Spiders and their relatives (Class: Arachnida)
While Malaise traps are most useful for capturing flying species, 69 species collected in the Fall School Malaise Trap Program were spiders which certainly don’t fly! These 69 spider species belonged to 57 different genera of 21 families – a very diverse group! Westside Secondary School in Orangeville, Ontario collected the greatest number of spider species with 14.
One very interesting find of the Fall program was the spider species Pholcus manueli which was collected at Glendale Secondary School in Hamilton, Ontario and represents the first record of this species from Canada! Pholcus manueli is a cellar spider, belonging to the family Pholcidae. Cellar spiders are often confused with harvestmen (order Opiliones) and share the common name of daddy longlegs. Cellar spiders and harvestmen are rumoured to be some of the most venomous animals in the world but they are, in fact, harmless to humans. Cellar spiders typically live indoors where they build webs and hang upside down, waiting for their insect prey.
In previous years, occurrences of Pholcus manueli were restricted to Asia and to the southern regions of the United States. However, within the past five years, the range of this species has expanded to the midwestern United States, particularly Ohio, where it has taken the place of another invasive species, Pholcus phalangioides, and become very abundant in barns, sheds, and basements. The collection of this species in Hamilton with the School Malaise Trap Program suggests that it is continuing to spread northward, potentially due to climate change. The quick spread of Pholcus manueli may seem surprising particularly when you consider that this species is not known to disperse through ballooning, where a spider produces a ‘parachute’ out of silk threads that can carry it in the wind for long distances. However, this species may be able to disperse long distances through phoresy, where one animal attaches to another, perhaps a mammal or bird, for transport. Can you think of other ways that this spider species could have arrived in Canada?
Check out our Fall 2014 Detailed Program Report here!