Tiny butterflies.!

[David Lazarus]

I can understand this evolutionary process, and it makes perfect sense for males to gain an advantage as you explain, Guy. From observation though, it seems that in many species of butterfly, like Gatekeeper, the males emerge before the females. This year I didn’t see a female Gatekeeper for days after the males were on the wing.
If I remember in previous years, the tiny males including this particular male, they seem to emerge later, closer to the end of the flight period. He was flying around manically trying to find a virgin female before stopping for energy. I can’t see how he has gained any advantage at all.
It might even be a case of survival of the fittest where these tiny late emerging males and their gene stock are actually ‘weeded’ out in time. Maybe?

[Padfield]

Interesting! I'll change my theory, then! If they're not feeding up fast to get in on the act early, perhaps they're feeding up fast to avoid missing it altogether! Maybe eggs laid at the very end of the season lead to cats permanently behind schedule and they have to catch up by pupating early. Either that or arrive at the party after everyone else has paired up ...

Guy

[David Lazarus]

Interesting! I'll change my theory, then! If they're not feeding up fast to get in on the act early, perhaps they're feeding up fast to avoid missing it altogether! Maybe eggs laid at the very end of the season lead to cats permanently behind schedule and they have to catch up by pupating early. Either that or arrive at the party after everyone else has paired up ...

A number of very thoughtful theories there Guy. . . Perhaps a combination of all of the above. I think they are very cute and have their place in the colony. I hope he eventually finds a mate and continues his line

[David M]

...I remember seeing a documentary about some species of monkey where males fell into two distinct physiological types: small, fast and sneaky; and big and tough. Both led to reproductive advantage, for quite different reasons! I wonder if something similar might happen in butterflies. Feeding up fast and pupating early might lead to a small butterfly, but for a male it will perhaps mean he's the sole player for a while and can catch those females that have never seen a seriously butch butterfly. The alternative strategy of building up bulk to impress the females is more useful later on. For females, perhaps, it is most advantageous to emerge mid-season, when there is a maximum number of potential mates to choose from.

Those are interesting thoughts, Guy, and not ones I've ever considered.

My experience of 'dwarf' butterflies has usually been restricted to visits to hotter, drier regions of Europe, where it's easy to draw the conclusion that lack of vigorous foodplant is most likely the reason.

Even then, generally it has been Lycaenids that have been affected, leading to the supposition that it is the effects of an arid climate on low growing foodplants that has led to this phenomenon.

If ever I start seeing dwarf Hairstreaks then I will be forced to rethink things!

[David Lazarus]

If ever I start seeing dwarf Hairstreaks then I will be forced to rethink things!

[millerd]

Visiting a local colony of Brown Argus today, I was struck with how variable in size they are. I came across what appeared to be a particularly large female...

...and then a tiny one (also female I think).

The latter was very obliging with regards to photos, and I was able to place the tip of my left forefinger right next to the butterfly in the same plane...

...which would give an approximate wingspan of just over 1 cm.

As these two females (and the other Brown Argus seen today) emerged around the same time from the same small colony with (I imagine) largely the same environmental factors applying, I wonder what made them so different in size.

Dave

[David Lazarus]

OMG Dave - how cute is she? Wow

[bugboy]

When I was a young teenager I reared a load of Brimstone from a gravid female I'd captured. In hindsight I should have released most of the larvae back into the wild but in my youthful stubbornness I tried to rear the lot. after getting through the first couple of instars I'd come home from school to find them roaming around their cage looking for more food having eaten everything I'd provided the previous evening. Well I didn't lose any but all the resulting adults were about 2/3 to half normal size. Not providing them with a continuous supply of food had stunted their growth as a larvae (they did moult the correct amount of times)