External factor - factor controlling metamorphosis in insect, Biology

Assignment Help:

External factors - Factors Controlling Metamorphosis in Insects

In few cases an external factor may be accountable for initiating moulting, as for instance in the blood sucking Rhodnius the intake of food (blood meal) is such type of a factor. Another example where external factor is essential to initiate a moult is the case of the pupa moth Platy samia cecropia. After pupation the insect falls into a quiescent state along with a reduced rate of metabolism - diapause - that continues throughout winter. It is essential that during this time the pupa be exposed to cold, or else the diapause is prolonged indefinitely. The diapause might be broken precociously if the pupa is exposed to cold (3° to 5° C) for at least two weeks.

The temporary cooling activates the very important processes in the pupa and on return to a warmer environment development is completed, the pupa moults and the imago emerges. In other insects factors like humidity, population density etc., appear to start metamorphosis. Though in the majority of insects no external cause of any moult has been detected and moults follow one other at intervals that appear to be ascertained entirely by the internal processes in the animal.


Related Discussions:- External factor - factor controlling metamorphosis in insect

Ecological pyramids - ecosystem, Ecological Pyramids - Ecosystem The a...

Ecological Pyramids - Ecosystem The ancient Egyptians constructed elaborate tombs called pyramids. The base of the pyramid is broad and it supports the upper levels of the str

Calculate temperature for survival & growth of microorganism, Calculate Tem...

Calculate Temperature for Survival and Growth of Microorganisms? Survival and growth of microorganisms is also affected by the temperature. According to their temperature requi

Ecology, what is an ecosystem energy pathway

what is an ecosystem energy pathway

What are some prophylactic measures against hiv infection, What are some pr...

What are some prophylactic measures against HIV infection? The major prophylactic measures against HIV infection are: the use of condoms in sexual relations, not to share syrin

How is arthropod reproduction characterized, Q. How is arthropod reproducti...

Q. How is arthropod reproduction characterized? Reproduction in beings of the phylum Arthropoda is sexual with larval stage in some insects and crustaceans (arachnids) present

Determine dominant individual fromhomozygous or heterozygous, Why can cross...

Why can crossing of an individual that manifests dominant phenotype with another that manifests recessive phenotype (for the same trait) determine whether the dominant individual i

Equipment of cardio pulmonary bypass , Equipment : To maintain effective c...

Equipment : To maintain effective circulation and carry out functions of the lungs during an open heart operation the equipment should have: 1) Blood Pump 2) Oxygenator 3

Pulmonary arterial system changes, Q. Pulmonary Arterial System Changes ? ...

Q. Pulmonary Arterial System Changes ? a) Pulmonary Plethora With increased pulmonary arterial blood flow, pulmonary branches are visualized beyond the inner 2/3 of the lung

Leptospirosis, Leptospirosis Synonyms: Weil’ disease, canicola fever...

Leptospirosis Synonyms: Weil’ disease, canicola fever, 7-day fever Leptospirosis is an important and widespread zoonosis. It was first described by Adolf Weil in 1886 when h

Write Your Message!

Captcha
Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd