libutron: Darwin’s Beetle - Chiasognathus grantii Also referred to as Grant’s Stag
libutron: Darwin’s Beetle - Chiasognathus grantii Also referred to as Grant’s Stag Beetle, or the Chilean Stag Beetle, the species Chiasognathus grantii (Coleoptera - Lucanidae) is recognized for being analyzed and illustrated by Darwin to substantiate his theory of sexual selection. This beetle lives on tree trunks and feeds at sap flows in the forests of Chile, Argentina and Paraguay. Males are 39 to 48 mm in body length. They have a small, narrow head, and very long mandibular horns, these are shiny with greenish and purple. Females are smaller than males, less metallic in coloration, and their jaws are considerably shorter. Detailed studies show that the male horn of the Darwin’s Beetle function as weapons in male-male combat (bottom photo). The typical result is that physically larger, healthier, and more aggressive males monopolize the reproductive potential of the majority of females. References: [1] - [2] - [3] - [4] Photo credit: [Top: ©Felipe Rabanal | Locality: Chiloé, Chile, 2009] - [Bottom: ©Patrich Cerpa | Locality: Cherquenco, Vilcún, Chile, 2008] -- source link
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