**5. Conclusions**

Considering the fact that, generally, neonicotinoid residues are found in honeybee colonies at low levels (e.g., ng/bee and ng/g), it is very important to have a reliable methodology to collect representative samples for neonicotinoids analyses.

In this regard, the good preparation and follow up of honeybee colonies and honey/pollen flows by using classic methods or techniques, new technologies (electronic sensors and the IoT), the validation of the mono-floral envisaged samples by specific mellissopalinological analyses, and their preservation at low temperatures from collection until neonicotinoid residues analysis are very important steps.

The presented approach for monitoring neonicotinoid residues in honeybee colonies could help to maximize the chances for their identification and quantification in di fferent monitoring studies or evaluations, in order to better evaluate the exposure of honeybees to the neonicotinoids used in di fferent real field melliferous crops.

As could be seen from the levels of neonicotinoid residues found in di fferent locations in Romania, their presence in all the sampled locations correlated with the worldwide scientific evidence on their lethal or sublethal toxic e ffects in chronic exposure, demonstrate the existence of important risks for honeybee health and local beekeeping.

**Author Contributions:** Conceptualization, E.C., A.S., G.O.V. and D.C.; data curation, E.C. and A.S.; formal analysis, E.C., A.S., G.O.V., D.C., T.C. and R.A.S.; funding acquisition, E.C. and A.S.; investigation, E.C., A.S., G.O.V., D.C., T.C. and R.A.S.; methodology, E.C., A.S., G.O.V., D.C., T.C. and R.A.S.; project administration, A.S.; resources, E.C., A.S., G.O.V., D.C., T.C. and R.A.S.; validation, E.C., A.S., G.O.V., D.C., T.C. and R.A.S.; visualization, E.C., A.S., G.O.V. and D.C.; writing—original draft, E.C., A.S. and G.O.V. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Ministry of Agriculture and Rural Development, Romania, gran<sup>t</sup> number ADER 4.1.5/2017.

**Acknowledgments:** We acknowledge administrative and technical support received by the Institute for Beekeeping Research and Development, Bucharest, Romania. The authors thank to the reviewers for the constructive analysis of the article.

**Conflicts of Interest:** The authors declare no conflict of interest. The funders had no role in the design of the study, in the collection, analyses, or interpretation of data, in the writing of the manuscript, or in the decision to publish the results.

**Ethics Statement:** We declare this study does not need approval of any institution and/or governmental agency that regulates research with animals.
