View
224
Download
3
Category
Preview:
Citation preview
Uniramians – Centipedes, millipedes and insects
Characterized by one pair of antennae and appendages that don’t branch
Centipedes• Carnivores• Poison claws in
head• Eat arthropods,
earthworms, snakes, mice
• Have ONE pair of legs per segment (not necessarily 100 legs!)
• Have venomous bites against predators
Millipede• Two pair of legs
per segment• Herbivores• Feed on dead and
dying plant material
• Protect themselves by rolling into a ball or use “nasty chemicals” to dissuade their predators
Feeding
• 3 pairs of appendages used as mouthparts
• One is the mandible
• Amazing modifications of the mouthparts
• Bees have glands in abdomen that secrete wax to build bee hives for food storage and larvae nurseries
• Bee saliva changes nectar into honey
movement• Three pairs of
walking legs are greatly varied
• Many insects have highly specialized legs for jumping and capturing prey
Adaptations for flight
• Enlarged thorax for muscles
• Oversized mitochondria supply muscle cells with energy
• Special blood supply to wing muscles keep muscles warm (sometimes warmer than outside) for optimal efficiency
Insect colonies• Collections of
individuals of the same species that live together
• SOCIETIES are colonies where individuals are DEPENDENT on the others for survival
• Termites, wasps, bees and ants form societies
• Have division of labour
• Different individuals (called castes) will have specialized bodies to perform their task in the society
• Examples of castes:
• reproductive females (queens)
• reproductive males
• Workers• warriors
TermiteQueen
workers
• Reproductive males ONLY fertilize the eggs
• In BEE SOCIETIES, the queen mates with one or more males only ONCE.
• She receives all the sperm she needs in that mating
• The successful reproductive male then dies
• All unsuccessful reproductive males are turned out of the hive, and soon die
• Workers do all the work for the hive
• Bee workers are all female and are able to do all jobs (except reproduce)
• Ant and termite workers are specialized for specific jobs
Insect Communication• Non-social insects
communicate mainly to find mate only
• Cricket males rub their forelegs together
• Male cicadas buzz by vibrating a membrane on their abdomen
• Male fireflies produce a series of light flashes
• The wingless females (glow worms) flash back their reply, and the males will find them
• (sometimes another genus will mimic this signal and prey on the expectant male)
• Social insects have more complicated communication systems
• Pheromones are often used
• Ex. Ants drag their abdomen all the way home from a food source to leave a trail for other ants to find the food
• The Queen Bee produces “queen substance” that prevents other females being able to lay eggs
• When queen substance is low in the hive, the worker bees will feed a few female larvae a special diet which causes these larvae to develop into queens
• Worker bees “dance” to tell other workers where they found food
• Two basic dances: the round dance and the waggle dance
The Round Dance• The bee walks in a circle, then retraces that circle in the opposite direction
• Means that food is within 50 meters of the hive
• Good quality food will be indicated by more frequent changes of direction
• The kind of flower found is determined by smelling the messenger
The Waggle Dance• The bee wiggles her abdomen while walking in a straight line
• She circles around and wiggles back up the same line
• She will then circle around on the other side of the line, and repeats
• The waggle dance means that the food source found is more than 50 meters away from the hive
• The direction of the straight line is the direction the other bees must travel away from the hive to find the food
1 million species of insects have been identified so far, which is about ½ of all animals known to science
Sizes could vary from .25mm to 50 cm
Many male insects have appendages called claspers, which help them stay in position during mating.
Recommended