Competition, cooperation, and parental effects in larval aggregations formed on carrion by communally breeding beetles Necrodes littoralis (Staphylinidae: Silphinae)
Aggregations of juveniles are dominant forms of social life in some insect groups. Larval societies are shaped by competitive and cooperative interactions of the larvae, in parallel with parental effects. Colonies of necrophagous larvae are excellent systems to study these relationships. Necrodes littoralis (Staphylinidae: Silphinae), a carrion beetle that colonizes cadavers of large vertebrates, forms massive juvenile aggregations. By spreading over carrion anal and oral exudates, the beetles form the feeding matrix, in which the heat is produced and by which adults presumably affect the fitness of the larvae. We predict that exploitative competition shapes the behavior of N. littoralis larvae in their aggregations. However, cooperative interactions may also operate in these systems due mainly to the benefits of collective exodigestion. Moreover, indirect parental effects (i.e., formation of the feeding matrix) probably modulate larval interactions within the aggregations. By manipulating parental effects (present/absent) and larval density (0.02−1.9 larvae/g of meat), we found a strong negative group-size effect on fitness components of N. littoralis, in colonies with parental effects over almost the entire density range, and in colonies without parental effects for densities larger than 0.5 larva/g. This was accompanied by positive group-size effects in terms of development time (it shortened with larval density) and thermogenesis (it increased with larval density). A pronounced positive group-size effect on juvenile fitness was found only in colonies without parental effects and only in the low-density range. These results support the hypothesis that larval societies of N. littoralis are shaped by exploitation competition.
You can access the full paper here: Competition, cooperation, and parental effects in larval aggregations formed on carrion by communally breeding beetles Necrodes littoralis (Staphylinidae: Silphinae)
This project was my first experience working on a project that wasn’t solely my own. It was conducted in the Laboratory of Criminalistics at the Faculty of Law and Administration at Adam Mickiewicz University in Poznań, under the leadership of prof. UAM dr. hab. Szymon Matuszewski. The project was funded by the Polish National Science Centre, and it gave me the opportunity to apply my skills in a highly collaborative and specialized environment. It was a formative experience that allowed me to contribute to a significant forensic research initiative.
Officially, my role in this project is outlined in the “Author contributions” section of the main text. According to the formal description: “J.W. prepared raw data for the analyses, performed analyses, discussed the results, prepared figures, and reviewed the manuscript”. But if we’re being honest, you could just say: “J.W. did all the math stuff and tried to make it look good".
Completed as part of the project "Thermogenesis, feeding matrix and parental care in carrion beetle Necrodes littoralis L. (Silphidae): spatiotemporal patterns, determinants, mechanisms and fitness effects of heat production in the matrix", funded by the National Science Centre of Poland, where I contributed as a project team member.
Due to the nature of the project and the data-sharing policies, I am unable to provide access to either the datasets or the R scripts used in this study. This restriction is in place because I do not have the permission of the project leader to share these materials. All analyses were conducted using R under the supervision and guidelines set by the project team.