SECRETS OF INSECTS Successful Survival

Vikram Singh Rathor

2020-11-02 16:48:08

Credit: pixabay.com

Credit: pixabay.com

Insects are most numerous & successful creatures on Earth. Their species richness or diversity surpasses any other group of organisms. Throughout the insect evolution, several factors have combined to make insects the most successful of all species on this planet. There are several reasons for their success, mainly their ability to fly and reproduce quickly, their generally small size, and their protective cuticle (external exoskeleton), their insulated central nervous system and their unusual wing folding mechanism.

The early fliers were not able to fold their wings back along their bodies but by the middle of Carboniferous period, some insects had evolved this ability, and it allowed them to use a far greater range of microhabitats, such as cracks and crevices in dead wood, inside leaf litter, or under stones. The descendants of these species were highly successful, and today it is only dragonflies and mayflies that cannot fold their wings in this way.

Even the developmental stage includes the secrets as insect develop to adulthood by molting periodically throughout their life. Winged insects changes either by a gradual process, called incomplete metamorphosis (where the young look like smaller versions of the adults called nymph - as in dragonflies and mayflies), or undergo a more sudden transformation, called complete metamorphosis (where the young look very different to the adults - as in beetles, moths and butterflies), in which the fully grown larva pupates and attaches itself to the underside of a leaf and sheds its last larval skin. The larva remains immobile and the pupal cuticle underneath hardens and becomes dark. The pupal stage proceeds in response to climatic conditions (the pupa made it possible for insects to survive a period of stress). Pupation could remain for about 4 to 5 weeks, depending on conditions such as temperature and the supply of food. Larvae became "eating machines" and adults "breeding machines." The success of the pupal stage can be seen clearly today.

Factor

Effect

CUTICLE (EXTERNAL EXOSKELETON)

Tough and waterproof, the cuticle helps to protect insects from predators and also from dehydration

FAST REPRODUCTION

Insects evolve at a high rate and adapt quickly to changing environmental conditions.

FLIGHT

This allows insects to escape from enemies, to find new habitats and food sources rapidly, and to establish new colonies.

WING FOLDING & PROTECTION

Insects able to fold their wings back along their bodies & protect it under hard covering known as elytra, wings folding allowed them to use a far greater range of microhabitats, such as cracks and crevices in dead wood, inside leaf litter, or under stones. It also meant that they could hide from predators through decreased surface area.

INSULATED CENTRAL NERVOUS SYSTEM    

Insulation of the central nervous system allows nerves to work efficiently and also allows survival in hot or dry places.

SIZE

Small size allows utilization of a wide range of microhabitats —a tree, for example, may support hundreds of insect species.

SHORT LIFE CYCLE

This allows many generations within a given time for selection and evolution to take place.

VARIATION IN THE LIFE STYLE OF DIFFERENT STAGES

Variation in the life style of different stages in an insect's life (e.g. caterpillar versus butterfly) reduces competition for resources within the species.

SENSORY SOPHISTICATION

The sensory capabilities of insects surpasses most other organisms.

EVOLUTIONARY INTERACTIONS

Evolutionary interactions with other organisms - coevolution leads to greater specialization and speciation.

ADAPTATION OF APPENDAGES

Appendages such as mouthparts, wings and legs have often become highly specialized.