week 7 - insect body morphology

Question 1

body morphology
Within the basic body plan, many structures have…

Answer 1

… become adapted to perform specific functions

Question 2

body morphology
These adaptations have occurred in both…

Answer 2

… adult and juvenile insects

Question 3

body morphology
Adaptations have occurred in…

Answer 3

… mouthparts, legs, wings, ovipositor, antennae and ‘whole body’ structures.

Question 4

body morphology
Collembola

Answer 4

Collembola are ancient – now actually considered to be separate Class within Super-Class Hexapoda.

Two main groups: elongate and globular.
Habitat: soil and leaf litter (100, 000 ind/m3)
Diet: detritus
One of the most abundant macroscopic animals

< 8mm in length
< 6 abdominal segments

Question 5

body morphology
legs only come off of..

Answer 5

thoracic segments

Question 6

body morphology
furcula

Answer 6

folded up underneath

he ‘spring’ of springtails = Collembolan furcula

Function – to escape predators and (possibly) unfavourable environments.

Question 7

body morphology
elongate collembola vs. gobular collembola

Answer 7

globular
Many are soil dwellers
* Furcula often reduced (some dont have it)
* Thorax and abdomen fuse

Question 8

body morphology
honey bee

Answer 8

Sub-class: Pterygota
Division: Holometabola
Order: Hymenoptera

see notes for structure

Question 9

body morphology
honey bee
legs

Answer 9

Distinct modifications of leg segments for pollen collection and transport.
* Pollen is collected by spines on first tarsal segment and transferred to the tibia of opposite leg – the pollen ‘basket’ for transport back to hive.
* A spur at the base of tibia on middle leg dislodges pollen masses from the basket.

adaptive advantage: more pollen in less trips (better for hive)

Question 10

body morphology
Ovipositor/Sting in Bees and Wasps

Answer 10

Variable in structure and function in the order Hymenoptera – a series of valves.

primary function to lay eggs

Question 11

body morphology
Ovipositor/Sting in Bees and Wasps
Hymenoptera has two sub- orders:

Answer 11

Symphyta (e.g. sawflies) – some valves are adapted to saw/cut into plant tissues and wood for egg laying
(eggs less visible, environment protected)

Apocrita Parasitica
*Function: ovipositor pierces host to deposit eggs. *Can be very long to limit proximity to host

Question 11

body morphology
Ovipositor/Sting in Bees and Wasps
Hymenoptera: Bees
what if ovipositor lost?

Answer 11

Ovipositor is modified as a sting and egg laying function is lost

Question 12

body morphology fleas

Answer 12

Division: Holometabola
Order: Siphonaptera

• External parasites feed on blood
  Some well known flea species include: * Cat flea (Ctenocephalides felis),
• Dog flea (Ctenocephalides canis),
• Human flea (Pulex irritans),
• Northern rat flea (Nosopsyllus fasciatus),
• Oriental rat flea (Xenopsylla cheopis) – Black Death.

*Need blood meal before capable of reproduction

Question 13

body morphology fleas
adaptations

Answer 13

• Tube-like mouth-parts adapted to feeding on the blood of their hosts.
• Bodies are laterally compressed permitting easy movement through the hairs or feathers.
• Legs are long, the hind pair well adapted for jumping (around 200 times their own body length)
• Body is hard, polished, and covered with many hairs and short spines directed backward, which also assists its movements on the host.
• Tough body is able to withstand great pressure, likely an adaptation to survive scratching etc

Question 14

body morphology
click beetles

Answer 14

Sub-class: Pterygota
Division: Holometabola
Order: Coleoptera

Question 15

body morphology
click beetles
‘click’ mechanism

Answer 15

• Function: to regain normal walking position when tipped over or fall from plants onto back (and deter predators if on back).
• A ‘spine on ventral surface projects back into cavity on the mesothorax.
• Spine pushes quickly into cavity (click noise) and beetle ‘rolls’ to one side and can move onto legs.

Question 16

body morphology
sound production and hearing sound
e.g. Preying Mantis (Order: Mantodea)

Answer 16

The praying mantis has one ear (eardrum), located on the ventral side of the abdomen, between the four trochanter of its hind legs. Detects echolocation calls of bats

Delicate hindwings, camouflage markings on the heavier protective forewings. Many have a pair of dots on their wings which simulate a pair of eyes for defensive posturing. When defending, the mantis may rear up and wave its forelegs while simultaneously rattling its wings together to create a hissing noise

Question 17

body morphology summary

Answer 17

Great diversity of specialized morphological adaptations in insects
* Collembolan furcula - jumping
* Bee legs – pollen collect and transport
* Click beetles – righting mechanism
* Ovipositor – sawing, piercing, stinging
* Fleas – body shape, hair arrangement
* Sound production (and detecting sound)
Provide many clues to understanding the biology/life style of an insect

Question 18

body morphology
sound production
Tremulation (vibration) –

Answer 18

e.g. species specific flight sounds

Question 19

body morphology
sound production
Percussion –

Answer 19

e.g. Cicadas (Order: Hemiptera)
Special organ called a tymbal)

Question 20

body morphology
sound production
tridulation (frictional mechanisms) –

Answer 20

widespread (at least 7 orders), e.g. Crickets (Order: Orthoptera)