Tag Archives: biology

Trigger warning for creationist visitors to National Zoo

Here’s a photograph I took several years ago at the National Zoo’s “Think Tank” exhibit on primate cognition. Darwin Day is one week so I thought I’d share.

Colin Purrington Photography: Evolution graphics &emdash; Think Tank warning for creationists

The text is a little hard to read so here’s transcription:

“This exhibit is about animal thinking. It contains some things you may agree with, some you may disagree with, and others that may even trouble you. Come explore and see what you think.” 

The warning sign was crafted by Smithsonian staff to cater to snowflake creationists who complained about the “Changes over millions of years have resulted in today’s humans” panel that covered the age of the earth, human evolution, and how natural selection works. 

The “see what you think” part suggests to visitors that the facts presented within are up for debate and thus shouldn’t undermine somebody’s alternative views about human origins or the age of the earth. But, of course, the warning signage undermines the experience for all visitors. I.e., a curious but uninformed visit might assume that the exhibits are just wild guesses about what might have happened. A shameful use of tax dollars, in my opinion.

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Galapagos mug with English and Spanish maps

I read a lot of books and articles about the Galapagos Islands, and it’s a tad annoying that the islands all have two names — colonial British, and modern Spanish. Most books (but not articles) have a map, but it’s invariably just a monolingual map and also fixed on a given page so it’s hard to refer to frequently. So out of frustration I designed myself a bilingual map mug. Just hold in right hand when reading modern works, and in the left hand when reading something older like Charles Darwin’s, Voyage of the Beagle. It’s also useful when reading about the various endemics that were given names according to the islands where they were first described. E.g., when reading about Microlophus albemarlensis barringtonensis (one of the lava lizards), a quick glance at the mug will tell you that the subspecies is on Isla Santa Fé, though primary species description was for the specimens on Isla Isabela.

I put it up on Redbubble in case you need one for yourself, or need a geeky gift for somebody who’s doing some reading in advance of a trip to the Galapagos.

Mug with English/Spanish maps of the Galapagos

If you’re curious about the map, it’s one I scanned from Darwin’s, Journal of Researches. It’s probably not suitable for navigation purposes, FYI, especially if filled with hot canelazo.

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Kleptoparasitic fly stealing ant juice from jumping spider

I was photographing a spider a few days ago, and one frame that I was about to trash (jumping spider’s eyes not in focus) happened to show a kleptoparasitic fly that was drinking fluids from the captured ant. Because the fly is not especially visible I haven’t tried that hard to ID the fly (probably Milichiidae or Chloropidae), but I did find an interesting page showing a fly in Australia that was found near a salticid called an ant eater (Zenodorus orbiculatus).

Colin Purrington Photography: Insects &emdash; Kleptoparasitic fly on ant killed by jumping spider

If you have time to waste, here are some fun facts about kleptoparasitic flies:

  • Some species are attracted to volatiles released by captured prey (e.g., stink bugs). I have pics.
  • There are apparently some that are specialists on spiders (Brake and von Tschimhaus 2010).
  • It’s usually just females; when males present they might be looking for mating opportunities with females (Ibid.).
  • In Africa. there’s a milchiid that can induce ants to regurgitate (Wild and Brake 2009).
  • Some plants in the Apocynaceae seem to have evolved the ability to mimic the venom volatiles of paper wasps. The scent is attractive to kleptoparasitic flies because the wasps use the venom when they hunt (Heiduk et al. 2015). This is referred to as kleptomyiophily, apparently (new word for me).

If you really need to more, check out the http://www.milichiidae.info/. Sorry: the Chloropidae don’t have their own site.

I think the spider is Phidippus princeps. Happy to be told otherwise. Here are some better pics of the spider:

Colin Purrington Photography: Spiders and ticks &emdash; phidippus-princeps-eating-ant-003

Colin Purrington Photography: Spiders and ticks &emdash; phidippus-princeps-eating-ant-001

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Using mosquitoes’ sweet tooth to control Zika transmission

Now that everyone wants to kill mosquitoes that transmit Zika virus, can somebody please make a transgenic plant that expresses mosquitocidal Bti (Bacillus thuringiensis subsp. israelensis) toxins? Just stick the Bti gene behind a phloem-specific promoter so that the protein gets pumped into the nectar. Then when males and female mosquitoes drink (and almost all do), they die. You could then plant acres of the modified plant nearby towns to protect people from Zika (and anything else transmitted by mosquitoes). The beauty of this method is that you could reduce populations of mosquitoes from an area without spraying, and do so for generations if you modified nectar-producing perennials. I know it’s trendy to dislike GMOs (like vaccines), but I think many people would support them under these circumstances.

And yes, apparently Bti toxins can kill adult mosquitoes (including Aedes aegypti), not just larvae. Klowden and Bulla 1984 demonstrated it, for example. And yes, Aedes aegypti drinks nectar (and probably fruit juice).

Of course, even if somebody had the incentive to make such a plant, it could take a decade to wade through the red tape involved in getting non-regulated status from governments. So if you want to do something today, leave out containers of sugar water (10%) that is laced with Bti (e.g., Mosquito Dunks, which you can buy online or at hardware stores). Maybe add something floral to attract them, too. (A review of olfactory cues suggests that imitation cherry and apple can work. If you don’t have those sitting around, I’d wager a few drops of jasmine flavoring or rose water would work, and those are easily found at local stores.) Even if the Bti doesn’t immediately kill the adult, adults sucking up a big sugar meal can transfer the bacteria to water where they lay eggs, and thus eventually cause the death of any larvae that develop. Note that bees and ants might get interested in your sugar water, but the Bti is completely harmless to them.

And if you don’t want to use Bti, there are plenty of articles on using sugar baits laced with insecticides (e.g., Qualis et al. 2013, Junilla et al. 2015). They really can work: mosquitoes absolutely love sugar and will drink up poisons in the process. These are great if you don’t want to use crop dusters to destroy all insects in the area.

If you have kids and want to entertain them, add food dyes to the sugar bait and then challenge them to find mosquitoes with bellies full of sugar water. For older kids that might be amused by actual science, use two dyes to test attractiveness of two different volatiles (or different sugars). It’s probably rare to recapture one right after a nectar meal, but when distended they reveal gut contents nicely.

Colin Purrington Photography: Insects &emdash; White-footed woods mosquito (Psorophora ferox) nectaring on goldenrod

FYI, the photograph above is a white-footed woods mosquito (Psorophora ferox), not Aedes aegypti. It doesn’t transmit Zika, but illustrates to the unbelieving that mosquitoes drink nectar. 

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