Lecture 16: Reproduction Continued, Social Behavior Flashcards
Which animals have separate sexes?
Most vertebrates, insects
Define simultaneous hermaphrodites in animals.
Both sexual functions present in an individual at the same time.
Happens in many mollusks, worms, some insects, custaceans.
What are the two subtypes of sequential hermaphroditism?
Protandry: male -> female
Protogyny: female -> male
Graphs
What are the three types of parthenogenesis?
Thelytoky
Arrhenotoky (haplodiploidy)
Cyclical
Describe Thelytoky
Production of only females (often result of bacterial infection; result of hybridization in some
grasshoppers and stick insects).
Has two forms:
1. Apomixis (no meiosis)
2. Automixis
(diploidy restored after meiosis w/ no fertilization)
Describe Arrhenotoky (haplodiploidy).
Production of only males parthenogenetically;
males haploid, females diploid (sexually produced).
Ex. Hymenoptera, Thysanoptera, some Hemiptera (e.g., some scales, whiteflies), some Diptera, some Coleoptera
Describe cyclical parthenogenesis.
Asexual production for part of the cycle (ex. during summer) and sexual reproduction during the other period (ex. winter).
What is polyembryony?
When two or more offspring (embryos) results from one fertilized egg.
Found in parasitoid Hymenoptera.
What is pedogenesis?
Pupae or larvae reproduce (not the adults).
Mostly parthenogenic and viviparous.
Define social behavior.
Any interactions with other individuals of the same species.
List at least 5 benefits of social behavior.
- Increased protection of young/cooperative brood care
- Increased vigilance
- Warning coloration
- Increased colony defense
- Dilution effect: increased biodiversity resulting in decreased prevalence of pathogen/parasite
- Increased foraging/hunting success
- Weather protection
- Increased mating success
- Reduced predation pressure
List 3 costs of social behavior.
- Competition for mates and food
- Increased rates of parasitism
- Social parasitism/slave-making
