www.ukbutterflies.co.uk

Today I was photographing Marbled Whites at Denbies Hillside, Surrey. It struck me that a large percentage of Marbled Whites at this site are infested with red mites. Apparently these mites pierce the butterfly with their mouthparts and suck the body fluids...yum

What I'd like to know is this; why are Marbled Whites so very susceptible to picking up these red mites when other species with similar emergence periods, and flying in the same meadows, are seemingly immune to infestation? I think I've seen a Ringlet with a mite, or maybe it was a Meadow Brown? But that was a one-off sighting. Is it something to do with choice of nectaring source, or their habit of close communal roosting? Or something completely different?

It's something I've puzzled over for some years, so thoughts and answers appreciated.

Cheers,

Gibster.

I've been thinking about this subject this evening and I think I can recall seeing one meadow brown and at least one blue (can't remember which type) with a mite on last year at Denbies at about this time. You are definitely right in saying that marbled white seems to carry the majority if not all of these parasites. I've never seen a mite in the spring on a butterfly but a few years back I photographed a comma in my garden nectaring on buddleia which had a red mite on.

I wonder if these mites are just more visable on marbled whites than on other butterflies.

It ain't just marbled whites! These pictures were taken at the beginning of August last year at Fontmell Down. Almost all the common blues I saw had mites... and some - like the one in the picture - seemed to be more mite than butterfly...

Hi Gibster and Susie,
These mites (Trombidium breei) are found very commonly on Marbled White and Meadow Brown, and often on Grayling, other browns, some blues and skippers. I've noticed higher rates of incidence following periods of inclement weather, when these species have spent lengthy periods hunkered down in longer grasses.
Neil

Hi Kipper, is much known about the life cycle of these mites? Why don't I see any in the spring? Is it because they are tiny or because the majority get killed off over winter and only a few (or just eggs?) remain until the following year?

Hi Susie,
It's the larval stage we are looking at here. Like most successful parasites they have perfected their life-cycle timing to ensure efficiency, which means highest numbers when Meadow Brown is at peak, Marbled White is fully out, and Gatekeeper is emerging ..... clever critter (but ruination of many an otherwise good photo). Research has shown a higher level of incidence on middle-aged male butterflies. It's very unfair to pick on this group.
Neil

Oh, so the red critters are the larva and then they turn into something else? I didnt know that! Thanks Kipper.

Just done a quick google and discovered that these creatures are basically the same as ticks in adult form; tiny wee red beasties with legs.

This is a great thread, Gibster, well done!

Certainly is a great thread...it means I get to (rather vicariously) add Trombidium breei to my Pan-species list: "Mites = 1"

I'll be checking Meadow Browns more carefully from now on. Thinking about it, I've seen blues with mites too. Guess they're just more obvious on Marbled Whites? Or I spend more time watching Marbled Whites than Meadow Browns when in long grasses???

Cheers for the info chaps, tis appreciated.

Gibster.