I think I'm not missing the point so much as trying to refine the point. If you read the two abstracts I've pasted below you might start to see my line of thinking. In addition, A. V. Murylev 2011 comments that in Russia they use cold resistance to differentiate between subspecies of Apis mellifera. Qin Ming (2017) in China does something similar when she compares the cold resistance between Apis cerana and Apis mellifera ligustica.
I think it's an interesting idea to use the line where the Africanized honey bees cease to handle winter well in North America when we're deciding if wintering studies done in one area of North America are relevant for another area. I'll admit, the line where AHB ceases to overwinter may be an irrelevant line for European honey bees, so may not be a very good idea, but apparently something significant happens along that line, at least for AHBs.
I'm also subtly rejecting Randy's notion that the "proper" term for winter bees is "diutinus" bees. I think there is a difference between the two, although by saying so I'm applying categorical labels to what is actually a continuous variable. I can certainly agree that bees can extend their lifespan in the face of drought, extended poor weather, and an absence of brood. However, I do think there is a difference between bees being able to extend their lifespan for a month or two or three during a drought and bees being able to fully transition to a winter bee state, where they can survive for 250 days and withstand temperatures as cold as -9 C or -10 C without freezing solid. There are distinct differences between Apis mellifera subspecies in their ability to withstand winter and one simple label of "diutinus" obscures that fact. I guess I'm saying lots of insects can be diutinus but only a unique subset of insects and some subspecies of Apis mellifera can go so far as to create winter bees.
From Higher vitellogenin concentrations in honey bee workers may be an
adaptation to life in temperate climates
G.V. Amdam et al 2005
Abstract. The honey bee originated in tropical Africa and
later dispersed to northern Europe. It has been suggested that
a higher hemolymph storage capacity for the glycolipoprotein
vitellogenin evolved in temperate regions, and that the
trait constitutes an adaptation to a strongly seasonal environment.
We have investigated whether the relative vitellogenin
levels of European and African honey bees are in accordance
with this hypothesis. Our data indicate that European workers
have a higher set-point concentration for vitellogenin
compared to their African origin. Considered together with
available life history information and physiological data, the
results lend support to the view that “winter bees”, a longlived
honey bee worker caste that survives winter in temperate
regions, evolved through an increase in the worker bees’
capacity for vitellogenin accumulation.
From Honey Bees in the Tropics Show
Winter Bee-Like Longevity in
Response to Seasonal Dearth and
Brood Reduction
Stephanie Feliciano-Cardona et al 2020:
We found that worker longevity in the gAHB colonies [Africanized Honey Bees in Puerto Rico] increases in the wet season (maximum longevity ca. 88 days vs. 56 days) in response to dearth of floral resources. A more
pronounced increase in longevity was observed in response to manipulative reduction
of the amount of open brood (maximum longevity 154 days).We showed that gAHBs do not lack the adaptation to alter their longevity seasonally, though the magnitude of changes is less intense than those observed in EHBs during temperate
winters. This suggests that increased longevity in response to limited capacity to rear
brood is a shared character of Africanized and European honey bees.
(This is Tracey again- for comparison, Apis mellifera can live for a maximum of 212-252 days (Mattila, Harris, and Otis 2001 referencing Fukuda and Sekiguchi 1966).)
***********************************************
The BEE-L mailing list is powered by L-Soft's renowned
LISTSERV(R) list management software. For more information, go to:
http://www.lsoft.com/LISTSERV-powered.html
|
