IB1091027 Sex and reproduction
March 31, 2010, Pages 20-30, 50-56
1 List two advantages of parthenogenesis:
a. It’s Rapid
b. Assures matching with environment
2. Sexual reproduction generates variation, which is essential for survival in a changeable
world.
3. Use the words provided below to complete the paragraph:
ovaries, zygote, sperm, ova, gametes, testes
Biparental sexual reproduction involves the production of sex cells called gametes, each
of which contains half the genetic complement of an individual. Two gametes fuse to
form a(n) zygote. Gametes contributed by males, which are small and mobile, are called
sperm and are produced in organs called testes. From the testes they travel through the
seminal vesicles, where they are accompanied by various accessory fluids, and they are
expelled from the body through the aedeagus. Female gametes, called ova, are generally
large and immobile and are produced in organs called ovaries, which consist of one or
more follicles.
4. In humans, individuals with XY chromosomes are male; in Lepidoptera, individuals
with XY chromosomes are female. The term used to describe the XY condition is
heterogametic.
5. In some insects, sex is determined by the X:A ratio, which is the ratio of sex
chromosomes to autosomes
6. Name one type of insect whose sex is determined by temperatures experienced by the
developing larvae. Mosquitoes (Snow Pool Populations)
7. Wohlbachia is a bacterium-like parasite that can cause
a. death of male offspring b. feminization c. cytoplasmic incompatibility d. a, b and c
8. Name an arthropod with:
external fertilization sowbug, lobsters (most crustaceans)
indirect sperm transfer spiders, silverfish, springtails
direct sperm transfer most insects
What's a spermatophore? Sperm package, used for sperm transfer from male to female.
9. Why is external fertilization rare among terrestrial arthropods? Sperm is delicate and
dessicates (dries out) easily.
10. Do you find spermathecae in male or female insects? What does a spermatheca do?
Stores sperm for later fertilization.
11. What is a hermaphrodite? Individual with both male and female reproductive organs.
What famous insect, which infested citrus orchards in the nineteenth century and was
controlled by vedalia beetles, is a hermaphrodite? Cottony-cushion scale.
12. In which order(s) does parthenogenetic reproduction occur?
a. Hymenoptera b. Thysanoptera
c. Homoptera
d. a, b, and c
13. In which order(s) is haplodiploidy commonly found?
a. Hymenoptera
b. Thysanoptera
c. Hemiptera
d. Neuroptera
14. An order with species displaying arrhenotoky is hymenoptera, Thysanoptera, Acari;
an order with species displaying thelytoky is Homoptera.
An order with species displaying paedogenesis is telegraph pole beetle (Coleoptera).
15. What is a species? A group of interbreeding individuals which is reproductively
isolated from other such groups.
16. List two post-zygotic reproductive isolating mechanisms:
a Hybrid Sterility
b. Hybrid Inviability
17. According to sexual selection theory, males exhibit salesmanship and females exhibit
Sales Resistance.
18. What is sexual dimorphism? Provide an example. Males and Females differ in
morphology (structures, size, coloration etc.). Male Stag Beetles have structures that
females do not.
19. Provide examples for these prezygotic reproductive isolating mechanisms:
courtship ritual Drosophila, Hercules Beetles
pheromones Longhorned Beetles
sound crickets, cicadas, mosquitoes, and patent leather beetles
nuptial gift scorpionflies
lek black swallowtail males fly to tops of hills (“hilltopping”)
20. What is the lock-and-key hypothesis? Greatly elaborated male genetalia is specific for
conspecific females as a prezygotic reproductive isolating mechanism.
21. Provide an example of a species that engages in traumatic insemination. Bed Bugs
22. An intraspecific chemical signal is called a(n) pheromone.
23. List two advantages of chemical signalling over other forms of communication:
a. specificity b. economy c. flexibility, d. ecological versatility
24. From what species was bombykol isolated? Silkworm moth Bombyx mori
25. List three ways insect sex pheromones can be used to control pests.
a. monitoring b. mating disruption
c. attracticide
26. Match the pheromone with its function:
Aggregation- attracts males and females to common location
aphrodisiac pheromone- allows females to evaluate prospective mates
sex pheromone- attracts males to prospective mates
alarm pheromone- alerts conspecifics to the presence of danger
trail pheromone - alerts conspecifics to the presence of food
27. Name three insect species portrayed mating by Isabella Rossellini in her “Green
Porno” films. Praying mantis, fly, honey bee