Insect bio: social structures + biocontrol

which order is social within exopterygote?

blattodea (termites)

which order is social within endopterygote?

hymenoptera- bees, wasps, ants

outline the social behaviour of blattodea

important pests in tropical regions

highly social

large colonies in mounds- termitarium

what is the advantage of social behaviour in insects?

decentralised, self-organised

use these features to exploit food sources and environments

groups of insects that have lost the ability to reproduce can exist within insect communities- performing specialised function

outline the termite castes

1. primary reproductives (become king and queen)

   1. winged adults (swarmers)

   2. establish colony

2. secondary (supplementary reproductives if either primary dies

   1. wingless adults or reduced wings

3. workers- wingless and sterile

   1. forage, store food, brood, maintain nests

4. soldiers- wingless and sterile

   1. functional morphology- mandibulate and nasute

   2. defense

outline nasute termites

have robust pointy heads

mouthparts form a tube, shoot chemicals out as a defense

large antennae to pick up signals from colony

outline mandibulate termites

heavily armoured head- push and manoeuvre outsiders

large antannae

large mandibles

outline termite feeding

• wood, grass, fungi: diet of workers

• prepared diet: diet of soldiers

  • stomodael: salivary secretion and regurgitated intestinal contents

  • proctodaeal: droplets from the rectal pouch taken from anus after tactile stimulation

outline the lifecycle of termitariums

1. new colonies founded by primary reproductives- leave in a swarm from an existing colony

2. fly short distance, shed wings, excavate small chamber, mate

3. reproduction

4. reproductive forms live for around 50 years, sterile casts 2-4

5. supplementary reproductives develop if primary queen dies

outline ant societies

female castes: queen and worker

workers can exist in different size classes

new queens+males have wings, lost after mating + male dies

complex genetics depending on species

queen exerts strong influence over workers

What are the different mechanisms of biological control?

• predator species

• parasite species

give an example of a predator species used in biocontrol

ladybirds are used against aphids

the larvae of ladybirds suck out the insides of the aphid and leave its exoskeleton

the 4th ladybird instar larvae consumes aphids completely

the adult ladybird feeds on aphids as well

give an example of a parisitic biocontrol agent

parasitic wasps used to control aphids

female lays its eggs into aphids

the larvae of the wasps develop in the aphids and the aphid dies 7-8 days after

outline biocontrol

a pest management strategy using natural predators, parasites or pathogens to control pest populations without the use of synthetic chemicals

what is the impact of climate change on aphids?

• northern and southern borders of aphids expected to shift poleward- expanding range to further areas

• warmer winters mean aphids may survive in regions that once limited their presence

• large distribution of aphids means lower crop yield as they are destructive to crops

what are the consequences of climate change for food security?

lower nutritional value

increased atmospheric CO2 levels reduce nutritional content (vitamin, minerals, protein) of crops, worsening malnutrition in pops. already vulnerable to food insecurity

what are the different forms of sociality?

solitary- eg preying mantis

gregarious- acting as individuals in a group- locust

sub-social- parents and offspring- bees

highly social- caste systems-termites

which species can fold their wings? what is the advantage of this?

butterflies and moths

provides protection from damage, heat regulation, better manoeuvring

how does metamorphosis serve as an adaptive survival strategy for insects?

allows exploitation of different ecological niches

reduces competition for resources between life stages

enhances survival through specialised forms for feeding, growth and reproduction

give an example of a species where the different life cycles have different diets

butterflies: larvae are terrestrial and feed on plant leaves

adults are terrestrial and feed on nectar from flowers