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my research project on sperm competition in bats
Hi folks – long time, no blog!
I have written before about the relationship between testes size and brain size in micro bats (aka echolocating, insect-eating bats as opposed to fruit or nectar eating bats). Many of you have also emailed me information about the scientific study that was published in 2006 by research team Pitnick et al. that first demonstrated this relationship. Thank you very much for that and in exchange I thought I might give you a bit of an update on what I am in the middle of doing to further our understanding of the brain-testes relationship in bats.
For my masters degree I am looking at whether or not there are any differences in the brain volume of male and female micro bats. I have been wondering if there might be ever since reading about Pitnick et al.’s study. My thinking was that if there is, indeed, some sort of inverse relationship in bats between brain size and testes size whereby the two metabolically expensive organs trade off against each other then it stands to reason that perhaps females could have larger brains than males since they don’t have testes competing with their brains for dominance in the body. At least, I thought, this might be the case in species where males have very small brains due to their enormous testes which hog all the body’s resources.
My study is fairly small in scale but I am hoping that it will still prove interesting. I am comparing averages of male and female brain volumes in 9 Australian micro bat species – some that have mating structures where females are promiscuous and some where females are loyal to a single mate (a dominant male harem leader). To do this we are CT scanning a collection of skulls and then using computer technology to create 3D models of the brains as a way to ascertain volume.
Here’s a picture of the first skull we scanned. It makes me laugh every time I look at it – such a big machine to scan such a tiny object (that little spot on the blue towel is the skull):
And here is a model I am putting together of that same skull. It needs work but it’s still pretty cool:
Interestingly, the factor that influences testes size in micro bats in female sexual behaviour. When females are highly promiscuous and take many sexual partners the males tend to have much larger testes than species where females are loyal to a single mate. It is assumed that the large testes trait develops in species where females are promiscuous because there is greater competition among sperm for access to the eggs in these individuals and so those males with more sperm available tend to be selected for over time. It is similar to how if you are really keen to win a meat raffle you will buy more tickets.
The same relationship between female promiscuity and testes size occurs in primates, including humans and for that matter, basically all animals. You can look at most any wild animal and get a good idea of the level of female promiscuity by looking at the testicles of the males. The difference with bats is that because bats weigh very little (as little as 2 grams!!) and have an extremely tight energy budget they cannot afford to have both heavy brains and heavy testes and so they trade one tissue type against the other.
Pitnick and his colleagues in their landmark study originally predicted that the opposite relationship would occur – ie that large brains would equal large testicles. They postulated that species with promiscuous females would have larger brains as a way for the males to avoid being cuckolded. They were surprised when they discovered that the opposite was true and remarked that “perhaps monogamy is more neurologically demanding.” I think many of us would attest to the truth of this statement!
If my study shows that there are any size differences in male and female bat brains as a function of testes size it may potentially mean that female promiscuity is a force strong enough to influence male intelligence in a measurable way. An intriguing notion but at this stage very much a theoretical one.
*Sidenote: the boys on the construction sites where I have been working have heard me talk about animal testicles so much that they have become terrified I’m going to show up at their bedroom door one day with my calipers! Actually that’s not completely true .. some have actually volunteered for the job! .. all in the name of science, right? 😉
** Oh and yes the bat in the picture above is alive! It was just very very cold because I pulled it from a tree which had just been buldozed on a construction site in the very early hours of a winter morning.
Is it possible to be a vegetarian and still eat the occasional cheeseburger?
I love cheeseburgers. Like. I LOVE cheeseburgers. I could easily give up chicken, pork, fish, shellfish, and virtually all other meat forms so long as once a month or so I could burry my face into the delicious, juicy, mouth-waterwatering goddess blessing that is a good cheeseburger.
But I feel guilty.
On and off from the age of 17 I have attempted to kick meat out of my life. I would do really well with it for a while but then have some kind of minor life crisis – a breakup, a job loss, backing into a guard rail, etc. – and then I’d fall off the wagon. In these times of high anxiety nothing could calm me like a Big Mac or a Dicks Double Delux could (those of you who are from Seattle know what I’m talking about).
But I really do want to be a vegetarian. Honestly, I want to be a vegan. I respect the lifestyle choice so much and I am aware that if everyone on Earth was a vegan, we would be able to easily feed all the world’s people. And that’s amazing! I am also aware of the effect of livestock on carbon emissions and of what goes on in factory farms – and of what goes on even to animals lucky enough to live on organic, free range farms when they are trucked to the slaughterhouse.
I feel like the most ginormous hypocrite in the world for the fact that I still occasionally eat meat. It’s no longer a regular thing but it still does happen. The other day, for example, I ate a venison pie. It was on a four-wheel driving course and I was the only woman there. The boys were all eating pies and so I ate a pie .. and it was delicious .. but I hate to think of what was involved in getting it to the table.
Some of my other weaknesses are oysters, sardines, and buffalo (I guess I just love weird stuff).
About two years ago I started to (yet again) begin transitioning meat out of my life. I stopped eating it at home but still allowed myself to eat it, if I wanted it, when I went out. For a long time I was happy with that. I was aware that it wasn’t ideal but at least I had lessened my consumption .. and that was (and continues to be) what I recommend for other people. I don’t tell people that they have to become perfect non-chemical, non-GMO, Vegans – it’s just great to substitute meatless, more humane, and more natural choices whenever possible.
And yet I expect more than that of myself. I don’t know if I just have higher expectations for myself than I do for the rest of the world or what, but I am finding myself with a lot of guilt for ever eating meat at all – and yet I really struggle with giving it up. Gahhh!!
What are everyone’s thoughts??
Photo credit – with thanks.
My month of not buying crap – end of month review
Well I have completed my month without buying crap!! It was mostly successful. I did channel my shopping energy into doing all of my Christmas shopping but that doesn’t count against my challenge because the deal was to not buy anything for myself. The challenge also excluded food, misc. consumables like shampoo and cleaning products, and the purchase of experiences. Confession time, though. The three items I was planning to buy at the end of the challenge I actually bought on the last day of the month (yesterday). Doh!! I threw my back out last week and haven’t been able to drive because of the Codeine pain pills I’m been on. My friend offered to take me out yesterday, though, and we ended up going over to Target. I guess that means I failed but oh well, I’m still really proud of what I achieved. I’m planning to do another month without buying crap in August so I’ll have a chance to redeem myself.
I also saw on the news that there is an official “buy nothing new month” movement happening in Australia where you’re encouraged to buy nothing new for the entire month of October. I’ll most definitely be participating so for 2012 I’ll be doing three buy nothing new challenges. The movement has been getting a lot of slack in the media because of the way it essentially encourages people to boycott retailers for a month. I think this is ridiculous, though, because honestly, most Australians aren’t going to be taking part in the challenge and so the retailers are going to be just fine. It brings up a few important issues, though, that are worth talking about.
1. Everything we buy is made from natural resources and has to be disposed of somewhere
We need to remember that the crap we buy and the packaging all that crap comes in doesn’t just magically manifest in the universe and then magically disappear after we’re finished with it. It all comes from natural resources in one way or another. And it all has to go somewhere in the end. It’s worth reminding ourselves that when we put something in the trash can, it doesn’t just disappear into the ether. Scientists estimate that plastic takes between 500 and 1000 years to break down. Plastic has only been around for about 50 years which means that every piece of plastic that has ever been thrown away is still just sitting there, in the land fill or the ocean or wherever the hell it landed. Every diaper, every plastic McDonalds straw, every piece of plastic packaging that ever came into your life or your parents life is still around. It’s pretty disgusting when you actually sit back and think about it.
2. We need to learn that we can’t spend our way out of our problems
How much debt is the United States in? Well, as of 5AM PST on the July 1, 2012, it’s $56,925,015,397,300. We’re broke. In fact we’re so far beyond broke that if we were just broke we’d be really freaking excited. And yet the government still has the nerve to try to tell us what we should be doing with our money?! Like they know what they’re talking about or something?! It’s just stupid. And a lot of us have bought into the bullshit idea that spending your way into debt is a matter of patriotism. DUMB! In life if you want to experience financial peace, you have to stop buying stupid crap you don’t need. Congress would do well to work this out and put an end to their debt crisis. Honestly people, debt never helps anything.
In terms of my challenge, though, and everyone else involved the bigger campaign, we’re just trying to do our part to help the planet a little. I don’t beleive that by setting out on a challenge like this that we’re harming the economy because nothing about this challenge says you can’t spend money on going out to eat, going to movies, or doing other things that cost money but that don’t encourage excessive consumerism. And even if this challenge was taken on by so many people that the retailers did feel it, the future of our forests and oceans is always going to be more important to me than they are. I’m sorry but I just can’t apologise for that.
Want to help the environment? Be a little cheap!
To decrease my spending and wasteful ways I have come to appreciate SO MUCH all the free things in life like the radio, the library, free podcasts, and hand holding (aww).
Another thing that I’m learning to love is thrift stores! I still have a slight aversion to buying clothes at thrift stores although I’m starting to get over that. I’ve always, though, been really into them when it comes to furniture (not couches – yuck – but old wooden hutches, book cases, etc). Every single piece of hard furniture that I own was either given to me or purchased at a thrift store – and I have some killer pieces! I’m also really into buying old kitchen stuff from thrift stores – casserole dishes, teapots, china, wine glasses, etc.
I really like the look of sexy, modern pieces mixed with really old, interesting pieces. There is something sort of sterile about a house (or wardrobe) made up completely of brand new stuff. And similarly, someone who hasn’t bought a new item since 1974 is just weird. I think you need a mix.
Also, I have been gifted some unwanted cosmetics/bath goods and clothes, lately (thanks Shaz and Lesh!) and that has been just awesome. If I didn’t constantly throw stuff out (and therefore had stuff I didn’t want) I would throw a clothes swap with my friends. It’d be fun to put on a chick flick, order a pizza, and have everyone throw their old frocks and purses and things in a pile for people to try on.
It all got me thinking – the environmental impact of keeping up with the Jonses’ .. or Kardashians, for that matter – is just huge!
All the new stuff we buy costs energy and resources to make and then has to be packaged in disposable plastic crap, and shipped in big, dirty trucks around the country or world to get to us. Actually, there are so many more costly, energy-zapping, resource-squelching steps than just that. Most things are manufactured in one area (with all the supplies similarly manufactured and trucked into that area) and then shipped somewhere else for labeling, then shipped somewhere else for packaging, then shipped to a storage warehouse, then eventually shipped to a store where you will buy it and then throw it away five minutes later.
OMG we are wasteful!
Imagine what the environmental impact would be if we all acquired 20% of our possessions from “second hand” sources. It’d be massive! I know, I know .. the word “second hand” sucks! I cringe at it myself at but hey, “vintage” is second hand, right! “Antique” is second hand! It can be cool.
So .. my point, what is my point? Ah yes. Free community resources and cheap, used stuff is awesome! It not only helps you get your finances under control but it makes a huge positive environmental impact, too. This probably seems obvious to most of you but I think we could all do with bringing less new crap into our homes.