The black widow spider is well known for being the most venomous spider species to inhabit North America. Unfortunately, researchers have shown that black widows are moving farther north into regions of North America where they were once non-existent. While black widows have long been deemed extremely rare within Massachusetts, a recent study is showing that this may no longer be the case, as black widow sightings and bites have been increasing within the state for the past few years.

According to researchers, the distribution range of black widow spiders has increased into the north by 31 miles during the last 60 years. Since the black widow habitat range is limited largely by the spider’s climatic needs, this increase is most likely due to slightly higher northern temperatures that resulted from global warming. The researchers who published this data believe that an increase of 31 miles northward is a low estimate, and it is more likely that the spiders have become established as far as 60 miles north of the last updated distribution range. This would bring the spiders into Montreal, but no specimens have yet been discovered in the city.

Black widows are now well established in southern areas of Canada, making it likely that Massachusetts is now home to far more black widow spiders than previously assumed. This significant habitat increase will now make it necessary for public health officials in some northeastern cities to educate the public about black widow bites for the first time in history.

Not long ago, a Massachusetts resident discovered and photographed a black widow specimen that he found in Martha’s Vineyard. Experts who examined the photograph were shocked to see the specimen so far north, but one expert believed that black widows could travel rapidly to more northern locations by “ballooning”. Ballooning occurs when a spider uses its silk to create a sort of sail that pushes the spider through the air by means of wind currents. This form of migration allows spiders to travel vast distances at very high altitudes. It was also theorized that the specimen could have arrived in Martha’s Vineyard by hitching a ride on a shipment of produce that departed a region where the spiders are common.

Do you believe that black widow bite cases will increase in Massachusetts in the years to come?