TLS Online TPP Program

#Id: 9427

#XL - T Zoology

TLS Online TPP Program

#Id: 9428

#XL - T Zoology

A- Parental investment is high in females than male

Reason - Eggs are much larger than sperm.

Females are responsible for gestation and lactation.

B - Parental investment is high in males than female - very rare

Male Mormon crickets transfer a protein-containing spermatophore to females during mating. Almost 30% of a male’s body weight is made up by the spermatophore.

C- Parental investment of males is equal to female

Degree of mate choice should be equal between the sexes.

No sexual dimorphism

Present in bird

TLS Online TPP Program

#Id: 9429

#XL - T Zoology

TLS Online TPP Program

#Id: 9430

#XL - T Zoology

Bateman’s principle

In most cases, it is the male’s secondary sexual traits that are exaggerated.

This shows that sexual selection is more common and intense on males than females

TLS Online TPP Program

#Id: 9431

#XL - T Zoology

Bateman put several males and females together in bottles for several days. 

He concluded that the number of offspring sired by a male increased in proportion to the number of females he mated.

In contrast, the number of offspring produced by a female did not increase with the number of males she mated.

TLS Online TPP Program

#Id: 9432

#XL - T Zoology

The outcome of sexual selection is strongly influenced by the operational sex ratio