Scientists Mull Why Size Matters

Researchers from all over the world have banded together to try and answer one of biology’s most intriguing questions. Why are males larger than females in some animal species (such as most mammals), yet females larger than males in others (most insects)?

Study leader, Wolf Blanckenhorn, of the Zoological Museum at the University of Zurich, believes that enlisting many scientists to investigate the evolution of sexual size dimorphism overcomes the limitation of single researchers working with – and thus having data on – only particular animal groups.

Blanckenhorn’s brigade set out to investigate how sexual size dimorphism comes about by looking at comparative data on 155 species of insects and spiders (arthropods) from 7 major groups. The results, published in The American Naturalist, suggest that growth ratedifferences between the sexes are more important than growth period differences in mediating size dimorphism in arthropods.

Depending on the species group, males and females tend to have equal growth periods (beetles and water striders), males have longer growth periods than females (some groups of flies), or males have shorter growth periods than females, albeit not quite in proportion to the size difference between the sexes.

In most arthropod groups females are larger, so they must therefore grow more rapidly – a pattern markedly different from primates and birds, which were also analyzed and in which differences in growth period between the sexes were generally more dominant.

Blanckenhorn discusses three potential explanations for why female arthropods can grow faster than males. The most intriguing of these explanations is that, although it is generally more efficient to produce (small) sperm than (large) eggs, it may be costlier to produce male gonads and genitalia than it is to produce female gonads and genitalia. As a result, males might need more time to mature at larger body sizes.

Related articles:
Females Get Into Sexual Selection Game
Researchers Investigate Giant Sperm Paradox
Balls vs Brains In Batty Battle For Evolutionary Success

Source: The American Naturalist

, ,

Comments are closed.

Flareon Eevee Evolution Standing Shiny Animal Stuffed Plush picture

Flareon Eevee Evolution Standing Shiny Animal Stuffed Plush

$13.59



Marttiini MN127012 Scandinavian Knife by Arctic Evolution picture

Marttiini MN127012 Scandinavian Knife by Arctic Evolution

$25.88



Pokemon Glurak Charizard Evolution Holo picture

Pokemon Glurak Charizard Evolution Holo

$105.45



(2) 2017 Topps AMC Walking Dead Evolution Trading Card Blaster Boxes NEW SEALED picture

(2) 2017 Topps AMC Walking Dead Evolution Trading Card Blaster Boxes NEW SEALED

$34.99



Pokemon Eevee Evolutions Plush Lot of 9 Complete Great Condition picture

Pokemon Eevee Evolutions Plush Lot of 9 Complete Great Condition

$125.00



Pokemon Evolution Stone Box Fire Water Lightning Premium Bandai without Candy picture

Pokemon Evolution Stone Box Fire Water Lightning Premium Bandai without Candy

$144.90



Bandai Digivolving  Spirits Evolution Wargreymon Die cast Evolution Figure #01 picture

Bandai Digivolving Spirits Evolution Wargreymon Die cast Evolution Figure #01

$45.00



Pokemon Japanese Gengar Promo Card Masaki Communication Evolution Campaign picture

Pokemon Japanese Gengar Promo Card Masaki Communication Evolution Campaign

$368.70



Alive 1: The Final Evolution by Tadashi Kawashima picture

Alive 1: The Final Evolution by Tadashi Kawashima

$5.71



9pcs/bag Eevee evolution action figure toys kids Monster Collection Figurine 5cm picture

9pcs/bag Eevee evolution action figure toys kids Monster Collection Figurine 5cm

$31.00



Powered by WordPress. Designed by WooThemes