Strategies of Sexual Reproduction in Aphids

Abstract

II AcknowledgementsMy visit at the University of East Anglia in Norwich was funded by the Deutscher Akademischer Austausch Dienst. I thank Prof. Anthony F. G. Dixon for excellent support and supervision in Norwich and Prof. Stefan Vidal for the same in Göttingen.Further thanks go to: Prof. Matthias Schaefer for yielding the theme to me; Thomas Thieme for a tip on preparing the sperm storage organ of female aphids and pictures of Euceraphis betulae and Uroleucon cichorii that have been presented during a talk at Rennes (France); Geoffrey A. Parker for discussing his old and classic publications on yellow dung flies with me via e-mail; Sebastian Domhof for precious statistical advice as well as Lars Reimer for helpful chats on statistics; Angelika Metje for tending thistles; Fabien Halkett for a tip at

Giant females vs dwarfish males of the genus Stomaphis Walker (Hemiptera: Aphididae) - an aphid example of the ongoing course to permanent parthenogenesis?

“…A similar guarding behavior was observed in other lachnid males (genera Lachnus Burmeister and Cinara Curtis), where additionally oviparous females were marked with phero mones from the males' hind tibiae and aedeagus (Dagg & SCHeurer 1998). Males of lachnids cannot retract their aedeagus into the abdomen (Dagg 2002), whereas males of other aphid taxa retract their aedeagus into the abdomen immediately after copulation and often do not feature the striking postcopulatory courtship (e.g. Myzus persicae (Sulzer) DoHerty & HaleS 2002; Uroleucon (L.) Dagg 2002).…”

“…It is not known whether males compete for the female but it is possible, due to limited space in ant chambers, in the case of species having a cryptic mode of life. A similar guarding behavior was observed in other lachnid males (genera Lachnus Burmeister and Cinara Curtis), where additionally oviparous females were marked with phero mones from the males' hind tibiae and aedeagus (Dagg & SCHeurer 1998). Males of lachnids cannot retract their aedeagus into the abdomen (Dagg 2002), whereas males of other aphid taxa retract their aedeagus into the abdomen immediately after copulation and often do not feature the striking postcopulatory courtship (e.g.…”

“…Males of lachnids cannot retract their aedeagus into the abdomen (Dagg 2002), whereas males of other aphid taxa retract their aedeagus into the abdomen immediately after copulation and often do not feature the striking postcopulatory courtship (e.g. Myzus persicae (Sulzer) DoHerty & HaleS 2002; Uroleucon (L.) Dagg 2002). The studied species of the ge nus Stomaphis also have an enormous aedeagus, still not retracted after copulation, and probably they also mark oviparous females.…”

“…The East Palaearctic representatives of the genus Stomaphis are characterized by even more diverse parameres than European ones (Sorin 1995(Sorin , 2012wieCzorek et al 2012), however, their mating be havior has not been reported. Generally, relatively little is known about copulatory behavior of aphids (FoSter & Benton 1992;KozłowSKi 1991;Dagg 2002Dagg , 2003Dagg & SCHeurer 1998;Depa et al 2014), but species with more femalebiased sex ratios are not expected to show guarding behavior, whereas species with less femalebi ased sex ratios are expected to show guarding behavior or copulate for a longer time than is necessary for ferti lization (Dixon 1998). However, in case of Stomaphis it is very difficult to establish the male-female ratio, due to their very cryptic life mode.…”

“…Relatively little is known also about the copu latory behavior of aphids. This gap has been partly filled with detailed descriptions of male genitalia provided by wieCzorek et al (2011,2012) and single observations of mating behavior of selected species of Aphididae (Dagg & SCHeurer 1998;Huang & CaillauD 2012).…”