Master's Defensio

18.02.2021

Andreas Löscher BSc

Comparative analysis of the male reproductive system

in whip spiders.

Advisors: Harald Krenn, Michael Seiter & Thomas Schwaha

Master's Defensio - Thursday, February 18th 2021

Abstract

Whip spiders (Arachnida, Amblypygi), like many other soil arthropods, transfer their spermatozoa indirectly via a stalked spermatophore. While the complex courtship behaviour and the morphological differences of spermatophores and corresponding female genitalia between taxa have received great attention in the past, comparative research on the entire reproductive system is lacking so far. In this study, male whip spiders of four different neoamblypygid taxa have been studied using micro computed tomography and their reproductive system has been segmented and visualized with the use of 3D image reconstruction. It consists of paired testes and two pairs of accessory glands, the ventral and lateral glands, which project their ducts into the anterior part of the ventrally located unpaired spermatophore organ, where the respective seminal and secretory reservoirs are located. While this general organization of the male reproductive system bears a lot of similarities between taxa and a general scheme is evident, there are some notable differences with regards to the gross morphology of the individual structures. The most surprising findings include the complete absence of ventral glands in Damon medius (Damoninae), unique spherical ventral gland reservoirs in Charon grayi (Charontidae) as well as differences in organization of the seminal and secretory reservoirs and their connections to the inner genital slit. In addition to that, the secretory products of both, ventral and lateral glands, are stored in combined secretory reservoirs in Euphrynichus bacillifer (Phrynichidae) and Phrynus hispaniolae (Phrynidae).