise of this theory is two-fold: males compete against one another for the chance to reproduce with females; females are choosy in who they mate with. If natural selection can be described by the adage “only the strongest survive,” then with sexual selection, “only the sexiest reproduce.” Since survival and reproduction are the currency of an organism’s life, those that are better at doing either (or better yet both) will pass those traits on to their offspring. This is what natural selection is all about.

Now, on to the fun facts!

Fun fact #1: Darwin married his first cousin. In his notes was discovered a t-chart with “marry” or “not marry” written in the header. When pondering over the advantages of marriage, he wrote “constant companion and a friend in old age … better than a dog anyhow.” His reasons against marriage included “less money for books” and “terrible loss of time!”

Fun fact #2: Darwin was often sick due to a heart illness. He fathered ten children, three of whom died young. In evolutionary terms, his fitness would be a unit of 7.

Fun fact #3: Darwin went to Cambridge University and was meant to go to medical school before he became enraptured by natural history.

Fun fact #4: Darwin was said to have written sparingly on sex given his prudishness and the fact that it was one of his daughters who edited and read his work!

Fun fact #5: He was buried in Westminster Abbey in London.

This was a very sneaky snapshot on my part! (Credit: Kristin Hook)

This was a very sneaky snapshot on my part! (Credit: Kristin Hook)

Eye of the Tiger (Beetle)

Shamelessly plugging some cool research going on in the Gilbert lab here at Cornell in the Department of Entomology and this nice write-up in Nat Geo. Not precisely mating related, although the article does mention that these tiger beetles also use their incredible speed to quickly chase down their mates. Can you imagine how terrifying THAT must be? I mean look at this thing!

Hairy-necked Tiger Beetle Credit: Daniel Zurek

Hairy-necked Tiger Beetle   (Credit: Daniel Zurek)

In many animal species, males and females are different in some way – such as in their size or color – which is called sexual dimorphism. Might speed be a sexually dimorphic trait in this species? Not likely. If natural selection acts on these beetles to be able to catch their prey quickly, having only one sex do so would be quite an evolutionary dead end. Thus, I would predict that both are equally fast. But it’s often the case that males seek females. (Ever find spiders wandering around in your house? Chances are these are males out on the prowl.) This may be a situation where there is strong selection on males to be faster. Think about it. Faster males may be better at getting the girl, and thus spreading their genes (and the beetle love). Those in the slow lane, not so much. Assuming speed is a heritable trait, over time, males will become a tiny bit faster than females, and voila, suddenly you are a female tiger beetle being chased down by a speed demon. Better get away while he stops to unblur his image of you!

Greetings and Salutations

Hello! And welcome to my very first blog! I know this has been done before by many others and that you have a lot of other options of blogs to look through, so thank you for taking the time to check out mine!

Who am I? My name is Kristin, and I’m a graduate student working on my Ph.D. in animal behavior. No, I’m not a veterinarian. No, I can’t tell you what that weird, oozing rash is on your cat Mewbacca’s (insert-kitty-parts-here). What I am is a behavioral ecologist in training.

Behavioral ecology is a sub-field within biology that seeks to understand  the evolutionary basis for animal behavior. We are a curious people that are driven to understand things like how ants or bees make decisions as individuals even though they live in large, complex societies.

Photo By: Kristin Hook

Leaf Cutter Ants in Costa Rica (Photo By: Kristin Hook)

Why some spider species are social and what benefits they might gain from living in a group and being cooperative.

Credit: Dr. Linda Rayor

Social Huntsman Spiders from Australia (Credit: Dr. Linda Rayor)

Why male fiddler crabs have ONE GIANT CLAW!

Credit: Copyright: Tanya Detto

Male Fiddler Crab (Credit: Copyright: Tanya Detto)

I mean, really, that thing is just silly looking. Might they use it to compete for females? Is bigger always better? Are they always honest about what their claw says about them, or can they be deceptive?

What female water bugs really find sexy when looking for a mate to glue their eggs to. Males in this group are the ones who care for offspring, termed paternal care. Is this a common form of care? When is it common and in what animal species? And what, pray tell, are those mischievous females up to?

Giant Water Bug     Photo By: ?

Giant Water Bug Male with Eggs Glued to His Back

Why males of many birds are so colorful and gaudy and what they are saying when they sing, call, or dance!

Photo By: Kristin Hook

Blue-Footed Booby Feet in Ecuador (Photo By: Kristin Hook)

Photo By: ?

Blue Bird of Paradise

These are just a few examples to whet your appetite.

Though behavioral ecology tends to center around animals and their behaviors, the field can be further subdivided into different types of behaviors (e.g. social, parental, sexual).

The burning in my id is mating behavior, or green porno, if you will. One question that still boggles me is why females mate multiply, termed polyandry. We know that there are many costs to mating, so why would females choose to do so many times with different males? There are many hypotheses as to why, but one thing is certain: the female’s choice to mate with different males often puts the sperm of one male in direct competition with the sperm of another male within her reproductive organs, or tract. This is especially true if she is able to store sperm, as is known in many female animals, including insects and birds.

And now we’ve arrived to my favorite party conversation topic – the study of sperm competition! It has quite a heavy hand as a selective force in a) shaping sperm to be fierce, competitive, and numerous and b) making female reproductive tracts as selective as possible so that not just anyone can fertilize her eggs.

Sperm Competition

Well done, ladies.

So this is my start. I intend for this blog to be a source of entertainment and information. My passion for animals and their behavioral oddities will be the focus. I will undoubtedly write about animal stories involving mating, but I also intend to keep an eye out for the latest in research and pass that along to you as well. I would also love to hear from you – what you’d like more of, what you read about that I overlooked and should post, what questions you have, et cetera.

A bigger question that remains is why should we care about animal behavior? I consider myself lucky that I get to spend my day thinking about organisms and their behavioral oddities and working with other people who also think about these interesting questions. Through experimentation, we attempt to answer them. Sometimes that works, and sometimes we have to go back to the drawing board. Finding these answers is exciting, and knowing more than we did before serves the purpose of progressing our science and moving to the next step or question. It also provides us with a deeper appreciation for the natural world. Why would you want to bother saving something if you didn’t know what was contained within it? This is the importance of basic research, or discovery science. It provides us with foundational knowledge that may then lead to practical real-world applications.

Though starting this blog is a partially selfish endeavor (to practice writing on science topics that I hold dear and simultaneously working on my communication skills), it is mostly purposed for sharing research and news of the weird with you, whether you’re a scientist or not. I dislike how divided academia and the research community are from non-scientists, non-researchers, and non-academics. Education is a right, not a privilege. I’ve dedicated the last four years of my life to learning about  the curiosities and oddities of animal behavior – both the theories and the experimentation. It’s about damn time I share those stories.

K Hook