What are the different types pf habitat
Terrestrial
- rainforest
- deserts
- houses
- Antarctica
Aquatic - freshwater
- lakes
- rivers
- glacial streams
Marine- sea-air interface only
- very few species
Parasitic - habitat = another organism
- many parasitic wasp
- several parasitic flies
- parasitic beetles
- ectoparasitic moth
Describe the life cycle of an aphid parasite
- Oviposition
- Growth of parasite larvae. Greenbug alive
- Greenbug dies. Parasite pupates. Result is mummy
- Adult parasite emerges
- Adult parasite
- Oviposition
Majority of insects have ~1 year life cycle. Shortest generation time = 2 weeks
Describe the modification of insect mouthparts
Ladybird - biting mouthparts; diet - aphids
Mayfly nymph - filter feeding; diet - aphids
Aphid - piercing and sucking; feeding damage & transmits disease
Mosquito - piercing and sucking; disease transmission
Describe the different types of sociality
Solitary - preying mantis, locusts, bees
Gregarious - act as individual but aggregate in groups e.g. bees, locust, collembola
Sub-social - most primitive level of interaction involving parents and offspring e.g. bees and wasps
Highly social - complex social ‘caste’ system e.g. ants, bees, termites
What are some reasons for success and diversity
- exoskeleton
- long history
- short generation time and fecundity
- metamorphosis
- adaptability to changing environments
- small size
- sociality
What are the common features of insects
Body divided into:
- head: 1 pair of antenna and mandibles, 2 pairs of maxillae
- thorax: 3 pairs of legs, usually 2 pairs of wings
- abdomen: no locomotory appendages genital opening usually at posterior end
How are insects classified
- all insects are in the class INSECTA
- there are 2 sub-classes: Apterygota and Pterygota
- the sub-class Pterygota has two divisions
1. Exopterygota (Hemimetabola)
2. Endopterygota (Holometabola)
What are the main features of Entognatha and Apterygote insects
- no wings; a primitive feature
- metamorphosis slight or absent (nymphs/ young are effectively miniature adults - cant reproduce)
- one or more pairs of pre-genital appendages on abdomen
- adult mandibles articulate with head capsule at single point
- contains collembola (springtails) and Thysanura (silverfish)
What are the main features of Pterygote
- winged (sometimes secondary wingless)
- metamorphosis occurs
- adults have no pre-genital abdominal appendages
- adult mandibles articulate with head capsules at 2 points
- contains all the important order
What are the main features of Exopterygote
- single metamorphosis
- immature states are nymphs - increasingly resemble adult
- pupa rarely present
- wings develop externally
- nymphs (called naiads if aquatic) and adults often feed on same food resources
- includes: dragonfly, termites, cockroaches, greenfly
What are the main features of Endopterygote
- metamorphosis complex
- immature stages are larvae - differ from adults in form and function
- larvae assimilates food
- pupa present - does not feed, tissues reorganised
- wings develop internally
- contains: flies, butterflies, moths, bees, wasps, ants
Describe sexual reproduction in insects
requires synchronisation with each other and environment
Mechanisms
- overt displays e.g. fireflies
- attraction to resource - food
- pheromones - typically female
- swarms - mostly male
- copulation - direct except in apterygotes
Old Age Pensioners Sing Carols
Describe asexual reproduction in insects
Parthogenesis (development from an unfertilised egg)
- can be obligatory or facultative
- virtually all order have at least one asexual representative
- highly successful means of rapidly exploiting favourable conditions
- female only eggs = thelytokous
- male only eggs = arrhenotokous
- male and female eggs = amphitokous
Hermaphroditism (male and female reproductive organs)
Polyembryony (two or more embryos from one egg)
What is phenology
the study of timing of periodic plant and animal life cycle events and how these are influenced by seasonal and inter annual variations in climate
What are environmental gradients
Photoperiod - constant recurring gradient = noise free signal
- long day and increasing day lengths = good indicators of spring or simmer (migration north)
- short day and decreasing day length = good indicators of autumn or winter (migration south)
Temperatrue - inconsistent/ variable = noisy signal
Warm or cold spell not a good indicator
What is polyphenism
The capacity of a genotype to produce two or more distinct phenotypes in response to an environmental factor such as temperature, photoperiod, or nutrition
What are collembola
- ancient order, now considered to be separate class within super class Hexapoda
- apterygote - without wings, no metamorphosis
- two main sub-orders (elongate and globular)
Habitat: soil and leaf litter
Diet: detritus
What are the differences between elongate and globular collembola
Elongate: The spring of springtails = collembolan furcula: function – to escape predators and possible unfavourable environments
Globular:
- many are soil dwellers
- furcula often reduced
- thorax and abdomen fused
What are the 5 categories of sound production
- Tremulation (vibration) e.g. species-specific flight
- Percussion
- Stridulation (frictional mechanism)
- Click mechanism - deformation of modified area of cuticle
- Air expulsion (rare)
Terrance Plays Sound Concerts Always
Describe the 4 main types of insects in a colony
- Primary reproductive (eventually become King and Queen) - winged adults (swarmers) Role: establish colony
- Secondary (supplementary reproductive if either primary dies) - wingless adults or reduced wings
- Workers - wingless and sterile. Roles: foraging, food storage, brood/ nest maintenance
- Soldiers - wingless and sterile. Functional morphology: mandibulate and nasute (chemical defence). Role = defence
What are the 2 main feeding habits of termites
- Wood (rotten or sound), grass, fungi, normal diet or workers
- Prepared diet
- stomodaeal - salivary secretion and regurgitates intestinal contents
- proctodaeal - droplets from the rectal pouch taken from anus after tactile stimulation
- prepaid diets are sole diet of soldiers
