Differences in sexual behavior of two distant populations of the funnel-web wolf spider Aglaoctenus lagotis

Abstract

Generally, sexual repertoire within a species is conserved, but frequencies of occurrence of sexual behavioral acts often vary, and wide geographic distributions may favor these variations. Aglaoctenus lagotis is distributed along South America and belongs to Sosippinae, a subfamily of wolf spiders that builds funnel webs. Previous reports, based on different populations, suggested variations in sexual behavior and life cycle. Our objective was to describe and compare the sexual behavior of two populations of A. lagotis: 'Southern Uruguay' (SU) and 'Central Argentina' (CA). We carried out intrapopulation trials, in the laboratory, with 15 female-male pair matings. The most representative courtship acts in SU were web-stretching, striding-forward and forelegs-elevating, whereas in CA they were alternate-waving, web-stretching and leg-tapping. Juddering, forelegs-elevating and striding-forward were exclusive for SU, while alternate-waving and simultaneous-waving were exclusive for CA. We also found differences in copulatory characteristics such as frequencies of insertions and ejaculations. We documented body-shaking during copulation for the first time. Some sexual acts were exclusive of each population, while the shared ones differed in pattern and frequencies of occurrence. In addition to variations in sexual periods, these differences may favor divergence processes or an exceptional high level of flexibility in the sexual behavior of A. lagotis.

Reproductive isolation between two populations ofAglaoctenus lagotis, a funnel-web wolf spider

“…Additionally, Santos & Brescovit () characterized A. lagotis as a highly variable species, although no interpopulation studies were reported prior to González et al . ().…”

“…González et al . () described different sexual repertoires in two distant populations of A. lagotis (south Uruguay and central Argentina), both of which were dissimilar to the description published by Stefani et al . () for populations from Brazil.…”

“…Females from both localities performed leg tapping, commonly during the first stages of courtship interactions (González et al ., ). Copulation occurs with the male mounted on the female dorsum and opposite to her (the typical copulating position for all lycosid spiders), and males performed several ejaculations per insertion of their palps, which differed in duration and frequency between southern Uruguay and central Argentina individuals (González et al ., ). Additionally, a later study showed that those distant populations present marked differences in their phenological patterns, so much so that sexual periods occur in different seasons (González, Costa & Peretti, ).…”

Funnel-web construction and estimated immune costs inAglaoctenus lagotis(Araneae: Lycosidae)

“…Meanwhile, we could not explain the unexpected higher implant cover percentage recorded for weaving females compared to those prevented from weaving. Perhaps the dimensions of the tubes selected for preventing weaving are too small for females, which are larger than subadults and males (Gonzá lez et al 2013), making confinement stressful (and probably indirectly affecting immune cost). Another consideration might be that females who wove coincidently had better body conditions.…”

“…The species is widely distributed, from Uruguay to Colombia (Piacentini 2011), being present in different environments (Sordi 1996;Santos & Brescovit 2001). The existence of two forms has been reported within the species, differing from each other at least in sexual behavior (Gonzá lez et al 2013) and phenology (Gonzá lez et al 2014), suggesting a divergence process (Gonzá lez et al 2015). One of the forms (the ''similar to southern Uruguay, SU'') constructs its webs exclusively on the herbaceous stratum, and the other (the ''similar to central Argentina, CA'') can construct them also on the arbustive and arboreal strata (Gonzá lez et al 2014).…”