Field studies need to report essential information on social organisation – independent of the study focus

Abstract

Comparative studies on social evolution are ideally based on large datasets to ensure high statistical power, but their scientific validity also relies on the quality of the data. However, even though social organization, i.e., the composition of social units, is measured in many field studies testing specific hypotheses, these data are often not adequately reported. Here, 2 we summarise which data on social organization should always be reported regardless of the study focus to make them available for comparative studies. As an example, we report data from a literature survey on one of the four superorders of placental mammals, the Xenarthra from South America (armadillos, anteaters and sloths), of which all 30 species are generally assumed to be solitary living. In total we found 4510 articles. The titles and abstracts of 61 publications indicated that data on social organization were collected, but only 12 publications contained sufficient information for us to determine the social organization. We found reliable information on nine species, of which seven were strictly solitary. Two species showed a combination of solitary-living and pair-living with one including female groups. This review therefore indicates that Xenarthra may not be exclusively solitary. Our literature survey further shows that valuable data are often not reported even though it can be assumed that these data had been collected. We report examples from 23 additional studies on monotremes, marsupials, and two other placental superorders showing similar issues in reporting data. It is important to make authors aware that this information would be valuable for comparative studies. In sum, we recommend including data on the composition of social units, sex of individuals, occupancy of sleeping sites, frequency of observations and trapping events, home range overlap, and the proportion of the individuals in the study area, independent of the study question in all publications.

Kinship composition in mammals

“…Recently, Makuya et al [111] highlighted that social organization data are often not fully or clearly reported in the published literature, ultimately hampering advances in our understanding of the evolution of sociality. For kinship composition specifically, it is important that, when possible, future studies report their pedigree data together with demographic data, such as the identity, age and sex of members of the same social unit, in line with the FAIR science principles [20,111]. Comparative research crucially relies on data shared in an open and standardized way [20,111].…”

The evolution of marsupial social organization

“…We believe that overgeneralizations, like assuming that most species of a taxon are solitary living, can lead to conclusions that are in contrast with the existing data [11] which might then bias comparative studies [50]. In sum, we need more field studies [50] that report data in a way they can be used in comparative analyses [27].…”

“…This is why intra-specific variation is important for understanding social evolution. Unfortunately, many papers we found failed to present their field data in a way that they could be included into our database [27]. Often no data but only a general statement about the assumed main form of social organization was reported, especially in mainly solitary species such as the Tasmanian devil or the koala.…”

“…Two hundred fifty-three articles did not contain useable data on social organization. Based on our criteria, 83 articles could not be included in the analyses [26], as the authors only stated the main form of social organization, but did not present the data on the composition of social units, the sex of individuals, occupancy of sleeping sites, home range overlap or the proportion of the individuals marked and studied in the study area [27]. In other words, these studies were excluded because either IVSO was ignored as a possibility, or if the existence of IVSO was reported, it was impossible to determine the degree of it.…”

Primate Social Organization Evolved from a Flexible Pair-Living Ancestor

“…To determine the forms of social organization present in each population, we recorded the adult sex composition of all social units in a population using the classical definitions from Kappeler and van Schaik (8) and adding "sex specific group" as an additional category (Table S1). Studies that did not report the sex of individuals were not taken into account, following (30).…”