Aquatic Entomology Lecture 5 - Reproduction and Mating behavior

# of eggs carried

Potential fecundity

Ability to produce egg or sperm

Sexual Maturation

Timeline (Organisms (3))

• Time it takes to mature

  odonates: days-weeks

  mayflies/stoneflies: hours

Two variables that affect sexual maturation and fecundity

Temperature: Abiotic

Resources: Food, space

Need to eat prior to laying eggs

Anautogenous

Do not need to eat prior to laying eggs (+ why)

Autogenous, bc of resource limitation

What do insects do when food resources scarce

• Catabolize their own body

  • breakdown flight muscles

• Cannibalize their own eggs

  • Corixidae, Dysticidae

Where do insects mate?

• In the air, on the ground, on water surfaces

• Swarms

Group of same species that come together

Swarms

How can swarms form

• Really short-lived insects

• Mostly males

• Low density

Communication in mating systems (4)

Vision

Vibrational signals

Sound communication

Chemical

Vision (organism)

• allows organism to find own species and correct sex (dimorphism)

• organism: dragonflies

Vibrational signals (Organisms (2))

• strikes substrates which causes vibration

• organism

  • stonefly —> vibration on surface

  • toe-biters —> creates waves in water

Sound communication (organism)

• organism: water boatman

  • Males creates several sounds

  • Females create one

Chemical (organism)

• Releases pheromone

  • chemoreceptors in antennae pick up pheromones to attract mates

• organism: stonefly

After finding a mate what happens? (2, 1)

• Where: in the air, on the ground, on the water surface

  1.) Copulation

  2.) Sperm transfer

• Then either fertilization or reproduction again

Copulation

when genitals connect

Sperm transfer

packaged as spermatophore

• sperm can be in it

• sperm can be divided from non-sperm protein part

term for when females reproduce again

Polyandry

term for when males reproduce again

Polygyny

male is transferring sperm from posterior to anterior abdomen

male is transferring sperm to female

Males remain with femauls after mating

Male gaurding

Males insert fluid in female genital hole, fluid hardens

Mating plug

Intersexual arm race concept (organism)

Organism: Dytiscidae

Males: suction pads

Females: striations on elytra

Insect growth stage

• Exoskeleton prevents too much growth without molting

Each time insects molt

New instar (stadia)

Types of immature

• Nymphs

• Larvae

Types of Larvae (8)

• Oligopodous

  • Campodeiform

  • Scarabaeiform

• Polypodous

• Apodous

  • Eucephalous

  • Hemicephalus

  • Acephalous

Type of larva: 3 pair jointed, well developed legs

Oligopodous

Type of larva: 3 pair jointed, well developed legs + dorsal-ventrally flattened

Campodeiform

Type of larva: 3 pair jointed, well developed legs + NOT dorsal-ventrally flattened

Scarabaeiform

Type of larva: well-developed head capsules, 3 pairs of small legs

Polypodus

Type of larva: lacks leg

Apodous

Type of larva: lacks leg + well developed head capsule

Eucephalous

Type of larva: lacks legs + reduced head capsule

Hemicephalus

Type of larva: lacks legs + lack head capsule

Acephalous

Molting process (7 steps)

Under endocrine and nervous control

1.) Epidermal cells separate from cuticle

2.) Epidermal cells undergo mitosis

3.) Molting fluid released in gap between cuticle and epidermal cells

4.) Form new cuticle

5.) Molting fluid break downs old cuticle

6.) Molting fluid reabsorbed

7.) Ecdysis occurs

What is pupal stage and what are the types (2)

• Little movement and non-eating stage

• Types: Exarate and Obtect

type of pupae: legs and wings are free

exarate

type of pupae: wings are glued down

obtect

Environmental influences on number of generations per year (5)

1.) Temperature

2.) Photoperiod

3.) Water chemistry

4.) Food resources

5.) Biotic Resources

# of generations per year

one generation per year

Univoltine

two generations per year

Bivoltine

3 or more generations per year

Multivoltine

More than 1 year per generation

Semivoltine

What do insects do when habitats become inhabitable (3)

Dormancy

Quiescence

Diapause

state of suppressed development

Dormancy

immediate response to limiting environmental factors

quiescence

programmed into lifecycle

Diapause

Diapause phases controlled by hormones (3)

Pre Diapause (larva)

Diapause (pupa)

Diapause Termination (adult)