Aquatic Entomology Lecture 4 - Locomotion

muscles in the leg attach to the thorax

extrinsic muscles

entirely in leg

intrinsic muscles

(joint) one point of articulation: can rotate

monocondylic

(joint) two points of articulation: only move in one plane

dicondylic

monocondylic joints (1)

• tibia-tarsus

dycondylic joints (4)

• Thorax-coxa

• Coxa-trochanter

• Trochanter-femur

• Femur-tibia

How do insects walk

legs are FLEXXED which lifts the tip OFF the ground. The leg can also be EXTENDED which pushes the leg outward which creates thrust

each side is counterbalance by the otherside to insects always have 3 points on the ground

How insects move in water (4)

• Swimming with jointed appendages

• Body

Swimming with jointed appendages

• Assumption: High Re

• Legs row and act as paddles —> result in motion in the opposite way

1.) Perfect transverse phase synchrony

2.) Alternative-leg swimming

Swimming leg modification: Oar like (Modifications, Mechanisms (2))

Modification: Flattened segments and addition of swimming hairs

Mechanism:

1.) Power stroke: Creates thrust, maximizing surface area, /\

2.) Recovery: Decreases surface area, V

Swimming with legs at surface (Challenge, ORGANISM)

Challenges: Can create waves that lower efficiency)

Organism: Whirling Beetle

Swimming via undulation (mechanism)

• Move body (up and down or side to side)

• Insects with and without legs can use this method

Jet Propulsion (Method, ORGANISM (2))

Organism: Larval dragonflies and some damselfies

• usually walks

• uses jet propulsion for emergencies

  • water drawn into hindgut and ejected forcefully

Vertical movement using buoyancy (Organism)

• Moving up and down the water colum using stored air

• Organism: Phantom Midge Larvae: Chaoboridae

Types of movement on the water surface (9)

• Surface walking, rowing, running, jumping

• Skimming, sailing skating

• Meniscus climbing

• Marangoni propulsion

Rowing and jumping (Organism)

Gerrids

Walking (organism)

Hydrometridae (Water measurers)

Insects stay in contact with water while flying to help with support

Skimming

Insects use wings as sails

Sailing

Use gills to hang down from water surface. The gills act as a foot along surface

Skating

Curve the surface film and create forces to drive them up to meniscus (organism)

Maniscus climbing

organism: thirps

Exude surfactant which reduces the surface tension. This results in a force that propels them forwards. (organism)

Marangoni propulsion