Reproduction Flashcards
What is a major communication method that allow patchily distributed insects to gather and breed in great numbers?
Swarming, where insects meet at specific gathering sites through the use of species specific pheremones.
Aggregation pheremones are sex pheremones, making them a particular worry for us.
How can we use pheremones to manage for pine beetle?
Aggregation pheremones in traps
Anti aggregation pheremones can protect trees on a small scale local level.
What are some specific mating adaptations in insects?
- Extraordinary variation in genitalia - reflect lock and key reproductive isolation.
- Multiple matings is the norm for insects leading to strong selection pressures to ensure the males a high chance of success.
- evolution of unique elaborate aedagus. Will only work on same species.
Define sperm precedence and sperm competition
Sperm precedence refers to the phenomenon where the last male to mate is the most likely to succeed in fertilization. “Last in first out”.
Sperm competition refers to the wicked adaptations made by insects in order to overcome sperm precedence. Adaptations due to a combo of internal fertilization, sperm storage and multiple matings.
What specific adaptations have been developed to overcome sperm precedence?
Suicidal Monogamy: exploding penis in bees acts as copulatory plug
Specialized penises in odonates can be adapted to plunge competitions sperm deeper into the Spermatheca where it is less likely to succeed. Or shovel competitors sperm out.
Prolonged mating and mate guarding in odonates as well as weaponized mate guarding in dung beetles.
Nuptial gifts: sodium gift in Lepidoptera. Food gift in scorpion wasp.
Neuropeptide Secretions from male accessory glands serve to stimulate oviposition and deny further reproductive success in Diptera and Coleoptera.
Traumatic insemination in Hemiptera. Penis pierces abdomen and sperm enter body cavity, migrating to ovaries.
What is the most important reproductive adaptation in insects?
- Spermatheca of female: unique to insects. Can store sperm for long periods of time in social insects.
- nutritious secretions from spermathecal gland maintain long term viability.
- sperm release from Spermatheca is regulated.
What is puddling?
Lepidoptera males gather around wet areas to sieve sodium gifts to give to females as a copulatory gift. Female needs this resource since her diet is mostly nectar.
What is haplodiploidy?
Sex determining system common in Hymenoptera. Females develop from fertilized eggs (diploid). Males develop from unfertilized eggs (haploid) By parthogenesis (Virgin birth).
Queen can regulate the sex ratio of her colony by regulating the lay of fertilized vs Unfertilized eggs.
