Assortative-mating
Guides
Eurosta solidaginis
Goldenrod Gall Fly, Goldenrod Ball Gall Fly
Eurosta solidaginis is a tephritid fruit fly that induces spherical stem galls on goldenrod plants (Solidago spp.). The species is notable for its freeze tolerance, surviving temperatures down to -80°C through the production of unique acetylated triacylglycerols that remain liquid at low temperatures. Populations exhibit host-race formation, with genetically differentiated populations associated with different Solidago host species showing assortative mating. The galls serve as nutrient-rich overwintering chambers and have been demonstrated to accumulate environmental contaminants at higher concentrations than surrounding plant tissues, making them useful as biological pollution detectors.
Timema boharti
Bohart's timema
Timema boharti is a small walkingstick species in the family Timematidae, endemic to California. It inhabits xeric pinyon-juniper woodland with chaparral intrusions at elevations around 915 m. The species exhibits two distinct colour morphs—greyish and green—with assortative mating by colour phase. It is nocturnal and has been collected in late April, with both mating pairs and late-instar nymphs observed. Like other Timema species, it is wingless and feeds on host plants within its specialized habitat.