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Larva Weight vs Adult Size prediction chart?


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So, I saw this thread http://beetleforum.net/forums/index.php?showtopic=2274 which really got me thinking about larval weight vs adult size ratios/comparisons. I think it would be really interesting if there was some sort of species chart that related L3 weight at pupation to adult length. Does such a chart already exist, possibly in countries like Japan or Germany, where the hobby is much more common on a national level? If not, it may be a worthwhile project for breeders to post recorded measurements so that others can get an idea of the adult sizes they can expect. It might be a good idea to start off with one species that lots of people have and then add other species to the chart in the same manner.

A chart would be nice to have for reference, but the mathematical relationship between larval weight and adult size is even more interesting to me. I would expect a logarithmic trend if the relationship was graphed, as each species likely has a maximum adult size that it can reach (or, maybe not. this is just a speculation. it would be fascinating if the relationship was linear although my experience in biological studies suggests that most "higher" animals have some kind of biological limitation to size). If enough data points were taken and the relationship was graphed, there would be a mathematical expression that could predict adult size as a function of larval weight. Constants, such as slope and y-intercepts, would be defined for each species. So you could either look at the chart or plug your weight into an equation. Obviously, the equation/chart will not be 100% accurate, but the more data points that go into it the more accurate it will become. It seems pretty simple and easy to do, actually.

 

I think some US native species that are commonly bred in culture, such as Dynastes granti or Dynastes tityus, would be good candidates for this project. If I get my hands on some L3's before my own pairs produce them, I will post larval weights and adult sizes. Cheers

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I have always been interested in this too. Most of my D. tityus are still L3 and growing so I can't have measurements until they emerge. However all my Larvae weigh between 17g-22 grams and I have one larva that weighs 27 grams and hope that it will be a nice major male.

 

I also recorded the weights of my Phileurus truncatus larvae and observed some interesting things. Most larvae that became males reached between 10g-12 grams while larvae that became female were between 13g-14grams.

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For the Phileurus truncatus, do you have sizes for the adults? That is very interesting data, I appreciate your contribution. When do you think your Dynastes tityus will pupate? I think it might be a good idea to track larvae individually and then use all of their individual values to calculate an average instead of a range. You could also indicate which data points are male and which are female, a variable that apparently may be important in predicting adult size, as your data suggests for one species

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The D. tityus I have were hatched about this time last year. I was hoping they would emerge this year but its October and they are still gaining weight. I keep all of them separate and labeled and record their progress. 6 of them came from Maryland but the specimen that is 27 grams is the only Dynastes tityus larvae I have ever found. it was found in Christmas, FL and I'm hoping to breed it to the females I have. I really hope the males genetics will pass on to the offspring and I can one day breed huge D. tityus beetles.

 

As for the Phileurus truncatus data, it is all in my beetle journal and I still have to transfer it onto a spread sheet document. I can send you this data once I have it transferred.

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