Spider species tally triples on P.E.I. thanks to citizen census

Some enthusiastic citizen scientists have helped to triple the tally of spider species on Prince Edward Island.

'A lot of our collectors are asking: what can we help with next?'

UPEI student Caleb Harding had to sort through 4,300 spiders to find the adult specimens to be sent for identification. (Nancy Russell/CBC)

Some enthusiastic citizen scientists have helped to triple the tally of spider species on Prince Edward Island.

Nature PEI put out a call for help last summer with a spider census

  They attracted a group of 29 core volunteers who they trained and sent out on the hunt. Many returned with "Ziploc bags full of frozen spiders."

Some collectors kept bringing in samples—Bob Harding, Nature PEI

"There were a few people who were very prolific," observed lead researcher, UPEI PhD student Kyle Knysh. "They collected hundreds of spiders."

Tally triples

  At the start of the census, only 38 species of spiders had been identified on the Island, compared to 437 in Nova Scotia and 382 in New Brunswick. Scientists suspected there were many more species on P.E.I. just waiting to be discovered — which turned out to be the case.
Some of the 4,300 specimens that Caleb Harding had to sort through in the laboratory at UPEI. (Nancy Russell/CBC)

"We've tripled the number of known species on the Island," said Knysh, noting the specimens have been sent off-Island for verification and a final tally is still months away.

The volunteers used sweep nets to brush foliage and collect the spiders, as well as pit traps, which consist of cups buried in dirt up to the brim.

They collected 4,300 specimens over the summer and into the fall. 

Specimen transfer training at spider workshop organized by Nature PEI, August 8, 2015. (Nature PEI)

As part of his studies in Environmental Biology, UPEI student Caleb Harding put them in individual vials and identify them by family. 

A tangled web of spider samples

Harding admits it was a slow process at first, but when he got going, he could identify the family in about ten minutes.

Making the work even more painstaking, most of the thousands of spiders were immature and could not be used.  The adult specimens were properly preserved, labelled and shipped to a specialist hired as part of the project.

Caleb Harding building a pitfall trap for spiders in sphagnum, August 1, 2015. (Nature PEI)

As he sorted, Harding started seeing some patterns.

"The big guys that are on everybody's houses, they always wanted to show the biggest one they could find so we had a bunch of those," laughed Harding.  "Even though it was the specimen over and over again, it was really good seeing how widespread it was on P.E.I."

Invasive species

There were surprises, says Harding, including two or three new families of spiders.  And 11 per cent of the spiders were invasive species, or not native to the Island.

Zebra Jumping Spider (Salticus scenicus) having supper, on July 28, 2015, one of the samples collected in the spider census. (Nature P.E.I.)

"A lot of them are found inside peoples' houses so it's possible that they came in through all different means," said Harding. 

Knowing more about the Island's spider population is important for the future, especially considering the number of non-native spiders, said Knysh.

"A species that is introduced often competes with our native fauna and can be negative for our native species," he explained.

Keen collectors

Nature PEI's Bob Harding is excited by the results of the spider census, but also the level of participation by Islanders.

"It's created a great deal of enthusiasm and confirmed that this citizen science approach is very effective," said Harding. "While we stopped collecting in the fall, some collectors kept bringing in samples."

The group had to politely ask the helpful volunteers to stop and suggested they take photographs of spiders for Nature PEI instead.

   And even that wasn't enough for some of the keeners.

"A lot of our collectors are asking: what can we help with next?" 

The search is on ... for spiders

8 years ago
Duration 1:15
Kyle Knysh sets up a pit trap comprised of a beer cup buried to the brim to capture specimens for Nature PEI's spider census.