Effect of some characters on the population growth of mite Varroa jacobsoni in Apis mellifera L colonies and results of a bi‐directional selection

Abstract

Two lines of honey bees (Apis mellifera ligustica) were selectively propagated by instrumental insemination using the population growth of the Varroa mite as a criteria. Different infestation rates are at least partially genetic since selection produced significant bi‐directional differences between lines over a period of three subsequent generations. There was no correlation between several behavioural and physiological characteristics which are potentially associated with Varroa resistance (hygienic behaviour, physical damage to mites, infertility of the intruding mites) and the development of the Varroa population after artificial infestation. There was a positive significant correlation between the total mites in the colonies and the amount of reared brood. Colony infestation was also positively correlated with the amount of honey harvested.

Variable Population Growth of <I>Varroa destructor</I> (Mesostigmata: Varroidae) in Colonies of Honey Bees (Hymenoptera: Apidae) During a 10-Year Period

“…The annual average r values for most years in this study (r ϭ 0.105Ð 0.214 wk Ϫ1 ) were similar to the values from other studies (r ϭ 0.108 Ð 0.236 wk Ϫ1 ) (Thrybom and Fries 1991;Calatayud andVerdu 1993, 1995;Kraus and Page 1995;Marcangeli et al 1995;Branco et al 1999;Vandame et al 2000;Lodesani et al 2002). However, the three lowest values (r ϭ Ϫ0.008 Ð 0.047 wk Ϫ1 ) were well below the lowest growth rates reported elsewhere, and they occurred during a period (1998 Ð 2000) of below normal rainfall in Louisiana.…”

“…However, the three lowest values (r ϭ Ϫ0.008 Ð 0.047 wk Ϫ1 ) were well below the lowest growth rates reported elsewhere, and they occurred during a period (1998 Ð 2000) of below normal rainfall in Louisiana. At least one other study has noted differences in growth of mite populations among years in the same location (Lodesani et al 2002).…”

Biology and control of Varroa destructor

“…Additionally, most of these parameters are mutually influenced and part of complex multifactorial interactions. Some authors tried to extract the most important factors by the use of multifactorial analyses (Arechavaleta-Velasco and Guzman-Novoa, 2001; Harris et al, 2003;Lodesani et al, 2002). They confirmed significant correlations between the amount of brood and/or the fertility of the mites and population growth; however, prediction to what extent a starting mite population in the spring will increase until autumn is still not possible.…”

Genotypic variability and relationships between mite infestation levels, mite damage, grooming intensity, and removal of Varroa destructor mites in selected strains of worker honey bees (Apis mellifera L.)

“…Other studies have not found this correlation to be clear and significant (Lodensani et al, 2002;Locke and Fries, 2011), or have found that other factors, such as mite reproduction, better explain the variability in mite infestation levels between colonies (Ritter and de Jong, 1984;Rosenkranz and Engels, 1994;Harris and Harbo, 1999;Martin and Medina, 2004;Mondragon et al, 2005;Locke and Fries, 2011). Moreover, the validity of using the proportion of injured mites as a criterion to select bees for mite resistance has been questioned (Rosenkranz et al, 1997;Bienefeld et al, 1999), because a considerable number of injured mites found on hive bottom boards may not have been damaged by the bees.…”

“…The degree to which grooming behavior is affected by genetic effects is still not well known, and results of experiments are contradictory. For example, Moretto et al (1993) calculated an h 2 value of 0.71 for this behavior; however, later studies found low h 2 values for this trait Lodensani et al, 2002;Stanimirovic et al, 2010). It is possible that these contradictory results are a consequence of differences in the accuracy with which different assays assess grooming behavior.…”