External Morphology Flashcards
define exoskeleton/cuticle
- skeleton on the outside
- it is comprised of hard segments connected by a flexible membrane
cuticle function
- Color and texture display
- Contains internal organs
- Attachment/anchor for muscles -> movement
- Base for sensory organs
- Water retention
cuticle function - movement and flexibility
- Flies (Diptera) and some others use the cuticle to power wings
- Indirect flight muscles attach to thorax, not wings. Muscles flex thorax, thorax flaps wings
cuticle function - water retention
- the cuticle is covered with waxy hydrocarbons to prevent water loss
- Insects are small: not much water to lose
- Small size = high surface area to volume ratio. This means even more water loss
segmented body plan
- head
- thorax
- abdomen
segmented body plan - head
- feeding and sensory input
- sensory organs
- Mouthparts
head - sensory organs
- antennae
- compound eye
- ocelli
head: sensory organs - antennae
- tactile and chemosensory
- Organs of touch and smell
head: sensory organs - compound eye
- image forming
- integrates images from multiple facets called ommatidia
head: sensory organs - ocelli
- there are 3
- simple eye (as in, not compound)
- Senses light and motion
head: mouthparts - types of mouthparts
- Mandibulate (mandibles)
- Sponging
- Piercing-sucking
- Lepidoptera proboscis
- Multi-purpose bee mouthparts
head: mouthparts - mandibles
- often used for chewing, manipulation
- Labrum, maxilla, labium: generally used for getting food into mouth
head: mouthparts - Sponging mouthparts
Pseudotrachea are grooves on the labellum that suck up liquid via capillary action
head: mouthparts - Piercing sucking
- Mosquito example: pierce host, then suck blood
- Mouthparts have been modified to form a straw to deliver saliva and suck liquid
- other organisms can pierce plants (sap), vertebrates (blood), or prey (suck out guts)
head: mouthparts - Lepidoptera proboscis
Specialized mouthparts of butterfly
head: mouthparts - Multi-purpose bee mouthparts
- Mandibles and siphon: Can be used for building
- function is helped by lapping with hairs on glossae
- Some bee “tongues” are so long that they extend beyond the end of the abdomen
segmented body plan - thorax
- used for locomotion
- Legs
- wings
segmented body plan: thorax - legs
- Modifications
- Tripod gait for walking
thorax: legs - modification
- thorax has three segments
- Fore legs (prothorax)
- Mid legs (mesothorax)
- Hind legs (metathorax)
thorax: legs - tripod gait
two legs on one side, one on the other, and alternate so body is always supported by a tripod
thorax: wing - modification
- Elytra
- Hemielytra
- Minute (small/tiny) insects
- No wings
wings - elytra
- Forewings are armor
- ex: beetles (coleoptera)
wings - hemielytra
- Anterior part of forewings are armor
- true bugs (Hemiptera)
wings - minute insects
- Wings swim through air – analogous to oars
- Example: thrips (Thysanoptera)
wings - no wings
many insects have no wings or lose wings after dispersal
wings - no wings example
Bristletails, lice and fleas
wings - no wings after dispersal example
Ants and termites
segmented body plan - abdomen
- Dorsal segments are tergites
- Ventral segments are sternites
- digestion and reproduction
- ovipositor
abdomen - ovipositor
- Injects eggs into host organism (caterpillar) or substrate (plant)
- Secondarily modified into stings in bees, ants, and aculate wasps (hymenoptera)
