Butterfly egg is covered by a rigid outer layer called "Chorion" which is lined with a waxy substance which prevents the egg from drying out. Surface of the egg has some thousands of tiny pores which collectively acts as an air exchanger. Minute architecture of these pores do not let water to be evaporated through them.
At the tip of the egg or the center of the upper surface (according to the shape of the egg) there is a minuscule opening called "Micropyle". This is the entry gate for a sperm cell into the egg.
Egg laying behaviors, shape of the egg, positioning, colour and developmental times are so diverse and varies with species but many characters become common within same families or genera.
Eggs are locked in position by a glue that mother secretes. This glue is a rapidly hardening liquid at first but quickly hardens like a cement holding a structure.
Go to this link(Butterfly eggs) and you'll see some mesmerizing electron micrographs of butterfly eggs.
As we know butterfly larvae (almost all) have their unique one or a set of host plants on which they feed. A mother may lay her eggs carefully on a selected part of the selected plant, anywhere on the plant or sometimes not on the plant at all (may be a rock near the plant). Some species of skippers are known to drop there eggs at the bottom of the host plant (but none in SL ;) ).
The high number of eggs laid by an individual does not exclusively indicate an exponential growth of populations for 98%-99% percent of laid eggs do not survive to become an adult butterfly due to various reasons. These include mutations/defects, predation, being eaten by parasites, harsh weather (not common in SL but in regions with harsh climates), sometimes starvation, disease (both bacterial and viral diseases) and above all else man made chemicals such as pesticides and herbicides.
 |
Eggs of some common butterflies of SL |
No comments:
Post a Comment