page_title: Raft spider
section_title: Behaviour
hierarchical_section_title: Raft spider / Behaviour
caption_attribution_description: English: Juvenile Dolomedes fimbriatus Polski: Młody Dolomedes fimbriatus
context_page_description: The raft spider, scientific name Dolomedes fimbriatus, is a large semi-aquatic spider of the family Pisauridae found throughout north-western and central Europe. It is one of only two species of the genus Dolomedes found in Europe, the other being the slightly larger Dolomedes plantarius which is endangered in the UK.
context_section_description: Like many other species of the genus Dolomedes (Greek translation= crafty or wily), the raft spider typically hunts on the surface of the water with its front appendages outstretched and relies on aquatic vibrations to detect prey. Juveniles are thought mainly to hunt in terrestrial vegetation. Their diet consists largely of freshwater invertebrates such as water beetles, pond striders and dragonfly larvae,  but they occasionally feed on small vertebrates such as sticklebacks and small frogs. To avoid predation by birds, the raft spider can fully submerge itself in water and has been known to hide underwater for several minutes.
  As is the case with some other Dolomedes species, Dolomedes fimbriatus is sexually cannibalistic, meaning that the female will sometimes eat the male before, during or immediately after mating. Males will try to court the female and prevent her from attacking by signalling their presence using vibrations on the female dragline. However, Dolomedes fimbriatus is one of the few species known to attempt to attack nearly all approaching males. This behaviour is regarded as unusual among biologists as it can prevent both the male and the female from copulating successfully.
  If successful copulation takes place, the female will carry her fertilised egg sac around with her, before placing the egg sac inside a silken nursery tent that she has made. The female will then guard the nursery until the spiderlings are ready to disperse into the surrounding habitat.
caption: Juvenile Dolomedes fimbriatus
exif: {"Image Make": "Canon", "Image Model": "Canon EOS 200D", "Image XResolution": "300", "Image YResolution": "300", "Image ResolutionUnit": "Pixels/Inch", "Image Software": "Adobe Photoshop Camera Raw 10.4 (Windows)", "Image DateTime": "2019:06:15 17:58:04", "Image Artist": "Pawel Walasiewicz", "Image Copyright": "Pawel Walasiewicz", "Image ExifOffset": "270", "Thumbnail Compression": "JPEG (old-style)", "Thumbnail XResolution": "72", "Thumbnail YResolution": "72", "Thumbnail ResolutionUnit": "Pixels/Inch", "Thumbnail JPEGInterchangeFormat": "956", "Thumbnail JPEGInterchangeFormatLength": "15484", "EXIF ExposureTime": "1/500", "EXIF FNumber": "8", "EXIF ExposureProgram": "Manual", "EXIF ISOSpeedRatings": "100", "EXIF SensitivityType": "Recommended Exposure Index", "EXIF RecommendedExposureIndex": "100", "EXIF ExifVersion": "0230", "EXIF DateTimeOriginal": "2019:06:14 16:58:27", "EXIF DateTimeDigitized": "2019:06:14 16:58:27", "EXIF ShutterSpeedValue": "1120723/125000", "EXIF ApertureValue": "6", "EXIF ExposureBiasValue": "0", "EXIF MaxApertureValue": "3", "EXIF MeteringMode": "Pattern", "EXIF Flash": "Flash fired, compulsory flash mode", "EXIF FocalLength": "60", "EXIF SubSecTimeOriginal": "59", "EXIF SubSecTimeDigitized": "59", "EXIF ColorSpace": "Uncalibrated", "EXIF FocalPlaneXResolution": "88104193/32768", "EXIF FocalPlaneYResolution": "88104193/32768", "EXIF FocalPlaneResolutionUnit": "3", "EXIF CustomRendered": "Normal", "EXIF ExposureMode": "Manual Exposure", "EXIF WhiteBalance": "Auto", "EXIF SceneCaptureType": "Standard", "EXIF CameraOwnerName": "Pawel Walasiewicz", "EXIF BodySerialNumber": "013070004520", "EXIF LensSpecification": "[60, 60, 0/0, 0/0]", "EXIF LensModel": "EF-S60mm f/2.8 Macro USM", "EXIF LensSerialNumber": "000005add9"}