Honey bee colony losses in Brazil in 2018-2019

Abstract

A research was conducted to assess honey bee colony losses in Brazil, including their likely causes. Beekeepers responded to two complete annual questionnaires (n=268 in 2018 and n=254 in 2019). There was a total of 175,003 hives of Africanized honey bees (Apis mellifera Linnaeus), (µ=335 hives per beekeeper, min=9 and Max=3,600), of which 27.2% were lost. A Generalized Linear Model (GLM) for total loss (TL) and a Wald method for average loss (AL) were used to estimate 95% confidence intervals (CI) for loss rates based on year: 2018, TL=30.5%, CI (28.5-32.4), AL=39.5, CI (37.0-41.9); and 2019, TL=23.8%, CI (22.5-25.2), AL=31.3%, CI (29.5-33.1). Pesticides were speculated to be the leading cause of colony losses (47.3%), followed by climate (drought, flood, rain: 11.6%), malnutrition (lack of flowering, lack of energy and/or protein source, wrong nutrition: 9.7%), absconding (10.2%), mismanagement (wrong migratory activity, migration to mangrove, beekeeper’s personal problems: 7.9%), predators (3.9%), queen problems (2.8%), and varroa (1.6%). Other parasites, theft, toxic pollen (Brazilian sacbrood) and bushfires accounted for the remaining 5% of losses. Due to tropical temperatures, there is no substantial winter loss. In contrast, the highest incidence of losses occurred from September to January, coinciding with the intense agricultural activity. In summary, according to participants, there were significantly higher losses in 2018 compared to 2019, with pesticides alleged to be the main cause of honey bee colony losses in Brazil. However, beekeepers usually multiply colonies during the following season, sustaining pollination and honey production, thereby supporting agricultural activity.