THE INHERITANCE OF COURTSHIP BEHAVIOR AND ITS ROLE AS A REPRODUCTIVE ISOLATING MECHANISM IN TWO SPECIES OFSCHIZOCOSAWOLF SPIDERS (ARANEAE; LYCOSIDAE)

Abstract

The courtship behaviors of two morphologically similar spider species, Schizocosa ocreata and S. rovneri, are distinctive and prevent interbreeding. We used “forced” copulation between these species to investigate the mode of inheritance of the courtship behavior and to determine whether postmating isolating mechanisms exist. F1 hybrids proved to be behaviorally sterile, but they were capable of producing viable offspring when forced to interbreed. Analysis of the courtship behaviors of F1, F2, and backcross progeny showed that the inheritance of some aspects of these behaviors is consistent with models involving single autosomal loci. The inheritance of secondary sexual characteristics in the males is also investigated. The genes for courtship behavior and secondary sexual characteristics do not assort independently. The origin of the premating isolating mechanisms may be explained by either an initial habitat separation between the two groups, or by a founding event with each group subsequently diverging in slightly different habitats. It is suggested that the differences in the microhabitats may have a profound effect on what type of signal (visual or vibratory) would be effective.

Assessment of Potential Predation Costs of Male Decoration and Courtship Display in Wolf Spiders Using Video Digitization and Playback

“…), lacks decorative foreleg tufts and the conspicuous leg-tapping display involved in the courtship of its congener. It does, however, exhibit a body "bounce," in which it thrusts the abdomen and cephalothorax against the substratum and simultaneously produces a vibratory signal via palpal stridulation (Uetz and Denterlein, 1979;Stratton and Uetz, 1981, 1983, 1986. Female S. rovneri respond receptively more often to conspecific male vibration signals than visual cues.…”

“…(1) Schizocosa ocreata (Hentz) has decorative tufts of dark bristles on the forelegs as well as a highly visual and locomotive courtship display, which involves conspicuous tapping of the tufted forelegs and stridulation with the pedipalps (Uetz and Denterlein, 1970;Stratton and Uetz, 1981, 1983, 1986. Females of this species exhibit receptivity with equal frequency to isolated visual and vibratory courtship signals from conspecific males (Scheffer et al, 1996).…”

“…Members of this genus are wandering, non-web-building wolf spiders that inhabit most of the deciduous forest region of eastern North America Redner, 1978, 1990). The S. ocreata clade contains at least six closely related species that appear to have recently speciated as a consequence of behavioral reproductive isolation (Stratton and Uetz, 1986;Miller et al, 1998). Females are nearly indistinguishable morphologically, while males are distinguishable by the presence or absence of decorative tufts or pigments on the forelegs and species-specific courtship behaviors.…”

Genetics of divergence in male wing pigmentation and courtship behavior between Drosophila elegans and D. gunungcola

“…Intermediate behavioral phenotypes are common in species hybrids and have been found for a variety of traits, including migratory behavior in birds (Helbig, 1991) and courtship behavior in birds (Ficken and Ficken, 1968) and spiders (Stratton and Uetz, 1986). Pioneering work by Shaw (1996Shaw ( , 2000 characterized the quantitative genetic basis of differences in male courtship song and female preferences among species in the cricket genus Laupala.…”

Female responses to isolated signals from multimodal male courtship displays in the wolf spider genusSchizocosa(Araneae: Lycosidae)

“…In these potentially cannibalistic species, such as some spiders, the efficacy of courtship signals is presumed to be subject to high selection pressures, thus making spiders ideal organisms for studies of sexual selection. The importance of specific species recognition signals in spider courtship displays has been demonstrated by several studies (Stratton & Uetz 1981, 1983, 1986Uetz & Stratton 1982), while others have shown the importance of female choice (Jackson 1977;Watson 1991Watson , 1993Clark & Uetz 1992;Scheffer et al 1996;McClintock & Uetz 1996). However, the selective pressures acting upon the evolution of these signals are not necessarily mutually exclusive.…”