Interactions

On the page I created about the habitat of the Cyclosa conica spider, I utilized a common theme throughout my writing comparing the Cyclosa’s habitat to your search for a dream home. As part of that analogy I asked you to picture what your ideal neighbors would be like. Would you prefer those that left you alone, or those that interacted with you? Well, this next page on our expedition through the life of the Cyclosa conica is dedicated to taking you through the journey of the social life of these spiders, their interactions with their neighbors, and how this species fits into the “social” hierarchy of its environment. Throughout this article you can expect to find information regarding the Cyclosa’s predation and food acquisition routines, enemies, and role as a potential host to a harmful parasite. Let’s get started!

How does the Cyclosa spider satisfy its intense and all-consuming cravings for food? Well, they can be seen as backstabbing and deceiving “neighbors” to members of the Dipterans (order of flies) such as Tabanus longiglossus (horsefly) and Hymenopterans (insect order)such as Dolichovespula maculate (hornet) (Tso 1998) who become unsuspecting meals for the Cyclosa. This clever spider’s predation strategy utilizes its home to lure unsuspecting prey into their unforgiving wrath. The location of the web in the dark forest understory, combined with the web’s composition of delicate silk (Tso 1998) and incredibly thin mesh that is 2.5 +/- .05 mm in diameter (Opell 2001) makes this web the perfect trap for unsuspecting prey. The web decorations, or stabilimenta, located vertically down the center of the web act as a type of camouflage for the spider (Tso 1998). Tso found that when stabilimenta were present in webs Cyclosa captured 150% more prey (Tso 1998). Once captured, the spider incorporates the remains of the victim into its stabilimenta in a sort of vicious predation cycle (Tso 1998). This is one reason why I am thrilled that Cyclosa doesn’t enjoy the taste of humans!

There are many “angry neighbors” or predators of the Cyclosa conica who aim to take down this intelligent organism. An experiment conducted by I-Chia Chou and a group of fellow researchers tested the ability of stabilimenta within webs to deter the Cyclosa from predatory actions of the paper wasp, or Vespa affinis (Chou et al. 2005). A close relative in the same genus as this organism has also been found to feed on spider varieties. This organism is called the Asian Giant Hornet. Surprisingly, the research concluded that Cyclosa’s who built undecorated webs were attacked less frequently than those with decorations incorporated into their web structure (Chou et al. 2005). However, the wasp’s intended target when attacking the decorated-web spider was the stabilimenta instead of the actual Cyclosa (Chou et al. 2005). This means that these web decorations act as a camouflage and a decoy for the spider. Another infamous predator of the Cyclosa spider is the notch-eared bat (Kervyn et al. 2012). The Cyclosa don’t get as lucky as with the previous predator when it comes to this endangered organism. This extremely receptive bat forages near forest edges where the Cyclosa resides and utilizes echolocation and the faint buzzing of prey stuck in their webs to find and attack the Cyclosa on its web (Kervyn et al. 2012). Another predator of this magnificent spider is the Western Fence Lizard that can be found in the Cyclosa homes all throughout the Angelo Reserve. This tests the theory of keeping your friends close and your enemies closer!

Parasitism can be compared to a “neighbor” that comes to visit and won’t leave under any circumstances. This annoyance tends to mooch off of the host for the benefit of only themselves. A common phenomena among numerous spiders, including Cyclosa conica, is symbioses with bacteria (Stefanini and Duron 2012). In some cases, these symbioses turn out to be reproductive parasites that attack the reproductive system of its host in order to spread its species further into a population (Stefanini and Duron 2012). The spread of these organisms is facilitated through the cytoplasm of a female’s egg that is inherited from the mom (Stefanini and Duron 2012). This particular bacteria of interest regarding the Cyclosa, Cardinium, has only recently been discovered and the full effects of it are still being determined (Stefanini and Duron 2012). So far, it has been found that 6-7% of arthropods have this bacteria within themselves (Vera et al. 2012). Albeit the small numbers, this is pretty substantial considering the diversity surrounding arthropods. Certain negative effects of this parasite that have been discovered are feminization, thelytokus parthenogenesis, and cytoplasmic incompatibility (Vera et al. 2012). Woah, now those are some confusing terms, let’s break these down! Feminization is basically making males more feminine by changing their characteristics to be those of the females (Stefanini and Duron 2012). Thelytokus parthenogenesis simply put is when eggs that are unfertilized end up producing daughters that have two sets of chromosomes, also known as diploid organisms (Pearcy et al. 2006). Cytoplasmic incompatibility is a complex concept where parasites, such as Cardinium, change aspects of the egg and sperm so that they cannot combine to create working offspring (Stefanini and Duron 2012). These all aim to change the gender of the host organism to female and to promote the production and survival of daughters. This is because females are the vessel utilized to spread this parasite (Stefanini and Duron 2012). This bacteria has been found in Cyclosa conica, but the details about whether it actively infects the organism as a parasite are to be determined (Stefanini and Duron 2012). This being said, stay tuned in the lively drama of the life of a Cyclosa conica to see how this dilemma turns out.


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