Question

If dispersal is costly, why are some species so successful at invading new areas far from their native range?

In dark-eyed juncos, increased testosterone is associated with increased aggression and territorial defense, and also decreased parenting behavior. This research suggest: what?

Answer 1

Question 1 answer- Yes, the dispersal is always costly but even then, some species are successful at invading new areas far from their native range due to following reasons-

• The new areas are sometimes abundant in nutrients and free from competition.
• Organisms of migrating species mostly adapts themselves in new environmental conditions.
• Since these adaptabilities are inheritable hence can easily be transmitted to their progeny which leads to stable establishment.

Question 2 answer- This study suggests that, in these organisms the parental care is usually carried out by mother and father usually carry out the function of territory protection.