Life cycles

Introduction
Public summary: 

Ever wondered what happened to a creature between it being an egg and an adult? Look at our jars life cycles collection for Butterflies, Bees and Frogs and see for yourself!

Jars of specmens of frogs, bees and butterflies from different lifecycle stages
Useful information
Kit List: 

Sets of preserved life cycles of frogs, bees, and butterflies.

Butterfly: Eggs (on a piece of cabbage), Larvae (caterpillars), Pupae, Adult butterfly
Bees: Larvae, Pupae, Male/drone, Worker, Female
Frog: Eggs, tadpoles, mature frog

A magnifying glass

Packing Away: 

Pack jars carefully back in box (same box as Horrible Housemates)

Frequency of use: 
5
Explanation
Explanation: 

*** OVERVIEW/THINGS YOU MIGHT LIKE TO TALK ABOUT ***

- The life cycles of frogs, bees, cockroaches, and butterflies.
- Social structure of bee colonies and communication amongst bees
- Using stages of insect development to "date" a decomposing corpse
- Insect growth using the cockroaches

*** BASIC PROCEDURE AND EXPLANATION ***

1) Ask the child to choose a set of vials that they find interesting.

2) Once they have chosen a vial, ask them if they know what is inside the set of vials? (frog, butterfly, cockroaches or bees)

3) Next, say that this set of vials shows the life cycle of the butterfly/bee/frog. During this life cycle, the animal changes from an egg to an adult animal (which produces or fertilizes eggs which will go through the life cycle again).

4) You can then ask the child to try to put the vials in the proper order (egg -> adult) without looking at the numbers of the top of the vial. Once they have done this, you should go through exactly what is in each vial.

5) Start by describing the egg. This is one cell (a tiny ball of nutrient and information (DNA)) which divides lots and lots of times to produce larvae.

6) Next discuss the larvae. Emphasize how the larvae spends all its time eating and eating and eating! This is so it can grow really fast and store energy for metamorphosis!

7) Finally, explain the pupae stage - at this point the larvae undergoes metamorphosis and becomes an adult! What is metamorphosis? It refers to something changing from one form to another completely new form. Isn't it amazing that the larval form can change into the adult form in just about two weeks?!

8) After you've finished explaining the life cycle of the animal, you might ask the child if humans go through metamorphosis. Explain that while humans don't go through metamorphosis, we do change a lot in our mummy's tummy! We also go from an egg (one tiny cell smaller than the full stop at the end of this sentence) which divides lots of times to create a baby!

*** TIPS FOR DEMONSTRATING ***

1) Always count the total number of insects you have on display before you start demonstrating…make sure that none of these disappear during the day (they roll away very easily)!

2) Get out one set of vials at time to avoid overwhelming/distracting the children

*** OTHER THINGS TO TALK ABOUT ***

**BEES**
Larvae -> Pupae -> Worker/Queen
1) Social Structure of Bees (http://www.indianchild.com/honey_bee.htm)
- Each bee colony has a very organized social structure.
- Bees tell each other where food is through different dances - call these waggle dances
- Males/drones:
- Develop from unfertilized eggs (parthenogenesis) - means females can produce as many males as they want to (as don't have to mate with male first)
- mate with queen to produce new queen
- Worker bees;
- Develops from fertilized eggs
- jobs like clean/ incubate eggs/feed drones and larvae/guard hive/find food
- Female bee: Queen
- Develops from fertilized eggs
- lays eggs, mother to all bees in the colony. ~2000 eggs/day
- Produces pheromones which controls the behavior of her workers
- Fed lots food!

2) Communication Among Bees (http://www.indianchild.com/honey_bee.htm)
- Bees communicate by pheromones (chemicals produced by the queen that the other bees "smell") and dances.
- This communication is very important to maintain the organization/social structure within the colony so that all of the bees can survive (the queen, workers, and drones cannot live alone - they depend on each member of the colony).

dancing. round dance, go in a circle and waggle in the direction of food is in (long distance). Waggle dance, food is nearby direction of run indicates direction and length of waggle shows how far.
Stingers, die after they've stung as pulls organs with it.

Honey. Why do they make it? What from? uses nectar to feed larvae. Honeycomb, useful to farmers as pollinators.

**FROGS**
1) Egg -> Frogspawn -> Tadpoles -> Frogs

2) Frogspawn is like jelly, provides a food source for the growing embryo (the black spot)

3) Tadpoles - sometimes eat each other (cannibalism). They start with no legs, then develop hind legs, then front. Then become froglets.

4) Tree frogs; where do they lay their eggs? - in the water collected at the bases of leaves. Are often brightly coloured and very poisonous (used to make poison arrows. The Golden Tree Frog is toxic enough to kill 20 people or two elephants, chickens and dogs have died from touching paper that has been touched by a frog! Poison stops nerve impulses leading to muscle contraction.

Amphibian, need to stay damp as they breathe through their skin, like lungs aveloli. They sing to each other by inflating their ***. They're mammals and have a backbone.

**BUTTERFLIES**
Ova -> Larvae -> Pupae -> Adult
1) Patterns/colouration - eye spots deflect attack from the butterfly's body , camouflage is another way of increasing the likelihood of survival allowing it to rest undetected

3) Forensic Entomology: (http://www.forensicentomology.com/appear.htm)
- Forensic Entomology examines the stages of develop of insects in a decaying corpse to determine when the body died!
- For example, many insects will lay eggs on a corpse. These eggs will hatch and become larvae, which feed on the decaying corpse. By examining the size/weight of the larvae, these scientists can determine how old the corpse is!

caterpillars eat vegetables, 14 years of eating before they turn into a butterfly, they can be poisonus and brightly coloured to warn predators. Some butterflies only live a couple of weeks. Have bright colours to warn birds they taste bad and eye spots and camouflage. Monarch butterflies migrate from Canada to Mexico (3000 miles) using landscape (mountains/sun) to navigate. Some moths use earth's magnetic field. Some eat plants like milkweed which make them poisonous to other animals.

*** SCIENCE BACKGROUND FOR DEMONSTRATORS ***

More information on Forensic Entomology (http://www.forensicentomology.com/appear.htm)
"What information can a forensic entomologist provide at the death scene?"

Forensic entomologists are most commonly called upon to determine the postmortem interval or "time since death" in homicide investigations. The forensic entomologist can use a number of different techniques including species succession, larval weight, larval length, and a more technical method known as the accumulated degree hour technique which can be very precise if the necessary data is available. A qualified forensic entomologist can also make inferences as to possible postmortem movement of a corpse. Some flies prefer specific habitats such as a distinct preference for laying their eggs in an outdoor or indoor environment. Flies can also exhibit preferences for carcasses in shade or sunlit conditions of the outdoor environment. Therefore, a corpse that is recovered indoors with the eggs or larvae of flies that typically inhabit sunny outdoor locations would indicate that someone returned to the scene of the crime to move and attempt to conceal the body.

Similarly, freezing or wrapping of the body may be indicated by an altered species succession of insects on the body. Anything that may have prevented the insects from laying eggs in their normal time frame will alter both the sequence of species and their typical colonization time. This alteration of the normal insect succession and fauna should be noticeable to the forensic entomologists if they are familiar with what would normally be recovered from a body in a particular environmental habitat or geographical location. The complete absence of insects would suggest clues as to the sequence of postmortem events as the body was probably either frozen, sealed in a tightly closed container, or buried very deeply.

Entomological evidence can also help determine the circumstances of abuse and rape. Victims that are incapacitated (bound, drugged, or otherwise helpless) often have associated fecal and urine soaked clothes or bed dressings. Such material will attract certain species of flies that otherwise would not be recovered. Their presence can yield many clues to both antemortem and postmortem circumstances of the crime. Currently, it is now possible to use DNA technology not only to help determine insect species, but to recover and identify the blood meals taken by blood feeding insects. The DNA of human blood can be recovered from the digestive tract of an insect that has fed on an individual. The presence of their DNA within the insect can place suspects at a known location within a definable period of time and recovery of the victims' blood can also create a link between perpetrator and suspect.

The insects recovered from decomposing human remains can be a valuable tool for toxicological analysis. The voracious appetite of the insects on corpses can quickly strip the remains down to the bones. In a short period of time the fluids (blood and urine) and soft tissues needed for toxicological analysis disappear. However, it is possible to recover the insect larvae and run standard toxicological analyses on them as you would human tissue. Toxicological analysis can be successful on insect larvae because their tissues assimilate drugs and toxins that accumulated in human tissue prior to death."

Risk Assessment
Date risk assesment last checked: 
Mon, 08/01/2018
Risk assesment checked by: 
gcs33
Date risk assesment double checked: 
Fri, 02/02/2018
Risk assesment double-checked by: 
Miffles
Risk Assessment: 
DESCRIPTION Looking at dead insects in small sealed tubes & talking about them
RISKS
  • Smashing a specimen tube and magnifying glass can cause cuts, and the preservative to come out. Preservative is 1% Propylene phenoxetol, which should not be irritant to eyes or skin at that concentration, but which may be harmful if ingested. Propylene phenoxetol is a preservative used in personal care product and is safe.
  • ACTION TO BE TAKEN TO MINIMISE RISKS
  • Keep a careful eye on the tubes and magnifying glass. If necessary, reduce the number of tubes on display.
  • Make sure all are tightly closed with sellotape on top of the seal to make it obvious that the tube should not be opened.
  • Demonstrator must know the location of the nearest eyewash.
  • ACTION TO BE TAKEN IN THE EVENT OF AN ACCIDENT
  • Call first aider in case of injury.
  • Wash skin with that has come into contact with preservative with water.
  • If preservative gets into eyes call a first aider. Use eyewash to wash out of eyes if trained and confident to do so.
  • Unless large quantities ingested, recommend that parents take child to GP if child becomes ill, and state that 1% propylene phenoxytol was the substance ingested.
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