A Plague of Beetles
This morning our worker called us out to see what he called la plaga – a plague – of beetles. It was early morning, the beetles were on the back side of the leaf, so I was shooting in the bright, long-shadowed tropical sun hence the poor quality of this and the next image.
Here’s the culprit.
Ted MacRae of Beetles in the Bush says that it is a member of the chafer group (subfamily Melolonthinae) of the scarab beetle family, but he did not have a species name for it. He says the larvae are likely somewhere in the soil, eating the roots of (other) plants.
Update: Ted kindly pulled some strings among his beetle expert friends. Here’s his report:
According to my friend, Arthur V. Evans, an expert in the family Scarabaeidae, the beetle in your photos is Magnus bolax of the subfamily Rutelinae (closely related to the Melolonthinae). I could not find any particular information about this species other than collection listings and various checklists; thus, its occurrence as a defoliating pest of your Calathea lutea seems to be a one-off thing. A nice picture of a mating pair can be seen on page 6 in the September 2007 issue of SCARABS, a newsletter devoted to the study of scarab beetles.
Magnus bolax is one of 541 species of scarab beetles that have been recorded from Panamá (Ratcliffe 2002) it is a hugely diverse family.
P.S. Another interesting factoid I forgot to mention – the Latin word from which the genus name is derived means “large”, while the meaning of the specific epithet is “lump” – this beetle’s name means, literally, “large lump”. I find that immensely amusing!
Ted’s note that this beetle is not known as a defoliating pest is supported by Carla Black, who has lived and observed in Panama for some years. Here’s what she had to say about la plaga:
