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Ceratina dupla vs. Ceratina calcarata females

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  • Sam Droege
    Given the prevalance of these two species, I thought it worth sending out a quick note about discriminating the females. Expanding on Sandra Rehan work on
    Message 1 of 3 , Aug 17, 2006
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      Given the prevalance of these two species, I thought it worth sending out a quick note about discriminating the females.  Expanding on  Sandra Rehan work on discriminating Ceratina dupla from C. calcarata I recently found another character that will help separate the two, this requires more experience but is useful for discriminating inbetween specimens.

      I have added the following to the Ceratina guide:

      With experience and a good series of both species the propodeal triangle can be used to discriminate among ambiguous specimens.  In dupla the basal striations extend usually rather uniformly about two-thirds of the way to edge across the entire width, these striations are usually dense enough that it is difficult to discriminate individual members.  In calcarata the basal striations extend about two-thirds or more of the way in the center but this proportion decreases to the sides, thus leaving a non-uniform, unstriated portion of the rim of the triangle; the striations can be more widely spaced and usually are clearly separable from their neighbors, additionally the entire triangle tends to be longer in comparison to dupla.
    • John S. Ascher
      Sam: Are you sure this applies to all populations (e.g., dupla floridana)? I wasn t confident in the characters on the poster by the Canadians. The punctures
      Message 2 of 3 , Aug 18, 2006
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        Sam:

        Are you sure this applies to all populations (e.g., dupla floridana)?

        I wasn't confident in the characters on the poster by the Canadians. The
        punctures seemed to vary a lot.

        On another subject, I find it easy to distinguish Megachile brevis vs.
        mendica and question their being indistinguishable. I find Mitchell's
        characters of the tergal apex useful and rarely have problems. I can even
        tell texana vs. mendica most of the time, although some specimens are
        genuinely puzzling.

        John





        > Given the prevalance of these two species, I thought it worth sending out
        > a quick note about discriminating the females. Expanding on Sandra Rehan
        > work on discriminating Ceratina dupla from C. calcarata I recently found
        > another character that will help separate the two, this requires more
        > experience but is useful for discriminating inbetween specimens.
        >
        > I have added the following to the Ceratina guide:
        >
        > With experience and a good series of both species the propodeal triangle
        > can be used to discriminate among ambiguous specimens. In dupla the basal
        > striations extend usually rather uniformly about two-thirds of the way to
        > edge across the entire width, these striations are usually dense enough
        > that it is difficult to discriminate individual members. In calcarata the
        > basal striations extend about two-thirds or more of the way in the center
        > but this proportion decreases to the sides, thus leaving a non-uniform,
        > unstriated portion of the rim of the triangle; the striations can be more
        > widely spaced and usually are clearly separable from their neighbors,
        > additionally the entire triangle tends to be longer in comparison to
        > dupla.


        --
        John S. Ascher, Ph.D.
        Bee Database Project Manager
        Division of Invertebrate Zoology
        American Museum of Natural History
        Central Park West @ 79th St.
        New York, NY 10024-5192
        work phone: 212-496-3447
        mobile phone: 917-407-0378
      • John S. Ascher
        FYI, I wasn t intending to reply to this whole list but only to Sam. ... -- John S. Ascher, Ph.D. Bee Database Project Manager Division of Invertebrate Zoology
        Message 3 of 3 , Aug 18, 2006
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          FYI, I wasn't intending to reply to this whole list but only to Sam.


          >
          > Sam:
          >
          > Are you sure this applies to all populations (e.g., dupla floridana)?
          >
          > I wasn't confident in the characters on the poster by the Canadians. The
          > punctures seemed to vary a lot.
          >
          > On another subject, I find it easy to distinguish Megachile brevis vs.
          > mendica and question their being indistinguishable. I find Mitchell's
          > characters of the tergal apex useful and rarely have problems. I can even
          > tell texana vs. mendica most of the time, although some specimens are
          > genuinely puzzling.
          >
          > John
          >
          >
          >
          >
          >
          >> Given the prevalance of these two species, I thought it worth sending
          >> out
          >> a quick note about discriminating the females. Expanding on Sandra
          >> Rehan
          >> work on discriminating Ceratina dupla from C. calcarata I recently found
          >> another character that will help separate the two, this requires more
          >> experience but is useful for discriminating inbetween specimens.
          >>
          >> I have added the following to the Ceratina guide:
          >>
          >> With experience and a good series of both species the propodeal triangle
          >> can be used to discriminate among ambiguous specimens. In dupla the
          >> basal
          >> striations extend usually rather uniformly about two-thirds of the way
          >> to
          >> edge across the entire width, these striations are usually dense enough
          >> that it is difficult to discriminate individual members. In calcarata
          >> the
          >> basal striations extend about two-thirds or more of the way in the
          >> center
          >> but this proportion decreases to the sides, thus leaving a non-uniform,
          >> unstriated portion of the rim of the triangle; the striations can be
          >> more
          >> widely spaced and usually are clearly separable from their neighbors,
          >> additionally the entire triangle tends to be longer in comparison to
          >> dupla.
          >
          >
          > --
          > John S. Ascher, Ph.D.
          > Bee Database Project Manager
          > Division of Invertebrate Zoology
          > American Museum of Natural History
          > Central Park West @ 79th St.
          > New York, NY 10024-5192
          > work phone: 212-496-3447
          > mobile phone: 917-407-0378
          >
          >
          >
          >
          > Yahoo! Groups Links
          >
          >
          >
          >
          >
          >
          >
          >


          --
          John S. Ascher, Ph.D.
          Bee Database Project Manager
          Division of Invertebrate Zoology
          American Museum of Natural History
          Central Park West @ 79th St.
          New York, NY 10024-5192
          work phone: 212-496-3447
          mobile phone: 917-407-0378
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