Field evaluation of Varroa-resistance traits in surviving Apis mellifera colonies in Argentina

Exploring Two Honey Bee Traits for Improving Resistance Against Varroa destructor: Development and Genetic Evaluation

Insects ◽

10.3390/insects12030216 ◽

2021 ◽

Vol 12 (3) ◽

pp. 216

Author(s):

Matthieu Guichard ◽

Benoît Droz ◽

Evert W. Brascamp ◽

Adrien von Virag ◽

Markus Neuditschko ◽

...

Keyword(s):

Apis Mellifera ◽

Honey Bee ◽

Honey Bees ◽

Varroa Destructor ◽

Field Trial ◽

Genetic Evaluation ◽

Phenotypic Correlation ◽

Apis Mellifera Mellifera ◽

Novel Traits ◽

Resistance Traits

For the development of novel selection traits in honey bees, applicability under field conditions is crucial. We thus evaluated two novel traits intended to provide resistance against the ectoparasitic mite Varroa destructor and to allow for their straightforward implementation in honey bee selection. These traits are new field estimates of already-described colony traits: brood recapping rate (‘Recapping’) and solidness (‘Solidness’). ‘Recapping’ refers to a specific worker characteristic wherein they reseal a capped and partly opened cell containing a pupa, whilst ‘Solidness’ assesses the percentage of capped brood in a predefined area. According to the literature and beekeepers’ experiences, a higher recapping rate and higher solidness could be related to resistance to V. destructor. During a four-year field trial in Switzerland, the two resistance traits were assessed in a total of 121 colonies of Apis mellifera mellifera. We estimated the repeatability and the heritability of the two traits and determined their phenotypic correlations with commonly applied selection traits, including other putative resistance traits. Both traits showed low repeatability between different measurements within each year. ‘Recapping’ had a low heritability (h2 = 0.04 to 0.05, depending on the selected model) and a negative phenotypic correlation to non-removal of pin-killed brood (r = −0.23). The heritability of ‘Solidness’ was moderate (h2 = 0.24 to 0.25) and did not significantly correlate with resistance traits. The two traits did not show an association with V. destructor infestation levels. Further research is needed to confirm the results, as only a small number of colonies was evaluated.

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Descriptive Analysis of the Varroa Non-Reproduction Trait in Honey Bee Colonies and Association with Other Traits Related to Varroa Resistance

Insects ◽

10.3390/insects11080492 ◽

2020 ◽

Vol 11 (8) ◽

pp. 492 ◽

Cited By ~ 1

Author(s):

Sonia E. Eynard ◽

Christina Sann ◽

Benjamin Basso ◽

Anne-Laure Guirao ◽

Yves Le Conte ◽

...

Keyword(s):

Honey Bee ◽

Empirical Bayes ◽

Descriptive Analysis ◽

Field Studies ◽

Colony Losses ◽

Bee Colony ◽

Bee Health ◽

Honey Bee Health ◽

Varroa Resistance ◽

Resistance Traits

In the current context of worldwide honey bee colony losses, among which the varroa mite plays a major role, the hope to improve honey bee health lies in part in the breeding of varroa resistant colonies. To do so, methods used to evaluate varroa resistance need better understanding. Repeatability and correlations between traits such as mite non-reproduction (MNR), varroa sensitive hygiene (VSH), and hygienic behavior are poorly known, due to practical limitations and to their underlying complexity. We investigate (i) the variability, (ii) the repeatability of the MNR score, and (iii) its correlation with other resistance traits. To reduce the inherent variability of MNR scores, we propose to apply an empirical Bayes correction. In the short-term (ten days), MNR had a modest repeatability of 0.4, whereas in the long-term (a month), it had a low repeatability of 0.2, similar to other resistance traits. Within our dataset, there was no correlation between MNR and VSH. Although MNR is amongst the most popular varroa resistance estimates in field studies, its underlying complex mechanism is not fully understood. Its lack of correlation with better described resistance traits and low repeatability suggest that MNR needs to be interpreted cautiously, especially when used for selection.

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Evaluation of Traits for the Selection of Apis Mellifera for Resistance against Varroa Destructor

Insects ◽

10.3390/insects11090618 ◽

2020 ◽

Vol 11 (9) ◽

pp. 618 ◽

Cited By ~ 3

Author(s):

Ralph Büchler ◽

Marin Kovačić ◽

Martin Buchegger ◽

Zlatko Puškadija ◽

Andreas Hoppe ◽

...

Keyword(s):

Apis Mellifera ◽

Varroa Destructor ◽

Infestation Rate ◽

Mite Infestation ◽

Behavioral Traits ◽

Bee Colony ◽

Mite Reproduction ◽

Varroa Resistance ◽

Colony Survival ◽

Selection Of

Infestation with Varroa destructor is a serious cause of bee colony (Apis mellifera) losses on a global level. However, the presence of untreated survivor populations in many different regions supports the idea that selection for resistance can be successful. As colony survival is difficult or impossible to measure, differences in mite infestation levels and tests for specific behavioral traits are used for selective breeding for Varroa resistance. In this paper we looked into different definitions of mite infestation and linked these with brood hygiene (pin test), brood recapping and suppressed mite reproduction. We based our analyses on datasets of Apis mellifera carnica from three countries: Austria (147 records), Croatia (135) and Germany (207). We concluded that bee infestation in summer, adjusted for the level of natural mite fall in spring, is a suitable trait in the breeding objective, and also suggested including brood infestation rate and the increase rate of bee infestation in summer. Repeatability for bee infestation rate was about 0.55, for cells opened in pin test about 0.33, for recapping 0.35 and for suppressed mite reproduction (SMR) virtually zero. Although in most cases we observed correlations with the expected sign between infestation parameters and behavioral traits, the values were generally low (<0.2) and often not significantly different from zero.

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Field evaluation of nine families of honey bees for resistance to tracheal mites

The Canadian Entomologist ◽

10.4039/ent133793-6 ◽

2001 ◽

Vol 133 (6) ◽

pp. 793-803 ◽

Cited By ~ 2

Author(s):

Dennis van Engelsdorp ◽

Gard W. Otis

Keyword(s):

Apis Mellifera ◽

Formic Acid ◽

Honey Bee ◽

Honey Bees ◽

Field Evaluation ◽

Acarapis Woodi ◽

Tracheal Mite ◽

Colony Performance ◽

Tracheal Mites ◽

Mite Infestations

AbstractWe evaluated the resistance to tracheal mites, Acarapis woodi (Rennie) (Acari: Tarsonemidae), of colonies of honey bees, Apis mellifera L. (Hymenoptera: Apidae), headed by daughters of three queens from each of three honey bee stocks: (i) British Columbia "mite-resistant stock, (ii) Buckfast "mite-resistant" stock, and (iii) Canadian unselected stock. Colonies of all nine families were distributed among four apiaries; half of the colonies in each apiary were treated with formic acid to attempt to control tracheal mites. The study documented significant differences in resistance to tracheal mites among the families of bees, even within each of the three stocks. After the first 4 months of study (by November 1993), differences in mite infestations had developed among the nine families. Formic acid treatments had either short-lived effectiveness (1993) or no effect (1994) on tracheal mite infestations, thereby eliminating the opportunity to evaluate colony performance in the absence of mites. Mite infestations varied significantly among apiary sites. This study highlights the value of evaluating sets of colonies headed by sister queens when identifying mite-resistant stock for breeding purposes.

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Descriptive Analysis of the Varroa Non-reproduction Trait in Honey Bee Colonies and Association with Other Traits Related to Varroa Resistance

10.20944/preprints202007.0166.v1 ◽

2020 ◽

Cited By ~ 1

Author(s):

Sonia E. Eynard ◽

Christina Sann ◽

Benjamin Basso ◽

Anne-Laure Guirao ◽

Yves Le Conte ◽

...

Keyword(s):

Honey Bee ◽

Empirical Bayes ◽

Descriptive Analysis ◽

Field Studies ◽

Colony Losses ◽

Bee Colony ◽

Bee Health ◽

Honey Bee Health ◽

Varroa Resistance ◽

Resistance Traits

In the current context of worldwide honey bee colony losses, among which the varroa mite plays a major role, hope to improve honey bee health lies in part in the breeding of varroa resistant colonies. To do so, methods used to evaluate varroa resistance need better understanding. Repeatability and correlations between traits such as Mite Non-Reproduction (MNR), Varroa Sensitive Hygiene (VSH) and hygienic behaviour are poorly known, due to practical limitations and to their underlying complexity. We investigate (i) the variability, (ii) repeatability of the MNR score and (iii) its correlation with other resistance traits. To reduce the inherent variability of MNR scores, we propose to apply an Empirical Bayes correction. On the short-term (ten days) MNR had a modest repeatability of 0.4 whereas on the long- term (a month) it had a low repeatability of 0.2, similar to other resistance traits. Within our dataset there was no correlation between MNR and VSH. Although MNR is amongst the most popular varroa resistance estimates in field studies, its underlying complex mechanism is not fully understood. Its lack of correlation with better described resistance traits and low repeatability suggest that MNR need to be interpreted cautiously, especially when used for selection.

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Hygienic removal of freeze-killed brood does not predict Varroa-resistance traits in unselected stocks

Journal of Apicultural Research ◽

10.1080/00218839.2018.1426350 ◽

2018 ◽

Vol 57 (2) ◽

pp. 292-299 ◽

Cited By ~ 8

Author(s):

Gil Leclercq ◽

Tjeerd Blacquière ◽

Nicolas Gengler ◽

Frédéric Francis

Keyword(s):

Varroa Resistance ◽

Resistance Traits

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Differentiation Processes of the Ocellar Retina of the Honeybee (Apis Mellifera L.)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100159692 ◽

1990 ◽

Vol 48 (3) ◽

pp. 430-431

Author(s):

Maria Anna Pabst

Keyword(s):

Apis Mellifera ◽

Distal Part ◽

Cell Layer ◽

Single Layer ◽

Photoreceptor Cells ◽

Distal Segment ◽

Compound Eyes ◽

Thin Sections ◽

Ultrastructural Studies ◽

Adult Worker

In addition to the compound eyes, honeybees have three dorsal ocelli on the vertex of the head. Each ocellus has about 800 elongated photoreceptor cells. They are paired and the distal segment of each pair bears densely packed microvilli forming together a platelike fused rhabdom. Beneath a common cuticular lens a single layer of corneagenous cells is present.Ultrastructural studies were made of the retina of praepupae, different pupal stages and adult worker bees by thin sections and freeze-etch preparations. In praepupae the ocellar anlage consists of a conical group of epidermal cells that differentiate to photoreceptor cells, glial cells and corneagenous cells. Some photoreceptor cells are already paired and show disarrayed microvilli with circularly ordered filaments inside. In ocelli of 2-day-old pupae, when a retinogenous and a lentinogenous cell layer can be clearly distinguished, cell membranes of the distal part of two photoreceptor cells begin to interdigitate with each other and so start to form the definitive microvilli. At the beginning the microvilli often occupy the whole width of the developing rhabdom (Fig. 1).

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