Lecture 14 Flashcards
1
Q
Other modes of reproduction
A
-Parthenogenesis- nonfertilized eggs Three types: Thelytoky(female), Arrhentoky(male), Deuterotoky(male and female) -Paedogenesis (larval and pupal) -Hermaphrodism: ovatestis -Endosymbionts: Wolbachia
2
Q
Parthenogenesis
A
- Sexual reproduction involves 1n+1n to 2n(sperm+egg=diploid zygote)
- Can also reproduce asexually, without mating, and this is partenogenesis
- These species have females producing offspring without sperm/males
- Advantage in stable environment and abundant food resource
3
Q
Arrgenotoky
A
- MALES
- Type of parthenogenesis where all members of order (hymenoptera: ants, bees, wasps) and some thrips and scale insects
- Females are diploid 2n and males are haploids 1n. Females can control release of sperm and can lay a fertilized egg(female) or a unfertilized eggs (male)
- This regulation of sex is important for structure and social ants, bees, wasps
4
Q
Thelytoky
A
- FEMALES
- found in aphids, scale insects and cockroaches, and stick insects, and weevils
- These insects have females producing 2n eggs that are exactly like the mother
- Clones herself through parthenogenesis, large amount of offspring in short time
- Advantage of parthenogenesis species live in stable environment and exploits food source
5
Q
Pseudo-arrhenotoky
A
- Known as PGE
- Males develop from fertilized eggs but parental gene lost in somatic cells and not passed to offspring
- Beetles, mealy bugs, and scale insects
- equivalent to haploiddiploids arrhenotoky where males are haploid and develop from unfertilized eggs and certain diploid arrhenotoky where males fail to pass half of chromosome from mom
6
Q
Polyembrony
A
- Condition where 2 or more embryos devlop from one egg, TWINS
- Hymenoptera; Copidosoma, has parasite of a cutworm laying an egg which turns to 200 individuals
- Fall into two classes, hymenoptera nd strepsiptera
- From one egg, thousands of offspring can be made
7
Q
Paedogenesis
A
- Form of reproduction by larvae, without fertilzation
- Distinct from neotenic reproduction (no fertilization) and eventual maturation or metamorphosis of parent organism in adult form
8
Q
Parental Care
A
- Not common in insect world, but giant waterbug female glues eggs to male’s back
- Female taking care of eggs, young, earwig good example
9
Q
Metamorphosis
A
Each molt= a bit larger
It can also change physically depending on type of metamorphosis (3 types)
10
Q
Ametabolous
A
- Insects have little to no structural change as they grow. Immatures are called young, physically similar to adults except size and sexual maturity
- No external manifestation of age or reproductive state
- egg—>nymph—>adult; the same execept size
- NO WINGS
- ex. silverfish
- Also known as no metamorphosis
- Same habitats and habits
11
Q
Hemimetabolous
A
- Gradual changes, immatures called nymphs or naiads
- Maturation of wings, sex organs, and other adult structures occur in small steps from molt to molt
- Wings completely absent in first instar, then 2nd-3rd instar they are little stub, and grow until full developed
- Changes are usually visible externally, adults retain same features though
- INCOMPLETE metamorphosis
- Terrestrial insects have nymphs resembling the adults except the adults have wings. Similar habits and habitats
- Aquatic insects will have naiads distinct from adults, closely related but differ in habitats. Feed on different things
- Egg—-> nymph/naiad—–> adult (there is stage between young and adult, SUBIMAGO, may look fully developed but is sexually immature)
12
Q
Holometabolous
A
- Insects have immature forms (larva) very different from adults
- Larvae are feeding machines just so they can grow
- Larger in size each molt but don’t develop adult characteristics
- Fully grown larvae molt to immobile pupa stage so they can go under complete transition
- All unneeded parts digested and replaced with adult structures. Adults usually have wings (dispersal and reproduction)
- Egg—>larva—>pupa—> adult
- larvae do not look like adults
- DO NOT have similar habitats or habits
- COMPLETE metamorphosis
13
Q
Advantage to Complete Metamorphosis
A
- Reduced competition between immatures and adults
- Adults feed on new source of food
- Adults have different habitats
14
Q
3 forms of larvae
A
- Polypod larvae: (many leg)- 3 pair of thoracic legs and 5 pairs of abdominal legs (caterpillar)
- Oligo larvae: well developed thoracic legs, no abdominal legs (beetles)
- Apod larvae: (no leg)- no legs mostly flies, maggot
15
Q
Pupal types of holometabolous insects
A
- Obtect: Known as Chrysalis, enclosed with silken cocoon. Appendages held tightly like a shell. Examples are butterflies and moths
- Exarate: All the appendages are free in this type, and very visable. Examples are beetles and lacewings
- Coarctate: Known as puparium. Body is encased in hard exoskeleton of the next to last larval instar. Examples are flies.
21
Q
WHOLE PROCESS (picture)
A
First the brain sends message to the prothoracic gland, sends hormone(PPTH) to stimulate the production of Ecdysone. That way the prothoracic gland will produce ecdysone (molting hormone). There is another part, corpus allatum, that makes the juvenile hormone which is important for immature stages. Pictures shows how the juvenile hormones contribute to the larval-larval molting stages and larval-pupa molting stage. Ecdysteriod is important for every molting stage.
