A bee queen, marked with a 4, is seen on a honeycomb of apiculture company Zuerihonig in Oberengstringen, Switzerland August 21, 2018. Picture taken August 21, 2018. REUTERS/Arnd Wiegmann 

Bees are seen on a honeycomb section of a bee hive of apiculture company Zuerihonig in Oberengstringen, Switzerland August 21, 2018. Picture taken August 21, 2018. REUTERS/Arnd Wiegmann 

Beekeeper Anna Lobyntseva, 66, prepares a beehive frame with honeycomb to take honey at her apiary in the village of Radkovka, in Belgorod region, Russia August 10, 2018. Picture taken August 10, 2018. REUTERS/Tatyana Makeyeva 

Beekeeper Anna Lobyntseva, 66, uses an extractor to take honey from beehive frames with honeycombs at her apiary in the village of Radkovka, in Belgorod region, Russia August 10, 2018. Picture taken August 10, 2018. REUTERS/Tatyana Makeyeva 

A bee is seen on a honeycomb at the apiary of beekeeper Anna Lobyntseva, 66, in the village of Radkovka, in Belgorod region, Russia August 10, 2018. Picture taken August 10, 2018. REUTERS/Tatyana Makeyeva 

Beekeeper Anna Lobyntseva, 66, prepares a beehive frame with honeycomb to take honey at her apiary in the village of Radkovka, in Belgorod region, Russia August 10, 2018. Picture taken August 10, 2018. REUTERS/Tatyana Makeyeva 

Bees are seen on a honeycomb at the apiary of beekeeper Anna Lobyntseva, 66, in the village of Radkovka, in Belgorod region, Russia August 12, 2018. Picture taken August 12, 2018. REUTERS/Tatyana Makeyeva 

The queen bee is seen among other bees on a honeycomb at the apiary of beekeeper Anna Lobyntseva, 66, in the village of Radkovka, in Belgorod region, Russia August 12, 2018. Picture taken August 12, 2018. REUTERS/Tatyana Makeyeva 

Bees are seen landing on a frame of a beehive at the apiary of beekeeper Anna Lobyntseva, 66, in the village of Radkovka, in Belgorod region, Russia August 12, 2018. Picture taken August 12, 2018. REUTERS/Tatyana Makeyeva 

A beekeeper shows a honeycomb he took from a hive to a Reuters cameraman in Hamdan, Yemen July 31, 2018. Picture taken July 31, 2018. REUTERS/Khaled Abdullah 

A honeycomb filled with honey is displayed at a honey shop in Sanaa, Yemen July 29, 2018. Picture taken July 29, 2018. REUTERS/Khaled Abdullah 

A beekeeper holds a honeycomb he took from a hive at a farm in Hamdan, Yemen July 31, 2018. Picture taken July 31, 2018. REUTERS/Khaled Abdullah 

Honeycombs filled with honey are displayed at a honey shop in Sanaa, Yemen July 29, 2018. Picture taken July 29, 2018. REUTERS/Khaled Abdullah 

Bees are seen on a frame of a beehive in Denee, Belgium, May 15, 2018. Picture taken May 15, 2018.REUTERS/Yves Herman 

Bees are seen on a frame of a beehive in Denee, Belgium, May 15, 2018. Picture taken May 15, 2018.REUTERS/Yves Herman 

Bees are seen on a frame of a beehive in Denee, Belgium, May 15, 2018. Picture taken May 15, 2018. REUTERS/Yves Herman 

Bees are seen on a frame of a beehive in Denee, Belgium, May 15, 2018. Picture taken May 15, 2018. REUTERS/Yves Herman 

Bees are seen on the honeycomb in a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

Bees are seen on honeycombs inside a beehive in Gharghur, Malta, May 7, 2018. REUTERS/Darrin Zammit Lupi 

A woman shows a honeycomb at the Quinta Carmelita store, producers of natural and vegan products, in San Salvador, El Salvador February 6, 2018. REUTERS/Jose Cabezas 

A honeycomb is prepared for the harvest of honey from tens of thousands honeybees permanently placed in a courtyard of an office building at the lower house of the German parliament Bundestag in Berlin, Germany August 23, 2017. REUTERS/Fabrizio Bensch 

A honeycomb is prepared for the harvest of honey from tens of thousands honeybees permanently placed in a courtyard of an office building at the lower house of the German parliament Bundestag in Berlin, Germany August 23, 2017. REUTERS/Fabrizio Bensch 

Beekeeper Benedikt Polaczek prepares honeycomb and honeybees for the harvest of honey from tens of thousands honeybees permanently placed in a courtyard of an office building at the lower house of the German parliament Bundestag in Berlin, Germany, August 23, 2017. REUTERS/Fabrizio Bensch 

Beekeeper Benedikt Polaczek, with Member of Parliament Baerbel Hoehn of the environmental Greens party, prepares honeycomb and honeybees for the harvest of honey from tens of thousands honeybees permanently placed in a courtyard of an office building at the lower house of the German parliament Bundestag in Berlin, Germany August 23, 2017. REUTERS/Fabrizio Bensch 

Beekeeper Benedikt Polaczek prepares honeycomb for the harvest of honey from tens of thousands honeybees permanently placed in a courtyard of an office building at the lower house of the German parliament Bundestag in Berlin Germany August 23, 2017. REUTERS/Fabrizio Bensch 

Bees come in and out from a beehive at beekeeper Leonid Baranenko's bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko TPX IMAGES OF THE DAY 

Beekeeper Leonid Baranenko (R) with his son Mikhail take honey from beehive frames with honeycombs using manual centrifuge at his house in the village of Kanchany, Belarus June 24, 2017. Picutre taken June 24, 2017. REUTERS/Vasily Fedosenko 

Beekeeper Leonid Baranenko (R) with his son Mikhail take honey from beehive frames with honeycombs using manual centrifuge at his house in the village of Kanchany, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

A honeycomb filled with honey is seen at beekeeper Leonid Baranenko's bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picutre taken June 24, 2017. REUTERS/Vasily Fedosenko 

Beekeeper Leonid Baranenko prepares a beehive frame with honeycomb to take honey from it at his house in the village of Kanchany, Belarus June 24, 2017. Picutre taken June 24, 2017. REUTERS/Vasily Fedosenko 

Bees are seen on beehive frames with honeycombs at beekeeper Leonid Baranenko's bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

Bees are seen on a beehive frame with honeycomb filled with honey at beekeeper Leonid Baranenko's bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

Bees are seen on beehive frames with honeycombs at beekeeper Leonid Baranenko's bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

Beekeeper Leonid Baranenko prepares a beehive frame with honeycomb to take honey from it at his house in the village of Kanchany, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

Beekeeper Leonid Baranenko holds a beehive frame with honeycomb and honeybees as he collects honey at his bee-garden in the village of Mikhaylovka, Belarus June 24, 2017. Picture taken June 24, 2017. REUTERS/Vasily Fedosenko 

A Palestinian beekeeper carries a honeycomb as he collects honey at a farm in Rafah in the southern Gaza Strip April 25, 2017. REUTERS/Ibraheem Abu Mustafa 

A member of the "Assemblea Cavallerizza 14:45" movement checks a honeycomb at the apiary of the Cavallerizza Reale building, which is occupied by the movement in Turin, Italy, July 22, 2016. REUTERS/Marco Bello SEARCH "CAVALLERIZZA REALE" FOR THIS STORY. SEARCH "WIDER IMAGE" FOR ALL STORIES.

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

Beekeeper Zdenek Ruzicka checks a honeycomb from a beehive placed on the roof of the Prague City Hall in Prague, Czech Republic September 7, 2016. Honey produced by the bees is given to the City Hall's visitors as a gift. REUTERS/David W Cerny 

A beehive frame with honeycomb and honeybees is seen during the presentation to the media of tens of thousands honeybees permanently placed in a courtyard of a lower house of the German parliament Bundestag office building in Berlin, Germany, April 25, 2016. REUTERS/Fabrizio Bensch 

A beehive frame with honeycomb and honeybees is seen during the presentation to the media of tens of thousands honeybees permanently placed in a courtyard of a lower house of the German parliament Bundestag office building in Berlin, Germany, April 25, 2016. REUTERS/Fabrizio Bensch 

A beehive frame with honeycomb and honeybees is seen during the presentation to the media of several ten thousands honeybees permanent placed in a courtyard of a lower house of parliament Bundestag office building in Berlin, Germany, April 25, 2016. REUTERS/Fabrizio Bensch 

Baerbel Hoehn (R) of the environmental Greens (Die Gruenen) listens to Benedikt Polaczek of Berlin's beekeeper federation during the presentation to the media of tens of thousands honeybees permanently placed in a courtyard of a lower house of the parliament Bundestag office building in Berlin, Germany, April 25, 2016. REUTERS/Fabrizio Bensch 

A beehive frame with honeycomb and honeybees is seen during the presentation to the media of tens of thousands honeybees permanently placed in a courtyard of a lower house of the German parliament Bundestag office building in Berlin, Germany, April 25, 2016. REUTERS/Fabrizio Bensch 

Sharif inspects a honeycomb in Muhambal, Idlib province, Syria April 17, 2016. Sharif, along with his 2 sons Ahmad and Mohamad used to work as car mechanics in Ramouse area of Aleppo, but fled 3 years ago after it became a frontline. They have been working in beekeeping since. REUTERS/Ammar Abdullah