Boo! (Or, evolution is awesome)

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    The yellow fruit beetle or garden fruit chafer is a familiar pest to gardeners throughout Africa. (See more pictures.) They're nearly indestructible, and you don't want to touch them unless you want your hand to stink for days. Buried headfirst into the fruit or flower they're consuming, this is the view they present to potential predators -- and I only clicked last October what it is they want us to see.

    Incredible. The eyes, the gaping mouth, even the shiny white teeth. It's astounding something like this can evolve.

    So far I've not found any mention of this mimicry in the scientific literature. I've therefore not added it to the Wikipedia entry as it would be original research. But I've added the photo to the Scarabaeidae gallery though -- readers can draw their own conclusions.

    UPDATE 30/3/2011: See comment below by Prof. Renzo Perissinotto at the School of Biological & Conservation Sciences, University of KwaZulu-Natal.

    1. fjordaan 64 months ago | reply

      Uncropped image:
      Scary monster

    2. Cennydd 64 months ago | reply


    3. haaskalbaas 64 months ago | reply

      Of course! I HATE those things... but the face is kinda cute...on some peculiar level.

    4. fjordaan 64 months ago | reply

      Here's another view:
      Pachnoda sinuata

    5. Gilgongo 64 months ago | reply

      This is a wonderful example of Batesian mimicry. I know that because I am a descendant of the person who first documented it (can't remember exactly how related - I think it may be great great uncle, but I think I have his nose).

    6. londonson 64 months ago | reply

      Ek vergaap my hieraan! Ongelooflik.

    7. fjordaan 49 months ago | reply

      Prof. Renzo Perissinotto at the School of Biological & Conservation Sciences, University of KwaZulu-Natal, writes:

      What you have noticed is something that only a few of us are very familiar with, particularly those regularly observing and collecting fruit chafers (Scarabaeidae, Cetoniinae), the group in which your beetle, Pachnoda sinuata flaviventris (not simply the nominal P. sinuata) belongs. Most of these beetles feed on nectar, fermenting fruit and sap flows, but do not have a long feeding apparatus like the proboscis of butterflies and moths, which would allow them to stay vigilant at the surface of the flower/fruit while sucking the juices using an extensible device. They have to dig in, in order to access the target food and this generally results in them having to stick out the tip of the abdomen, known to the professional as "pygidium". Essentially they feed with their "bum in the air". Because it is at this stage the most vulnerable part of the animal's body, the pygidium of fruit chafers has undergone special adaptation to minimize losses from predators. As part of these are the sclerotization of its surface with multiple layers of chitin and the appearance of warning/deterring ornaments, such as eyes and teeth - of the kind exhibited by your specimen of P. sinuata flaviventris. Most fruit chafers species indeed have spots and lines (generally white) on the pygidium, often combined with elytral decoration, to avoid becoming "somebody's else dinner".

      Although your specific example has not been reported in the literature, as far as I know, there are many similar cases discussed in popular books, such as: 1) "Evans & Bellamy, 1996, An Inordinate Fondness for Beetles, Henry Holt Publ. (see section "How to Avoid Becoming Dinner", pp.118-129); 2) Holm E, 2008, Insectlopedia of Southern Africa, Lapa Publ. (see sections on "Colour Vision" and "Camouflage" , pp. 146-166).

    8. karlsabino 49 months ago | reply

      Awesome, and somehow very cute.

      I'm going to get a scary face tattoo on my butt, so I no longer have to worry about eating with my bum in the air too.

    9. haaskalbaas 49 months ago | reply

      Good plan, karlsabino man.

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