Reproductive Potential

Major contributing factor to insect success

High fecundity

Insects lay a lot of eggs

High Fertility occurs when

many of these eggs hatch

Insects are mostly

oviparous: laying eggs

- cockroaches can lay live eggs

Lacewing eggs

help them avoid predators when they lay on leaves

Ametabolous

- no metamorphosis

- Develop with little change to body form

- Primitive Group (Ex. silver fish)

- Adults look largely

Hemimetabolous (no pupal stage)

Incomplete metamorphosis

- Stages: Egg, Nymph, Adult

In Hemimetabolous, what can wings signify

if an adult or a baby

Nymphs who are hemimetabolous resemble

adults that have thin exoskeleton but lack wings

Multiple stages of development in nymphs result in

Nymphal instars

Holometabolous

* most diverse groups undergo this

complete metaphorphosis

Stages: egg, larva, pupa, and adult

Holometabolous: Larvae do what

* maggots = immature flies

exploit different food resources than adults

Adults larvae lay eggs

Directly onto food source so they can begin eating after hatching

Insects consume the most food where?

In the Larvae stage

Excess nutrition storied for adulthood is crucial for

metabolic expensive behaviors known for flight

more energy-> more successful Adult phases

Holometabolous: Pupae

non feeding stage

Pupation can last

* Large beetles have a long pupation

weeks, months or years depending on temp, or species of insect

Diapause

* insects undergo to survive winter

* some dont undergo diapause

reduced metabolisms in response to environmental cues

Stages of Diapause

* shorter days

1. Initiation: Signals prepare for diapause Ex.temp

2. Maintenance: Metabolism slowed; development halted

3. Termination: intensity of diapause decreased

4. Post-diapause: slowed metabolic activity to allow determination of conditions

Insects accumalte special proteins to

lower freezing point in their body like antifreeze

pharate adult

(new adult)

empty pupal exoskeleton

is exuvia

Benefits of Holometabolous Development

* most successful part

- Have longer time to feed

- Reduce their competition btw members of same species

- Diapause allows them to survive longer in environment conditions

Molting Allows

Wound healing { can happen in the immature stages no longer in the adults}

Renewal of exoskeleton

Insect Growth only occurs during

immature stages

- once adulthood reached growth stops

Behavior is often

sex-specific, dimorphic within a species

Reproduction can be viewed from

* takes time

resource perspective; cost and benefits

Sexual selection

* Development of elaborate secondary sexual characteristics

individuals compete for mate access

Mate choice requires one sex to?

and others to have a

Exhibit a trait

heritable perference

Why do some individuals possess traits that seem to reduce survival?

helps them mate alot quicker

Post copulatory sexual selection

occurs through sperm competition and cryptic female choice

Sperm competition

two or more males compete to fertilize an egg

Last male to fertilize females is capable of

fertilizing majority of eggs

Mating plugs prevent

other sperm from accessing eggs, and males will have to expand more resources to remove it

Mating practice

male pierces the abdomen of the female to avoid mating plug called Traumatic insemination

Traumatic insemination

sperm is carried through hemolymph

and is transferred due to open circulatory system

Adaption of mating plug leads to

- less time of courtship

- sperm gets closer to ovaries

Female Adapation:

Spermalege

sperm receptacles at site of penetration

Ectospermalege

* help restrict injury

visible external target

Mesospermalege

* help restrict injury

sac attached to inner abdomen under ectospermalege