Skalbagge

Skalbagge. På klistrad pappersetikett antecknat av intendent Knut Adrian Andersson: Goliathus giganteus Hane (den större vitstrimmiga) Hona (den mindre dito) Jätte Goliath Afrika, övre Guinea Skänkta 23/3 1015 av Sjökapten C. E. Göransson i Uddevalla. Goliathus goliatus, Linnaeus 1771 Goliathus goliatus is the first specimen of the genus that was described in 1771. It was known, till some years ago, as goliathus giganteus. It is the most widely distribuited specimen of the genus, occurring surely from Kenya to Togo. Goliathus goliatus is known for its large variability of colour. In past there was a prosperous activity of description by some authors that seemed to delight themselves describing an absurd number of different forms depending by the number, or position of white patterns or stripes on elytra or protorax. Of course, the temptation to do this is great, because all the lovers of these beetles are naturally induced to think that any different distribution of colour could reveal a different form. In any case, we should seriously recognize no more than 3 forms: the typical form (brown elytra), the conspersus form (elytra more or less showing white patterns), and the quadrimaculatus form (with elytra almost totally white, showing only 2 apical and 2 scapular black spots). About the reason of this great variability of colour, there is not a clear answer. Surely we can note that the withe forms occure more frequently in western part of the distribution area (Cameroon, Gabon), near the border of goliathus regius area distribution, that could mean that these two specimens could have crossed in past ant even now, giving intermediate forms. For unknown reasons, females of g. goliatus are more frequently white coloured than males (this happens also in captive rearing experience), and in some countries like Cameroon, it gets difficult to find females that are completely brown. About the size, g. goliatus can range from 50 mm to 110 mm, or at least this measure is the one commonly referred. Males reaching 110 mm are, actually, an absolute rarity and I have newer seen one. Males under 52-53 mm are also very rare in nature. I do not think that in nature this can occur, because usually goliathus molt in pupa when the larva reach a certain weight, and the diet in nature is very rich of animal proteins. In captivity it may happen that a larva molts in pupa when the time is reached but not the weight.