Varroa estimations during winter.

[greengumbo]

Very interesting Calum. Do you have a link to that (though I suspect my German will not be good enough ...)? Female mites in the presence of brood have a life expectancy of ~27 days. In the absence of brood it's months I believe. I wonder if mites raised in the presence of brood are predominantly committed to the shorter life cycle, or whether - like their bee hosts - 'winterised' mites are reared late in the season to wait out the long broodless period.

I'd like to find these mites raised in the absence of brood

Seriously though I've thought about this a fair bit in the past. I bet that just as winter bees are physiologically different, winter (or lets call them late autumn raised) mites have a very different physiology - lack of feeding for one thing. Jury is still out on whether they feed at all on adult bees while living phoreticaly. I've PM'd you as well fatshark.

[fatshark]

OK, OK ... I was djrunk ... one possibility might be that mites change their physiology according to the duration of the phoretic stage perhaps. If they're raised (on brood clever clogs ) and after the usual few days out and about dive into a new cell to make whoopee with themselves then they never change from being 'young' mites physiologically. However, if there's no brood to be had they're 'forced' into a different physiological state.

I guess this might (ho, ho, mite geddit?!) be tested by looking at what happens to and with phoretic mites from a terminally broodless colony when given a frame of eggs/larvae. Do the majority dive in, or only a subset ... and, if so, what's special about them? Are those that are left duds? Presumably not or winter miticides would be less dramatically beneficial than they are.

Which also makes me wonder about the post from Calum. What's the advantage to the mite NOT to be brood-associated in midwinter? If there's brood there surely they'd want to get in and reproduce? What proportion of capped pupae fail during winter? If it's high I can see there'd be an advantage to wait a bit. I'd have thought a heavily infested colony would have a high mite density/cell in the winter.

Interesting.

PS I thought that phoretic mites did feed on adult bees ... others do to ... though just 'cos it's on the internet doesn't make it true. Didn't Bowen-Walker do some 14C studies??
PPS. I've heard it's witchcraft raising mites in the absence of brood. Only the truly gifted have the knack.