Fen Raft Spider observational study record 005

Location:                                           Carlton Marshes: several dykes

Date:                                                  23.7.19

Time start:                                        11.30

Time finish:                                      15.00

Weather (from BBC weather app):

• General:                              Sunny and light winds. Feels hot
• Humidity:                            58%
• Pressure:                            1018 mb
• Temp:                                  22C
• Temp feels like:                25C
• Wind:                                  N 6mph
• Cloud cover/sun:              clear sky

Observational subject:

My aim today was to observe adult spiders. Only 4 days ago on a routine survey we found 38 webs and maybe a dozen adults. Today on a very hot day, circumnavigating most of the survey-allocated Dykes at Carlton across 3 hours,  I saw only maybe 8 of those webs, most looking tattered, and only one adult, in a deeply shaded recess in the margin, under vegetation. Too dark and too distant even for a decent photo.

3 days ago we had storms and brief but torrential downpours. These would have damaged or destroyed many of the webs we had seen on the routine survey. After speaking to a biology graduate friend, I understand that spiders tend to shelter in the cool in hot weather, and are prone to desiccation in such conditions. Maybe the FRS adults had all gone into the shade, or perhaps underwater. There was no sign of guarding adults in the very few webs with spiderlings present that I saw today.

Vegetation/macro location:

N/A

Observations:

It seems reasonable to conclude that the storms followed by hot weather affected my ability to find viable nursery webs and provides explanation for the apparent absence of adults.