# data[].attributes.headline
Grouping in Stegodyphus Dumicola (African Social Spider)

# data[].attributes.subject
Grouping in Stegodyphus Dumicola (African Social Spider)

# data[].attributes.body
In the African Social Spider, it was found that they actually follow what was previously laid out very closely. clutch size of these spider is actually larger than an individual spiders, but the amount of offspring that actually hatch is lower. However, these offspring have shown that they are much more likely to survive and make it to adulthood!

# data[].attributes.body
Although predators can more easily spot large groups, evidence points to decreased predation as one of the key reasons why groups form in the first place. Increased vigilance, intimidation in group size, and sheer luck that another individual in the group could be attacked instead all decrease the risk of predation on an individual basis.

Herding, flocking, schooling, even family groups can come together to decrease predation threats. For example, zebras use their stripes and numbers to confuse predators and decrease the threat to the entire group. Capybaras are incredibly social and will live with whatever is unthreatening to them - although they prefer female heavy groups - as a method to reduce the threat of predation.

# data[].attributes.body
In the guppy species Poecilia reticulata, schooling behavior increased noticeably when the threat of predation was higher! Schooling behavior (group living!) was also found to be heritable because even after generations in captivity, schooling behavior remained in those with ancestry in high predation, and did not evolve in guppies who had ancestry with low predation.

# data[].attributes.body
While living in groups does tend to decrease the total population size of offspring present, it actually increases the amount of offspring that survive to reproduce. Grouping together, there is more protection for the young offspring, and there is almost always a helper in the group to take care of the young even if the young are not related to them to make sure they get enough food.

# data[].attributes.body
The RDH predicts that when resources, such as food and water sources, are spread out that groups form in order to defend their territory and guarantee sufficient resource distribution amongst the group. The RDH also predicts that the dispersion and richness of available resources determines group and territory size.

# data[].attributes.body
Conclusion: Why did species evolve to live in groups?
The simplest answer is to meet the needs of the environment. Cooperation may become necessary based on the biological constraints of the species and the ecological niche it fulfills. In certain situations, individuals that formed groups had more success than solitary individuals, passing down group-living traits.

# data[].attributes.body
- Alex Kountry is the founder of HayFarmGuy and has been a backyard farmer for over 10 years. Since then he has decided to write helpful articles that will help you become a better backyard farmer and know what to do. He also loves to play tennis and read b. (2023, March 30). How do zebras protect themselves? (explained). HayFarmGuy. Retrieved April 20, 2023, from https://hayfarmguy.com/how-do-zebras-protect-themselves#:~:text=When%20zebras%20travel%20in%20herds%2C%20they%20are%20better,stripes%2C%20zebras%20are%20difficult%20for%20predators%20to%20identify.

- BILDE, T., COATES, K. S., BIRKHOFER, K., BIRD, T., MAKLAKOV, A. A., LUBIN, Y., & AVILÉS, L. (2007). Survival benefits select for group living in a social spider despite reproductive costs. Journal of Evolutionary Biology, 20(6), 2412–2426.

- Culbert, B. M., Gilmour, K. M., & Balshine, S. (2019). Social buffering of stress in a group-living fish. Proceedings: Biological Sciences, 286(1910), 1–9. https://www.jstor.org/stable/26788728

- Ezenwa, V. O., & Worsley-Tonks, K. E. L. (2018). Social living simultaneously increases infection risk and decreases the cost of infection. Proceedings: Biological Sciences, 285(1892), 1–5. https://www.jstor.org/stable/26580027

- Herrera, E. A., Salas, V., Congdon, E. R., Corriale, M. J., Tang-Martínez, Z., & Blake, B. H. (2011). Capybara social structure and dispersal patterns: variations on a theme. Journal of Mammalogy, 92(1), 12–20. http://www.jstor.org/stable/23259781

- Mbizah, M. M., Valeix, M., Macdonald, D. W., & Loveridge, A. J. (2019). Applying the resource dispersion hypothesis to a fission–fusion society: A case study of the African lion ( panthera leo ). Ecology and Evolution, 9(16), 9111–9119. https://doi.org/10.1002/ece3.5456

- Seghers, B. H. (1974). Schooling Behavior in the Guppy (Poecilia reticulata): An Evolutionary Response to Predation. Evolution, 28(3), 486–489. https://doi.org/10.2307/2407174

- Weston, P. (2017, September 18). Doting virgin aunts invite their spiderling nieces to eat them alive. Mail Online. https://www.dailymail.co.uk/sciencetech/article-4895008/Virgin-aunts-invite-spiderling-nieces-eat-alive.html

# data[].attributes.attachment_caption
Experimental Design for individual, novel group, or familiar group stress recovery

# data[].attributes.body
This study focused on the group-living cichlid fish, Neolamprologus pulcher. Stress was induced in individuals, and they then were monitored as they recovered from stress either alone, or with a social group. Individuals recovered from stress faster when their social group was present. Novel social groups also reduced stress-recovery time when they were non-aggressive to the recovering individual (Culbert et al., 2019).

# data[].attributes.body
Although the spread of parasites and diseases is higher in larger groups, being in a group can help mitigate the effects of parasitism. The results of the study performed by Ezenwa & Worsley-Tonks showed that anorexia induced by gastrointestinal nematodes was counterbalanced by the increased feeding behavior/time in larger groups of wild Grant's gazelles (2018).

# data[].attributes.body
Members gain direct benefits from group living such as increased food collection, protection from elements, learning, increased care for young, increased breeding opportunities and more.

This project focuses on: health benefits, protection/care of offspring, and decreased predation.

# data[].attributes.body
Group Living - groups (of one or more species) that live together intentionally and gain direct benefits from cooperation that lead to increased survival amongst the group members

# data[].attributes.body
The goal of this project is to examine the reasons different species form groups and how that leads to increased survival.

# data[].attributes.body
Chelsea Aiken
Naia Brandt
Andrew Medley
Megan Spring

# data[].attributes.body
BILDE, T., COATES, K. S., BIRKHOFER, K., BIRD, T., MAKLAKOV, A. A., LUBIN, Y., & AVILÉS, L. (2007). Survival benefits select for group living in a social spider despite reproductive costs. Journal of Evolutionary Biology, 20(6), 2412–2426.
https://onlinelibrary.wiley.com/doi/epdf/10.1111/j.1420-9101.2007.01407.x
This article takes a look at group living in spiders and the benefits of living together in colonies. It takes a look at the costs and the benefits of living together and specifically looks at two different populations of the spider species S.  dumicola. Colony sizes were determined by the remaining exoskeletons of the adults, due to the young consuming them. Looking into clutch sizes and eggs actually hatching,  they found that the larger the colony the larger the clutch of eggs, but the amount of eggs that actually hatch is very reduced. When comparing the population sizes and survivability (surviving until next mating season), they found that the larger the colony the more likely the offspring will live to mature and reproduce. They also found a correlation with the females reproductive success and offspring survival, where the success goes down with colony size, however the survivability like stated above is higher for offspring. Overall it seems they found that colony size does negatively effect the number of offspring, but positively effects the survival rates.

# data[].attributes.body
Seghers, B. H. (1974). Schooling Behavior in the Guppy (Poecilia reticulata): An Evolutionary Response to Predation. Evolution, 28(3), 486–489. https://doi.org/10.2307/2407174

This research used multiple methods of testing, focused on guppy (Poecilia reticulata) populations to determine if schooling behavior forms as an adaptive response to predation. First, the fish were observed in five different wild environments where the only discernible biotic or abiotic difference was the threat of predation. It was found that in areas with more predators, or higher intensity of predation, schooling behavior was well-developed whereas in areas of lower predation schooling was not strongly developed or entirely absent. Next, they tested if schooling behaviors were heritable by creating predator-naïve tanks from the five wild populations to see determine if populations that were well-developed with schooling maintained that degree of social living. It was found from these experiments that areas of high predation yielded schooling behaviors, even once the predators were removed, and areas of low predation showed almost no signs, but areas that had gene flow between high and low predation rates displayed schooling behaviors in only some trials leading to the belief that schooling is heritable. The last test was to confirm that schooling behavior was beneficial to avoiding predation, which was tested by exposing the predator-naïve populations to equal amounts of predators, and seeing which groups survived better. It was found that the schooling populations survived relatively better than non-schooling, but it was also believed that this was due to an interaction effect of responses to predation found between guppy populations. This article was well written with easily understood experiments and research objectives; however, it was a small research project and the data is now decades old with no new updates. I wonder how many generations of fish would retain schooling behaviors without predation, the genetic pathway that schooling has evolved, and if schooling behaviors would develop in guppies that previously had not strongly displayed schooling if predation was increased on those subjects over generations. I also wish that research was conducted on the native populations of guppies to determine if those with well-developed schooling behaviors actually had higher survival rates, than non-schooling prey fish in their biomes.

# data[].attributes.body
Mbizah, M. M., Valeix, M., Macdonald, D. W., & Loveridge, A. J. (2019). Applying the resource dispersion hypothesis to a fission–fusion society: A case study of the African lion ( panthera leo ). Ecology and Evolution, 9(16), 9111–9119. https://doi.org/10.1002/ece3.5456

This article focuses on the resource dispersion hypothesis (RDH) as an explanation as to why groups form even when there is no appearance of a functional advantage. The RDH predicts that when resources, such as food and water sources, are spread out that groups form in order to defend their territory and guarantee sufficient resource distribution amongst the group. The RDH also predicts that the dispersion and richness of available resources determines group and territory size. The researchers of this article argue that examination of fission-fusion groups (groups that frequently change as groups either split apart or merge together) may shed light on the RDH. They test the predictions of RDH in relationship to fission-fusion group dynamics through field research on 12 female African lions between the years of 2013 to 2015. They conclude that the first two predictions of the RDH are supported by their findings so that home range size is independent of group size and home range size increases with an increase in resource dispersion. The second two predictions of the RDH were not supported by their research stating so that group sizes did not increase with an increase of rich resources nor with an increase in diverse resources. Overall they conclude that more research into the RDH is needed, particularly in relationship to fission-fusion group dynamics. They confirm that fission-fusion groups are the result of an adaptive mechanism for dealing with both environmental and social conditions.

# data[].attributes.headline
"Why Do Animals Form Groups" a short video from NG Science

# data[].attributes.subject
"Why Do Animals Form Groups" a short video from NG Science

# data[].attributes.body
This short informational video shows some of the main reasons that animals form groups as well as some strong examples of animals forming groups in the wild.

# data[].attributes.body
Ezenwa, V. O., & Worsley-Tonks, K. E. L. (2018). Social living simultaneously increases infection risk and decreases the cost of infection. Proceedings: Biological Sciences, 285(1892), 1–5. https://www.jstor.org/stable/26580027

The research presented in this article examined the gastrointestinal nematode (GIN) cost of living in a group and whether the benefits of group living are enough to offset the negative effects of parasitic affliction. The researchers tagged wild Grant’s gazelles (Nanger granti) and individuals were randomly assigned to either the treatment or control group. Treatment animals received an injection of an anthelmintic drug while controls were injected with saline solution. They then followed and monitored these animals for approximately 500 days after treatment and measured parasite counts and group size. They found that although living in larger groups increased the rates of infection and re-acquisition of the parasite, individuals in larger groups also fed at higher rates than those in small groups, counteracting the cost of infection. Based on their findings, they concluded that living in large groups may have evolved in species like these as part of the selection pressure to reduce the impact of parasitism on those species’ fitness. This supports the idea that individuals living in groups can have higher parasite burdens than solitary individuals, and yet still experience less of a fitness reduction due to parasitism. The researchers were unsure about the specific mechanisms that caused the behavior they observed, but proposed the idea that competition within large groups may stimulate individuals to eat at higher rates. This study is important because it shed light on new benefits associated with infection among group living species that had not previously been well described.