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1127Re: [beemonitoring] Measuring bee body size

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  • ariellag@post.tau.ac.il
    Jul 13 1:54 AM
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      Hi all

      Thanks a lot for responding to my question on the best way to measure
      body size.
      Sam Droege asked me to summarize your suggestions for the benefit of
      the group, so here they are.

      The 1st one is from Jim Cane:

      The ocular micrometer of a dissecting microscope is perfect for
      measuring intertegular span of a bee. You will first need to
      calibrate it with a stage micrometer slide, but once done, it is good
      forever.


      The 2nd one is from Jack Neff:

      The ocular micrometer in your dissecting scope should work fine for
      measuring trans-tegular distances, especially if it has a relatively
      fine scale. It probably will be better than a digital caliper for
      very small bees. You should remember estimating mass from a single
      body measurement assumes a similarity of shape and you can get
      significant deviations from this when comparing long skinny bees (like
      Chelostoma) with "fat" ones like Xylocopa. In an ideal world, the
      best way to compare size is to actually weigh them.


      The 3rd is from Anita Collins:

      USDA did a lot of bee measuring to identify Africanized specimens vs.
      European. We actually did a dissection and projected a part, such as
      a leg, o n a digital pad. Software was then used to make the actual
      measurement, which was fed directly into a statistical calculation
      based on 10 samples.

      The 4th is from Charlie Guevara:

      Wards Science.com has a slide micrometer for about $15 USD. With that
      and the ocular reticule you already have...you can calibrate various
      'work-horse microscopes you have'. Be careful of using: 'zoom
      magnification adjust' microscopes...you may have trouble knowing
      exactly what magnification your using the ocular reticule (ocular
      micrometer) with...after hours of 'one of a kind/nonrepeatable'
      specimen data record sessions...you may not have exactly the same
      zoom-setting on the scope you’re working with!



      Thank you all

      Ariella
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