www.ukbutterflies.co.uk

I found this Marsh Frit today and I think I saw another nearby. These basically appeared out of nowhere in our small (~4½ acres) meadow beside Strangford Lough, and the nearest record is around 5 miles away. Presumably there is an as-yet unkown site nearby, probably on private land. My question is: what is the best way to manage our meadow to encourage these butterflies to breed? We don't have Succisa, although I have plans to introduce it and this find has made me a lot more motivated in this respect. We are probably going to switch from mowing to cattle grazing this year, which should help. Are there any other plants I should introduce for nectar? How much Succisa does there need to be before the population can sustain itself? Will introducing more nectar plants encourage more vagrants from the local metapopulation to visit?

also if anyone knows which sex it is that would be very helpful too

It's worth having a chat with the Butterfly Conservation Northern Ireland staff, who I'm sure will be interested in hearing about new sites for Marsh Fritillary.

https://butterfly-conservation.org/in-y ... and-office

One could grow Devil's-bit scabious (DBS) in an estimated 6-15 litre pot in good potting compost, that was stood on a “water table” tray. On July 29th (flowering after most Field Scabious), this plant was in bud, about to flower profusely in August.
I thought that in a mechanical single cut meadow, one could imagine the meadow being mown at about 200mm from the ground, leaving clump forming leaves for Marsh Fritillary (MF) larva but removing old flower heads, so that the perennial plant, put more energy into leaf formation, rather than seed producing, so meadow cut timing was specifically important for management of that species.
It was thought to have been an optional management technique used (not by me), when the profusion of Marsh Fritillary larvae, were threatening DBS perennials from coming back the following year & slowing woodland succession, in a specific space.
DBS plug plants were available to be posted from:
naturescape.co.uk (Nottingham).

The Marsh Frit in the photo is a male. They must be in the area so any great management they will move in, with the other close relatives ive studied, there seems to be a 75% male 25% female split unless its a very small population when its near to the 50/50 split or more females. As big batch layers this would be normal as not to over populate the area, if it was 50/50 split, in areas without the parasites that is.

Marsh Fritillary larvae also seem to be more careful not to gorge themselves on the foodplant, so it keeps up with their eating, something that Glanvilles dont do and strip masssses of plantains in their last week as caterpillars, often killing the plantain itself.

You should see larval webs if they have bred nearby or in your meadow if foodplants are there, in captivity they have a wider selection including Honeysuckle, plantain ond other scabious.

Devil’s-bit scabious
 (DBS) Habitat Management.
 One thought was, that in the right habitat, a Marsh Fritillary will breed about as easily, as a Cabbage White butterfly (although “Euphydryas”,usually, only had a single annual brood), so a key, was mostly about providing the right sustainable habitat. Observance of the Wildlife and Countryside Act 1981, needed to be seen as a personal benefit.
Grazing

Consider managing habitat, with a species of grazing animal, that found scabious distasteful, so that other competing plants were eaten instead.

Consider, when best to cut a meadow, so that the late flowering plants, had a chance to propagate with seed dispersal.

Consider what best time of year to manage habitat for scabious growth.

After flowering, during late autumn, winter and early Spring, DBS clump formed, but was vulnerable to having been outgrown and shaded from light, by taller growing species, that might also have helped hide hibernating Marsh Fritillary larvae.

DBS might have been most vulnerable to Marsh Fritillary larvae grazers, during penultimate and final instar caterpillar growth in Spring warmth. the following pictures have been put in seasonal order. It was thought that during cold temperatures below ?ºC, the larva did not move around much and didn't eat much scabious.

April 16th 2019, a warm, sunny Spring day. Marsh Fritillary larvae, Chambers Farm Wood: May 9th 2020 DBS from retailer, grown in pots, starting its growth spurt period to flowering size:
 
 May 20th 2019, Marsh Fritillary during flight period Chambers Farm Wood:
 July 22nd 2018 3rd Instar Larvae 
July 29th 2020. DBS from retailer, growth seen, just before flowering: "Early" meadow cutting (Single cut) of DBS, might have prevented it flowering and propagating seed.

Meadow Cutting (Without me having identified any scabious)
August 5th 2018 for Lincolnshire Wildlife Trust at their headquarters in Horncastle. This was a traditional scything method of meadow cut. This was thought not to be Marsh Fritillary habitat:
 
August 9th 2019, Southrey Wood,
DBS might have been an essential native nectar source, for overwintering and late season butterflies:
 
DBS flowering September 13th 2017, Southrey Wood
(Picture to follow).
For further information, I would like to refer one back here again, having discovered the link from a previous post. My thoughts were worked out independently of this:
https://butterfly-conservation.org/site ... ry-psf.pdf
Interesting to note, that there was no mention that I could see, of specifically, letting old flower heads stand, to propagate seed by natural dispersal. Apparently, Sheep like eating scabious.
Kind Regards