The evolution of cooperation is a fundamental problem in biology, especially for non-relatives, where indirect fitness benefits cannot counter within-group inequalities. Multilevel selection models show how cooperation can evolve if it generates a group-level advantage, even when cooperators are disadvantaged within their group. This allows the possibility of group selection, but few examples have been described in nature. Here we show that group selection can explain the evolution of cooperative nest founding in the harvester ant Pogonomyrmex californicus. Through most of this species’ range, colonies are founded by single queens, but in some populations nests are instead founded by cooperative groups of unrelated queens. In mixed groups of cooperative and single-founding queens, we found that aggressive individuals had a survival advantage within their nest, but foundress groups with such non-cooperators died out more often than those with only cooperative members. An agent-based model shows that the between-group advantage of the cooperative phenotype drives it to fixation, despite its within-group disadvantage, but only when population density is high enough to make between-group competition intense. Field data show higher nest density in a population where cooperative founding is common, consistent with greater density driving the evolution of cooperative foundation through group selection.
A total of 26 human subjects were used in this study. Each subject was classified as either lean or obese, according to their BMI measurement. First, the subjects underwent an oral glucose tolerance test. Blood samples were taken to measure glucose levels in the blood. After the test subject characteristics for each subject was obtained. These included age, BMI, body fat percentage, fat free mass (FFM), height, total mass, waist circumference, hip circumference, and waist to hip ratio. After the subject characteristics and blood glucose were measured the blood samples taken previously were then centrifuged, and the blood plasma was extracted. The blood plasma was then used to undergo an Insulin ELISA test. After extensive analysis, the Matsuda Index of each subject was obtained. Subjects with a Matsuda value of 6.0 or under were considered insulin resistant while subjects with a Matsuda value higher than 6.0 were considered insulin sensitive. Subjects were also required to submit a dietary record over the course of three days. The food intake was then put into a food processing software which gave a daily average of the macro and micro nutrients for each subject. Both the subject and dietary values were put into a multiple regression with a significance factor of p < 0.5 to see which factors contributed most to the Matsuda value.
It was found that BMI, height, total mass, insulin and fat free mass, all of which were subject characteristics, were considered to be significant. Some of these factors an individual has no control over, such as height and insulin. However other factors such as BMI, total mass and fat free mass can be affected by both a healthy diet and frequent exercise. This study validated that diet and physical activity can greatly influence an individual’s susceptibility to insulin resistance and ultimately T2DM.
Black-footed ferrets have become one of the most popular conservation success stories because of the miraculous rediscovery of the species after being declared extinct and the growing population today. The stability of the species is still highly variable as the ferrets are threatened by disease, habitat fragmentation, human infringement, and the extermination of their main prey item the prairie dog. The complexity of the issue arises from negative public perceptions of prairie dogs leading to less citizen support for protection which in turn undermines progress in black-footed ferret conservation. General issues with the bureaucracy of conservation helps to delay a formal protection of species at risk which would be especially important for species that are actively being removed or exterminated by humans like the prairie dog. Careful analysis of the black-footed ferret and the prairie dog through the lenses of their natural histories, conservation histories, and modern conservation methods suggest that the public’s opinion and support is the greatest tool for the protection of species at risk because of the complexity of conservation and the rallying bureaucratic motion.
Oxymonas is a genus of Oxymonad protist found in the hindgut of drywood termites (family Kalotermitidae). Many genera of drywood termites are invasive pests globally. The hindgut microbiome of Cryptotermes brevis, the West Indian drywood termite, has not been described in detail, and only one published sequence exists of Oxymonas from C. brevis. This study aims to analyze Oxymonas sequences in C. brevis from whole gut genetic material, as well as to dissect its place in phylogenetic trees of Oxymonas and how it fits into specific and evolutionary patterns. To amplify the 18S rRNA gene Oxymonas from C. brevis, the MasterPure DNA extraction kit was used, followed by PCR amplification, followed by agarose gel electrophoresis, followed by purification of the resulting gel bands, followed by ligation/transformation on to an LB agar plate, followed by cloning the resulting bacterial colonies, and topped off by colony screening. The colony screening PCR products were then sequenced in the Genomics Core, assembled in Geneious, aligned and trimmed into a phylogenetic tree, along with several long-read amplicon sequences from Oxymonas in other drywood termites. All whole gut sequences and one amplicon from C. brevis formed a single clade, sharing an ancestor with a sister clade of Oxymonas sp. from C. cavifrons and Procryptotermes leewardensis, but the other long-read fell into its own clade in a different spot on the tree. It can be conjectured that the latter sequence was contaminated and that the C. brevis clones are a monophyletic group, a notion further corroborated by a distantly related clade featuring sequences from Cryptotermes dudleyi, which in turn has a sister taxon of Oxymonas clones from C. cavifrons and P. leewardensis, pointing toward a different kind of co-diversification of the hosts and symbionts rather than cospeciation.
Although social hierarchies are commonly found all throughout nature, the underlying mechanisms of their formation are still ambiguous. Hierarchies form through a wide range of interactions between subordinate and dominant individuals, and the ponerine ant Harpegnathos saltator provides the perfect model to explore such dominance behaviors. When the queen is absent or her fecundity levels drop below a certain threshold, H. saltator workers undergo a dominance tournament, in which several individuals emerge as gamergates, reproductive workers that are not queens. During this tournament, several characterizable dominance behaviors are exhibited (antennal dueling, dominance biting, and policing), which can be used to study the behavioral and social dynamics in the formation of a reproductive hierarchy. Colonies of 15, 30, 60, and 120 workers were created in duplicate, and their dominance tournaments were recorded to study how these interactions impact gamergate establishment. Rather than studying these behaviors as isolated incidents, responses to policing behaviors (timid, neutral, or aggressive) and their duration were recorded along with the frequency of dueling. Three groups were determined: dueling future gamergates (DFG), dueling future non-gamergates (DFNG) and non-dueling individuals (ND). DFNG received many more policing attacks and the duration of these interactions lasted much longer. DFG consistently exhibited the most dueling. Timid and neutral responses were more common than aggressive responses, perhaps due to energy conversation purposes. Peaks in dueling correspond to peaks in policing, highlighting the dynamic behavioral interactions necessary for the formation of a reproductive hierarchy.
