Comparative reproduction of Varroa destructor in different types of Russian and Italian honey bee combs

Authors: De Guzman, Lilia; Rinderer, Thomas; Frake, Amanda

Submitted to: Experimental and Applied Acarology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/29/2008
Publication Date: 4/1/2008
Citation: De Guzman, L.I., Rinderer, T.E., Frake, A.M. 2008. Comparative reproduction of Varroa destructor in different types of Russian and Italian honey bee combs. Experimental and Applied Acarology 44:227-238

Interpretive Summary: We studied whether or not older comb supported less varroa reproduction in both Russian and Italian honey bees, whether Russian bees produced comb which inhibited varroa reproduction and whether comb foundation contained enough acaricides to influence varroa reproduction. This study was also conducted to determine if giving honey bee colonies specific types of combs might contribute to the Integrated Pest Management (IPM) of varroa mites. Neither foundation nor older comb clearly reduced the numbers of varroa mites. Russian honey bees built comb that resulted in fewer mites but only in Russian colonies. This study did not find a comb type useful for IPM. However, a new mechanism of resistance (some characteristic of the comb built by Russian honey bees) was discovered.

Technical Abstract: We studied whether or not older comb supported less varroa reproduction in both Russian and Italian honey bees, whether Russian bees produced comb which inhibited varroa reproduction and whether comb foundation contained enough acaricides to influence varroa reproduction. The major differences found in this study concerned stock. Overall, the Russian honey bees had lower (2.44 ± 0.18%) levels of varroa infestation than Italian honey bees (7.20 ± 0.60%). This decreased infestation resulted in part from a reduced number of viable female offspring per foundress in the Russian (0.85 ± 0.04 female) compared to the Italian (1.23 ± 0.04 females) honey bee colonies. In addition, there was an effect by the comb built by the Russian honey bee colonies that reduced varroa reproduction. When comparing combs having Russian or Italian colony origins, Russian honey bee colonies had more non-reproducing foundress mites and fewer viable female offspring in Russian honey bee comb. This difference did not occur in Italian colonies. The age of comb in this study had mixed effects. Older comb produced similar responses for six of the seven varroa infestation parameters measured. In colonies of Italian honey bees, the older comb (acaricide dark, AD) had fewer (1.13 ± 0.07 females) viable female offspring per foundress than were found in the acaricide new (AN) (1.21 ± 0.06 females) and pre-acaricide new (PAN) (1.36 ± 0.08 females) combs. This difference did not occur with Russian honey bee colonies where the number of viable female offspring was low in all three types of combs. The percentage of brood cells infested, percentage of multiple infestations, number of progeny per foundress and mortality of varroa all increased throughout the brood cycles. If the accumulation of cocoons has some effect on these parameters, it was undetectable owing to the overall mite population growth through these four brood cycles. This study did not find an acaricidal effect in comb drawn on foundation.