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University of Guelph
Environmental Sciences
ENVS 2210
Ernesto Guzman

ENVS Unit 06 155-190 Biodiversity: Making More Bees and Being Different - Mating - Mating is sexual union btwn ind that involves repro of two sexes, transmission of genetic info o Genetic info contained in gametes form male donor to female o Union=fertilization - In honeybees, eggs that dev into females do so after the union of sperm and egg nuclei in the egg, BUT males dev parthenogenetically from unfertilized eggs (arrhenotoky or haplo-diploidy) - Honeybees used polyandry (multiple mating), system where females have several mating partners, offspring have diff fathers lol - Fem part of fam in honeybee colony are sisters and half-sisters o Drones she mates with aren’t form her colony b/c bro-sis mating is not good in nature, products of the rare bro-sis mating are sterile - Queen enclose din cell and 5-10 days to mature to readiness to mate o Orientation flights o Becomes familiar w/ surroundings then goes to drone congregation areas where mating occurs  6 to 8 days old, adult drones fly to congregation areas (km from hive), ready to mate when about 12-14 days olds - Weather must be balmy, suitable for a picnic LOL, 20 deg.C or above, light winds less than 5 m/sec, sunny or partly cloudy o Mating usually takes place from 2-4 p.m. - When queen goes to mating area the drones sense her presence by sight, smell, and pheromone, then drone chases queen and forms drone comet lol - First drone to reach queen mounts her, then in copulation the male genitalia explode - Semen of drones retained and moved within queen by contractions of muscles of common oviduct then reaches spermatheca within 40 hours, queen starts laying 2 to 4 days after final mating Sex Determination - Men are XY, women XX - Diploid # chromosomes for honeybees is 32 (2 sets of 16 in pairs) in FEMALES but males have only 16 chromosomes (no pairs) o Drones can only have daughters not sons - When populations are small and well-isolated, inbreeding usually occurs o High levels homozygosity increases the likelihood that brood will be destroyed by workers - If number of sex alleles is larger in the population, chance of homozygosity is lower, so much greater % of survival - Cape honeybee of South Africa, females arise from unfertilized eggs, type of parthenogenesis called thelytoky - Sexual mosaics/gynandromorphs if sex determination goes wrong (part drone, part worker) o Bilateral w/ one side fem one side male o Segmental with one end male and the other female o Mosaic= diff patches of diff sexes throughout the body - Cause of gynandromorphy is polyspermy (result of more than one sperm, penetrating the egg Genetics and Breeding - Genetics  science of heredity that studies structure and function of genes and way geneses are passed from one generation to the next - Genedeterminant of characteristic of organism, chemical info coded in the DNA o Responsible for diffs btwn species and variation - Genome total of genes carried by ind or species o Eukaryotes amount of genetic material in haploid set of chromosomes  Honeybee genome is 16, humans are 23 - Genomics study of structure and organization of entire genomes - Chromosomes DNA molecules, RNA - Alleleone of two alternative forms of single gene o Genetic locus is the place on the chromosomes where particular gene and its alleles reside o Alleles for given gene are at same place on given chromosome - Honeybee has about 10 000 genes compared to 25 000 of humans - Mutation change in genetic material that isn’t caused by genetic recombination o Detected molecularly by comparing o Dominant R recessive r - ABO blood group system in humans well-known for multiple alleles - Genetic recombination is process where parents w/ diff genetic characters five rise to progeny to genes differ in parents are assoc in new combos - Genetic diffs btwn half-sisters a arise b/c queen mares w/ several drones - Sister fams have avg 75% genes in common so they are super-sisters o Half sisters share 25% genes in common - Inbred-hybrid breeding uses superior traits to surface in the phenotype when two inbred lines are crossed o Recurrent selectionprogeny from repeated hybridizations may be discarded or maintained, marketed - Strict inbreedingmother-son mating can be achieved in very fake conditions o Mother-daughter matings achieved by mating virgin queen w/ one of her brothers - Closed population breeding Breeders progressively improve stock by using queens and drones from colonies that show desirable traits - High and low pollen hoarding strains have been bred - Simple genetic studies modes of inheritance - Complex heritable traits  require longer term studies w/ controlled matings (171) - Hygienic behaviour heritable and highly desirable trait in resistance to diseases and mites o Two heritable components of colony’s hygienic beh: uncapping and then removal of corpses - Defensive behaviour known to be heritable, but colonies of honeybees vary in predisposition to defence and release of alarm pheromone - Selective breeding programsControl variability in breeder hives and keep it high enough to avoid inbreeding probs - More mates a queen takes, greater is genetic variability of progeny Honeybee Races - within species of Apis mellifera (Western honeybee) there is intraspecific variation - In
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