insects midterm 2

Nutritional

• (+,+)

• Food 

• Digestions 

• Nutritional metabolism

Reproductive 

• (+,-)

• Sex ratio determination 

• Cytoplasmic incompatibility 

• Speciation

Pathogenic

(+,-)

Fitness benefits 

Protection from heat, parasitism, pathogens 

why isn’t eusociality seen in more species of insects?

• limited resources

• inbreeding

• conflict over reproduction

age polyethism

worker division of labor based on age

caste polyethism

• social control of developmental rate

• environmental influences

• nutritional differences- can lead to size or developmental differences

peer-reviewed scientific research paper structure

• title

• abstract (summary)

• introduction (background)

• methods (study procedures)

• results (data)

• discussion (analysis)

• conclusion (contribution + future questions)

• references (list of resources)

When will you have to read a scientific research paper?

• term paper assignments for other classes

• conducting own research

• verify scientific claims with primary literature

• personal interest

false

symbiotic relationships are always mutualistic

vertical transmission

symbiont is inherited from the parent (usually mother)

symbiont and host co-evolve and may not survive without each other

very effective association

pressure to maintain association (coevolution)

can sometimes result in bottleneck (genetic)

horizontal transmission

symbiont is acquired from the environment or other individuals (not inherited)

4 things different Wolbachia strains can do to their hosts

• kills male embryos of hosts

• Parthenogenesis (makes offspring of host always female)

• cytoplasmic incompatibility

• increases or decreases fecundity

• provides host with nutrients like vitamin B

what is happening at A?

infected offspring

What is happening at C?

embryonic mortality

What is an advantage of biological control?

• cost-effective

• self-sustaining in the case of classical biological control

• no chemical environmental hazards

• integrates well with other methods of control except insecticides

reasons why pests aren’t naturally regulated in farms

• enemy release: introduced pests are not control by natural predators, pathogens, or parasites

• plant domestication makes crops more susceptible to pests

• monocultures have fewer alternative resources and microclimates, thus reduces natural enemy diversity and abundance

• Pesticides harm natural enemies of pest (if present)

What type of population control measure is this graph an example of?

chemical

What type of population control measure is this graph an example of?

biological

4 types of plants to disrupt pest establishment/activity

• companion crops: releases chemical cues that masks main crop

• repellant plants: releases chemical cues that actively repel pests

• barrier plants: physically block pest establishment

• trap crops: more attractive plant to pull pest away from crop

downsides of using plants to disrupt pest establishment/activity

• takes away area for planting main cash crops

• additional plantings may require significant additional resources like water and fertilizer

• plantings may compete with main cash crop for resources

• plantings complicate crop care and harvesting

What are the steps of classical biological control?

1. determine geographic region of origin of pest

2. search for pest and its natural enemies

3. test natural enemies for efficacy against pest

4. rear prospective natural enemies

5. test for safety against useful native insects

6. quarantine to avoid pathogens or parasites

7. release

direct pest vs indirect pest

• direct: pest damage results directly from pest activity such as feeding or oviposition

• indirect: insects that create conditions for another pest to cause damage

example of cultural method ot control pests

• Cultural control: adopting farming practices to reduce pests

• crop rotation

  • pathogen management

  • host switching

• sanitation

  • solarization (create condition where heat from sunlight kills pest)

  • treatment of machinery

• nutrient, water management: avoiding over-fertilization/overwatering

• plant resistant crops

economic injury level (EIL)

pest density that causes more damage than the cost of control

Economic threshold

level of pest population at which control should be begun to avoid reaching EIL

advantage of breeding plants to have pest resistance

• safe since no chemicals are used

• cost-effective

• compatible with other pest control methods

disadvantage of breeding plants to have pest resistance

• can require a long time (some plants take years for each generation)

• not always achievable

• not as well developed for ornamentals compared to crops

categories of pest control methods

1. Biological control

2. cultural control

3. genetic engineering

4. pesticides

5. pheromones to attract or repel pest

6. plant resistance

7. sterilizing insects

Altruism

behaviors that increase the fitness of another individual at a cost to the actor

The sperm of the fruitfly Drosophila bifurca is longer than any other species, uncoiled it is nearly 2 inches long. What benefit does this serve?

Sperm competition: long sperm acts as a physical barrier to block the uptake of sperm from other males

Male bruchid beetles have penis covered in spines that can damage the reproductive tract of the female after mating. How does this benefit the male?

the damage reduces the likelihood of other males being successful with mating with the female

What is the category of pollination

biotic and spread by animals

What is the category of pollination

abiotic and spread by wind

Animals that pollinate flowers other than insects

• birds: hummingbirds, honey creepers

• mammals: bats, mice, monkeys

order of socialities

1. quasisocial

2. subsocial

3. eusocial

4. communal

5 threats to honeybees

1. limited/monotonous floral resources

2. fungicides

3. pesticides

4. parasites

5. pathogens

polydnaviruses

• endogenous

  • exist in wasp genome

  • means vertically transmitted

• replicated inside of wasp, released with egg into host (eg caterpillar)

• virus subdues immune response allowing wasp egg and larva to “fly under radar”

sexual dimorphism

observable differences between sexes

mutlimodal

describes a courtship display that uses multiple sensory cues

sexual arms race

• reduce likelihood of another male mating

  • hooked/spined genitalia

    • scoop out sperm or destroy female genitalia

• sperm competition

  • chemical blocking in sperm proteins

  • physical blocking: plugs or long sperm

nuptial gift

nutritional supplement given by male to female before mating. it can influence pre- and post-mating selection

nuptial gift cost + benefit

cost: males invest more in mating-higher risk if female doesn’t produce offspring with male sperm; sometimes males “cheat” and there aren’t many nutrients in the “gift”

benefits: nutritional value to female may benefit offspring

three types of symbiotic relationships

• parasitism: one party benefits, one incurs costs

• commensalism: one party benefits, one neutral

• mutualism: both parties benefit

insecticide resistance

1. enzymatic

   1. enzyme binds to insecticide

   2. breakdown

2. mutation/existing genetic variation in existing insecticide target site

adaptations that insects that live underwater have

• aerial respiration “tubes”

• physical gills

• closed tracheal system

• “suckers” to help stick to surface due to high water flow

challenges to living underwater

respiration + water flow + surface tension