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Index of Subjects --Apple-Mail-199--72251452 Content-Transfer-Encoding: 7bit Content-Type: text/plain; charset=US-ASCII; delsp=yes; format=flowed Hi Dave, On 21-Oct-07, at 12:18 PM, David & Alison Webster wrote: >>> By the looks of it, this beetle should be easily able to float >>> on a rising column of warm air and I wonder if in fact they can >>> do this. >>> >> >> We actually discuss this in our AME chapter, since some authors >> (i.e. Pringle 1957) have suggested that the beetles move around >> through passive flotation in the manner of dandelion seeds. >> However, this is an erroneous notion, as one can easily observe >> directed flight behavior in various situations, for instance in >> searching for their ephemeral breeding sites such as dung, >> compost, and decomposing fungi. Despite their tiny size, and >> unusual wings, they can fly with the same (or even better) >> facility as many other species of beetles. >> > But note that ability for directed flight does not prove > inability to float on rising air (passive flotation); hawks and the > like. > Calculating the terminal velocity of a spherical body is, thanks > to Stokes, is a piece of cake. But non-spherical is another matter > and is perhaps fodder for a mid-winter project/discussion as some > on the list may know how to do this. > Yes, indeed: I should think that they can doubtless float in rising air (if birds as large as condors can do this than surely ptiliids can as well ;->). My comments pertained to speculation buy earlier authors that ptiliids (because of their size and the structure of their wings) were incapable of directed flight and simply floated around in air currents waiting to be deposited somewhere. In fact, they are quite adept at directed flight. Cheers, Chris _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. Christopher Majka - Nova Scotia Museum of Natural History 1747 Summer Street, Halifax, Nova Scotia, Canada B3H 3A6 (902) 424-6435 Email <c.majka@ns.sympatico.ca> _._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._. _. --Apple-Mail-199--72251452 Content-Transfer-Encoding: quoted-printable Content-Type: text/html; charset=ISO-8859-1 <html><body style=3D"word-wrap: break-word; -webkit-nbsp-mode: space; = -webkit-line-break: after-white-space; "> Hi Dave,<div><br><div><div>On 21-Oct-07, at 12:18 PM, David & Alison = Webster wrote:</div><br class=3D"Apple-interchange-newline"><blockquote = type=3D"cite"><blockquote type=3D"cite"><blockquote type=3D"cite"><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; "><span class=3D"Apple-converted-space">=A0=A0=A0</span>= By the looks of it, this beetle should be easily able to float on a = rising column of warm air and I wonder if in fact they can do = this.</div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> = </blockquote><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div><div = style=3D"margin-top: 0px; margin-right: 0px; margin-bottom: 0px; = margin-left: 0px; ">We actually discuss this in our AME chapter, since = some authors (i.e. Pringle 1957) have suggested that the beetles move = around through passive flotation in the manner of dandelion seeds. = However, this is an erroneous notion, as one can easily observe directed = flight behavior in various situations, for instance in searching for = their ephemeral breeding sites such as dung, compost, and decomposing = fungi. Despite their tiny size, and unusual wings, they can fly with the = same (or even better) facility as many other species of = beetles.</div><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; min-height: 14px; "><br></div> = </blockquote><div style=3D"margin-top: 0px; margin-right: 0px; = margin-bottom: 0px; margin-left: 0px; "><span = class=3D"Apple-converted-space">=A0=A0 </span>But note that ability for = directed flight does not prove inability to float on rising air (passive = flotation); hawks and the like. <span = class=3D"Apple-converted-space">=A0</span></div><div style=3D"margin-top: = 0px; margin-right: 0px; margin-bottom: 0px; margin-left: 0px; "><span = class=3D"Apple-converted-space">=A0=A0 </span>Calculating the terminal = velocity of a spherical body is, thanks to Stokes, is a piece of cake. = But non-spherical is another matter and is perhaps fodder for a = mid-winter project/discussion as some on the list may know how to do = this.</div><p style=3D"margin: 0.0px 0.0px 0.0px 0.0px; min-height: = 14.0px"><br></p></blockquote><br></div><div>Yes, indeed: I should think = that they can doubtless float in rising air (if birds as large as = condors can do this than=A0surely=A0ptiliids can as well ;->). My = comments pertained to speculation buy earlier authors that ptiliids = (because of their size and the structure of their wings) were incapable = of directed flight and simply floated around in air currents waiting to = be deposited somewhere. In fact, they are quite adept at directed = flight.</div><div><br = class=3D"webkit-block-placeholder"></div><div>Cheers,</div><div><br = class=3D"webkit-block-placeholder"></div><div>Chris</div><div><br = class=3D"webkit-block-placeholder"></div><div> <p style=3D"margin: 0.0px = 0.0px 0.0px 0.0px"><font face=3D"Times" size=3D"3" style=3D"font: 12.0px = Times">_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._= ._._._.</font></p> <p style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><font = face=3D"Times" size=3D"3" style=3D"font: 12.0px Times">Christopher Majka = - Nova Scotia Museum of Natural History</font></p> <p style=3D"margin: = 0.0px 0.0px 0.0px 0.0px"><font face=3D"Times" size=3D"3" style=3D"font: = 12.0px Times">1747 Summer Street, Halifax, Nova Scotia, Canada<span = class=3D"Apple-converted-space">=A0 </span>B3H 3A6</font></p> <p = style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><font face=3D"Times" size=3D"3" = style=3D"font: 12.0px Times">(902) 424-6435 <span = class=3D"Apple-converted-space">=A0 </span>Email <<a = href=3D"mailto:c.majka@ns.sympatico.ca">c.majka@ns.sympatico.ca</a>></f= ont></p> <p style=3D"margin: 0.0px 0.0px 0.0px 0.0px"><font face=3D"Times"= size=3D"3" style=3D"font: 12.0px = Times">_._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._._= ._._._.</font></p> </div><br></div></body></html>= --Apple-Mail-199--72251452--
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