The San Francisco Forktail is an active predator, and will feed on invertebrates and any other animal that it can capture. The larval San Francisco forktail is aquatic and will lie in wait until an invertebrate comes near, sometimes staying motionless for hours. It will then lash out, catching the prey from the water. The adult San Francisco forktail feeds on small invertebrates, and will also take spiders from their webs (5).
The San Francisco forktail displays unique behavioural traits that are not seen in other members of the genus Ischnura. The most notable difference is that the San Francisco forktail will often be observed sitting on horizontal surfaces, while similar species prefer resting on vertical ones, such as blades of grass. This is thought to be an adaptation to the warmer climate (6).
Another distinctive behaviour seen in the San Francisco forktail is its ability to fly from early March to mid November, with other species only flying for shorter time periods of about one month. The extended flight of the San Francisco forktail is believed to have evolved in response to the foggy weather conditions that are often observed in San Francisco (6).
The male and female San Francisco forktail possess quite different behavioural traits. For example, the male is often located in sunlit areas, on low vegetation near open water, while the female San Francisco forktail is frequently found foraging in grasses, or resting in shrubs. The female typically only moves to open water in order to mate and lay eggs (3). The juvenile is commonly seen to inhabit short dry grasses close to water until they mature (6)
The maturation times for the male and female San Francisco Forktail are slightly different, with the male maturing earlier. The average time for a female to mature has been recorded at around seven to ten days, whereas the male matures between five and seven days of age. The male also has a longer lifespan than the female San Francisco forktail (6).
Once sexually mature, the male may grasp the female and initiate mating. The male will guard the female until the eggs have been laid to prevent a rival male mating again with the female (3) (6). The female San Francisco forktail will lay its eggs in plant stems, and is capable of producing multiple broods during the breeding period. This species over winters as larvae (5).