In most species, normal diapause termination appears to require an interval of exposure to low temperatures (Mattoon et al. 1971, Hodek 2002, James 2008). In this study, species with stronger diapause, and possibly longer low-temperature termination requirements, suffered higher mortality under “forced” diapause termination conditions. Under natural conditions, termination probably occurs in winter followed by a temperature maintained quiescence — Ann. Entomol. Soc. Am. 107(1): 163-169 (2014)
* * *
The condition of post-diapause adults is indicated by their reproduction and longevity. It is perhaps the most serious drawback of studies on diapause development that the condition of post-diapause insects, stressed by Andrewartha (1952) by his words: "healthy completion of diapause", has been greatly neglected.
The success of diapause completion can be estimated by at least four parameters; none of them can be dismissed. (1) The easily visible consequence of diapause completion, such as incidence of developmental steps, often is the only parameter measured. (2) The rate of diapause development, i.e., the delay or duration is frequently recorded. (3) The effect on synchronization of life-history events has been much less often considered. (4) In spite of its importance, the vigour of post-diapause insects (indicated by long-term survival or fecundity) has usually been neglected. — Eur. J. Entomol. 99: L63-l73, (2002)
* * *
Colonies with midwinter brood rearing had populations by 1 May more than 4 times those of colonies without mid-winter brood rearing. Furthermore, the colonies with winter brood rearing swarmed substantially earlier than did those of the other group (mid May to late May v. late June to early July). Seeley, Visscher. Survival of honeybees in cold climates: the critical timing of colony growth and reproduction. Ecological Entomology 10, 81-88 (1985)
* * *
Comments:
Seeley and Visscher prevented brood rearing and saw a drastic effect on swarming. Swarming may not be in the interest of beekeepers but it is the way that honey bees reproduce colonies, hence its importance to the species and its evolutionary significance. If you view the colony life cycle as a whole, it parallels the life cycle of solitary insects in important ways.
The queen is mated in summer, enters a diapause, emerges from diapause and establishes a nest, where the next generation of queens is born. The old queen swarms out after completion of her role in establishing conditions for her daughter queen’s survival.
Having kept bees in San Diego, I can tell you we seldom saw the intense swarming that is often the case in Northern climates. This may be directly related to the lack of the pause in brood rearing. On the other hand, swarming may be stimulated by the very quick buildup seen in Northern bees, or the quick shift from cold to warm weather.
PLB
***********************************************
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
|
