How do scorpions cope with the permanent loss of their \tail\?

Author(s)

Solimary Garcia Hernandez

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto de Biociências (IBIOC/SB)
• Defense date: 2020-05-12

Examining board members

Glauco Machado; Rodrigo Egydio Barreto; Tiana Kohlsdorf; Camilo Iván Mattoni

• Advisor: Glauco Machado

Abstract

The voluntary loss of a body part, known as autotomy, may increase the chance of surviving surviving a predadory attack. However, this defensive mechanism also imposes costs to the individuals. Although autotomy is extensively studied, its costs to species that do no regenerate the lost body part are poorly known. Scorpions of the genus Ananteris show a unique form of autotomy in which individuals lose permanently the last abdominal segments, known as the \"tail\". After \"tail\" autotomy, individuals lose body mass, the stinger, and the last portion of the digestive tract, including the anus, which prevents defecation and leads to constipation. In this thesis, we experimentally investigated how \"tail\" autotomy affects the locomotor performance, the predation success, and the reproductive success of males and females of the scorpion A. balzani. We found that \"tail\" autotomy has minimal short-term effects on the locomotor performance of both sexes. In the long-term, however, autotomy reduces locomotor performance, especially in males. The predation success decreases after autotomy and consequent stinger loss. However, autotomized males and females are still able to capture prey, especially the small ones. The reproductive success of males is not affected after \"tail\" loss, but it impairs female reproduction by reducing their survival and offspring number. Although autotomized individuals pay costs in terms of locomotion and foraging, we demonstrate that the long time between \"tail\" loss and death is enough for them to reproduce. Thus, permanent \"tail\" autotomy in scorpions appears to be adaptive when compared with the alternative strategy of not autotomize and eventually die during a predator attack. (AU)

• FAPESP's process: 17/05283-1 - Implications of autotomy of metasoma for locomotion, reproduction, foraging, and defense in scorpions
• Grantee: Solimary García Hernández
• Support Opportunities: Scholarships in Brazil - Doctorate