Diloboderus abderus, male | Buenos Aires, Argentina
In her appeal for submissions for her upcoming issue of An Inordinate Fondness, Susannah lamented the paucity of beetles in the closing weeks of her northern winter and mentioned in passing that even I had gone more than a week without posting about this great order. I hadn’t realized that myself, so here I present Diloboderus abderus, one of the beetles that I encountered during my visit last weekend to La Reserva Ecológica Costanera Sur in Buenos Aires, Argentina. This species, known commonly in Argentina as bicho torito (“little bull bug”) is common enough in Argentina and southern Brazil, where its white grub larvae have become somewhat of a pest in lawns, pastures, and grass crops such as wheat by way of feeding on the roots. I first encountered this species during one of my previous trips to Argentina, where during a rain storm I saw literally hundreds of adults emerging from mowed grass medians in the city streets of Pergamino. These photographs show two of numerous dead individuals that I found laying on the ground of similar medians just outside the reserve. As with many scarab beetles in the subfamily Dynastinae (containing also the recently featured Dynastes tityus), males (above) are armed with pronotal and cephalic horns – presumably for use in sexual combat – while females (below) are unarmed.
Diloboderus abderus, female | Buenos Aires, Argentina
Copyright © Ted C. MacRae 2011
Beetles In The Bush 
Pretty amazing little bull! What’s the function of the fuzz at the base of the horns? If the that orange color were on a bird, I’d guess it’s used in a mating display.
I had suggested the same thing in my Dynastes tityus post, but the consensus seems to be that it helps males get a better grip on their opponent during combat. Makes more sense to me now that I think about it, as these beetles likely don’t have the best eyesight.
Everybody asks about that fuzz during events like ‘Meet the Beetles’ – wished I knew.
Beetle season is slowly starting again, I was collecting in the dunes of western AZ last week, so now I’m working on one blog on Tenebs and one on Dune Weevils.
Western AZ – what a great place to be for the beginning of beetle season (or any part of it!).
I had noticed the slacking on beetle posts, but would say you’re back on a roll with this one. Wish our lawn grubs/June bugs were this cool!
(And thanks for the nice ant during the brief break from beetles.)
Beetles were not so numerous this time around, and this may well be the most visually impressive beetle of the trip. I do sttill have some beetles from Brazil that I haven’t shared yet, as well as from last fall’s tiger beetle trip.
The twig ant was the best ant I photographed, but I’ve got a few Camponotus/Ectatomma-looking things (haven’t looked closely at them yet).
Camponotus/Ectatomma-looking things … ;~}
I know – can’t even narrow down to subfamily ;^)
It looks like a construction vehicle like a “Bobcat.”
😀
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Hi Ted,
I had to do a double take when I looked at this post since I finally took the time to photograph Diloboderus when I was there in February. I’ve always been impressed with these guys but I wasn’t motivated enough to snap a few pics until I finally found one alive. Glad you were able to make it to Costanera Sur– looking forward to hearing more about it.
Chris
I looked all over to see if I could find any adults still alive – I really don’t like photographing dead individuals unless I have to. The pic still turned out pretty good – can’t wait to see yours!
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Now this is a treat. My wife is from Argentina, and having spent some time down there the bicho torito has been one of my favorite photographic subjects.