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International audienceThis study adds new data from Korea and the Philippines to earlier mitochondrial DNA (mtDNA)-based studies of the phylogeography of Asian cavity-nesting honeybees. A non-coding region that lies between the leucine tRNA gene and the cytochrome oxidase II gene of the mitochondrial genome was sequenced in bees from 153 colonies of Apis cerana and A. nigrocincta, revealing 41 different haplotypes. Five sequences could not be aligned with the others, two (from India and Sri Lanka) because the sequences were exceedingly A+T rich, and three (from Taiwan, the Philippines, and A. nigrocincta) because most of the non-coding sequence was absent. The remaining 36 sequences were aligned, and used in a phylogenetic analysis of A. cerana and A. nigrocincta populations. Both neighbor-joining and parsimony analyses were carried out, yielding similar results. We found five major groups of haplotypes: an Asian mainland group, a Sundaland group, a Palawan group, a Luzon-Mindanao group, and A. nigrocincta. The geographic distribution of these mtDNA haplotypes appears to be strongly influenced by changes in sea-level during Pleistocene glaciations.Biogéographie d'Apis cerana F. et d'Apis nigrocincta Smith : résultats des études d'ADNmt. Nous avons étudié la variation de la séquence d'ADN dans une région non codante des génomes mitochondriaux de 153 colonies d'A. cerana et d'A. nigrocincta. Les échantillons d'A. cerana provenaient d'Inde, du Sri Lanka, du Népal, de Thaïlande, de Chine (Hong Kong), de Taïwan, de Corée, du Japon, de la péninsule de Malaisie et de Bornéo, des îles indonésiennes de Java, Bali, Lombok, Timor occidental, Flores et Sulawesi (Fig. 1, Tab. I) et des îles Philippines de Palawan, Luzon, Leyte, Mindanao, Cebu, Panay et Negros (Fig. 2, Tab. I). Les échantillons de nigrocincta venaient des îles indonésiennes de Sulawesi et de Sangihe. La figure 3 montre les séquences d'ADNmt trouvées dans les nouveaux échantillons de Corée (Japon1, Corée4, Corée7 et Corée9) et dans 11 échantillons des Philippines (Palawan1, Palawan2, Cebu1, MindanaoP, Luzon1, Luzon2, MindanaoL, Mindanao11, Mindanao2, Negros1 et PhilippineShort). Avec les haplotypes publiés précédemment [CITE] on arrive à un total de 41 séquences différentes non codantes parmi les 153 colonies échantillonnées. Deux des 6 haplotypes observés parmi les colonies d'Inde et du Sri Lanka n'ont pu être alignées avec les autres séquences d'A. cerana. La plus grande partie de la région non codante était absente de 3 haplotypes (TaïwanShort, SulawesiShort et PhilippineShort) (Figs. 3 et 7). La séquence non codante a probablement été perdue indépendamment à trois reprises. L'analyse phylogénétique des 36 séquences non codantes alignées (les séquences courtes et les deux séquences non alignées mises à part) a été faite à l'aide de deux méthodes statistiques (neighbor-joining et parcimonie maximum). Il en est résulté différents dendogrammes : le dendogramme de la figure 4 est issu de l'algorithme de neighbor-joining, celui de la figure 5 de l'analyse de parc...

The effects of changes in spring pollen diet on the development of honey bee, Apis mellifera L. (Hymenoptera: Apidae), colonies were examined in a 3-yr study (2002-2004). Pollen-supplemented and pollen-limited conditions were created in colonies every spring, and brood rearing and honey yields were subsequently monitored throughout the summer. In all 3 yr, colonies that were supplemented with pollen or a pollen substitute in the spring started rearing brood earlier than colonies in other treatment groups and produced the most workers by late April or early May. In 2002, these initial differences were reflected by a two-fold increase in annual honey yields by September for colonies that were pollen-supplemented during the spring compared with pollen-limited colonies. In 2003 and 2004, differences between treatment groups in the cumulative number of workers produced by colonies disappeared by midsummer, and all colonies had similar annual honey yields (exception: in one year, productivity was low for colonies supplemented with pollen before wintering). Discrepancies between years coincided with differences in spring weather conditions. Colonies supplemented with pollen or a substitute during the spring performed similarly in all respects. These results indicate that an investment in supplementing the pollen diet of colonies would be returned for situations in which large spring populations are important, but long-term improvement in honey yields may only result when spring foraging is severely reduced by inclement weather. Beekeepers should weigh this information against the nutritional deficiencies that are frequently generated in colonies by the stresses of commercial management.

Little is known about the development of the overwintering population of honey bees (Apis mellifera) colonies in temperate climates. Colonies were subjected to one of four requeening treatments: requeened in mid-summer with a mated, virgin or colony-reared queen, or left with the original queen (control). Worker survival in cohorts of newly emerged bees introduced to colonies in late summer and fall was followed until all marked bees had died. Winter bees were reared over a relatively similar length of time in all treatments, but they appeared earlier in control colonies compared to requeened colonies. The gradual increase in proportion of winter bees over time was similar among treatments, but requeened colonies lagged behind control colonies. The bulk of winter bees appeared much earlier in control colonies than in colonies that were requeened. This response demonstrates that cues within the colony (i.e., differences due to requeening) are perceived by workers as part of the conditions that influence summer bee or winter bee status.

1. Each autumn in northern regions, honeybee colonies shift from populations of short‐lived workers that actively rear brood to broodless populations of long‐lived winter bees. To determine if dwindling pollen resources trigger this transition, the natural disappearance of external pollen resources was artificially accelerated or delayed and colonies were monitored for effects on the decline in brood‐rearing activity and the development of populations of long‐lived winter bees. 2. Delaying the disappearance of pollen resources postponed the decline in brood rearing in colonies. Colonies with an extended supply of pollen reared workers longer into October before brood rearing ended than control colonies or colonies for which pollen supply was cut short artificially in autumn. 3. Colonies with extended pollen supply produced more workers throughout autumn than colonies with less pollen, but the development of the population of long‐lived winter bees was delayed until relatively later in autumn. Colonies produced similar numbers of winter bees, regardless of the timing of the disappearance of pollen resources. 4. Mean longevity of autumn‐reared workers was inversely related to the amount of brood remaining to be reared in colonies when workers eclosed. Consequently, long‐lived workers did not appear in colonies until brood rearing declined, which in turn was controlled by the availability of pollen. 5. Dwindling pollen resources provide a powerful cue that initiates the transition to populations of broodless winter bees because it directly affects the brood‐rearing capacity of colonies and indirectly indicates deteriorating environmental conditions associated with the approach of winter.