It is with regret that we report that the humanitarian, geneticist, and scientist, Professor Warwick Kerr, passed away this morning, September 15, 2018. He was six days past his 96th birthday. Dr Kerr, a Brazilian bee scientist, had one of the most maligned lives of any research scientist. He will be remembered by some as the man who gave us ‘Killer Bees’ – the African-European bee known for its (sometimes) aggressive behaviour. The Africanized Honey Bee, a hybrid which Dr Kerr was largely responsible for creating, helped turn his impoverished homeland of Brazil from a backwater of agriculture and honey production into one of the most prolific honey and agriculture countries in the world.
Dr Kerr was born in Brazil. He developed an early sympathy for his country’s poverty-stricken aboriginal hunters and farmers who supplemented their families’ diets with honey from native stingless bees. He also saw how other farmers struggled to pollinate their crops and produce honey with the imported European honey bees. Those bees originated in Portugal and were not well-adapted to Brazil’s tropical climate. His goal was to improve the lot of farmers. In the 1950s, he brought African bee stock to Brazil. He was an accomplished geneticist and planned to breed a tropics-adapted bee that would be successful in Brazil. A technician mistakenly removed queen excluders from the breeding hives and 26 imported queens swarmed.
They spread slowly at first, but there was no way to put them back in the box once they escaped into the rainforest. It seemed like an unmitigated disaster. As it happened, at the same time, Brazil was ruled by a vicious military dictatorship which Kerr vocally opposed. He was in deep trouble and imprisoned in 1964 when he publicly fought government corruption. In 1969 he was re-arrested, this time for protesting that Brazilian soldiers who had raped and tortured a nun went unpunished. Sister Maurina Borges, who ran the Ribeirão Preto Orphanage, was an activist; the soldiers were part of Brazil’s military dictatorship, committing crimes encouraged by the government. [See page 16 of this 2005 interview with Kerr.] He helped her and he protested, drawing attention to himself. The military couldn’t kill Dr Kerr as he had a powerful international reputation as a brilliant geneticist. So, the Brazilian government set about destroying the reputation of the great scientist, claiming that he had created assassin bees. He hadn’t, but it sold newspapers. The press ran with the story. Shamefully, that includes the North American press.
Before we return to the Africanized bees, it’s appropriate to highlight Kerr’s work as a geneticist. He had studied at the University of California then Columbia University, working under the fabled geneticist Theodosius Dobzhansky in 1952. Dr Kerr discovered the incredibly complicated caste system of the Brazilian stingless bee, Melipona.
Sex among stingless bees
Warwick Kerr first worked with Melipona bees, not honey bees. Some of Brazil’s poor and indigenous were wild honey gatherers, or meleiros. Meleiro, isolated and rural, is named for the meleiros people, who are named for the Melipona honey trees. There are only 7,000 meleiro people, but their precarious existence in the 1940s – which included raiding Melipona bee trees – concerned Dr Kerr during his bee research. He hoped that his work would draw attention to the importance of preserving Melipona, their habitat, and the people who lived off those bees. Understand and help the Melipona, and you help the meleiros, figured Kerr.
Kerr studied Melipona quadrifasciata, a eusocial stingless bee, native to southeastern coastal Brazil. The indigenous meleiros call it Mandaçaia, which means “beautiful guard,” as there are always guard bees defending the narrow entrance of their colony. Brazil’s Melipona builds mud hives inside hollow trees. These have narrow passages allowing just one bee to pass at a time. Stingless bees, they can give a nasty bite, but their intricate passage system also defends against predators.
Dr Kerr’s first influential paper “Genetic Determination of Castes in Melipona” (1949) researched the development of males, females, and workers among Brazil’s common stingless bee. Kerr found that their caste development was different from honey bees. Drones in both species are haploid, but in Melipona, things get weird for the girls.
In Apis mellifera, “a larva develops into a queen or into a worker depending upon the food it receives. In Melipona, on the other hand, caste determination is genotypic. Fertile females (queens) are heterozygous in some species for two, and in other species for three, pairs of genes, homozygosis for any one of which makes the individual develop into a worker.” – Kerr, 1949.
For the exotic Melipona quadrifasciata, alleles (one-half of a gene that controls an inheritance, for example the ‘b’ in a ‘Bb’ gene) determine caste. Drones (as in honey bees) are haploids with a single set of chromosomes; queens and workers are diploid (two sets of chromosomes, one from each parent), but queens have some specific alleles that are different, or heterozygous (for example, AaBb), while workers have identical, or homozygous, caste-determining genes (AABB, AAbb, aaBB, or aabb combinations). If you find this confusing, imagine sorting it out with 1940s technology, as Kerr did.
African Honey Bees
Warwick Kerr was responsible for bringing African genetic stock to Brazil in 1956. As a geneticist, he wanted to improve the health and hardiness of the European honey bee which came from Portugal in 1834. That European strain was poorly adapted to the tropics, so the Italian honey bee (Apis mellifera ligustica) was imported in the 1880s, but it wasn’t much better. A few farmers and monks kept the languid bees, mostly to collect beeswax for church candles.
In 1956, Brazil’s annual honey production from the European honey bees was just 15 million pounds. Brazilian agriculture was expanding and needed a tropical honey bee for pollination and honey production. After the African bees arrived, Brazil’s beekeepers produced 110 million pounds. Brazil went from 43rd in the world to 7th largest honey producer. By 1994, L.A. Times headlined: “Brazil’s honey production has soared since the ornery invaders took over beekeepers’ hives”. Today, most of the world’s organic honey is produced by Africanized honey bees in Brazil’s remote forests. The honey is doubly organic – produced in areas untouched by pesticides and produced in Africanized hives which are naturally resistant to varroa – so mite meds aren’t used in those colonies.
Honey bees with African genes are more aggressive than European bees. Beekeepers in Brazil had to learn appropriate management techniques. Although the venom is the same, more bees attack if their colony is disturbed. People have died from massive stings. Those deaths are sorrowful and this story about Dr Kerr’s bees should not dishonour personal tragedies. Some of the traits which make Africanized bees exceptional pollinators (refined olfactory sense, quicker movements, flights in inclement weather, superior navigation skills) also make them more likely to sting en masse. However, they can be managed by farmers and beekeepers. Indiscriminate killers they are not.
It may surprise some readers to learn that Kerr’s Africanized stock is now preferred by many beekeepers, even in the United States where its resistance to the deadly varroa mite and its superior honey production has made it a favourite. I correspond regularly with a southern California beekeepers who tells me that she would not want to keep any other type of honey bee.
The real Warwick Kerr
Kerr was born in São Paulo, Brazil, in 1922, into a middle-class family with Scottish roots. He received an agricultural engineering degree, then specialized in genetics. His work as an entomologist spanned decades, with research that included genetics of honey bees and native Brazilian bees, as we’ve just seen.
Warwick Kerr’s post-doc research was at the University of California, Davis (1951), and at Columbia University in New York, under the renowned evolutionary biologist Theodosius Dobzhansky. One of Kerr’s influential papers, “Experimental Studies of the Distribution of Gene Frequencies in Very Small Populations of Drosophila melanogaster“, cites Dobzhansky as an adviser and is co-authored by a University of Chicago genetics statistician. This fruit fly research was done way back in 1954 and the paper was one of the first to deal with the nascent field of genetics statistics. Eventually, Kerr published 620 research papers during his 60-year career.
Warwick Kerr was largely responsible for establishing the study of genetics in Brazil. He was a director of the National Institute for Research in the Amazon and worked at the University of São Paulo. Later, at the Universidade Estadual do Maranhão, he created the Department of Biology and served as Dean of the University.
Warwick Kerr said that his most important work was developing staff, technicians, teachers, and researchers in his country. At the University of São Paulo, he established a department of genetics which focuses on entomological and human genetics, using mathematical biology and biostatistics. Kerr had memberships in the Brazilian Academy of Sciences, the Third World Academy of Science, and the US National Academy of Sciences.
I’ll end with a pleasant little video made five years ago. In it, you will see that Dr Warwick Kerr’s interests had shifted to botany. The film is in Portuguese, but even if you don’t understand the language, you’ll get a good idea of the enthusiasm and curiosity which had filled Warwick Kerr’s life.