One of the most striking differences is that males and females have sexually dimorphic body sizes.

Why are males larger than females in most mammals?

One reason most mammal males are larger than females is that they need more food to have larger body sizes and to defend territory and fight with other males.

In addition, males also need to consume more energy than they produce and maintain fertility.

Sexual dimorphism simply means that there are morphological differences between males and females in addition to differences in their genitalia.

In mammals, fierce competition occurs between males.

In this competition, larger males will have greater strength and are often more aggressive, and can compete more effectively for resources and females.

Why are males larger than females in most mammals, but the opposite is true in insects?

In addition, biologists also believe that male mammals are more susceptible to physical mutations than females, which also leads to the size of males being larger than females.

If this change in size helps males compete more effectively for resources and mates, then the mutated gene will be preserved and passed on to the next generation.

In many mammals, females also show a preference for larger males.

The above is the reason why males of most mammals are larger than females.

Why are males larger than females in most mammals, but the opposite is true in insects?

Why are male insects smaller than females?

In most insect species, females are larger than males.

Therefore, male insects do not need to increase in size to support behavioral needs like mammalian males.

In addition, insects often find mates and food by flying, and the small size of males is useful for moving freely between tree branches and grass.

Wolf Blanckenhorn, of the Museum of Zoology at the University of Zurich, told LiveScience: `While females in insect species are growing enormous in size, males are devoting their energy and resources to growing.

Why are males larger than females in most mammals, but the opposite is true in insects?

For most insects, body size varies greatly between males and females.

In general, males are larger than females in most mammals, and the reverse is true in insects.

Male mammals need to increase body size to support physiological and behavioral needs, as well as gain competitive and reproductive advantages;

These biological differences make the size differences of mammals and insects so important, provide rich research material and evolutionary cases, and provide new perspectives.