Investigação

Início / Investigação / Apresentações / Varroa destructor population dynamics in a Mediterranean climate

Varroa destructor population dynamics in a Mediterranean climate

Ano
2002
Abstract

In Mediterranean climates, the milder winter climatic conditions and the possibility to collect food resources during a considerable part of the winter account for the permanent brood- rearing activity of honey bee colonies. This is relevant for the intrinsic growth rate of Varroa in these regions. In this context, this study aimed at investigating the impact of Varroa infestation on the amount of capped worker and drone brood, adult bee population and honey production on A. m. iberica colonies kept in a Mediterranean climate (N38º34', W07º54'). Furthermore, it took also into account the population dynamics of the mite and its distribution between brood and adult honey bees. Colonies were set-up and either maintained Varroa-free or artificially Varroa-infested and allowed to develop that infestation. Periodical evaluations of those colonies unravelled the pattern of colony capped worker and drone brood, adult bee population and honey storage across the season, and disclosed the population dynamics of the Varroa mite.All experimental colonies showed similar temporal patterns, where considerable increases in the studied variables were only observed from early spring onwards. Progressive reductions on capped worker and drone brood, bee population and honey storage in Varroa-infested colonies (compared with non-infested ones) became increasingly evident during spring and summer. By the end of the experiment, Varroa-infested colonies showed a unitary average reduction of 62 % in honey storage, meaning an annual colony loss of 18 kg of honey (compared with the average 29 kg of honey stored in non-infested colonies). This resulted not only from the overriding effect that Varroa infestation had on the adult honey bee population of infested colonies, but also from a statistically significant reduction on the amount of capped honey stored per bee and day during the main honey flow season, suggesting a direct effect of Varroa infestation on honey hoarding behaviour. Impressive Varroa population increases were observed in Varroa infested colonies, also reflecting the particularly high Varroa reinfestation rates observed in early winter. In infested colonies, mean increases of approximately 5487 % in established Varroa populations were observed within 195 days after artificial infestation. Colonies' mean Varroa population was then 3911 ± 831, corresponding to daily finite rates of Varroa population increase of 1.0208. An overall experiment daily finite rate of Varroa population increase of 1.0124 was observed. Most Varroa were found in capped worker brood, which also showed the highest apparent Varroa infestation rates

Palavras Chave

Varroa; Dinâmica populacional; Abelhas / Varroa; Population dynamics; Honey bees.

Tipo de Apresentação
Comunicação oral
Tipo de Revisão
Internacional
Âmbito Geográfico
Internacional
Situação
Publicado
Área de Trabalho
Referência

Murilhas, A. (2002). Varroa destructor population dynamics in a Mediterranean climate. 7th Expert Meeting of the European Group for Integrated Varroa Control, pp.1-8. European Group for Integrated Varroa Control. Bolonha, Itália.