Behavioral and spermatogenic hybrid male breakdown in Nasonia

Abstract

Several reproductive barriers exists within the Nasonia species complex, including allopatry, premating behavioural isolation, postzygotic inviability and Wolbachia-induced cytoplasmic incompatibility. Here we show that hybrid males suffer two additional reproductive disadvantages, an inability to properly court females and decreased sperm production. Hybrid behavioural sterility, characterized by a reduced ability of hybrids to perform necessary courtship behaviours, occurs in hybrids between two species of Nasonia. Hybrid males produced in crosses between N. vitripennis and N. giraulti courted females at a reduced frequency (23-69%), compared to wild-type N. vitripennis and N. giraulti males (>93%). Reduced courtship frequency was not a simple function of inactivity among hybrids. A strong effect of cytoplasmic (mitochondrial) background was also found in N. vitripennis and N. giraulti crosses; F2 hybrids with giraulti cytoplasm showing reduced ability at most stages of courtship. Hybrids produced between a younger species pair, N. giraulti and N. longicornis, were behaviourally fertile. All males possessed motile sperm, but sperm production is greatly reduced in hybrids between the older species pair, N. vitripennis and N. giraulti. This effect on hybrid males, lowered sperm counts rather than non-functional sperm, is different from most described cases of hybrid male sterility and may represent an earlier stage of hybrid sperm breakdown. The results add to previous studies of F2 hybrid inviability and behavioural sterility, and indicated that Wolbachia induced hybrid incompatibility has arisen early in species divergence, relative to behavioural sterility and spermatogenic infertility.

Asymmetric Assortative Mating Behaviour Reflects Incomplete Pre‐zygotic Isolation in the Nasonia Species Complex

“…All strains representative of the four Nasonia species used in our experiments constitute standard laboratory strains with an extensive behavioural (van den Assem & Werren ; Clark et al. ), ecological (Beukeboom & van den Assem ; Raychoudhury et al. ) and genetic (Bordenstein et al.…”

Behavioral and genetic characteristics of a new species of Nasonia

“…Evolutionary genetic studies of Nasonia have been conducted on sex-ratio (Werren, 1980; Skinner, 1982), interspecific differences in morphology (Weston et al ., 1999; Gadau et al ., 1999; Clark et al, in review), hybrid breakdown (Breeuwer & Werren, 1995; Gadau et al , 1999, 2002; Niehuis et al ., 2008; Clark et al ., in review), host-endosymbiont interactions (Breewuer et al ., 1992; Bordenstein et al ., 2001, 2006), courtship and mating behaviour (Beukeboom & van den Assem, 2002; Velthuis et al ., 2004; Burton-Chellew et al ., 2007) and early development (Lynch et al ., 2006; Rosenberg et al , 2009). Any additional species in the genus would broaden and strengthen this model system, especially for evolutionary genetic studies.…”

A Z-linked sterility locus causes sexual abstinence in hybrid females and facilitates speciation inSpodoptera frugiperda

“…), sticklebacks (Hatfield and Schluter ), and parasitoid wasps (Clark et al. ), but its molecular basis is only poorly understood and not much investigated, except in Drosophila (Noor ).…”