Readers’ wildlife photos

Thank Ceiling Cat that readers have responded with some batches of photos for me. But please think of me when you have photos to spare.

Today sees the return of Tony Eales from Oz, and he sent us some photos showing mimicry in insects. Tony’s captions are indented, and you can click on the photos to enlarge them.

On the weekend I went to Black Mountain Nature Reserve in Canberra and was struck by the number and variety of lycid beetle mimics. I’ve brought these up before. The pollen-feeding lycid beetles around here have a distinctive set of grooved brick-red elytra and black head and body and are very foul-tasting if not poisonous.  An extraordinary number and variety of other beetles and insects take advantage of this simple model to avoid predation. The mimicry is often Batesian but also can be Müllerian as with some soldier beetles.

JAC: Remember that Batesian mimicry involves an edible organism mimicking one that is toxic, dangerous, or distasteful, such as the first lycid shown below.  The evolutionary advantage of this mimicry is clear: if you are edible, and a predator has evolved (or learned) to avoid the “aposematic” (warning) color or pattern of another species that for some reason is inedible, you stand a better chance of living—and passing on your genes—if you evolve some aspect of the inedible organisms’s pattern or color. Such mimicry makes you liable to be avoided by the predator more often (the predator will mistake you for an organism it can’t eat). The black-and-orange pattern of the “model” species in the first picture is a typical “warning pattern”, for all lycid beetles are toxic. (Why, by the way, is it advantageous for a species to evolve an easily recognized pattern if it’s toxic, inedible, or dangerous? After all, the first mutant individual with a conspicuous pattern is liable to be picked off by a predator that hasn’t yet learned to avoid it. It would seem, in such a case, that it’s disadvantageous to evolve a conspicuous color or pattern!)

Müllerian mimicry, on the other hand, involves a group of organisms (they need not be related) that are all toxic, dangerous, or distasteful, evolving similar patterns to resemble each other. Can you think of an evolutionary advantage of an insect that’s already inedible evolving a color or pattern resemble another inedible species?

There are also “mimicry rings” that involve a combination of Batesian and Müllerian mimicry. In the cases below, I’m not sure which mimics of the lycid beetles are Batesian or Müllerian.  (By the way, how can we know if a given species of insect is toxic, distasteful, or dangerous? Remember, it has to be so to predators that may attack it in nature, not to us.)  Note that the species below are probably in such a ring, as there are, besides the toxic Porrostoma lycid model, five other beetles and one fly. It’s very unlikely that the fly, at least, is toxic or noxious, and that is surely a case of Batesian mimicry.

Typical lycid beetle Porrostoma sp.:

The Leptospermum or tea-trees in this part of the reserve were beginning to flower and it’s a great time to look for pollen and nectar-feeding beetles and the like. I managed to find no less than three of the four lycid-mimicking jewel beetles in Australia within only a few hundred square metres.

Castiarina rufipennis:

Castiarina erythroptera:

And the fairly rare Castiarina nasuta:

There were also several Washing Beetles, Phyllotocus sp., so called because they often mistake drying white clothes for giant flowers and in season, land on the washing in huge annoying numbers.

And a lycid mimicking click beetle Anilicus sp.:

And best of all I finally found my first lycid-mimicking fly species. The large and beautiful Pelecorhynchus fulvus from the flower-feeding snipe fly family Pelecorhynchidae: