They have this rather unappealing title because of the curious bags or larval sacs in which the caterpillars live after their equally remarkable birth through parthenogenesis - the process which requires only a mother. Dads have no role.
Mother bagworms go to extraordinary lengths to preserve their children, if deductions from scientific experiments are correct. One was prompted by a study of the largest of the UK's 20 species, which go under the typically catchy micro-moth names of Pachythelia villosella and Acanthopsyche atra, whose wingless adult females resemble maggots.
The micro-moth Bible suggests that this appearance is actually designed to attract a bird or reptile predator - the exact opposite of all the clever moth defences from camouflage to the jamming of bats' radar signals which have often been described on this blog. Why on earth so? The Bible describes experiments which have shown how bagworm larvae have thrived after being passed in bird and reptile poo, "suggesting that predators could be one way of helping the wingless female to disperse her offspring".
Dispersal is important for fresh generations, but this is an extraordinary phenomenon if true. I am surprised that generations of feminists have not used it as an analogy of the sacrifices made by women for others through history. If one such is reading this, please pass it to a wider world.
Bagworm cases are also fascinating, often adorned with bits of plant, soil or dead insect and thus assuming the weird appearance of the object which my granddaughter spotted on her kitchen ceiling, forming the subject of the last post. I am still awaiting the views of the micro-moth experts on the saintly Upper Thames Moths blog on whether the commentor's diagnosis of the mystery object is correct. But its role in revealing bagworms to me has been marvellous. Renewed thanks.
Back home there was a Brimstone- above - in the garden and Holly Blues, Speckled Woods and Tortoiseshells are all abundant among our butterflies. The moth trap, too, enjoyed its best night of the year last night and here are some of its inhabitants, the first three of them very welcome annual highlights which I have been expecting for the last few weeks
|Small Magpie (above a lurking micro)|
|Loads of annoying brown and grey jobbies, including...|
|...this one (Update with MANY thanks to Trent in Comments: this is a Brown Rustic) and...|
|...this one...(Update, which thanks to Trent again, is a Middle-barred Minor whose prominent middle bar I should have clocked)|