BioBlitz

Spiders

 

Cayuga Nature Center   Smith Woods   Total species found
  2 7       0     2 7

 

Spiders are found everywhere on Earth, except the ocean and Antarctica, and are particularly diverse near the tropics. There are currently about 48,000 spider species identified, with an estimated 150,000 to 170,000 species in existence. Although there are 117 spider families, over 75% of the spider species are found in only 21 common families. Many spider species are common in upstate NY, such as this dark fishing spider. Despite what its common name might imply, these spiders are most frequently found far away from water, usually in wooded settings, but also in homes. They are mostly shy of humans, but their bite usually feels like a wasp sting.

Spiders are the dominant terrestrial predators on Earth. Populations in upstate New York are large and diverse. The combination of grassland, temperate woodland, and many edges (exactly the conditions found at the Cayuga Nature Center) make spiders happy here. Our warm and moist summers also increase the number of insect prey. Populations are most abundant in late summer, as the summer spiderlings move away from their egg sacs. 

It is estimated that spiders eat prey equivalent in weight to all the humans on earth every year! 

 

 

Findings

During the Spider Talk & Walk, about thirty people went out to explore the fields behind Cayuga Nature Center. One group noticed an unusual-looking spider that initially was taken for a white berry or bird droppings. Once pulled out of the tree and examined more closely however, Professor Linda Rayor observed that it had dorsal bumps on the abdomen, and it dawned on her that she was actually holding a rare bolas spider, Mastophora hutchinsoni. Informed of the find, the entire spider group then cheered and whooped with excitement! The Bolas spider is incredibly rare; Professor Rayor had never before seen one in this area in all her 24 years of active spider collecting. Bolas spiders are known to inhabit upstate NY, but they are always rare everywhere they are found. Bolas spiders evolved from orb weavers who make a typical spiral orb web in the Family Araneidae. But the bolas no longer makes orb webs. Instead they twirl a single short line of silk that has a ball of glue at the end. The spiders emit pheromones that attract male moths looking for love. The moths fly into the glob of glue and are hauled up by the spider for a tasty dinner. What is particularly impressive is that the Bolas sider changes the pheromone over the course of a summer so that initially, when the spider is smaller, it lures in smaller moth species, and then changes to attract larger moth species later in the summer. Incredibly, bolas spiders will also change the pheromones they produce during a single day so that they attract moths that fly early in the evening first, and then change pheromones to attract later-flying moths. The behavior of Bolas spiders is entirely unique in the animal kingdom! Professor Rayor brought the bolas spider to her lab where she laid two vase-shaped egg sacs! When the spider was close to death, Professor Rayor prepared her and the egg sacs to be displayed in a large museum exhibit on spiders currently traveling around North America.