Tim writes:

I listened to the latest TWIP this morning. Dickson mentioned the herbicide atrazine but thought it was a fungicide. It is actually a herbicide in the photosynthesis inhibitor class. Another bit of trivia about ag chemicals is that old chemicals like atrazine are making a big comeback in usage due to resistance problems emerging in fields. Too many farmers were spraying nothing but glyphosate on fields due to that being the first GM herbicide resistance trait and now weeds have caught up.

On the subject of monarchs having a bad taste so birds leave them alone you seemed dubious of bird memory and the difference one birds experience meant for monarchs on the whole. I think the reason it works out well as defense for monarchs is that the generation interval for insects is much quicker than birds and some birds live quite long lives and would most likely experience the taste of monarch early in life and not forget because they are not only bad tasting but I believe poisonous due to milkweed that they feed on as larvae. I’ve tasted milkweed and if monarchs taste like that I can see why birds would avoid them.

I found it interesting you have the view of humans as separate from the general ecology of the earth. Full disclosure: I wrote a paper comparing humans to weeds and pathogenic bacteria in college but have since changed my mind on that subject. I’ve been working on changing people’s minds about that on social media because it seems once we view ourselves as separate from the rest of the world we live in it seems to give people license to do things that make no sense from an ecological sustainability standpoint. To put another way stealing a term from economics, theres a risk of moral hazard when one divorces themselves from their surroundings. I’m not saying this to criticize your thoughts on it and I’m sure you have a much more nuanced full view of the subject. Just some thoughts of mine on that topic.

Scott writes:

Hi Vincent and Dickson!

I just finished with ep64 and wanted to drop you guys a note to hopefully fill up your inbox since you only had 4 emails.  I am a Hydrogeologist working for an environmental consulting company in Cincinnati OH, which is currently overcast 24F, 79% humidity, winds at 8 mph out of the S/SE.  Though hydrogeology has almost nothing to do with biology i love listening to TWIP, TWIV and TWIM while doing my mundane data manipulation and am a lover of anything science.  The furthest we tend to dive into biology would be the injection into groundwater of Dehalococcoides for the sequential reductive dechlorination through the daughter products cis-dichloroethene and vinyl chloride to ethene (guess its a little more relevant to TWiM than TWiP).  Please keep going off topic! I love hearing the banter back and forth between you guys! Anyway i love the podcast and look forward to every episode.  Hopefully, there are many more to come!

John writes:

Hello TWIP!

I just finished listening to episode #67 in which Vincent asks, “Why was a priest doing experiments?”

I’m parasitologist who will be ordained a priest this June and will teach biology at Creighton University. I earned my PhD in evolutionary biology from OSU before entering the Society of Jesus (AKA Jesuits) in 2003. After ten years of studying philosophy and theology, teaching biology and doing research, I could probably devote an entire TWIP podcast to the topics of priests “doing experiments” as well as parasitology and religion, but let me briefly state the following:

Christianity helped develop science because it assumes (unlike some Eastern philosophies) that the world is real and not an illusion.

Christianity also assumes that the world of creation remains distinct from the world of the supernatural Divine. So unlike many pagan religions that believe in nature gods, Christians assume that Nature follows laws that can be studied.

Finally, Christians believe that God created the world good. Thus, Creation reflects the Creator and so learning about Nature teaches us something about God. In other words, investigating the world of nature and is worth doing.

You (and your listeners) can check out some of my on-line articles on this and related topics at The Jesuit Post, https://thejesuitpost.org/author/jsheasj/

Thanks for the great podcasts and keep up the good work. I plan to use some of these podcasts when teaching parasitology.


Alex writes:

Hi Both Vincent and Dick,

Love the podcasts, in every way but for one thing.  Vincent is very clear to hear, Dick fades in an out  – meaning a volume can never be perfectly set.  I thought I’d illustrate as below 😉

Please fix this so I can continue to enjoy stories from the world of Parasitism….



Christophe writes:

Hi Vincent,

Just thought i would pass on this link incase you had not heard about it already.

I have not watched this documentary series yet but i think i will try and track it down. I heard about it on the BBC Science hour podcast today and woul d like to hear Dickson and your thoughts on it.

I love the TWip/TwiV/TWiM podcasts  – i am only a high school graduate and self taught web designer but find all the TWiP/V/M fascinating – keep up the great work.

“Swallowing three cysts which are twitching with tapeworm larvae sounds like the stuff of nightmares.

But for the past two months, BBC presenter Michael Mosley has been taking part in a toe-curling experiment, allowing three worms to live and grow in his gut.

As part of BBC Four’s natural world season Dr Mosley infested himself with some of the world’s most prevalent parasites including leeches, lice and mosquitoes.”




Robin writes:


Marianne writes:

Dear Drs. Racaniello and Despommier;

I do enjoy your podcast, as I do all the TWiX. I’ve written to TWiV previously, but this is my first opportunity to email TWiP. Your request for emails in the last episode sealed the deal.

I couple of episodes ago you bemoaned the lack of ecological based parasitism research. I smiled to myself because my first undergraduate research experience was in this field. I was a summer student on a field project trapping the prey species of the pine marten of Newfoundland (http://en.wikipedia.org/wiki/Newfoundland_pine_marten) and studying their parasites. I learned a lot that summer, including that I was not cut out for field work. Two months in a cabin on the east coast of Newfoundland was enough for me. I happily started my career in the lab studying immunology, virology, cancer and now vaccines.

More recently, I’ve been thinking more about parasites, due to my increased interaction with rescued cats. After losing two older cats, we decided to adopt a kitten from a local rescue that helps trap, spay/neuter and then adopt or release feral cats. Before we could adopt our chosen kitty, he had to clear a pretty significant coccidia infection. Of course, through my renewed interest in the subject through listening to TWiP, I was interested in what type of infection our little Felix had, but learned that most vets only look for the presences of oocytes in the stool and since the treatment is basically the same for all coccidia, they don’t differentiate. We then fostered a stray mother cat who gave birth to 5 kittens about 12 hours after we brought her inside. Those kitties were happy and healthy until 2 of them went to a local pet store who helped out with adoptions. They both became quite ill with coccidia, while the two we kept in our house remained healthy. I suspect that the well meaning pet store was unwittingly spreading some of these pesky parasites to young kittens through previous inhabitants. Luckily, after several antibiotic courses, all are happy and healthy in their adoptive homes.

On a related note, just last week I saw this story, regarding Toxoplasma gondii cropping up in a beluga whale in the Beaufort Sea.


The story also mentions that Sarcocystis pinnipedi may be responsible for a large die off of grey seals off Cape Breton in 2012.  They are suggesting that the parasites are being released by ice thaw. What do you think?

Oh as for the obligatory weather report, its a balmy 4oC here in Halifax, Nova Scotia, Canada. However we are expecting a mix of rain, freezing rain and snow overnight and they are anticipating the temperature to dip to -7oC (wind chill of -14oC) by morning! Still a bit of winter left here in Canada!


Oskar writes:

Hello TWiPers!

I’m studying the third and final year of the Biomedical scientist programme at the Gothenburg university, Sweden. I’ve just spent my work studies at a medical parasitology lab where I introduced the “old timers” to TWiP. Naturally they became hooked immidiately. Listening to you guys really made it easy and fun to learn the theoretical part of working in a parasitology lab, so I just wanted to say thank you!


The temperature here is a chilly 3 degrees C with rain.