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Ch 28-4 – Insects and Their Relatives. Uniramians – Centipedes, millipedes and insects. Characterized by one pair of antennae and appendages that don’t branch. Centipede and Millipede. Wormlike body Many leg-bearing segments. centipede. millipede. Centipedes. Carnivores
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Uniramians – Centipedes, millipedes and insects Characterized by one pair of antennae and appendages that don’t branch
Centipede and Millipede • Wormlike body • Many leg-bearing segments centipede millipede
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
Millipede Many legs!!
Insects • Have 3-part body • 3 pairs of legs attached to thorax
Feeding • 3 pairs of appendages used as mouthparts • One is the mandible • Amazing modifications of the mouthparts
Other modifications for feeding – mosquitos saliva – anticoagulant
Bees legs and bodies are covered in hair for collecting pollen
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
flight • Flying ability varies greatly • Butterflies have limited manoeuvrability
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
Ant Colony ANTS!
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 Termite Queen workers
Termite soldier Worker
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