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Camouflage Masters
Stick Insects are the master of camouflage, what can we notice about their camouflage? How do they defence against their predators?
- We notice that Stick Insects
have at least the following methods to hide themselves from predators;
- 1. Their bodies colour and shape made them look like part of the plant.
- 2. When staying motionless, they always put their front legs in front of their head, made themselves look more like part of the plant.
- 3. They usually feed at night, in day time they just hangs motionless on the plants.
- 4. They eat the whole leaf, usually they will not leave part of the leaf not eaten with some bite marks, like most grasshoppers do.
- 5. Even when they move, they simulate the motion like the movement which is caused by wind blowing.
- 6. Their eggs look like seeds, so the predators do not notice their existing by the seeds.
- 7. The Goliath Stick Insect throw their dropping to very far away so that the predators do not notice them by their dropping.
- 8. When disturbed, they may just drop to the ground and play dead.
- By watching the stick insects, we notice that they has at least the following defence mechanisms. Of course their primary mechanism are their heavily camouflage. Their appearances and movement resemblance to leaves so that they can hind away from predators. Their second defence mechanism is to scare its predators. When disturbed, some stick insects, such as the Goliath Stick Insect, will display the bright red colour under its wings and the eyes-pattern between the thorax and hind legs, together with swishing sound apparently coming from the wings. Its will also kick its spiny legs which will help frighten the predator. We also noticed that some stick insects that we found, some of their legs are missing, or some legs are a little bit smaller than normal. This could be its last defence mechanism, when its legs held by its predator, e.g. a bird, it loses its leg deliberately and drop to the ground, the bird may not find it for its heavily camouflage.
- 1. Their bodies colour and shape made them look like part of the plant.
We also notice that the number of stick insects is very low when comparing with other insects, such as grasshoppers, which they live in similar habitat. It seems that nothing stop the grow of the population of stick insects. So we gauss being rare is another survival factors of stick insects. The predators cannot depend on stick insects as a constant food source and have less chance to learn how to recognize the stick insects. Being rare is a way of camouflage.
Stick Insects are heavily camouflage, how do they find their mate for reproduction?
Most insects have their special ways for finding their mate for reproduction.
To name a few, the butterflies and dragonflies have very good eye sight, so
they attract their mates by colours and patterns. The crickets and cicadas sing
their love songs. The moths use their sense of smell. The ants have their
mating flight while some butterflies have gathering on the hill top. For Stick Insects,
it seems that they do not have any special methods to find their mates. They
have poor eye sight as well as heavily camouflage, so it is not easy for them
to 'look' for their mates. They do not produce any love songs, their antenna is
not well developed as moths to smell their mates. They do not have special
gathering event like ants of butterflies. How do Stick Insects find their mate?
This seem the job of the male stick insect, because usually only the male can
fly. How do the males locate a female? I checked that we do not have answer on
this question yet.
For a frog species in the desert, because it is very difficult to find a mate, if a male frog meet a female frog, even not in the mating season, the male will hold itself on the back of the female frog until mating season. We saw some male stick insects doing the same thing. Its seem that the stick insect employ the same method as the desert frogs.
I read form books that some stick insect species can reproduce without mating. The eggs will hatch without fertilized by males. This could be a evolution solution that temporally fix this problem.
Katydid Camouflage
We found that Katydids usually active at night. Actually their 'active' in not really active. They feed on leaf and walk around within a small area. In day time they usually stand still on a leaf near the tips of the branch. Usually it will take us minutes to find them although we know where to look for them.
Gum Leaf Katydid like to hide on the tips of the branch, but not on the top of the tree. This may help them to avoid the predation from birds. This also explain why we can find them easier than those species hiding on the tree top.
We notice a interesting way of the Gum Leaf Katydids handling their droppings. Most insects, such as the Giant Grasshoppers, just let their droppings drop vertically onto the ground, or the leave just under them. So sometime we can use their droppings to locate them. For the Gum Leaf Katydids, we notice that every time, when their droppings are half way out,. they use their hind leg, left of right, to kick them far away. This will sure help them to hide away from the predators. This habit is somewhat similar to the Goliath Stick Insects. To see another way of dropping handling, please click here.
- The Katydid's dropping, 3mm in length, evenly distributed on the floor, not just concentrated on one spot under the insect.
They always eat the shard skin after moulting. So that their predator cannot find them by their skin.
