How to Swat a Fly

25 October 2008 at 18:30 (Behaviour management, Insects & Arachnids, Science)

Some of this is not breaking news, but some is.  When I was watching someone in another classroom in futile pursuit of said dastardly, dirty diptera, I realised that there is a lot of interesting science behind successful swatting.

Flies are hard to swat for a number of reasons.  They avoid predation by both sensory detection and behavioral responses.  With its large eyes, a fly can see nearly 360°, including behind itself.  This means that it’s nearly impossible to “sneak up” on a fly. Because an insect’s flicker fusion frequency is 250 Hertz or more (compared to the human 50), they are vastly more sensitive to motion. Flies can see a flyswatter coming at them, no matter how slow or fast you move it. As anyone who has ever examined their prey has noted, flies are also hairy.  These “hairs” (setae) make them sensitive to changes in ambient air speed and direction — they can feel the acceleration of the air from the pressure wave created by the flyswatter.

Michael Dickinson and others at the California Institute of Technology have recently teased out other details to the flys’ success.  They used high-speed imaging to discover that Read the rest of this entry »

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Moldy bagels

25 October 2008 at 1:42 (Teaching/Tutoring)

Only teachers get excited by such things as bagels sprouting fluffy fungal mycelial masses.  “Oh, boy!  Some Rhizopus and Penicillium, just what I needed for this week’s lab exam!”

Yes, I’m in the thick of making up, administering, and grading endless rounds of exams. Both classes have exams every week, and they also have periodic larger exams.  As this is the first time I’ve taught either course, I’m up to my tuchis in the exam-writing process, so the whole process keeps me busy as a beehive*.

And of course, every teacher loves to collect those oddball answers to test questions.  Here are some from college students studying botany & horticulture (correct answers in parentheses). [N.B. for those concerned with the politically correct, none of these students were identified to me as having dyslexia or other learning issues.  However, there’s a good chance that many of us are suffering sleep deprivation.]

List a specific epithet describing the growth habit of a plant:
Palin_short, dwarf (pumila) Read the rest of this entry »

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