I’m finding it quite hard to write about the “captive” butterflies in my usual style. True they are stunning creatures and certainly have the wow factor about them but I miss the chase, the expectation anxiety and there is no interesting habitat or weather to talk about and less emotion, less buzz with the exotics. Still what they lack in these factors they make up for in interesting behaviours, and they provide an opportunity to find out something new as well as complicated identifications...
Heliconius?
I started off thinking that this species was
Heliconius erato (Linnaeus, 1758), the Small Postman. When I looked at the under wing shot a bit closer I wasn’t happy that the red spots actually numbered four as one looked like a small dash almost as if one spot had been damaged which would mean that it had three spot. Also the white marking didn’t reach anywhere near the wing margin. These features made me think that it wasn’t the Small Postman but was just a Common Postman,
Heliconius melpomene (Linnaeus, 1758).
This species is one of the heliconiine found from Mexico to South America and has up to 30 sub-species showing a huge range in variation in the wing markings and this one could be
H.melpomene rosina? The species has an erratic flight and is found in open areas in forests and can be locally common along river edges and streams. This along with the fact that it roosts communally is worth remembering for possible photograph opportunities in butterfly houses.
It is very similar to
Heliconius erato and both have similar bold markings on their upper wings which demonstrate to potential predators that they are both toxic. In fact all of the information above holds true for
H.erato so if I’ve got the identification wrong no worries!
They look similar to each other because they are actually co-mimics. I remember reading about them in the book Dazzled and Confused which was recommended by Pete. Despite there being so many different sub species/colour morphs of
H.melopmene spread throughout Central and South America there are
H.erato mimics to match all the geographical variations. Indeed genetic studies have shown that the wing patterns are associated with a small number of gene loci which are homologous in both
H.erato and
H.melopmene so this could be parallel evolution. This is thought to be due to Mullerian mimicry. By sharing the same warning livery the species share the cost in educating predators that they are both toxic . If a butterfly tastes bad which has red and white stripes it doesn't matter to the predator whether it's
H.erato or
H.melopmene they'll avoid both and so a nasty mouthful next time and in this way both species suffer less from predation overall.
Have a goodun
Wurzel
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