ENT201 - Exam 1 - Courtship, Mating and Reproduction

Insect Reproductive Organs Location

The abdomen (the central region for digestion, circulation, and reproduction).

Male Reproductive Structures

Testes, sperm, vas deferens, accessory glands, seminal vesicles, ejaculatory duct, aedeagus (pen i s), and claspers.

Female Reproductive Structures

Ovaries, eggs, oviducts, accessory glands, spermatheca, vagina, and ovipositor.

Bisexual Reproduction

Offspring develop from eggs fertilized by separate male and female individuals (most common mechanism).

Hermaphroditic Reproduction

A single individual possesses both functional ovaries and testes (rare in insects).

Polyembryony

A form of asexual reproduction where a single fertilized egg divides to produce multiple genetically identical offspring.

Parthenogenesis

"Virgin birth"—offspring develop directly from unfertilized eggs without male involvement.

Paedogenesis

Reproduction by immature or larval stages before reaching adult maturity ("kids having kids").

Indirect Insemination

Male transfers sperm to the female using a packet called a spermatophore rather than direct organ contact.

Direct Insemination

Direct transfer of sperm from the male aedeagus into the female vagina.

Spermatheca — Primary Function

A specialized female organ that stores and maintains live sperm for fertilizing eggs over long periods.

General Insect Sex Determination (XX vs. XY/X0)

Typically, XX produces females and XY (or X0) produces males.

Lepidoptera (Butterflies & Moths) Sex Determination

Reverse system: females are the heterogametic sex (ZW) and males are homogametic (ZZ).

Haplodiploidy (Bees, Ants & Wasps)

Females develop from fertilized eggs and are diploid (XX); males develop from unfertilized eggs and are haploid (X).

Oviparous

Females lay unhatched eggs externally into the environment (most common).

Viviparous

Females retain embryos internally and give birth to live young nourished directly by the mother.

Ovoviviparous

Eggs are retained inside the mother with yolk nourishment and hatch immediately upon laying (or just prior).

"Last in, First out" Sperm Competition

The last male to mate with a female often displaces previous sperm and fertilizes the majority of the eggs.

Insect Courtship Signals (Examples)

• Visual displays, acoustic calls/signals, nuptial gifts ("candy"), and sex pheromones ("perfume")

Extent of Insect Parental Care

Most insect babies are completely on their own after eggs are laid; social insects (bees, ants, termites) are the primary exception.