Commercial probiotic formulas Bactocell and Levucell promote spring brood production in Apis mellifera L. (Hymenoptera: Apidae) colonies

Honey bees are essential pollinators for several economically important crops. In temperate countries, honey bee colonies face multiple threats during the overwintering period, such as food availability, diseases, and confinement. Beekeepers commonly use chemicals to improve colony health during winter, but these products can have a negative impact on bee health and pathogens can develop resistance to them. Thus, there is a need for further development of alternative treatments. The aim of this study was to evaluate the impact of one endogenic bacterium (Bombella apis) and 2 commercial probiotic formulas (Bactocell and Levucell) on colony survival, spring development, and Vairimorpha (formerly Nosema) spp. spore count. Probiotic treatments were given in 1: 1 sugar syrup in October 2017 and April 2018, once a week for 2 wk. One experimental group was given Fumagilin-B, the only product approved in Canada to prevent nosemosis, once in October. The administration of 2 commercial probiotics, Bactocell (Pediococcus acidilactici) and Levucell (Saccharomyces cerevisiae boulardii), led to a significant increase in the number of sealed brood cells in spring. None of the probiotic treatments impacted the honey bee gut load of Vairimorpha spp. spores. The results suggest that beneficial microorganisms can improve spring development and performance of honey bee colonies.

Preservation of Domesticated Honey Bee (Hymenoptera: Apidae) Drone Semen

Preservation of honey bee (Apis mellifera L., Hymenoptera: Apidae) sperm, coupled with instrumental insemination, is an effective strategy to protect the species and their genetic diversity. Our overall objective is to develop a method of drone semen preservation; therefore, two experiments were conducted. Hypothesis 1 was that cryopreservation (-196 °C) of drone semen is more effective for long-term storage than at 16 °C. Our results show that after 1 yr of storage, frozen sperm viability was higher than at 16 °C, showing that cryopreservation is necessary to conserve semen. However, the cryoprotectant used for drone sperm freezing, dimethyl sulfoxide (DMSO), can harm the queen and reduce fertility after instrumental insemination. Hypothesis 2 was that centrifugation of cryopreserved semen to reduce DMSO prior to insemination optimize sperm quality. Our results indicate that centrifuging cryopreserved sperm to remove cryoprotectant does not affect queen survival, spermathecal sperm count, or sperm viability. Although these data do not indicate that centrifugation of frozen-thawed sperm improves queen health and fertility after instrumental insemination, we demonstrate that cryopreservation is achievable, and it is better for long-term sperm storage than above-freezing temperatures for duration of close to a year.

Pupal development of Aethina tumida (Coleoptera: Nitidulidae) in thermo-hygrometric soil conditions encountered in temperate climates

The pupal development of Aethina tumida Murray (Coleoptera: Nitidulidae) was studied at various combinations of thermo-hygrometric soil conditions (temperatures of 16, 18, and 20 degrees C and soil water content levels of 0.37, 0.56, and 0.73 m3 water per cubic meter of dry soil) representative of southeastern Canada. Survivorship and development duration of A. tumida pupae, as well as sex ratio and life span of emerging adults, were assessed. Assays were conducted in growth chambers on an average of 50 third-instar larvae per thermo-hygrometric combination. Results show that survivorship of pupae decreased with lower temperature and higher soil water content. Pupal development time shortened as temperature increased (69-78 d at 16 degrees C, 47-54 d at 18 degrees C, and 36-39 d at 20 degrees C), but was longer in dryer soil. Optimal soil water content for pupal development was 0.56 m3 water per cubic meter of soil. We estimated that the minimum development temperature for pupae is between 10.2 and 13.2 degrees C, depending on soil water content. The sex ratio of emerging adults was influenced by soil water content. We measured one female to one male for dry and intermediately wet soils and three females to one male for wet soils. Higher soil water content reduced the life span of emerging adults by half. This study contributes to a better understanding of A. tumida population dynamics in eastern Canada.

Investigation of an outbreak of cercarial dermatitis

We present the investigation of an outbreak of cercarial dermatitis that occurred in a recreational-tourist lake in the Quebec City region (Canada) in the summer of 1999. A case-reporting form was sent to 450 families likely to have activities that would bring them in contact with the lake's water. The snails were characterized and the prevalence of their infestation by schistosomes was investigated. In total, 63 episodes consistent with cercarial dermatitis were reported. Sixty-nine percent of the cases occurred from swimming at the same beach. This location was the one where the only population of snails in the lake was identified. Shoreline residents were informed that they should not feed waterfowl, and a clean-up of the snail population was done at the start of the following summer. There were no cases of cercarial dermatitis at this site the following summer.