Wednesday, July 11, 2012

Tuesday, July 10, 2012

What is a dissertation anyway?!

Now the question is out there - what is a dissertation anyway?!  Perhaps it seems I ought to to have breeched this topic with you earlier dear reader but here we are so let's dive in.


A long essay on a particular subject, esp. one written as a requirement for the Doctor of Philosophy degree
Ok sure- this definition is true but in the sciences a dissertation is based on research you have conducted.  Generally this includes subsets or chapters.  Historically (at least in biology) these may have been on a single topic like 'the ecology of the Naked mole rat' or 'behavior of the wood shrew.'  Nowadays it is more common for each chapter to be on a different topic but with the umbrella of some unifying theme.

My dissertation focuses on how animals might use reproductive delays to allocate limited resources to reproduction (i.e., are delays adaptive?)
The number of chapters of a dissertation seem to vary but are usually around 3-4 in the US (I think 4 like I will have is fairly common).  

Reproductive delays are pauses in reproduction that occur between mating and egg fertilization, between fertilization and implantation of the embryo in the female, or after an embryo has implanted. Stated simply, females with reproductive delays can take a break (energetically speaking) mid-pregnancy while the embryo (at various stages depending on what type of delay) sits in a convenient sort of suspended animation.  The mother can continue her pregnancy at a later date when food or weather is more favorable.  This type of reproduction while understudied is not uncommon.  Over 200 mammals are able to delay some part of a pregnancy. 

My dissertation addresses 4 questions (each a chapter) regarding delays.  I won't go into the details here.  Regardless, all the data are in and while I have a lot written some things more so than others I find that the final push is upon us! 

So now back to work.  Just know this break was good for both of us and in no form nor shape represents any sort of procrastination!  Yes the sock drawer is organized, and I've read numerous posts from my home-girl Orangette's blog but I'll have you know ... the dissertation will be done tomorrow...right?

Ah that reminds me of one of my favorite songs from days gone by 'Come Next Monday' by KT Oslin all about what you are going to do... (tomorrow).

Monday, July 9, 2012

the Mariana fruit bat and Pagan Island need you!

I have been traveling recently and so I am still catching up as one always does for a few days after their return home.  Amid the various e-mails was one from the Society for Integrative and Comparative Biology (SICB) about a conservation issue I thought I should mention here.  To quote the letter directly:  "The government of the Commonwealth of the Northern Mariana Islands is considering a proposal from Japanese investors to lease nearly one-fourth of Pagan Island as a dumping ground for tons of tsunami debris.  Pagan Island hosts much of the endemic flora and fauna of the Mariana Islands, including several threatened and endangered species." 

One of the species on the island is the endangered Mariana fruit bat (Pteropus mariannus) (picture below).  These bats have already been reduced in numbers both due to consumption by humans, introduction of predators to islands and may suffer from bioaccumulation of DDT in their food sources.  In Guam this bat went from 60,000 individuals (historical estimates) to fewer than 200 today (re- Paul Alan Cox and Oliver Sacks). 
***This is by no means the only species that would be impacted by the proposal.

Please see the information at the link below regarding a petition to stop this from happening.  There are already over 3,000 signatures but more are needed.  You can sign the petition by going here: (a banner on the upper right hand of the page will allow you to sign) and read more about the biodiversity of this island.  It only takes a second to sign.  Also if you can pass this along it would be much appreciated!

Thanks for your time and accept my apology for the soapbox moment but I think this was information worth sharing...

Bats in Movies 1_ the Neverending Story bat

This evening as I sat down to watch a movie from my childhood: 'the Neverending Story' and noticed that in addition to a 'Rockbitter' and Troll called 'Nighthob' one of the first characters we meet is a bat.  This seemed like a fun topic to blog about.  I've been intending to start a list of movies with bats in them anyway together with comments on the overall accuracy of the depictions.  So lets start here with this 1984 classic!
Surprisingly, (in my opinion) the bat is depicted rather accurately.  Indeed, if I were pressed to identify it I would suggest a real species namely the Lesser horseshoe bat (Rhinolophus hipposideros) .  This species would be consistent with the filming location (and hence bats the film-makers may have seen) in Germany. (See below to see if you agree with my ID of this bat!) 
In fact, I am inspired to see if I can contact the filmmaker (Wolfgang Peterson) to ask where he got this idea and who he may have consulted to make the mechanical model bat used in the film!  Perhaps the author (Micheal Ende) of the book upon which the movie is based should be credited with the accurate depiction.  I am not sure but in either case it seems the movie does a good job! 

So why is this an accurate depiction? 

The bat's wings are made of it's hands and the thumbs are free.  This is something many makers of movies and toys often mess up.  Thumbs are free of the wing at least in microbats whereas in megabats two digits are not part of the wing (see here for a video).
Also in the movie, the wings appear to function in a manner very similar to how bats actually fly.  When it does fly, the bat is carrying something about 1/3rd it's weight (the troll).  While I can't be sure how much the troll might weigh (a 'not accurate' part of the description) female bats are known to carry their near-adult-sized offspring while flying.  Thus, this seems feasible.  I also like how the troll fastens himself under the bat which would likely help keep the center of mass of the bat in place.

At one juncture the bat is seen to drift off to sleep while flying (i.e. it is narcoleptic).  This obviously would NOT be a good strategy.  Bats instead sleep while roosting in caves, rock crevices, trees or buildings.  Also, the bat seems to not mind the loud sounds around it and keeps sleeping while hanging (in the clip here).  This would not be  the case.  Bats have excellent hearing and would be disrupted by the loud sounds around them.  Of course... keep in mind the loud sounds are coming from the 'rockbitter' and other fanciful characters so we can leave some room for imagination!

Similarly, trolls using bats as modes of locomotion... well if trolls were to exist and a bat was 2 times their size they would surly be able to manage!  Joking aside I found this to be a very cute depiction of a bat that I had not recalled from when I saw the movie over 20 years ago.  If you haven't seen it check it out!