Maternal and pre eclosional factors affecting alarm behaviour in adult honey bees (Apis mellifera L.)

In various orchard fruit trees, thinning of blossoms and fruits is important to increase fruit size and quality and to promote a new bloom in the following season. Several chemical thinning agents are currently commercially available, but they are inconsistent and produce side effects in crop plants and insect pollinators. Because of environmental concerns, developing alternative eco-friendly bloom thinning agents is necessary. We developed an eco-friendly bloom thinning formulation (BTF) using minerals and extracts of various medicinal plants. Our BTF spray (0.1%, <i>w/v</i>) decreased the number of fruits per tree (46.5%) and fruit yield per tree (81.5%) but increased the fruit weight (196.8%) compared with the control treatment; the spray induced a small number of larger mango fruits in the treated trees. We also investigated the effect of BTF on the olfactory behavior of <i>Apis mellifera</i> L. (Hymenoptera, Apidae), a major insect pollinator. We analyzed the behavioral changes of adult workers at two different concentrations (0.1% and 1%) of nine different BTF spray components using a Y-tube olfactometer. The behavioral responses of honey bees to nine BTF components showed significant differences. However, honey bees showed no clear attraction or repellent behavior towards the tested BTF components. Our results suggest that the newly developed eco-friendly BTF is practically applicable in mango orchards without interrupting honey bee behavior.

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Review on Sublethal Effects of Environmental Contaminants in Honey Bees (Apis mellifera), Knowledge Gaps and Future Perspectives

International Journal of Environmental Research and Public Health ◽

10.3390/ijerph18041863 ◽

2021 ◽

Vol 18 (4) ◽

pp. 1863 ◽

Cited By ~ 2

Author(s):

Agata Di Noi ◽

Silvia Casini ◽

Tommaso Campani ◽

Giampiero Cai ◽

Ilaria Caliani

Keyword(s):

Apis Mellifera ◽

Honey Bees ◽

Sublethal Effects ◽

Integrated Approach ◽

Anthropogenic Contamination ◽

Knowledge Gaps ◽

Pollination Services ◽

General Decline ◽

Polycyclic Aromatic ◽

The Impact

Honey bees and the pollination services they provide are fundamental for agriculture and biodiversity. Agrochemical products and other classes of contaminants, such as trace elements and polycyclic aromatic hydrocarbons, contribute to the general decline of bees’ populations. For this reason, effects, and particularly sublethal effects of contaminants need to be investigated. We conducted a review of the existing literature regarding the type of effects evaluated in Apis mellifera, collecting information about regions, methodological approaches, the type of contaminants, and honey bees’ life stages. Europe and North America are the regions in which A. mellifera biological responses were mostly studied and the most investigated compounds are insecticides. A. mellifera was studied more in the laboratory than in field conditions. Through the observation of the different responses examined, we found that there were several knowledge gaps that should be addressed, particularly within enzymatic and molecular responses, such as those regarding the immune system and genotoxicity. The importance of developing an integrated approach that combines responses at different levels, from molecular to organism and population, needs to be highlighted in order to evaluate the impact of anthropogenic contamination on this pollinator species.

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