ENVS 2210 Chapter Notes -Eusociality, Hymenoptera, Zygosity

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Published on 17 Apr 2013
School
University of Guelph
Department
Environmental Sciences
Course
ENVS 2210
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
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- 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
- Genedeterminant 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
- Alleleone 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 selectionprogeny from repeated hybridizations may be
discarded or maintained, marketed
- Strict inbreedingmother-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
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Document Summary

Mating is sexual union btwn ind that involves repro of two sexes, transmission of genetic info: genetic info contained in gametes form male donor to female, 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: 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: orientation flights, 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.

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